Sophie Lee - SSC
From KstructIB
4 TOPIC 1: CELLS
1.1 Cell theory
1.1.1 1 State one contribution made by each of the following: Robert Hooke, Anton van Leeuwenhoek, Matthias Schleiden, Theodor Schwann and Rudolf Virchow. Robert Hooke - discovered cell structure of plants Anton van Leeuwenhoek - viewed unicellular cells and nuclei Matthias Schleiden - proposed cell theory in lieu with Theodor Schwann Theodor Schwann - proposed cell theory in lieu with Matthias Schleiden; discovered Schwann cells Rudolf Virchow - demonstrated that cell theory applies to diseased tissue as well as living tissue
1.1.2 2 Describe three advantages of using light microscopes. Light microscope:
allows experimenter to view image directly allows specimen to be viewed in natural state (must dry for electron microscope) is economical easier to prepare
1.1.3 2 Describe two advantages of using electron microscopes. Electron microscope:
has high resolving power gives interior/3-D view
1.1.4 1 Define organelle. Organelle - a small body with a specialised structure within a cell for a specific function
1.1.5 2 Compare the relative sizes of molecules, cell membrane thickness, viruses, bacteria, organelles and cells, using appropriate SI units. Size comparison:
molecules - 1 nm macromolecules - 100 nm cell membrane - 10 nm virus - 75 nm bacteria - 1 m organelle - 3 m cell - 10 m
1.1.6 3 Explain the importance of the surface area to volume ratio as a factor limiting cell size.
surface area : volume ratio decreases as volume increases less molecules can be absorbed to support cell as volume increases when just enough molecules are absorbed, cell cannot increase volume
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1.2 Prokaryotic cell structure
1.2.1 2 Draw a generalised prokaryotic cell as seen in electron micrographs.
1.2.2 1 State one function for each of the following: ribosomes, mesosome, slime capsule, cell wall, flagellum, cell surface membrane, plasmid and naked nucleic acid. Ribosomes - produce proteins for use inside the cell Mesosomes - primitive vacuoles (deep furrows) to store food / waste Slime Capsule - protect organism Cell Wall - protect cell and provide rigidity Flagellum - mechanism for locomotion; propels cell Cell Membrane - protect cell and provide structure Plasmid Nucleic Acid - store genetic information Naked Nucleic Acid - store genetic information
1.3 Eukaryotic cell structure
1.3.1 3 Discuss the possible origin of eukaryotic cells, referring to the theory of endosymbiosis. Theory of endosymbiosis:
cells and organelles survive separately cells have food; need energy organelles have energy; need food organelles move into cells
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cells specialise and evolve to larger organisms
1.3.2 2 Draw a diagram to show the ultrastructure of a generalised animal cell as seen in electron micrographs. 1. Chromatin 5. Ribosomes 9. Mitochondrion 2. Nucleoplasm 6. Golgi Apparatus 10. Smooth Endoplasmic Reticulum 3. Nuclear Envelope 7. Vesicle 4. Rough Endoplasmic Reticulum 8. Vacuole / Lysosome
1.3.3 1 State one function of each of these organelles: ribosome, rough endoplasmic reticulum (rER), lysosome, Golgi apparatus, mitochondrion, nucleus and chloroplast. Ribosome - protein synthesis Rough Endoplasmic Reticulum - transport and protein synthesis Lysosome - clean-up and intracellular digestion Golgi Apparatus - packaging and secretion Mitochondrion - cellular respiration Nucleus - cellular reproduction and control protein synthesis Chloroplast - photosynthesis (plant cells only)
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1.3.4 1 State two similarities between prokaryotic and eukaryotic cells. Similarities between prokaryotic and eukaryotic cells:
cell membrane cytoplasm ribosomes nuclear material cell wall (plant cells) enzymes
1.3.5 1 State two differences between the eukaryotic nucleus and prokaryotic nuclear material. Prokaryotic and Eukaryotic Nuclear Material Prokaryotic Eukaryotic contained in cytoplasm contained in nuclear envelope
plasmid/naked DNA DNA double helix no nucleoplasm nucleoplasm no nucleolus nucleolus
1.3.6 2 Describe three differences between plant and animal cells. Plant and Animal Cells Plant Animal
large central vacuole small individual vacuoles cell wall no cell wall chloroplasts no chloroplasts no lysosomes lysosomes no centrioles centrioles
1.3.7 1 State the composition and function of the plant cell wall. Plant cell wall:
primary cell wall - cellulose microfibrils for protection secondary cell wall - cellulose microfibrils and lignin (alternate layers) for strength and rigidity middle lamella - adheres to adjacent plant cells, binding them together
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1.4 Membranes
1.4.1 2 Draw a diagram showing the fluid mosaic model of a cell membrane including the phospholipid bilayer, cholesterol, glycoproteins and intrinsic and extrinsic proteins.
1.4.2 3 Explain how the hydrophobic and hydrophilic properties of phospholipids help to maintain the structure of cell membranes. Phospholipid bilayer:
hydrophobic (water hating) ends point into membrane ==> avoid water hydrophilic (water liking) ends point out of membrane ==> meet water because phospholipids are hydrophobic and hydrophilic, they band together to form a bubble-like
bilayer
1.4.3 1 Define diffusion. Diffusion - the movement of molecules from an area of greater concentration to an area of lesser concentration.
1.4.4 1 State that osmosis is the passive movement of water molecules, across a partially-permeable membrane from a region of lower solute concentration to a region of higher solute concentration. Osmosis - passive movement of water molecules across a partially-permeable membrane
- low to high solute concentration
1.4.5 2 Describe passive transport across membranes in terms of diffusion including osmosis. Passive Transport - movement of molecules from high to low concentration (diffusion for small particles, osmosis for water, or carrier pores for large particles)
1.4.6 2 Describe active transport across membranes including the roles of protein carriers, ATP and a concentration gradient. Active Transport - movement of molecules across membranes from low to high concentration
molecule enters carrier pore ATP causes shape of pore to change, moving molecule into cell
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1.4.7 2 Compare endocytosis (phagocytosis/pinocytosis) and exocytosis. Phagocytosis Pinocytosis Exocytosis
cell goes to food food comes to cell food leaves cell forms vacuole forms vacuole forms vacuole
1.5 Cell division - mitosis
1.5.1 1 State that all cells arise from division of other cells (cross reference 1.1.1)
Cell Theory: all cells arise from division of other cells
1.5.2 2 Describe the cell cycle as an alternation between interphase and mitosis. Cell Cycle:
Interphase - normal state Mitosis - cell division Prophase - chromatin form chromatid dyads - spindle forms; centrioles move to opposite ends of cell; asters form Metaphase - dyads line up at equator; centromere attaches to spindle fibres Anaphase - chromatids separate polar fibres push, centromeric fibres pull Telophase - furrowing occurs; nucleus reforms; spindle disappears
1.5.3 1 State that interphase is an active period in the life of a cell, where many biochemical reactions, DNA transcription and DNA replication occur. Interphase: cellular metabolism takes place - active period in life of cell - biochemical reactions occur - DNA transcription occurs - DNA replication occurs
1.5.4 2 Outline how replicated DNA molecules (chromosomes) are moved to opposite ends of the cell by microtubules. Microtubules in the movement of chromosomes:
Asters - centre of polar and spindle fibres Polar fibres - lengthen as chromosomes move Spindle fibres - shorten as chromosomes move
1.5.5 1 State that the products of mitosis are two genetically identical nuclei.
