Lisa Numann - Topic 3
From KstructIB
Topic 3
3.1.1 State that eukaryotic chromosome is mae of DNA & Protein
3.1.2 State that chromosomes can be stained to show banding
3.1.3 State that the chromosomes structure and branding can be used to arrange the chromosomes into pairs through karyotyping and gene mapping
3.1.4 Describe the application of karyotyping: detection of diseases, trisomy and monosomy
3.1.5 Define Gene
an heritable factor that controls a specific characteristic consists of a length of DNA
3.1.6 Define Allele
specific form of a gene differs from other alleles by one-few bases that occupy the same locus
3.1.7 Define Genome (i) total genetic material of an organelle, cell or organism
3.2.1 &3.2.3 Define gene mutation the consequence of a base substitution mutation
gene mutations chromosomal mutations: segments, whole or sets of chromosomes (deletion, duplication, inversion and translocations) gene mutations: point mutation (one nucleotide in change/substitution) or frame shift mutation (insertion/deletion of nucleotide) sickle cell anemia HB^A = normal HB ^S = sickle Example of a substitution point mutation that produces a mutant form of hemoglobin. Hemoglobin crystallizes when oxygen content goes down from exercise. This mutation causes sickle shaped red blood cells which clot blood vessels and causes weakness, oxygen shortage, pain in body, enlargement of heart and atrophy of brain cells.
3.2.2 Outline difference between insertion and deletion
insertion: one/more nucleotide pairs are added to a gene causes frame shift mutation and the wrong amino acid addition to proteins deletion: frame shift mutation from a loss of a DNA fragment through breakage or loss of a nucleotide from a gene causes wrong amino acid addition to proteins
3.3.1 State that meiosis is a reduction division in terms of diploid and haploid number of chromosomes.
3.3.2 Outline the process of meiosis including pairing of chromosomes followed by two divisions which result in four haploid cells.
3.3.3. Explain how movement of chromosomes during meiosis can give rise to genetic variety in the resulting haploid cells due to crossing over and different allele combinations because of the Law of Segregation
Law of Segregation: gene pairs separate to form sex cells.
3.3.4 Explain that non-disjunction can lead to changes in chromosome number
example: Down’s Syndrome (Trisomy 21)
3.4.1 & 3.4.2 Define genotype vs. phenotype
genotypes are the alleles posses by an organism phenotypes is the physical expression of the genotype
3.4.3-3.4.5 Define dominant, recessive and codominant
dominant: alleles with same effect on the phenotype whether it is present in heterozygous or homozygous form recessive: alleles which only have effect on phenotype is present in homozygous form codominant: alleles with partial effect on phenotype when present in heterozygous form
3.4.6 Define Locus
the particular position on homologous chromosomes of a gene
3.4.7&3.4.8 Define Homozygous & Heterozygous
homozygous: when two alleles of gene are identical heterozygous: when two different alleles form one pair
3.4.9 Define carrier
carrier: individual with recessive allele of a trait which thus does not have an effect on the phenotype
3.4.10 Define test cross
test cross: test performed between suspected heterozygous genotype with a known homozygous recessive genotype
3.4.11 Draw a Punett Square for following problems:
Dominant/Recessive Codominant Blood Sex-linked
3.4.12&3.4.22 Draw a pedigree chart
3.4.13 State that some genes have more than 2 alleles
3.4.14 Describe ABO blood groups as an example of codominance and multiple alleles
3.4.15 Outline how the sex chromosome determines gender and sex determination
XX: female XY: male Always a 50-50 chance
3.4.16 State that some genes are present on the X chromosome and are absent from the shorter Y chromosome in humans.
3.4.17 Define sex-linkage
sex linkage: when genes are carried on the sex pair of chromosomes
3.4.18 State two examples of sex-linkage
color blindness hemophilia Duchenes Muscular Dystrophy
3.4.19 State that human females can be homozygous or heterozygous with respect to sex-linked genes.
females are carriers for the x-linked alleles.
3.5.1 Discuss genetic screening
testing a population for the presence or absence of a gene.
3.5.2 Discuss 3 advantages and/or disadvantage of genetic screening:
advantages pre-natal diagnosis of diseases search for genes that predispose individuals to medical problems determining suspects in criminal investigations disadvantages people trying to crate perfect human insurance companies prejudiced who determines whether experiments should be done?
3.5.3 State that the human genome project is an international cooperative venture to sequence the complete human genome.
3.5.4 Describe 2 possible advantages of this project:
genetic disease detection genome libraries production of gene probes to detect sufferers or carriers of genetic diseases Production of drugs based on DNA sequences.
3.5.5 Define clone
clone: group of organisms of identical genotype or a group of cells descended from a single parent.
3.5.6 Outline a technique used in the cloning of farm animals
animal selected body cells extracted from organism grown in solution that stops cell cycle early division of a fertilized egg produces 8 cells each, forming embryo one egg cell is extracted from surrogate mother nucleus is removed from egg cell with micropipette body cell is inserted inside covering of egg cell electric shock opens cell membranes and triggers cell division embryo begins to develop in vitro. embryo is implanted into surrogate mother containing genes for protein desired.
3.5.7 Discuss ethical issues of cloning human embryos:
idea of super race playing God producing mistakes
3.5.8 Discuss the results of crop plant and animal breeding:
crops are designed to improve nutritional balance, produce proteins, become resistant to herbicides animal breeding is designed to produce expensive medicines at a cheaper rate and increase food production.
