Genetics

Question 1

DNA profiling and steps

Answer 1

Generating a pattern of bands from a DNA sample to be analysed
1. Release DNA
2. CUT DNA INTO FRAGMENTS USING ENZYMES
3. Separate on basis of size
4. Fragments create a pattern

Question 2

What is a Gene

Answer 2

A section of DNA that codes for a particular protein

On chromosomes (locus)
Homologous Pairs: genes of similar trait

22 autosomes
23 sex chromosomes

Question 3

heriditary and allele

Answer 3

The passing of features and traits from parent to offspring by means of genetics

Allelus are dominant or recessive
Heterozygous
Homozygous

Question 4

Genotype/Phenotype

Answer 4

Phenotype: Brown Eyed - physical makeup
Genotype Bb - genetic makeup

Question 5

Genetic Crosses

Answer 5

2 parents on sides of punnet square

Question 6

Sex Linkage

Answer 6

The gene for a particular condition is located on a sex chromosome (X or Y)
XY - Male
XX - Women

Sperm controls sex of progeny (child)

Genes that control traits are found of the sex chromosomes (X)

Sex linked condition: Haemophilia

Question 7

Law of Segregation

Answer 7

Traits are controlled by pairs of factors (alleles) which separate at gamete formation
Each cell contain two factors for each trait

Each gamete contains only one factor, fertilisation makes 2 factors

Mono hybrid crosses
Pea plants: purple and white
Alleles: ppairs of factors - heriterable traits

Question 8

Law is Independent Assortment

Answer 8

Members of a pair of factors (alleles) separate independently from members of another pair at gamete formation

9:3:3:1: heterozygous with heterozygous
1:1:1:1: heterozygous with homozygous

(If genes are linked, law will not apply)

Question 9

Eukaryotic chromosome structure

Answer 9

Many linear chromosomes
Supercoied DNA
2 copies of genome, condensed, centromere and arms, X shaped

Question 10

Chromosomal Theory of Inheritance

Answer 10

Chromosomes occur in matched pairs
46 number of chromosomes: 23 pair of homologous replicated chromosomes, with centromere and sister chromatids

Meoisis = n=23

Question 11

mutations: types and causes

Answer 11

Genones alter slowly over time, beneficial traits survive (natural selection)

Genetic Variation: difference in DNA/alleles
Mutuations:
Chromosomal (incorrect number, translocation)
Gene: change in the amount or structure of DNA - deletions, insertions, substitution

Cause: exposure to mutagens,radiation, spontaneously

Question 12

Protein Synthesis

Answer 12

Code from gene in DNA in nucleus is copied from the gene (single stranded so can fit through nuclear pores
) to ribosomes (protein - making)

1. Initiation: DNA unwinds by enzymes breaking the strands apart
2. Transcription: making mRNA using DNA as a template (complementary bases align) messenger rna then leaves nucleus and go to ribosomes
3. Translation: tRNA in the cytoplasm carry the correct amino acid to connect through peptide bonds and chain continues to stop codon
4. Protein folding