Mitosis ==> 2 genetically identical nuclei
1.5.6 1 State that tumours (cancers) are the result of uncontrolled cell division and that these can occur in any organ. Tumours (cancers):
result from uncontrolled cell division can occur in any organ
10 TOPIC 2: THE CHEMISTRY OF LIFE
2.1 Elements of life
2.1.1 1 State that the three commonest elements of life are carbon, hydrogen and oxygen. Three most common elements of life:
carbon hydrogen oxygen
2.1.2 1 State that a variety of other elements are needed by living organisms including nitrogen, sulphur, phosphorus, iron and potassium. Other elements needed:
nitrogen sulphur phosphorus iron potassium
2.1.3 1 State one role for each of the elements mentioned in 2.1.2.
nitrogen - used by plants to synthesise amino acids and nucleotides sulphur - found in cysteine and methionine; thylakoid membrane markers (sulfolipid) phosphorus - create hydrophilic phosphate group in a phospholipid iron - binds oxygen to red blood cells in hemoglobin potassium - stimulate electrical signals in neurons
2.1.4 2 Outline the differences between an atom and an ion. Atoms and Ions Atom Ion
smallest possible indivisible unit of an element is an atom not necessarily charged charged particle
2.1.5 1 Define organic. Organic - anything containing carbon
2.1.6 2 Outline the significance of water in biology including transparency, cohesion, surface tension, solvent properties and thermal properties, referring to the polarity of water molecules and hydrogen bonding where relevant. Transparency:
reactant in photosynthesis and digestion cushions cells by occupying spaces in between lubricant to reduce friction
Cohesion Tension Theory:
water adheres to cell walls in xylem water coheres to itself in xylem, causing tension (H-bonding) tension pulls water up xylem:
Solvent Properties:
polar property allows coat to form over charged particles
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allow molecules to pass in and out of cells transport medium between and inside cells
Thermal Properties:
large heat capacity to protect against temperature extremes heat loses its effect in breaking hydrogen bonds cools more slowly than other substances moderating effect benefits organisms living in and near water evaporative cooling to survive at high environmental temperature
2.1.7 3 Discuss the significance of water to organisms as a coolant, transport medium and habitat, in terms of its properties. Significance of Water:
coolant - evaporative cooling allows survival at high temperatures transport medium - polarity allows substances to disperse into ions habitat - large heat capacity for moderating effect on environment
2.2 Carbohydrates, lipids and proteins
2.2.1 2 Draw the basic structure of a generalised amino acid.
H
|
COOH-C-NH2
|
R
2.2.2 2 Draw the ring structure of a-D-glucose. H |
H - C - OH
|
H C ---------- O H
\ / \ /
C OH H C
/ \ / \ / \
HO C ---------- C OH
| |
H OH
2.2.3 2 Draw the basic structure of glycerol and a generalized fatty acid.
H H H
| | |
H --- C -------- C -------- C --- H Glycerol
| | |
OH OH OH
+
OH OH OH
| | |
O = C O = C O = C 3 Fatty Acids
| | |
H - C - H H - C - H H - C - H
| | | =
H - C - H H - C - H H - C - H
| | | Triglyceride
H - C - H H - C - H H - C - H
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| | |
H - C - H H - C - H H - C - H
| | |
H H H
2.2.4 2 Outline the role of condensation and hydrolysis in the relationships between monosaccharides and disaccharides; fatty acids, glycerol and triglycerides; amino acid, and dipeptides and polypeptides. Hydrolysis Condensation Action water used in bonding water released in bonding Sugars disaccharide ==> monosaccharide monosaccharide ==> disaccharide Fats fat ==> fatty acid + glycerol fatty acid + glycerol ==> fat Glycerides triglyceride ==> glycerol glycerol ==> triglyceride Peptides polypeptide ==> dipeptide dipeptide ==> polypeptide dipeptide ==> amino acid amino acid ==> dipeptide
2.2.5 2 Draw the structure of a generalised dipeptide, showing the peptide linkage.
H H O H CH3 O | | || | | // Dipeptide
H - N - C - C - N - C - C
| | \ Peptide Linkage
R R OH
2.2.6 3 Explain the relative solubility of carbohydrates, lipids and protein in water.
carbohydrates - soluble lipids - not soluble protein - semi-soluble
2.2.7 2 Compare the energy content of carbohydrates, lipids and proteins.
carbohydrates - high lipids - moderate proteins - low
2.2.8 1 List two examples each of monosaccharides, disaccharides and polysaccharides. Monosaccharides
glucose fructose galactose
Disaccharides
sucrose maltose lactose
Polysaccharides
starch glycogen cellulose chitin
2.2.9 1 State one function for a monosaccharide and one for a polysaccharide.
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Monosaccharide: glucose - produce ATP Polysaccharide: glycogen - store glucose until needed for ATP production
2.2.10 1 State three functions of lipids.
fat: storage depots for energy phospholipid: cell membranes wax: waterproof insect surfaces, reduce transpiration steroid: provide support (cholesterol), create hormones (testosterone, estrogen,
progesterone)
2.3 Enzymes
2.3.1 1 Define enzyme. Enzyme - specialized protein catalyst that lowers the energy required for a reaction
2.3.2 1 Define active site. Active site - place where the enzyme binds onto a substrate
- shaped to attach to a specific substrate
2.3.3 2 Describe the lock-and-key model.
enzyme will only attach to one substrate enzyme recognizes substrate because it fits like a lock and key
2.3.4 1 List three factors that affect enzyme activity. Factors Affecting Enzyme Activity:
temperature pH value substrate concentration
2.3.5 2 Outline the effects of temperature and substrate concentration on enzyme activity. Enzyme Activity:
increased substrate concentration = increased enzyme activity moving away from optimal temperature decreases enzyme activity
2.3.6 1 Define denaturation.
