DNA and Chromatin Regulation

Question 1

DNA is packed into chromosomes in the form of

Answer 1

Chromatin

Question 2

Chromatin is a combination of

Answer 2

Histone proteins, DNA, and non-Histone proteins

Question 3

Chromatin has repeating units which are called

Answer 3

Nucleosomes

Question 4

What are Nucleosomes?

Answer 4

Repeating units of chromatin made of 146 base pairs of double helical DNA that is wrapped around 8 histones

Question 5

What are 4 types of Histones?

Answer 5

• H2A
• H2B
• H3
• H4

Question 6

Where does Acetylation occur?

Answer 6

At the amino terminal tails of histone proteins

Question 7

Acetylation is done by the enzyme

Answer 7

Histone Acetyltransferase

Question 8

What is the enzyme which reverses Acetylation?

Answer 8

Histone Deacetylase

Question 9

What does Histone Deacetylase allow for?

Answer 9

The condensed chromatin structure and less transcription of those genes

Question 10

What is Acetylation?

Answer 10

The uncoiling of chromatin structure, allowing for it to be accessed by the transcription machinery for expression of genes

Question 11

What is Epigenetic Regulation?

Answer 11

Modifications that regulate gene expression are inheritable

Question 12

What are two forms of DNA?

Answer 12

• Heterochromatin

- Euchromatin

Question 13

What is Euchromatin?

Answer 13

Less densely packed DNA and transcriptionally active

Question 14

What is Heterochromatin?

Answer 14

Densely packed DNA and transcriptionally inactive

Question 15

What is combined with DNA Methylation?

Answer 15

Histone Deacetylation

Question 16

Histone Deacetylation occurs during

Answer 16

Gene Silencing

Question 17

What is Gene Silencing?

Answer 17

More permanent method of down-regulating the transcription of genes

Question 18

What is DNA Methylation?

Answer 18

The addition of a methyl group to the cytosine via enzyme Methyltransferase

Question 19

DNA Methylation occurs where?

Answer 19

In Cytosine-rich sequences, or CpG Islands

Question 20

What does DNA Methylation alter?

Answer 20

The expression of genes

Question 21

DNA Methylation occurs as

Answer 21

Cells divide and differentiate from embryonic stem cells to different tissues

Question 22

DNA Methylation is associated with

Answer 22

Genomic imprinting and X-chromosome inactivation

Question 23

How can DNA Methylation affect gene transcription?

Answer 23

• May physically impede the binding of transcriptional proteins to the gene
• Methylated protein may be bound by methyl CpG-binding domain proteins

Question 24

What can methyl CpG-binding domain proteins recruit?

Answer 24

Additional proteins to the locus which modify histones and form heterochromatin