Mendels genetics 2 Flashcards Preview

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Flashcards in Mendels genetics 2 Deck (21)
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1
Q

How many chromosomes does a body cell have?

A

46

2
Q

How many chromosomes does a sex cell have?

A

23

3
Q

Sex-linked

A

A trait that is carried on a gene on a sex chromosome

4
Q

What is genetic sex determined by?

A

The presence or absence of the Sry gene on the Y chromosome

5
Q

Hemizygous

A

Only having 1 copy of each gene e.g XY

6
Q

Lyonization

A

One of two female X chromosomes is switched off

7
Q

Dosage compensation

A

ensuring that the same level of hormones are expressed in both males and females

8
Q

Barr Body

A

The inactive X chromosome in females

9
Q

Mosaicism

A

When a person has 2 or more genetically identical different sets of cells in their body

10
Q

Loss of function

A

Inactivation mutations (gene product reduced or lost)

11
Q

Gain of function

A

activating mutations (increasing activity of an allele)

12
Q

Heterosis

A

also known as Hybrid vigour, individuals that are heterozygous at many gene loci

13
Q

Overdominance

A

The heterozygote produces a more dominant phenotype than the homozygote that is also superior

14
Q

Polygenic inheritance

A

Two or more genes effect a single phenotype, e.g skin colour

15
Q

Penetrance

A

The proportion of individuals in a group with a given genotype that express the corresponding phenotype

16
Q

What is SRY?

A

the sex-determining region of the Y chromosome contains TDF

17
Q

What is an example of overdominance?

A

sickle-cell anaemia

18
Q

What is a mutation?

A

New alleles that can lead to a loss or gain in function

19
Q

What is Genetic Drift?

A

Change in allele frequency based on random sampling effects

20
Q

What is Gene Flow?

A

Due to Physical barriers, the population either side begins to differ, can be introduction of alleles on either side through immigration

21
Q

What is an example of lyonization?

A

Tortoiseshell cats