Nucleotides+ Nucleic Acids

Question 1

What does a nucleotide consist of

Answer 1

Pentose sugar, base, phosphate group

Question 2

What is the pentose sugar in DNA called

Answer 2

Deoxyribose

Question 3

What is the pentose sugar in RNA called

Answer 3

Ribose

Question 4

Bases in DNA

Answer 4

Adenine, thymine, cytosine, guanine

Question 5

What is a purine

Answer 5

Double ring structure eg A G

Question 6

What is a pyrimidine

Answer 6

Single ring structure eg C T

Question 7

bases in RNA

Answer 7

Adenine guanine cytosine uricil

Question 8

What is the bond between two nucleotides

Answer 8

Phosphodiester bonds

Question 9

How is a polynucleotide formed

Answer 9

Bond formed between phosphate group of one nucleotide and hydroxyl group on carbon 3 of the pentose sugar

Question 10

What are enzymes?

Answer 10

Enzymes are biological catalysts that speed up chemical reactions by lowering the activation energy required for the reaction to proceed.

Question 11

What is enzyme specificity?

Answer 11

Enzyme specificity refers to the ability of an enzyme to catalyze only one specific reaction or a group of similar reactions.

Question 12

What are the lock-and-key and induced fit models?

Answer 12

Lock-and-key model: The active site of the enzyme is an exact match for the substrate.
Induced fit model: The enzyme’s active site changes shape slightly to accommodate the substrate more effectively.

Question 13

How do enzymes lower activation energy?

Answer 13

Enzymes lower activation energy by stabilizing the transition state, reducing the energy required for bonds to break and reform.

Question 14

How do temperature, pH, and substrate concentration affect enzyme activity?

Answer 14

Temperature: Increasing temperature increases kinetic energy, leading to more frequent enzyme-substrate collisions.

pH: Each enzyme has an optimum pH; deviation disrupts bonds and reduces activity.

Substrate concentration: Increasing substrate concentration increases the rate of reaction up to a saturation point.

Question 15

What is enzyme saturation?

Answer 15

Enzyme saturation occurs when all active sites of the enzyme molecules are occupied by substrates.

Question 16

How do inhibitors work (competitive vs non-competitive)?

Answer 16

Competitive inhibitors compete for the active site, reducing enzyme activity.
Non-competitive inhibitors bind to an allosteric site, changing the enzyme’s shape.

Question 17

What are cofactors, coenzymes, and prosthetic groups?

Answer 17

Cofactors: Non-protein molecules or ions that assist enzyme activity.
Coenzymes: Organic cofactors that temporarily bind to the enzyme.
Prosthetic groups: Permanently attached cofactors that are part of the enzyme’s structure.

Question 18

What is the effect of denaturation on enzymes?

Answer 18

Denaturation disrupts the enzyme’s tertiary structure, causing the active site to change shape and resulting in a loss of catalytic activity.