14 Denaturation: shape of active site changes enzyme has different shape as substrate Caused by:
temperature over 40C (over 60C in volcano vents) pH not optimal (saliva - 7; stomach - 2/3) heavy metal - Pb2+, Fe3+, radiation, pollutants mechanical - pressure
Occurs when:
bonds are broken interfere with polarity pressure changes
2.3.7 3 Explain two applications of enzymes in biotechnology. Enzymes in Biotechnology:
restriction enzymes: cut DNA into fragments at predetermined locations reverse transcriptase: translate viral RNA into more easily managed DNA ligase: join DNA fragments together by complementary base pairing
2.4 DNA structure
2.4.1 2 Outline DNA nucleotide structure in terms of sugar (deoxyribose), base and phosphate.
-----------
| O | <-- Phosphate | | | | O - P - O - CH2 Nitrogen Base | || | | O | | O | |/ \|
----------- C H H C
/ \| |/
H C - C <-- Sugar (Deoxyribose)
| \
OH H
2.4.2 1 State the names of the four bases in DNA. Nitrogen Bases:
adenine (purine) guanine (purine) thymine (pyrimidine) cytosine (pyrimidine)
2.4.3 2 Outline how the DNA nucleotides are linked together by covalent bonds into a single strand.
phosphate and sugar share an electron (covalent bonding) nucleotides join to form polymer (DNA strand) backbone = phosphate-sugar-phosphate-sugar bases project to one side of polymer
2.4.4 3 Explain how a DNA double helix is formed using complementary base pairing and hydrogen bonds.
DNA unzips with assistance of helicase enzyme free floating nucleotides form hydrogen bonds (purine-pyrimidine) with DNA strand complementary base pairing = purine-pyrimidine pairs adenine-thymine, cytosine-guanine
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2.4.5 2 Draw a simple diagram of the molecular structure of DNA.
PO4 H OH N-BASE H H | \ / | \ / CH2 C | H - C - C - OH | / \ | / \
H - C H C - H H - C C - H
\ \ / | \ / |
HO - C - C - H | C CH2
/ | / \ |
PO4 H OH N-BASE ------------ N-BASE OH H PO4
| \ / | /
CH2 C | H - C - C - OH
| / \ | / \ \
H - C H C - H H - C H C - H
\ \ / | \ / |
HO - C - C - H | C CH2
/ | / \ |
PO4 H OH N-BASE ------------ N-BASE OH H PO4
| \ / | /
CH2 C | H - C - C - OH
| / \ | / \ \
H - C C - H H - C H C - H
\ / | \ / |
HO - C - C - H | C CH2
/ \ | / \ |
H H N-BASE OH H PO4
2.5 DNA replication
2.5.1 1 State that DNA replication is semi-conservative.
Semi-conservative: half of each DNA helix is from original
2.5.2 2 Outline DNA replication in terms of unwinding the double helix and separation of the strands by helicase followed by formation of the new complementary strands by DNA polymerase.
DNA unzips: helicase breaks down hydrogen bonds between nitrogen bases during complementary base pairing, DNA polymerase bonds phosphate with sugar
2.5.3 3 Explain the significance of complementary base pairing in the conservation of the base sequence of DNA.
complementary base pairing = every replicated DNA strand will be identical to original semi-conservative strands preserve original code
2.6 Transcription and translation
2.6.1 2 Compare the structure of RNA and DNA. DNA RNA Sugar deoxyribose ribose Bases adenine, guanine, thymine, cytosine adenine, guanine, uracil, cytosine Strands double stranded single stranded Helix yes no
2.6.2 1 State one function of messenger RNA and one function of transfer RNA.
mRNA - carries genetic code from DNA to protein synthesis site (ribosome)
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tRNA - carries specified amino acid to protein synthesis site (ribosome)
2.6.3 2 Outline DNA transcription in terms of the formation of a RNA strand complementary to the DNA strands by RNA polymerase.
mRNA forms by complementary base pairing to DNA strand RNA polymerase binds sugar and phosphate groups together mRNA strand completed
2.6.4 2 Describe the genetic code in terms of codons composed of triplets of mRNA.
genetic code expressed in three-letter codons each codon specifies a certain amino acid
2.6.5 2 Describe translation including the roles of mRNA codons, tRNA anticodons and ribosomes leading to peptide linkage formation. During translation:
mRNA moves to cytoplasm and ribosomes attach tRNA anticodons carry specified amino acids to the mRNA complementary base pairing between codon and anticodon adds amino acid to sequence peptide bond forms between amino acid and growing polypeptide
2.6.6 1 Define the terms degeneracy and universal as they relate to the genetic code. Degeneracy - there is more than one codon for a particular amino acid Universal - all organisms utilize the same codons for the same amino acids
2.6.7 3 Explain the relationship between one gene and one polypeptide and its significance.
each polypeptide is encoded in a specific gene on the DNA helix gene controls amino acid sequence in a polypeptide
2.7 Genetic engineering, DNA fingerprinting, gene therapy
2.7.1 1 State that genetic material can be transferred between species because the genetic code is universal (cross reference 2.6.6).
genetic code is universal therefore, genetic material can be transferred between species
2.7.2 2 Outline a basic technique used for gene transfer involving plasmids, a host cell (bacterium, yeast or other cell), restriction enzymes (endonuclease) and DNA ligase.
donor DNA removed from cell restriction enzyme cut out selected fragment plasmid removed from host cell restriction enzyme cut hole in plasmid to insert fragment fragment mixed with plasmid and DNA ligase DNA ligase anneals fragment into plasmid
2.7.3 1 State two examples of the current uses of genetic engineering in agriculture and /or pharmacy.
disease resistant crops and animals bacteria-manufactured insulin
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2.7.4 3 Explain one potential harmful result of genetic engineering.
more resilient diseases: disease pressured to change, and so will become tougher and
harsher
2.7.4 1 State that PCR (polymerase chain reaction) copies and amplifies minute quantities of nucleic acid.
