Lisa Numann - Topic 1

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Topic 1

1.1.1 State the contributions of Robert Hooke, Anton van Leeuwenhoek, Matthias Schlieden, Theoder Schwann and Rudolph Virchow.

Robert Hooke: first used the term “cell”
Anton van Leeuwenhoek: developed lens to observe unicellular organisms and nuclei.
Schleiden & Schwann: developed the part of the cell theory stating that plants are made up of cells, hence all living things are made up of cells.
Virchow: developed part of the cell theory stating that cells must come from other cells.

1.1.2 Describe 3 advantages of using light microscope

specimen can be living
specimen can be thicker
cheaper
easier to use

1.1.3 Describe 2 advantages of using an electron microscope

higher resolution
three dimensional as opposed to two

1.1.4 Define organelle

organelle: specified structure within a cell

1.1.5 Compare the sizes of a molecule, a cell membrane thickness, a virus, bacteria, organelles and cells.

molecule: 1nm
cell membrane: 4nm
ribosome: 20-30nm
virus: 40-70nm
bacteria: 1μm
nucleus: 5 μm
eukaryotic cell: 100 μm

1.1.6 Explain the importance of surface are to volume ratio

volume grows faster than surface area
cell divides because there is not enough surface area to cover entire cell
normal surface are to volume ratio is recovered after division

1.2.1 Draw a prokaryotic cell

1.2.2 State functions of:

ribosome: site for protein synthesis
mesosome: does tasks of missing organisms
slim capsule: protects from virus and antibvodies
cell wall: protects, maintains shape, prevents excess water uptake
flagellum: movement
cell surface membrane: regulates what enters and exits
plasmid: contains prokaryotic DNA
naked nucleic acid: prokaryotic DNA without histone proteins

1.3.1 Discuss the origin of the eukaryotic ell.

endo: into cell
symbiosis: when two things live close together (mutualistic relationship)
modern cell has organelles with two membranes, for example the mitochondria.
internal membrane resembles prokaryotic membrane.
mitochondria could once have been a prokaryote with its own ribosomes and DNA.
chloroplasts contain similar evolutionary evidence.

1.3.2 Draw animal cell.

1.3.3. State functions of:

ribosome: site for protein synthesis
rough E.R: tags proteins for the membranes
lysosomes: digest all major organic compounds (eats &spits)
golgi apparatus: routes products to endoplasmic reticulum
mitochondrion: breaks down sugars and releases energy
nucleus: control center of cell
chloroplasts: site for photosynthesis

1.3.4 State two similarities between prokaryotic and eukaryotic cells.

both contain ribosomes
both contain DNA

1.3.5 State two differences between eukaryotic nucleus and prokaryotic nuclear material

shape of DNA: eukaryotic DNA is linear while prokaryotic DNA is circular
content of DNA: eukaryotic DNA has histone proteins while prokaryotic DNA does not.

1.3.6 Describe three differences between animal and plant cells

plant
has cell wall
has chloroplasts
has no lysosomes
has no centrioles
animal
has lysosomes
has centrioles
has no cell wall
has no chloroplasts

1.3.7 State the function and composition of a plant cell wall.

primary cell wall: made of cellulose
middle lamella: jelly
secondary cell wall
function: maintains shape

1.4.1 Draw the fluid mosaic model

phospholipid bilayer
cholesterol
glycoproteins
intrinsic &extrinsic proteins

1.4.2 Explain hydrophobic versus hydrophilic structure of phospholipids maintaining cell structure.

tail: hydrophobic
head: hydrophilic
no membrane exists without both
together they forma  barrier

1.4.3 Define diffusion

diffusion: movement from higher concentration to lower concentration.

1.4.4. Define osmosis (i) osmosis: diffusion of water particles across a semi-permeable membrane.

1.4.5 Explain passive transport versus active transport

passive: random movement on own energy (fluid)
active: against natural flow, movement from less to more, requires energy, uses ATP

1.4.6 Describe protein carriers, ATP and concentration gradient. Explain the gain and loss of water using terms.

protein carriers: pumps (active) and channels (passive)
ATP: energy molecule used in active transport against the concentration gradient.
concentration gradient: difference of concentration between two substances
hypotonic: more water, less solute
hypertonic: less water, more solute
osmosis: movement of H2O in and out of cell
isotonic: equal amounts of water and solute
equilibrium: equal amounts moving in and out
turgor pressure: pressure inside the cell
flaccid: animal cell shrinking
turgid: plant cell turning stiff
cytolysis: animal cell exploding
plasmolysis: plant cell shrinking
homeostasis: balance

1.4.7 Compare endocytosis and exocytosis:

endocytosis: food/liquid going into the cell
exocytosis: waste going out of the cell
phagocytsosis: endocytosis of food
pinocytosis: endocytosis of liquid

1.5.1 State that all cells arise from division of other cells.

1.5.2 Describe the cell cycle as an alternation between interphase and mitosis.

1.5.3 State that interphase is an active period in the life of a cell, which is divided into three phases:

G1 phase: transcription
S phase: pelication
G2 phase:L production of organells

1.5.4 Outline how replicated DNA molecules (chromosomes) are moved to opposite ends of the cell by microtubules by the following phases during mitosis:

prophase
separate when nuclear membrane disappears
nucleolus disappears
centrioles go to poles
spindle fibers appear
chromosomes get shorter and thicker
metaphase
centrioles become asters
the chromosomes line up “single file” at the equator
spindle fibers attach to centromere with kinetochore
anaphase
the chromatids are pulled towards opposite poles
telophase
the nuclear membranes reappear
nucleolus reappears
asters become centrioles in animals
spindle fiber disappears
chromatids get longer and thinner and become chromatin.

1.5.5 State that the products of mitosis are two genetically identical nuclei

1.5.6 State that tumors are the result of uncontrolled cell division that can occur in any organ.