L12-13 Inheritance

Question 1

Polygenic traits show…

Answer 1

Continuous variation

Question 2

Mendel’s laws state that…

Answer 2

1. Each gene is segregated (Law of Segregation)

2. Copies of each gene segregate independently of each other (Law of Independent Assortment)

Question 3

Linked genes cannot…

Answer 3

Assort independently

Question 4

A monohybrid cross is a…

Answer 4

1 trait cross

Question 5

The ratio of genotypes for offspring of a monohybrid cross is…

Answer 5

1 : 2 : 1

AA : Aa / aA : aa

Question 6

The ratio of phenotypes for offspring of a monohybrid cross is…

Answer 6

3 : 1

AA, Aa and aA all express dominant allele ‘A’
aa expresses recessive allele ‘a’

Question 7

There are ( few / many ) single gene traits

Answer 7

Few

Question 8

Examples of true single gene traits are…

Answer 8

• Bitter broccoli- PTC tasting
• White cats
• Wet/dry earwax
• Albinism

Question 9

Hardy-Weinberg Equilibrium assumes (3)…

Answer 9

Infinite population, random mating and no evolutionary forces acting

Question 10

p^2 + 2pq + q^2 = 1, where

Answer 10

p is the dominant and q is the recessive allele

Question 11

The equation Harvey-Wineberg equation can be used to determine the (theoretical)…

Answer 11

Frequencies of homozygous (pp , qq) heterozygous (2pq) genotypes

Question 12

Autosome

Answer 12

A non-sex chromosome

Question 13

Identify 6 autosomal recessive traits in humans…

Answer 13

1) Albinism
2) Phenylketonuria
3) Tay-Sachs
4) Cystic Fibrosis
5) Sickle-cell Anaemia
6) Haemochromatosis

Question 14

Haemochromatosis is the result of an autosomal recessive allele and results in excess iron. It is treated by…

Answer 14

Chelation or phlebotomy (blood letting)

Question 15

Identify 3 autosomal dominant conditions…

Answer 15

1) Polydactyly
2) Hypercholesterolemia
3) FASPS (Familial advanced sleep phase syndrome)

Question 16

In pedigree diagrams, autosomal recessive conditions generally occur in offspring of…

Answer 16

Unaffected parents, i.e. it appears to skip generations

Question 17

In pedigree diagrams, autosomal dominant conditions are usually passed on in…

Answer 17

50% of offspring

Question 18

Sex-linked genes ( have different / have the same ) inheritance patterns to autosomal genes

Answer 18

Have different

Question 19

Serious X-linked disorder cases are all ( male / female ) inherited from ( recessive / dominant ) mother

Answer 19

Male, recessive

Question 20

Y-linked disorders are rare, as they…

Answer 20

Tend to affect male fertility and thus are not passed on

although the advent of in vitro fertilisation has changed this

Question 21

Léri-Weill Dyschondrostenosis

Answer 21

Mutation or lack of SHOX gene in PAR1 region on X or Y chromosome

Question 22

Tortoiseshell cats are female because…

Answer 22

Cat coat colour is X linked and the tortoiseshell pattern results from X-inactivation

Question 23

Genes are either autosomal or…

Answer 23

Sex-linked