PCR (polymerase chain reaction) copies and amplifies minute quantities of nucleic acid
2.7.6 1 State that gel electrophoresis involves the separation of fragmented pieces of DNA according to their charge and size.
gel electrophoresis = separate fragmented pieces of DNA according to charge + size
2.7.7 1 State that gel electrophoresis of DNA is used in DNA profiling.
gel electrophoresis used in DNA profiling
2.7.8 2 Describe two applications DNA profiling. Applications of DNA Profiling:
engineering bacteria to produce insulin isolate good traits to create a better crop criminal profiling forensic science
2.7.9 2 Outline the process of gene therapy using a named example. Gene Therapy: Insulin Production
cells removed from liver cells grown in culture gene for insulin production inserted into cells cells implanted back into liver
18 TOPIC 3: GENETICS
3.1 Chromosomes, genes and alleles
3.1.1 1 State that an eukaryote chromosome is made of DNA and protein.
eukaryote chromosome = DNA + protein
3.1.2 1 State that chromosomes can be stained to show banding.
stain chromosome ==> banding
3.1.3 1 State that the chromosome structure and banding can be used to arrange the chromosomes in their pairs.
arrange chromosomes in pairs by their structure and banding
3.1.4 2 Describe one application of karyotyping (cross reference 3.3.4). Karyotyping - determining defects before birth:
extract cell sample from placenta add colchine to stop cell division at prophase / metaphase add water to burst cell create a photographic image of scattered chromosomes cut out and pair chromosomes by their length and position of the centromere observe deviation from normal chromosome set
3.1.5 1 Define gene. Gene - a unit of hereditary information on a DNA strand controlling expression
3.1.5 1 Define allele. Allele - an alternative form of a gene that occurs at a given chromosome site (locus)
3.1.7 1 Define genome. Genome - a complete set of genes from any one species
3.2 Gene mutation
3.2.1 1 Define gene mutation. Gene mutation - an alteration from the normal nucleotide sequence
3.2.2 2 Outline the differences between an insertion and a deletion. Insertion and Deletion Insertion Deletion
extra nucleotide in sequence missing nucleotide in sequence
3.2.3 3 Explain the consequences of a base substitution mutation in relation to the process of transcription and translation, using the example of sickle cell anaemia. Consequences of a Base Substitution
Mutation: GAA GTA Transcription: CUU CAU Translation: valineglutamic acid
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Result: HbA HbS (Sickle Cell Anemia)
3.3 Meiosis
3.3.1 1 State that meiosis is a reduction division in terms of diploid and haploid numbers of chromosomes.
Meiosis: reduction division from diploid to haploid number of chromosomes.
3.3.2 2 Outline the process of meiosis including pairing of chromosomes followed by two divisions which result in four haploid cells. Meiosis: First meiotic division
Interphase - DNA replicates, centrioles double Prophase I - nucleus disappears, spindle forms, centrioles move, synopsis: dyad => tetrad Metaphase I - tetrads line up at centre, centromere attaches to spindle fibres Anaphase I - dyads separate Telophase I - furrowing, nucleus reforms, spindle disappears
Second meiotic division
Interkinesis - centrioles double Prophase II - nucleus disappears, spindle forms, centrioles move Metaphase II - dyads line up at centre, centromere attaches to spindle fibres Anaphase II - chromosomes separate Telophase II - furrowing, nucleus reforms, spindle disappears
Result: 4 haploid cells
3.3.3 3 Explain how the movement of chromosomes during meiosis can give rise to genetic variety in the resulting haploid cells. Genetic variety achieved: homologous chromosomes separate = one gene from each parent via independent assortment
3.3.4 3 Explain that non-disjunction can lead to changes in chromosome number, illustrated by reference to Downs Syndrome (trisomy 21). Non-disjunction - chromosomes separate improperly - eg. three 21 chromosomes in one cell = Downs syndrome
3.3.5 1 State Mendels Law of Segregation. Mendels Law of Segregation: Allele pairs separate during gamete formation and randomly reform pairs during fusion of gametes at fertilisation.
3.3.6 3 Explain the relationship between Mendels Law of Segregation and meiosis.
meiosis produces haploid cells which typically contain only one of each allele alleles reform when gametes fertilise
3.4 Theoretical genetics
3.4.1 1 Define genotype. Genotype: the genetic makeup that comprises the expression of a characteristic
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3.4.2 1 Define phenotype. Phenotype: the outward appearance caused by a genotype
3.4.3 1 Define dominant allele. Dominant allele: an allele that is expressed over another allele when other allele is present
3.4.4 1 Define recessive allele. Recessive allele: an allele that is masked when a corresponding allele is present
3.4.5 1 Define codominant allele. Codominant allele: a phenotypic situation where both alleles are expressed in a heterozygote
3.4.6 1 Define locus. Locus: the place on a chromosome where a gene is located
3.4.7 1 Define homozygous. Homozygous: having two identical alleles
3.4.8 1 Define heterozygous. Heterozygous: having different corresponding alleles
3.4.9 1 Define carrier. Carrier: possessing a recessive sex-linked gene that does not express itself
3.4.10 1 Define test cross. Test cross: crossing an organism with a homozygous recessive organism to determine if the unknown organism is homozygous or heterozygous.
3.4.11 2 Draw a Punnett Grid. Punnett Grid: A a A AA Aa A Aa aa
3.4.12 2 Draw a pedigree chart. -
i-----------|-----------i
-
3.4.13 1 State that some genes have more than two alleles (multiple alleles).
multiple alleles = more than two alleles (present for some genes)
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3.4.14 2 Describe ABO blood groups as an example of codominance and multiple alleles. Codominance: A and B are expressed simultaneously if present Multiple alleles: 3 alleles are available: A, B, and O
3.4.15 2 Outline how the sex chromosomes determine gender, by referring to the inheritance of X and Y chromosomes of humans.
X X = female; X Y = male in gamete formation, female passes on an X, and male passes on an X or a Y to determine gender
3.4.16 1 State that some genes are present on the X chromosome and absent from the shorter Y chromosome in humans.
3.4.17 1 Define sex linkage. Sex linkage: genes carried on the sex chromosomes, and therefore are more prevalent on males
3.4.18 1 State two examples of sex linkage.
colour-blindness - inability to differentiate between different colours haemophilia - absence of clotting substance in blood
3.4.19 1 State that a human female can be homozygous or heterozygous, with respect to sex-linked genes.
human female can be homozygous or heterozygous for sex-linked genes
3.4.20 3 Explain that female carriers are heterozygous for X-linked alleles. Carrier:
needs one normal allele to mask defective allele needs one defective allele to be a carrier
3.4.21 3 Calculate and predict the genotypic and phenotypic ratios of offspring of monohybrid crosses involving any of the above patterns of inheritance. A a A AA Aa a Aa aa
3.4.22 3 Deduce the genotypes of phenotypes of individuals in pedigree charts.
fill in as much data as known in Punnett square deduce heritage of parents continue working through reasoning until selected individual is reached
Probability of occurrence (as determined from Punnett square, drawn accordingly):
Genotypic Ratio: 1:2:1 Phenotypic Ratio: 3:1
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3.5 Applied Genetics
3.5.1- 2 Define genetic screening and discuss three advantage and/or disadvantages of genetic screening. Genetic Screening:
test for detecting genetic disease advantages
- Early diagnosis - Prenatal health of child - Reproductive and lifestyle decision
disadvantages
- Anxiety and pressure on personal choice - Disclosure of info about family members who declined testing - Discrimination
3.5.3 Identify and state the goal of the Human Genome Project. Human Genome Project:
international research effort attempt to map all genes on human chromosomes
3.5.4 Describe two possible advantageous outcomes of this project.
eliminate genetic defects develop new drugs develop gene therapy to fight disease
3.5.5 Define clone. Clone:
genetically identical organism descended from single ancestor cell
3.5.6 Outline a technique used in the cloning of farm animals. Cloning:
cells taken from donor cells placed in culture with low nutrients stop cell growth unfertilized egg taken from female; nucleus removed electric pulse fuses cell and egg; cell division starts embryo implanted in female uterus clone is genetically identical to donor
3.5.7 Discuss the ethical issues of cloning human embryos. Ethics of Cloning:
interests and rights of clones reason for cloning
3.5.8 Discuss the results of crop plant and animal breeding. Crop Plant:
Plants grow in less favorable environment larger crop yield
Animal Breeding:
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more meat / milk produced
24 TOPIC 4: ECOLOGY
4.1 Communities and ecosystems
4.1.1 1 Define ecology. Ecology - the study of the natural environment and of the relations of organisms to each other and to their surroundings
4.1.2 1 Define ecosystem. Ecosystem - all the interacting parts of the physical and biological worlds
4.1.3 1 Define population. Population - the number of a specific group of organisms in a given area
4.1.4 1 Define community. Community - an association of interacting populations, usually defined by the nature of their interaction or the place in which they live
4.1.5 1 Define species. Species - a group of actually or potentially interbreeding populations that are reproductively isolated from all other kinds of organisms
4.1.6 1 Define habitat. Habitat - place where an animal or plant normally lives, often characterised by a dominant plant form or physical characteristic (eg, the stream habitat, the forest habitat)
4.1.7 3 Explain what is meant by the biosphere. Biosphere - the atmosphere, lithosphere, hydrosphere, and all life forms residing in these areas
4.1.8 2 Describe what is meant by a food chain giving three examples, each with at least three linkages (four organisms). Food chain - a representation of the passage of energy through populations in the community
eg. apple tree aphid ladybug bird eg. phytoplankton zooplankton salmon orca eg. leaf leafcutter ant army ant anteater
4.1.9 2 Describe what is meant by a food web. Food web - a representation of the various paths of energy flow through populations in the community
4.1.10 1 Define trophic level. Trophic level - position in the food chain, determined by the number of energy-transfer steps to that level
4.1.11 3 Deduce the trophic level(s) of organisms in a food chain and a food web.
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primary producers (green plants) primary consumers (herbivores) secondary consumers (carnivores) tertiary consumers (carnivores)
4.1.12 2 Draw a food web given appropriate information, containing up to 10 organisms.
/ mouse snake hawk lice
grass <
\ rabbit weasel fox wildcats
\
\ hopper frogs birds eagles
4.1.13 1 Define autotroph (producer). Autotroph - an organism that assimilates energy from either sunlight (green plants) or inorganic compounds (sulphur bacteria)
4.1.14 1 Define heterotroph (consumer). Heterotroph - an organism that utilises organic materials as a source of energy and nutrients
4.1.15 1 Define detrivore. Detrivore - an organism that feeds on freshly dead or partially decomposed organic matter
4.1.16 1 Define saprotroph (decomposer). Saprotroph - an organism that breaks down dead or decaying matter
4.2 Photosynthesis, respiration and energy relationships
4.2.1 1 State that light is the initial energy source for almost all communities.
light = initial source of energy
4.2.2 2 Describe the fact that photosynthesis involves an energy conversion in which light energy is converted to chemical energy. 6CO2 + 6H2O + sunlight (light energy) C6H12O6 (chemical energy) + 6O2
4.2.3 1 State that white light from the sun is composed of a range of wavelengths (colours). Sunlight is composed of range of wavelengths, including:
infrared red orange yellow green blue violet ultraviolet
4.2.4 1 State that chlorophylls are the main photosynthetic pigments.
26 Chlorophyll:
main photosynthetic pigment
4.2.5 2 Outline the differences in absorption of red, blue, and green light by chlorophylls. Chlorophyll absorption:
absorption peak at 440 nm (violet) absorption peak at 675 nm (red) green least absorbed; longer blue wavelengths absorbed shorter blue wavelengths not absorbed
4.2.6 1 State that light energy is used to split water molecules to produce oxygen and hydrogen, and to produce ATP.
light energy ==> split water molecules ==> O2 + H ==> ATP
4.2.7 1 State that ATP and hydrogen, (derived from the photolysis of water) are used to fix carbon dioxide to make organic molecules.
ATP + H ==> fix CO2 ==> produce organic molecules
4.2.8 3 Explain that photosynthesis can be monitored by the production of oxygen, the uptake of carbon dioxide or the increase in biomass. O2 production
enclose plants in clear chambers, measure change in O2 concentration increased O2 levels means O2 produced by photosynthesis
CO2 uptake
enclose plants in clear chambers, measure change in CO2 concentration decreased CO2 levels means CO2 used by photosynthesis
Biomass increase
cut, dry, and weigh plants at end of growing season plant growth means energy entered ecosystem; ie, photosynthesis has occurred
4.2.9 2 Outline the effects of temperature, light intensity and carbon dioxide concentration on the rate of photosynthesis.
Temperature increases rate of photosynthesis until optimal point decreases rate of photosynthesis after optimal point Light intensity increases rate of photosynthesis compensation point at higher temperature requires more CO2 saturation point at higher temperature CO2 concentration increases rate of photosynthesis
4.2.10 1 State that respiration involves the breakdown of organic molecules to release energy stored by photosynthesis.
