Section 7 - Inherited change

Question 1

What is a gene?

Answer 1

An inherited instruction which codes for a polypeptide

Question 2

What is an allele?

Answer 2

Different version of the same gene due to a mutation

Question 3

What is a genotype?

Answer 3

The genetic constitution of an organism

Question 4

What is a phenotype?

Answer 4

Observable traits of an organism

Question 5

What does homozygous mean?

Answer 5

When the allele on each chromosome is the same

Question 6

What does heterozygous mean?

Answer 6

When the allele on each chromosome is different

Question 7

What does codominant mean?

Answer 7

When 2 alleles both contribute to the phenotype

Question 8

What is a monohybrid cross?

Answer 8

A cross in which the alleles of only one gene are involved

Question 9

What are the steps to formulating a monohybrid cross?

Answer 9

1. Determine gametes from each parents
2. Create a punnet square
3. Determine phenotypic ratio

Question 10

What is codominance?

Answer 10

When alleles share dominance of a characteristic

-When both codominant alleles are present, phenotype shows mixture of characteristics

Question 11

What is the expected ratio/ percentage of homozygous codominant genetic cross?

Answer 11

100% blended allele

white + red = pink

Question 12

What are the 4 different blood groups?

Answer 12

AB, A, B, O

Question 13

What is the expected ratio of a heterozygous codominant genetic cross?

Answer 13

1:1:1:1

25% of each

Question 14

What is the genotype of the blood group A?

Answer 14

AA or AO

Question 15

What is the genotype of the blood group B?

Answer 15

BB or BO

Question 16

What is the genotype of the blood group AB?

Answer 16

AB

Question 17

What is the genotype of the blood group O?

Answer 17

OO

Question 18

What is dihybrid inheritance?

Answer 18

Inheritance of 2 genes (with 2 different alleles each) on different chromosomes.

As alleles are on different chromosomes they can pass into the gametes in any combination

Question 19

What is a dihybrid cross?

Answer 19

A cross in which the alleles of 2 different genes are involved.

Question 20

What is the expected phenotypic ratio for a heterozygous dihybrid cross?

Answer 20

9:3:3:1

Question 21

What is a test cross?

Answer 21

Cross in which one of the individuals is homozygous recessive

Question 22

What is the expected ratio of a recessive and heterozygous dihybrid cross?

Answer 22

1:1:1:1

Question 23

What are linked genes?

Answer 23

Describes genes whose loci are on the same chromosome.

Question 24

What is autosomal linkage?

Answer 24

Applies to genes which are non-sex chromosomes

Question 25

What would the gametes from AaBb be if the genes were linked?

Answer 25

AB ab

Question 26

What are the sex chromosomes for most male and female?

Answer 26

Males- XY | Females- XX

Question 27

What sex chromosomes is bigger and carries more genes?

Answer 27

X chromosomes

Question 28

What is one limitation of using a line transect to collect data?

Answer 28

Transect line may not go through representative area

Question 29

What are two features of a climax community?

Answer 29

Abiotic factors are constant Populations are stable around carrying capacity Same species is present over long time

Question 30

Why are recessive characteristics more common in males?

Answer 30

No homologous allele present Characteristics caused by recessive allele have greater chance of appearing Will appear even through there is only 1 copy

Question 31

What is the chi-squared test?

Answer 31

Used to assess if observed results are significantly different to those expected Data must be categorial and consist of raw values Degrees of freedom: classes -1

Question 32

What is a null hypothesis?

Answer 32

There's no difference between observed and expected results

Question 33

In the chi-squared test, if the calculated value is LESS than the critical value then...

Answer 33

Accept null hypothesis More than 95% probability any difference is due to chance No significant difference between observed and expected results

Question 34

In the chi-squared test, if the calculated value is MORE than the critical value...

Answer 34

Reject null hypothesis Less than 5% probability that results are due to chance Significant difference between observed and expected results

Question 35

What is epistasis?

Answer 35

When the alleles of one gene mask the expression of the alleles of another gene

Question 36

What is dominant epistasis?

Answer 36

A dominant allele at one gene locus masks the expression of alleles at a second gene locus

Question 37

What is the expected ratio of a heterozygous cross involved in dominant epitasis?

Answer 37

12:3:1

Question 38

What is recessive epistasis?

Answer 38

Two recessive alleles at one gene locus will mask the expression of alleles at a second gene locus

Question 39

What is the expected ratio of a heterozygous cross involved in recessive epitasis?

Answer 39

9:3:4

Question 40

What is linkage?

Answer 40

2 or more genes on same chromosome, inherited together

Question 41

What is epistatsis?

Answer 41

The interaction between 2 alleles

Question 42

Suggest one reason why observed ratios are often not the same as expected ratios?

Answer 42

Fertilisation is random Fusion of gametes is random Sample is small