✅17 - Inherited Change

Question 1

What is a genotype?

Answer 1

The genetic makeup of an organism, all the alleles that it has

Question 2

What is a phenotype?

Answer 2

The observable or biochemical characteristics of an organism. The result of the interactions between expression of the genotype and the environment

Question 3

What is a gene?

Answer 3

A length of DNA

Question 4

What are alleles?

Answer 4

Different forms of genes

Question 5

What is a locus?

Answer 5

The position of a gene on a particular DNA molecule

Question 6

What are homologous pairs of chromosomes?

Answer 6

Pairs of chromosomes with approximately the same length, gene position and centromere location

Question 7

What is homozygous?

Answer 7

When an individual has two of the same allele

Question 8

What is heterozygous?

Answer 8

When an individual has two different alleles

Question 9

What does codominant mean?

Answer 9

Where two alleles both contribute to the phenotype

Question 10

What are multiple alleles?

Answer 10

When a gene has more than two allelic forms, of which only two may be present at the loci on an individual’s homologus chromosomes

Question 11

What is monohybrid inheritance?

Answer 11

Inheritance of a single gene

Question 12

What is the F1 generation?

Answer 12

First filial - two different pure breed organisms crossed to give hybrid offspring

Question 13

What is the F2 generation?

Answer 13

Second filial - heterozygous offspring from F1 generation crossed together to produce more offspring

Question 14

What is the law of segregation?

Answer 14

In diploid organisms, characteristics are determined by alleles that occur in pairs. Only one of each pair of alleles can be present in a single gamete.

Question 15

Why are actual results of genetic crosses rarely the same as predicted?

Answer 15

Due to statistical error

Question 16

How can results of genetic crosses be made to be closer to predicted ones?

Answer 16

By using a very large, representative sample

Question 17

What is dihybrid inheritance?

Answer 17

Two characteristics, determined by two different genes located on different chromosomes are inherited

Question 18

What is the law of independent assortment?

Answer 18

Each member of a pair of alleles may combine randomly with either of another pair

Question 19

What is an example of codominance?

Answer 19

The snapdragon plant, which has one allele for an ezyme that catalyses the formation of red pigment and one which produces no pigment - red and white. However, the two colour combine to give pink flowers

Question 20

What is an example of multiple alleles?

Answer 20

Blood group

Question 21

Which sex chromosomes do females have?

Answer 21

XX

Question 22

Which sex chromosomes do males have?

Answer 22

XY

Question 23

How many different types of gamete do males produce?

Answer 23

2, one X and one Y

Question 24

What are sex-linked genes?

Answer 24

Any gene carried on wither the X or Y chromosome

Question 25

Why can some genes be more prevalent in males than females?

Answer 25

The X chromosome is much longer than the Y, so more most of the X chromosome, there is no homologous equivalent and those recessive characteristics on the X chromosome will be more frequent in males

Question 26

What is an X-linked genetic disorder?

Answer 26

A disorder caused by a defective gene on the X crhomosome

Question 27

What is an example of an X-linked genetic disorder?

Answer 27

Haemophillia

Question 28

What are autosomes?

Answer 28

Any chromosome which is not a sex chromosome

Question 29

What is autosomal linkage?

Answer 29

When two or more genes are carried on the same autosome

Question 30

Why do linked genes remain together when passed onto offspring?

Answer 30

Because, assuming that there is no crossing over, they do not segregate in accordance with Mendel's law of independent assortment

Question 31

What is epistasis?

Answer 31

When the allele of one gene affects or masks the expression of another in the phenotype

Question 32

What is an example of epistasis?

Answer 32

In mice, where several genes determine coat colour

Question 33

How does epistasis in mice work?

Answer 33

Gene A controls distribution of black pigment and whether they are banded or not. The dominant allele of A leads to hairs with black bands, which recessive a produces uniform black hairs. Gene B controls expression of A. Dominant B leads to production of the pigment while recessive b leads to no pigment

Question 34

Which statistical test is used for genetics?

Answer 34

Chi Squared