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Aerobic cellular respiration: C6H12O6 + 6O2 6CO2+ 6H2O + 38 ATP Glucose broken down to released energy stored in photosynthesis
4.2.11 1 State that the carbon dioxide fixed by photosynthesis is released by respiration.
Photosynthesis: 6CO2 + 6H2O + light C6H12O6 + 6O2 Aerobic cellular respiration: C6H12O6 + 6O2 6CO2 + 6H2O +38 ATP Fixed CO2 is released
4.2.12 1 State that the energy released during breakdown/respiration of complex compounds in an organism is used within an organism to do work or is lost as heat. Energy released from aerobic cellular respiration:
performs work in an organism lost as heat
4.2.13 1 Define biomass. Biomass - dry weight of living material in all or part of an organism, population, or community
- commonly expressed as weight per unity area (biomass density)
4.2.14 3 Explain biomass and energy transfer in a food chain in terms of growth, respiration, cell activities and waste.
productivity of each trophic level is 10-20% rest of energy used for maintaining organism - ie, growth, respiration, cellular metabolism energy transformations heat loss entropy nutrients (matter) are recycled
4.2.15 1 State that when energy transformations take place, including those in living organisms, the process is never 100% efficient, commonly being 10 - 20%.
energy transformation is never 100% efficient (usually 10-20%) energy transformation converts some energy into heat
4.2.16 3 Explain what is meant by a pyramid of energy and reasons for its shape. Pyramid of Energy
the concept that the energy flux through a given link in the food chain decreases at progressively
higher trophic levels
breadth of each bar represents net productivity of each trophic level in the ecosystem each trophic level dissipates energy before consumed by next trophic level
4.2.17 3 Design a pyramid of energy given appropriate information.
4.2.18 3 Explain that energy enters and leaves an ecosystem, but nutrients must be recycled. Energy
enters ecosystem as light (usually) leaves ecosystem as heat nutrients are matter, cannot disappear, therefore are recycled
4.2.19 2 Draw the carbon cycle to show the process including photosynthesis, respiration, combustion and fossilisation.
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4.2.20 3 Explain the role of saprotrophs (decomposers) in returning elements to the environment in inorganic form. Saprotrophs
release nitrogen for use by plants
4.3 Populations, natural selection and evolution
4.3.1 2 Outline how population size can be affected by natality, immigration, mortality and emigration. Natality
population increases as new members are born balanced by mortality
Immigration
population increases as new members move in balanced by emigration
Mortality
population decreases as old members die balanced by natality
Emigration
population decreases as old members move out balanced by immigration
4.3.2 2 Draw a graph showing the sigmoid (S-shaped) population growth curve.
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4.3.3 3 Explain reasons for the exponential growth phase, the plateau phase and the transitional phase between these two phases.
population grows exponentially to limit of food supply food supply can support a limited number of organisms excess organisms die
4.3.4 1 Define carrying capacity. Carrying capacity - the maximum density of organisms that a particular environment can sustain in perpetuity
4.3.5 1 List three factors which set limits to population increase.
food supply predator population disease
4.3.6 1 State that populations tend to produce more offspring than the environment can support.
populations produce more offspring than environment can support
4.3.7 3 Explain that the consequences of the potential overproduction of offspring is a struggle for survival.
overproduction of offspring ==> struggle for survival
4.3.8 1 State that the members of a species show variation (cross reference 3.3.3).
members of a species show variation
4.3.9 3 Explain how, by natural selection, the best adapted will survive to breed. Natural Selection:
chooses best adapted to breed organisms not suited to the environment die and are eliminated organisms suited to the environment survive
Sigmoid Population Curve Time P op u la t io n
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4.3.10 3 Discuss the theory that species evolve by natural selection. Three kinds of natural selection:
directional selection - population shows a steady change through time stabilising selection - organisms within a population that represent extreme departures from the
norm eliminated, therefore maintaining the status quo
disruptive selection - abnormal features in organisms have a high survival rate
4.3.11 3 Discuss the need for evolution in response to environmental change.
eg. industrial melanism - peppered moth turns from white with black speckles to black with white
dots
eg. Galapagos finches - high competition causes finches to find food elsewhere. They adapt to new
surroundings to ensure survival.
4.4 Human impact
4.4.1 2 Outline two examples of local or global issues of human impact causing damage to an ecosystem of biosphere, one of which must be the increased greenhouse effect. Global Warming
increased CO2 and CFC emissions dwindling ozone layer less ozone more ultraviolet light entering biosphere more ultraviolet radiation less healthy plants and animals increased chances of cancer more ionised water ionised water water leaves cells El nino / la nina change ocean currents
Salmon Habitat Destruction
increase temperature salmon do not swim up river cut down trees increased sunlight increased temperature toxins in river salmon die before spawning parasites thrive on salmon remains / eggs dams in river salmon cannot swim to spawning grounds currents in spawning areas salmon eggs washed away
4.4.2 3 Explain the causes and effects of the two issues in 4.4.1, supported with data.
refer to previous question
4.4.3 3 Discuss measures which could be taken to contain or reduce the impact of these issues, with reference to the functioning of the ecosystem. Global Warming
reduce emissions stop killing ozone layer less ultraviolet light entering biosphere more healthy plants more healthy animals less ionized water water stays in cells no El nino / la nina ocean currents stay; fish live
Salmon Habitat Destruction
artificial spawning habitats salmon spawn and eggs cared for reduce toxin pollution salmon can swim to sea without dying plant trees by site lower temperature to let salmon spawn
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fish ladder allow salmon to swim past dams
4.5 Ecological techniques
4.5.1 2 Describe one method used to measure each of three abiotic characteristics of a habitat including light.
light: meter air quality: CO2 and other such detectors water quality: chemical tests
4.5.2 1 Define random sample. Random sample - an unbiased survey on selected members of a population
4.5.3 2 Describe one technique used to estimate the population size of one animal species based on a capture- mark-release-recapture method. Capture-mark-release-recapture Sampling
capture a preset number of animals from one area mark these animals with a distinguishing visual characteristic release the animals to the wild several days later, capture another preset number of animals count the number of recaptured marked animals population size = (recapture / capture) * (10000 / recapture)
4.5.4 2 Describe one method of random sampling used to compare the population numbers of two plant species based on quadrant methods. Random sampling based on quadrant method
divide area to be sampled into four quadrants in each quadrant, mark off area to be sampled count number of plant species in each sample
4.5.5 3 Evaluate graphical presentations of ecological data.
