Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Genetics Lecture > Dosage Compenstation > Flashcards

Dosage Compenstation Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

What is a dose?

A

An amount or quantity of something

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is a chromosomal dose?

A

A specific amount of gene expression, in particular, the expression of essential genes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is an essential gene?

A

A gene that is required for viability.
Ex: genes that specify enzymes in aerobic respiration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is haploinsufficiency?

A

One allele cannot provide enough gene product for normal development and function.
Occurs in a monosomy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is gene expression?

A

The production of a product from the information in a gene

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is dose of gene expression?

A

The quantity of gene products in particular genes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Are essential genes on X or Y chromosomes?

A

Essential genes are only found on the X chromosome.
So only found in pseudoautosomal and X-linked genes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How many doses of pseudoautosomal genes do males and females have?

A

Both sexes have two doses of these genes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How many doses of holandric genes do males and females have?

A

Males have one dose
Females have zero doses
There are no essential holandric genes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How many doses of x-linked genes do males and females have?

A

Males have one dose
Females have two doses
There are essential X-linked genes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Is the dose of X-linked genes important?

A

Yes, as they contain essential genes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is dosage compensation?

A

A mechanism that equalizes the dose of X-linked genes in males and females. There are two methods: X chromosome hyperactivation and X chromosome inactivation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is X chromosome hyperactivation?

A

Genes in the male’s X chromosome are up-regulated so that it is twice the activity of genes in each X of the females. Each sex has the equivalent of two doses of X-linked genes.
This occurs in many insects
So basically, the X chromosome is expressing more

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is X chromosome inactivation?

A

Gene expression of the female’s chromosome is silenced/ Each sex has the equivalent of one dose of X-linked genes. This occurs in mammals.
Basically, one X chromosome is no longer expressive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What happens to the X chromosome in females? (kinda worded wrong but oh well)

A

In females, one X chromosome is always inactivated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What happens to one X chromosome during X inactivation?

A

One X chromosome becomes tightly packed and condensed permanently. Enzymes cannot access this chromosome.

17
Q

Most genes on the X chromosome are inactivated, but some genes are spared. Which are spared?

A

Pseudoautosomal genes and some X-linked genes that are involved in the inactivation process

18
Q

What is the name of the X chromosome after it has been highly condensed?

A

Barr Body

19
Q

How do Barr bodies work?

A

If a cell contains more than one X chromosome, all but one chromosome will be inactivated. Each inactive X chromosome is considered a Barr body.

20
Q

Which sex chromosome combination cannot have Barr bodies? Why?

A

XY cannot have Barr bodies. There is only one X chromosome.

21
Q

When does X inactivation occur?

A

During the third week of fertilization

22
Q

Can the inactive X chromosome undergo replication?

A

Yes, it can replicate normally during interphase and will be segregated into daughter cells during mitosis.

23
Q

How does inheritance work with an inactive X?

A

Daughter cells will inherit the parent cell’s inactive X
When those daughter cells replicate, their daughters will also have the same inactive X
All cells descended from the original parent cell will have the same inactive X

24
Q

What is the frequency of X inactivation?

A

X inactivation is random, so each chromosome has a 50% chance of being inactivated

25
Q

What are the alleles for the X-linked gene involved in producing coat colors in cats?

A

XO = orange fur
XB = black fur

26
Q

Where is the coat color gene expressed on the cat?

A

It is expressed in the skin cells that produce hairs

27
Q

What is the genotype for male cats for the coat color gene?

A

XO Y
XB Y

28
Q

What is the genotype for female cats for the coat color gene?

A

XBXB
XOXO
XOXB

29
Q

What do female cats that are heterozygous for the coat color gene look like?

A

They have a tortoiseshell fur pattern

30
Q

When a female cat has a tortoiseshell coat color, what does each patch represent?

A

Each patch represents a group of skin cells with the same active X chromosome carrying either the XO allele or the XB allele

31
Q

What are the alleles for the X linked gene involved in red-green colorblindness?

A

XG = normal vision
Xg = red green colorblind

32
Q

What is the frequency of each allele to be active?

A

Genetics Lecture (17 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions