inheritance

Question 1

define gene

Answer 1

section of DNA that codes for a protein

Question 2

define allele

Answer 2

alternate version of a gene - mutations cause a different base sequence

Question 3

define dominant allele

Answer 3

is always expressed in phenotype

Question 3

define recessive allele

Answer 3

not expressed if dominant allele is present

Question 4

give an example of a genotype

Answer 4

Aa

Question 5

what is a phenotype

Answer 5

displayed characteristic due to inherited + environmental factors

Question 6

define homozygous genotype

Answer 6

2 of the same alleles

Question 7

define heterozygous genotype

Answer 7

2 different alleles

Question 7

what are the dihybrid cross results when both parents are heterozygous for both alleles

Answer 7

ratio always: 9:3:3:1

Question 8

what is the Hardy-Weinberg Equation

Answer 8

Question 9

what is the shorter equation for inheritance

Answer 9

p+q=1

Question 10

define alopatric speciation

Answer 10

the formation of new species caused by geographic isolation, where a physical barrier—such as a mountain range, river, or desert—splits a population

Question 10

which blood groups are co-dominant and recessive

Answer 10

Question 11

give suggestions of how species of bird’s beak could change on different locations

Answer 11

different food sources
different selection pressures due to different food sources

Question 11

define sympatric speciation

Answer 11

new species evolve from a single ancestral population while inhabiting the same geographic location, without physical isolation

Question 12

define evolution by natural selection

Answer 12

changing frequency of alleles within a population

Question 13

define stabilising selection

Answer 13

culls extreme variations
narrows width of distribution

Question 14

define directional selection

Answer 14

favours one extreme \shifts distribution to left/right

Question 15

define disruptive selection

Answer 15

favours both extremes
causes 2 curves

Question 16

what does disruptive selection result in

Answer 16

development of new species (speciation)
when population is divided reproductively no gene flow
eventually become genetically distinct from each other so can no longer produce fertile offspring

Question 17

what is genetic drift

Answer 17

when certain individuals survive something, because of luck, not best adaptations
causing descendants to inherit their alleles causing species allele frequency to change

Question 18

gene pool

Answer 18

all genes in a population

Question 19

contrast the x and y chromosome

Answer 19

y is smaller and is missing many if the genes found of the x chromosome

Question 20

what is a sex-linked trait

Answer 20

gene I present on X chromosome, there is no equivalent locus on y chromosome

women can carry 2 alleles of a sex linked gene/1 - homo/hetero
whereas men can only carry one, but won’t have another to counteract

Question 21

what is codominance

Answer 21

2 phenotypes can be expressed

Question 22

what is the formula for chi squared

Answer 22

Question 23

what are the chromosomes other than x and y called

Answer 23

autosomes

Question 24

define genotype spec

Answer 24

genetic constitution of an organism

Question 25

define phenotype spec

Answer 25

expression of this genetic constitution and its interaction with the environment