Inheritance (17)

Question 1

What is the genotype?

Answer 1

genetic construction of an organism

Question 2

What is the phenotype?

Answer 2

expression of an organisms genetic constitution combined with its interaction with the environment

Question 3

What is an allele?

Answer 3

different forms of a particular gene found at the same locus on a chromosome

Question 4

How many alleles could a single gene have?

Answer 4

many

Question 5

What is a diploid organism?

Answer 5

organism that carries 2 alleles per gene

Question 6

What is a dominant allele?

Answer 6

allele whose characteristic will always appear in the phenotype, whether 1 or 2 are present

Question 7

What is recessive allele?

Answer 7

allele whose characteristics only appears in the phenotype if no dominant allele is present

Question 8

What are codominant alleles?

Answer 8

2 dominant alleles that both contribute to the phenotype, either by showing a blend of characteristics, or characteristics appearing together

Question 9

What is meant by homozygous?

Answer 9

when both alleles dominant or both recessive

Question 10

What is meant by heterozygous?

Answer 10

when one alleles is dominant and one recessive

Question 11

What is meant by monohybrid inheritance?

Answer 11

when one phenotypic characteristic is controlled by a single gene

Question 12

What 2 ratios does a monohybrid cross produce?

Answer 12

3:1
1:2:1 due to codominance

Question 13

Is brown eyes phenotype, genotype, or gamete?

Answer 13

phenotype

Question 14

Is Bb phenotype, genotype, or gamete?

Answer 14

genotype

Question 15

Is B phenotype, genotype, or gamete?

Answer 15

gamete

Question 16

What is meant by dihybrid inheritance?

Answer 16

where 2 phenotypic characteristics are determined by 2 different genes present on 2 different chromosomes at the same time

Question 17

What are the 4 ratios that can result from a dihybrid cross punnet square?

Answer 17

9:3:3:1
3:1 due to linkage
9:3:4 due to epistasis
12:3:1 due to epistasis

Question 18

What is sex-linkage?

Answer 18

where an allele is located on 1 of the sex chromosomes, meaning its expression depends on the individual’s sex

Question 19

Which chromosome is the sex chromosome?

Answer 19

23rd chromosome

Question 20

Why are males more likely to express recessive sex-linked allele?

Answer 20

most sex-linked alleles are located on the X chromosome, therefore males only get one copy of the allele, so will express this characteristics even if it’s recessive - females get 2 alleles so this is less likely

Question 21

Which parents do males inherit sex-linked characteristics from and why?

Answer 21

their mother since the Y chromosome can only come from their father, therefore if mother is heterozygous for sex-linked alleles - she is a carrier and may pass the trait on

Question 22

What is autosomal linkage?

Answer 22

where 2 or more genes are located on the same non-sex chromosome

Question 23

Which are the non-sex chromosomes?

Answer 23

the first 22 chromosomes

Question 24

What is epistasis?

Answer 24

where 2 non-linked genes interact, with one gene either masking or suppressing the other gene

Question 25

What are the 2 types of epistasis?

Answer 25

recessive epistasis
dominant epistasis

Question 26

What is recessive epistasis?

Answer 26

where 2 homozygous recessive alleles mask the expression of another allele

Question 27

What is dominant epistasis?

Answer 27

where 1 dominant allele masks the expression of multiple other alleles

Question 28

What is the chi-squared test?

Answer 28

statistical test to find out whether the difference between observed and expected data is due to chance or a real effect

Question 29

What are the 4 criteria for chi-squared test?

Answer 29

• categorical data
• large sample
• only raw count data allowed (e.g. not percentages)
• no data values = 0

Question 30

What are the 2 steps in performing a chi-squared test?

Answer 30

1) formula results in a number
2) compare number to critical value for the corresponding degree of freedom

Question 31

If the p is less than or equal to 0.05, what does this mean?

Answer 31

significant difference
not due to chance
reject null hypothesis

Question 32

If the p is more than 0.05, what does this mean?

Answer 32

no significant difference
due to chance
accept null hypothesis

Question 33

How can the chi-squared test be used for investigating inheritance?

Answer 33

we can compare expected ratios with observed ratios to test our understanding of how different genes and alleles are inherited