Eukaryotes regulation

Question 1

Why is DNA compacted in eukaryotic cells?

Answer 1

To prevent tangling and store genetic information efficiently.

Question 2

How much DNA is in each human cell?

Answer 2

Approximately 2 meters.

Question 3

What proteins help in DNA packaging?

Answer 3

Histone proteins.

Question 4

What is a nucleosome?

Answer 4

The basic unit of DNA packaging.

Question 5

How are nucleosomes formed?

Answer 5

By wrapping DNA around histone proteins.

Question 6

What happens to nucleosomes after their formation?

Answer 6

They are compacted into higher-order structures.

Question 7

Are chromosomes randomly arranged in the nucleus?

Answer 7

No, they are arranged in specific patterns.

Question 8

Which chromosomes form a cluster in mouse lymphocytes?

Answer 8

Chromosomes 12, 14, and 15.

Question 9

Why is chromosome organization important?

Answer 9

It is crucial for gene regulation.

Question 10

What are epigenetic mechanisms?

Answer 10

Chemical changes in chromatin affecting DNA accessibility.

Question 11

How do epigenetic mechanisms control gene expression?

Answer 11

By altering nucleosome spacing and chromatin structure.

Question 12

Name a common type of epigenetic modification.

Answer 12

DNA methylation.

Question 13

What is DNA methylation?

Answer 13

Addition of a methyl group to cytosine residues in CpG sites.

Question 14

How does DNA methylation affect gene expression?

Answer 14

It represses gene expression by increasing DNA packaging.

Question 15

What is histone acetylation?

Answer 15

Addition of acetyl groups to histones.

Question 16

How does histone acetylation affect gene expression?

Answer 16

It activates gene expression by opening DNA fibers.

Question 17

What are miRNAs?

Answer 17

Small RNA molecules that bind to mRNAs to regulate gene expression.

Question 18

How do miRNAs affect gene expression?

Answer 18

They negatively control gene expression.

Question 19

What are lncRNAs?

Answer 19

Long non-coding RNAs that regulate gene expression.

Question 20

At what levels do lncRNAs regulate gene expression?

Answer 20

Transcriptional and post-transcriptional levels.

Question 21

What are ribozymes?

Answer 21

RNA molecules with catalytic activity.

Question 22

How can ribozymes regulate gene expression?

Answer 22

By targeting specific mRNAs to reduce their levels.

Question 23

Provide an example of a ribozyme’s therapeutic application.

Answer 23

A ribozyme targeting βS mRNA reduces βS mRNA levels in sickle cell anemia.

Question 24

What affects DNA accessibility in chromatin?

Answer 24

Nucleosome spacing and epigenetic modifications.

Question 25

What does chromatin structure determine?

Answer 25

Whether a gene is accessible for transcription.

Question 26

What happens when DNA is tightly packed?

Answer 26

Gene expression is repressed.

Question 27

What happens when DNA fibers are open?

Answer 27

Gene expression is activated.

Question 28

What is the role of regulatory RNAs in gene regulation?

Answer 28

They influence gene expression through interactions with DNA and RNA.

Question 29

Why is packaging DNA efficiently necessary?

Answer 29

To fit 2 meters of DNA into a cell nucleus and regulate gene activity.

Question 30

How does the nucleus ensure efficient storage?

Answer 30

By organizing chromosomes and modifying chromatin.