4.5.6 1 Define mean. Mean - the average found by adding the individual terms together and dividing by the number of terms
4.5.7 1 Define mode. Mode - the most common term value
4.5.8 1 Define median. Median - the value in the middle
4.5.9 1 State that the term standard deviation is used to summarise the spread of variables around the mean and that 68% of the values fall within one standard deviation of the mean (plus and minus). Standard deviation
summary of spread of variables around the mean 68% of values fall within one standard deviation of the mean
4.5.10 2 Calculate the means and standard deviation of two different frequency distributions.
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4.5.11 2 Describe how standard deviation is useful in comparing the means and the spread of ecological data between two or more sites.
standard deviation indicates variation from the normal allows statistical comparison between normal distribution in different locations
33 TOPIC 5: HUMAN HEALTH AND PHYSIOLOGY
5.1 Digestion and nutrition
5.1.1 3 Explain why digestion of large food molecules is essential (cross reference topic 2).
macromolecules digested chemically + mechanically absorption into body convert into energy and essential molecules
5.1.2 3 Explain the need for enzymes in digestion (cross reference topic 2). Need for enzymes in digestion:
speed up digestion lower activation energy
5.1.3 1 State the source, substrate, products and optimum pH conditions for one amylase, one protease and one lipase. Amylase
source: saliva, pancreas substrate: starch products: starch + H2O maltose optimum pH: 7
Protease: Pepsin
source: stomach wall substrate: protein products: protein + H2O peptide optimum pH: 2
Protease: Trypsin
source: pancrease substrate: protein products: protein + H2O peptide optimum pH: 8
Lipase
source: pancreas substrate: lipids products: fat droplets + H2O glycerol + fatty acids optimum pH: 8
5.1.4 2 Draw a diagram of the digestive system including mouth, oesophagus, stomach, small intestine, large
34 intestine, anus, liver, pancreas, gall bladder.
5.1.5 2 Draw a villus in vertical section.
5.1.6 1 Define absorption. Absorption - the process by which digested particles are assimilated into the body
5.1.7 3 Explain the concept of a balanced diet. Balanced Diet:
contains vitamins, minerals, and other necessary particles for the normal function of the body does not contain anything excessively or lacking in
5.1.8 3 Explain the general importance of vitamins and minerals. Vitamins / Minerals:
necessary for human metabolism deficiency inhibits normal metabolism disease
5.1.9 2 Outline one health problem concerned with malnutrition.
35 Health problem: scurvey Cause: vitamin C / ascorbic acid deficiency Syntoms: progressive body weakness
spongy / inflammed gums loose teeth swollen / tender joints tendencey toward ecchymosis hemmorrage
5.2 The transport system
5.2.1 2 Describe the action of the heart in terms of collecting of blood, pumping of blood and opening and closing of valves.
blood collected from superior and inferior vena cava into right auricle blood passes through tricuspid valve into right ventricle right ventricle pumps blood through pulmonary valve to lungs for reoxygenation blood returning from lungs enter left auricle blood passes through mitral valve into left ventricle left ventricle pumps blood to aorta for circulation left ventricle stronger than right ventricle to pump blood throughout body opening / closing of valves regulates pulse to produce more pressure on release, allowing the blood
to travel farther after it is pumped from the heart
5.2.2 2 Draw a diagram of the heart showing all four chambers, associated blood vessels and valves.
5.2.3 2 Outline the way the heart beats and is regulated in terms of its myogenic nature, nerve and hormone stimulation (cross reference 5.5). Heart beat
Myogenic in nature Sinoatrial node sends impulse across atria atria contract Atrioventricular node picks up stimulus from sinoatrial node signal purkinje fiber (nerve) Purkinje fiber causes ventricle to contract blood goes up
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5.2.4 3 Explain the relationship between the structure and function of arteries, capillaries and veins. Arteries
thick walls - holds in strong, pulsing current
Capillaries
thin walls - allows more goodies to diffuse narrow - permits blood to diffuse goodies more efficiently to the surrounding cells
Veins
thin walled - does not need to restrain strong, pulsing current valves - prevents blood from flowing in the wrong direction as it returns to the heart
5.2.5 1 State that blood is composed of plasma, erythrocytes, leucocytes and platelets. Blood contains:
plasma - a liquid matrix containing all the blood cells erythrocytes (red blood cells) - contains hemoglobin; carries oxygen from lungs to tissues leucocytes (white blood cells) - several types, each having a specific function in protecting the body
from invasion by foreign substances and organisms
platelets - formed elements necessary for blood clotting
5.2.6 1 State that the following are transported by the blood: heat, nutrients, oxygen, carbon dioxide, hormones, antibodies, waste products. Blood transports:
heat - mantain constant body temperature nutrients - provide body with products necessary for cellular metabolism oxygen - required for aerobic cellular respiration carbon dioxide - remove for exhalation in lungs hormones - allow communication between various organs in the body antibodies - natural defense against invaders waste products - remove toxins
5.2.7 2 Outline one health problem concerned with disorders of the transport system. Blood disorder: Sickle cell anemia Cause: Gene mutation in hemoglobin Result: red blood cells shaped in a crescent, sickle-like manner
less efficient oxygen transfer
5.3 Defence against infectious disease
5.3.1 1 State that disease can be caused by a variety of organisms. Disease
can be caused by variety of organisms
5.3.2 3 Explain how skin and mucous membranes act as barriers against microbes. Barriers against microbes
skin - impermeable to water
- barrier between inside and outside of body
mucus - trap microbes
- thick - prevent microbes from entering body
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5.3.3 2 Outline that phagocytic leucocytes ingest disease causing organisms in the blood and in body tissues.
phagocytic leucocytes ingest disease-causing organisms via phagocytosis in blood and body tissues ingested organisms digested for cellular metabolism
5.3.4 1 State the difference between antigen and antibody. Antigen: a foreign substance (usually protein) stimulating immune system to produce antibodies Antibody: a protein produced in response to the presence of some foreign substance in the blood or tissues
5.3.5 3 Explain antibody production. Antibody production:
membrane bound antibody: receptor on B cell receptor + toxin w/ antigen or bacteria B cell divides (with help of helper T cell) B cell plasma cell plasma cell secrete antibodies against antigen
5.3.6 2 Outline the effects of HIV on the immune system. Effect of HIV on immune system:
helper T cells, macrophages, and B lymphocytes attacked Stage I: HID - Detectable antibodies in bloodstream, swollen lymph nodes Stage II: ARC - weight loss, night sweats, fatigue, fever, diarrhea Stage III: AIDS - pneumonia, skin cancer, neuromuscular and psychological disturbances Stage IV: DEATH - victim dies
5.4 Gas exchange
5.4.1 2 Describe four features of alveoli that allow them to carry out gas exchange efficiently. Alveoli carry out gas exchange efficiently:
thin walls (1 cell squamous epithelium) capillary network to increase surface area for diffusion lipoprotein lining lower surface tension balloon-shaped maximize surface area
5.4.2 3 Explain the necessity for a ventilation system. Ventilation system:
allows gaseous exchange releases unneeded CO2 takes in needed O2
5.4.3 2 Draw a diagram of the gas exchange system including trachea, bronchi, bronchioles and lungs.
