Genetics and Populations Flashcards Preview

Biology Revision Year 2 > Genetics and Populations > Flashcards

Flashcards in Genetics and Populations Deck (63)
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1

Define Diploid

A cell or organism that has a pair of homologous chromosomes

2

What is a gene?

A sequence/section of DNA that codes for a particular protein

3

Define Allele?

A version of a gene

4

What is a Genotype?

The combination of alleles within an organism

5

What is a phenotype?

The physical expression of a genotype

6

What does it mean if an allele is dominant?

An allele that is always expressed

7

What is a recessive allele?

It is only expressed when homozygous

8

What results from co dominance?

Both alleles are expressed in the phenotype

9

What is the locus?

The position of a gene on a chromosome

10

What is dihybrid inheritance?

Inheritance of 2 characteristics controlled by separate genes

11

What is the expected phenotypic ratio of the F2 generation?

9:3:3:1

12

What is monohybrid inheritance?

Inheritance of characteristics controlled by a single gene

13

What percentage of a F1 generation would be heterozygous?

100%

14

What is the expected retail of genotypes in the F2 generation?

1:2:1

15

What would be the expected percentage of different phenotypes in the F2 generation?

3:1 (75% to 25%)

16

What is epistasis?

An interaction between genes where the expression of one gene suppresses the expression of another gene

17

What is an autosome?

Any chromosome that is not a sex chromosome eg) 44 autosomes

18

How are autosomes linked?

If they are on the same autosome they will stay together during independent segregation - meaning they will be inherited together

19

How does autosomal linkage affect phenotypic ratios?

Because they are inherited together more offspring have the same phenotype as their parents

20

What else can affect autosomal linkage?

Cross over

21

Species

A group of similar organisms that can breed and produce fertile offspring

22

Population

All the organisms of a single species in one place at the same time

23

Community

All organisms in one place in one time

24

Gene pool

All the alleles present in a population

25

Allele frequencies

How common the allele is

26

Evolution

Change in allele frequencies over time

27

Differential reproductive success

Organisms with a phenotype better adapted to their environment have a selective advantage, more likely to survive breed and pass on their genes

28

Speciation

The formation of a new species

29

What are the predictions of Hardy-Weinberg principles?

The frequency of alleles of a gene will stay constant over generations

30

What assumptions are made for a Hardy Weinberg calculation?

No mutation takes place No selection Random mating Large population No genetic drift Population is genetically isolated