Session 7-Genotype, Phenotype And Inheritance Flashcards Preview

Semester 1-MCBG > Session 7-Genotype, Phenotype And Inheritance > Flashcards

Flashcards in Session 7-Genotype, Phenotype And Inheritance Deck (29):
1

Define homozygous

Two alleles of a gene are the same (individual is a homozygote)

2

Define heterozygous

Two alleles of a gene are different (individual is heterozygote)

3

Define hemizygous

Only one allele of a gene is present on the X chromosome (ie males only)

4

Define dominant

Dominant allele in heterozygote determines phenotype

5

Define recessive

Non-dominant allele in heterozygote is recessive

6

Give an example of a co-dominant gene and explain its alleles

Human isoglutamin gene which codes for glycoproteins on the surface of RBCs
Alleles A and B are dominant over allele O
Alleles A and B are co-dominant

7

True or false: heterozygotes are affected in an autosomal recessive condition

FALSE

8

True or false: males and females are equally affected in an autosomal recessive condition

TRUE

9

What % chance do two heterozygotes have of producing offspring with an autosomal recessive condition?

25%

10

True or false: in an autosomal recessive condition, two affected (homozygous) individuals will have affected offspring only

TRUE

11

Give an example of an autosomal recessive condition

Cystic fibrosis

12

True or false: autosomal recessive conditions cannot skip generations

FALSE

13

True or false: heterozygotes are affected in autosomal dominant conditions

TRUE

14

True or false: males and females are not equally affected in autosomal dominant conditions

FALSE

15

What % chance does every affected individual have of producing offspring with an autosomal dominant condition?

50%

16

Give an example of an autosomal dominant condition

Huntington's disease

17

True or false: autosomal dominant conditions cannot skip generations

TRUE

18

Which males and females are affected by X-linked recessive conditions?

Hemizygous males and homozygous females

19

True or false: X-linked recessive conditions are more common in males

TRUE

20

What % chance does a heterozygous female carrier have of having sons with an X-linked recessive condition?

50%

21

True or false: males with an X-linked recessive condition cannot give the trait to their sons

TRUE

22

Give an example of an X-linked recessive condition

Haemophilia A

23

Which males and females are affected by X-linked dominant conditions?

Hemizygous males and heterozygous females

24

True or false: affected males cannot give X-linked dominant traits to their sons but they will give it to all of their daughters

TRUE

25

Give an example of an X-linked dominant condition

Rett syndrome

26

Give an example of a Y-linked condition

Swyer syndrome

27

True or false: all individuals with mitochondrial diseases inherit the trait from their mothers

TRUE

28

True or false: more than one gene can be involved in producing a particular phenotype

TRUE

29

Give an example of a polygenic condition

Albinism