Gene Expression

Question 1

What are DNA and RNA composed of?

Answer 1

Linear polymers of nucleotides linked by phosphodiester bonds.

Question 2

What is the primary structure of nucleotides?

Answer 2

A phosphate group linked by a phosphoester bond to a pentose sugar, which is linked to a nitrogenous base.

Question 3

Which bases are purines?

Answer 3

Adenine and Guanine.

Question 4

Which bases are pyrimidines?

Answer 4

Cytosine, Thymine (in DNA), and Uracil (in RNA).

Question 5

What is the structural difference between DNA and RNA sugars?

Answer 5

DNA contains deoxyribose (without an -OH group on the 2’ carbon); RNA contains ribose (with an -OH group on the 2’ carbon).

Question 6

What is Chargaff’s rule regarding DNA base pairing?

Answer 6

A pairs with T, and G pairs with C. The number of purines equals the number of pyrimidines.

Question 7

What is the structure of DNA as described by Watson and Crick?

Answer 7

DNA is a double helix with two antiparallel strands held together by hydrogen bonds between complementary bases.

Question 8

What are the types of chromatin in eukaryotic cells?

Answer 8

Heterochromatin (compact, transcriptionally inactive) and Euchromatin (less compact, transcriptionally active).

Question 9

What is the function of telomeres?

Answer 9

Telomeres prevent chromosome degradation, maintain stability, and play a role in aging.

Question 10

What are nucleosomes and their role in DNA packaging?

Answer 10

Nucleosomes are DNA wrapped around histone proteins, aiding in DNA condensation and regulation.