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5.4.4 1 State the difference between breathing and cell respiration. Breathing:
gas exchange
Cell Respiration:
glucose ATP
5.4.5 1 State that exercise improves the functioning of the heart and lungs.
exercise improves function of heart and lung
5.4.6 3 Explain how and why breathing rate varies with exercise. Exercise increase:
breathing rate increase more oxygen required for producing energy
Exercise decrease:
breathing rate decrease less oxygen required for producing energy
5.4.7 2 Outline one health problem concerned with gas exchange. Health Problem: Infant Respiratory Distress Syndrome
infant lacks lipoprotein lining in lung lungs collapse no gas exchange occurs (no surface area for gas exchange)
5.5 Homeostasis
5.5.1 1 Define homeostasis. Homeostasis - maintenance of internal environment within narrow limits (eg. temperature, blood pressure)
5.5.2 3 Explain the concept of homeostasis with reference to body temperature and levels of blood glucose.
39 Homeostasis of body temperature:
blood circulation distributes heat equally throughout body reflex: shivering, goosebumps to conserve heat reflex: sweating to reduce heat kept at 37C / 98F
Homeostasis of blood glucose:
liver regulates glucose level - excess stored as glycogen kept at 0.1% blood sugar
5.5.3 3 Explain the concept of negative feedback (cross reference 5.6.4 and 5.6.9). Control loop: A eg. A. Hypothalamus B. Hypothalamic releasing & release-inhibiting hormones B D C. Anterior Pituitary D. TSH / LH / FSH / ACTH / MSH / PRL / GH C
5.5.4 1 State that the nerve and the endocrine systems are involved in homeostasis.
homeostasis involves nervous and endocrine systems
5.5.5 1 State that the nervous system consists of the central nervous system and the peripheral nerves composed of special cells called neurons that can carry electrical impulses rapidly.
nervous system: central nervous system + peripheral nervous system peripheral nerves made of neurons (special cells that carry electrical impulses rapidly)
5.5.6 1 State that the endocrine system consists of glands which release hormones that are transported in the blood.
endocrine system made of hormone-releasing glands hormones transported in blood
5.5.7 1 Define excretion. Excretion: removal of metabolic wastes from the body
5.5.8 1 Define osmoregulation. Osmoregulation: control of water balance of the body brought about largely by the kidney
5.5.9 1 State that the functions of the kidney are excretion and osmoregulation. Kidney functions:
excretion osmoregulation
5.6 Reproduction
5.6.1 3 Explain that sexual reproduction promotes variation in a species (cross reference 3.3.3).
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sexual reproduction promotes genetic diversity
5.6.2 2 Draw diagrams of the adult male and female urinogenital systems. Urinogenital System: Female Male
5.6.3 3 Explain the role of hormones in regulating the changes of puberty (testosterone, oestrogen) in boys and girls, and in the menstrual cycle (FSH, LH, oestrogen and progesterone). Puberty:
testosterone - development of male sexual characteristics; sperm oestrogen - development of female sexual characteristics
Menstrual Cycle:
FSH (follicle stimulating hormone) - stimulates gonads to produce gametes LH (leutenizing hormone) - stimulates gonads to produce sex hormones (oestrogen / testosterone) oestrogen - development of uterine lining progesterone - growth of uterine lining
5.6.4 1 List the secondary sexual characteristics in both sexes.
Female: breast tissue, mammary glands, hair at arms / genitals, pelvis widens, fat hip / thigh Male: facial and body hair, deep voice, greater stature, tendency to accumulate mass
5.6.5 1 State the differences between copulation and fertilisation.
copulation: gametes released into a certain area fertilization: haploid gametes zygote
5.6.6 2 Describe early embryo development up to the implantation of the blastocyst.
acrosome fuses with egg membrane and releases enzyme that dissolves pathway into egg
nuclei fuse
zona pellucida changes to mask sperm-binding sites prevent polyspermy
zygote undergoes rapid cell division partition cell into blastomeres
dividing cells morula (tight cell mass resembling mulberry
hollow core developes blastocyst - inner cell mass embroyo
trophoblast placenta
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5.6.7 1 State that the fetus is supported and protected by the amniotic sac and amniotic fluid.
fetus supported and protected by amniotic sac and amniotic fluid
5.6.8 1 State that materials are exchanged between the maternal and fetal blood in the placenta.
materials exchanged between maternal and fetal blood in placenta
5.6.9 2 Outline the process of birth and its hormonal control (cross reference 5.5.3), including progesterone and oxytocin.
oxytocin induces uterus contractions
5.6.10 2 Describe four methods of family planning and contraception.
abstinence - restrain from intercourse withdrawl - withdraw penis just before male orgasm rhythm method - avoid intercourse for several days before and after ovulation birth control pill - synthetic estrogen and progesterone inhibit FSH release
5.6.11 3 Discuss the ethical issues of family planning and contraception.
5.6.12 2 Outline the techniques of amniocentesis and chorionic villus sampling. Amniocentesis:
needle inserted into uterus amniotic fluid removed; contains cells released from developing embroyo cells grown (3-4 weeks) in culture & examined in lab
Chorionic villus sampling:
thin tube inserted through vagina into tissue surrounding placenta cells removed from chorion (tissue surrounding fetus) cells examined directly (immediately) for abnormalities
5.6.13 2 Outline the process of in vitro fertilisation (IVF).
sperm injected into egg
5.6.14 3 Discuss the ethical issues if IVF.
forced; not natural
5.6.15 2 Outline three developments from human embryo research including embryo storage and early detection of chromosome abnormalities.
embryo storage: freezing
early detection of chromosome abnormalities: DNA sequencing
karyotyping
cloning: grow stem cells clones
