Bio Central Dogma

Question 1

Why is it essential that DNA is able to replicate?

Answer 1

To ensure genetic information is passed on during cell division.

Question 2

What unique structural features of DNA allow it to replicate?

Answer 2

Antiparallel strands and complementary base pairing.

Question 3

What are the key components of a nucleotide?

Answer 3

• Phosphate group
• Deoxyribose sugar
• Nitrogen base (Adenine, Guanine, Cytosine, Thymine)

Question 4

What are the 5’ and 3’ ends in DNA?

Answer 4

5’ end has a phosphate group, 3’ end has a hydroxyl group.

Question 5

What is the antiparallel nature of DNA structure?

Answer 5

One strand runs 5’ to 3’ and the other runs 3’ to 5’.

Question 6

What is the role of helicase in DNA replication?

Answer 6

Unwinds the DNA double helix.

Question 7

What is the role of DNA polymerase in DNA replication?

Answer 7

Synthesizes new DNA strands by adding nucleotides.

Question 8

What is the role of ligase in DNA replication?

Answer 8

Joins Okazaki fragments on the lagging strand.

Question 9

What is the role of primase in DNA replication?

Answer 9

Synthesizes RNA primers to initiate DNA synthesis.

Question 10

What are SSBs in the context of DNA replication?

Answer 10

Single-strand binding proteins that stabilize unwound DNA.

Question 11

How is DNA replication described as semiconservative?

Answer 11

Each new DNA molecule contains one original strand and one new strand.

Question 12

Why does the antiparallel nature of DNA require a leading and lagging strand?

Answer 12

DNA can only be synthesized in the 5’ to 3’ direction.

Question 13

What are Okazaki fragments?

Answer 13

Short segments of DNA synthesized on the lagging strand.

Question 14

What is the connection between RNA and protein?

Answer 14

RNA serves as the intermediary between DNA and protein synthesis.

Question 15

What is the difference between transcription and translation?

Answer 15

Transcription copies DNA into RNA; translation synthesizes proteins from RNA.

Question 16

What two molecule types are constructed during transcription and translation?

Answer 16

RNA during transcription and polypeptides during translation.

Question 17

What impact do mutations have on protein synthesis?

Answer 17

Mutations can alter amino acid sequences and protein function.

Question 18

What are three key differences between RNA and DNA?

Answer 18

• RNA is single-stranded
• RNA contains uracil instead of thymine
• RNA has ribose sugar instead of deoxyribose

Question 19

Define transcription.

Answer 19

The process of synthesizing RNA from a DNA template.

Question 20

Where does transcription take place?

Answer 20

In the nucleus of eukaryotic cells.

Question 21

Define translation.

Answer 21

The process of synthesizing polypeptides from RNA.

Question 22

Where does translation take place?

Answer 22

On ribosomes in the cytoplasm.

Question 23

What is a codon?

Answer 23

A three-nucleotide sequence in mRNA that codes for an amino acid.

Question 24

What does the codon AUG signify?

Answer 24

It is the start codon that codes for methionine.

Question 25

What is a stop codon?

Answer 25

A codon that signals the termination of protein synthesis.

Question 26

Do more than one codon code for each amino acid?

Answer 26

Yes, multiple codons can code for the same amino acid.

Question 27

What is RNA splicing?

Answer 27

The process of removing introns and joining exons in pre-mRNA.

Question 28

What is an anti-codon?

Answer 28

A three-nucleotide sequence on tRNA that pairs with a codon on mRNA.

Question 29

Differentiate between silent, missense, and nonsense mutations.

Answer 29

* Silent mutation: No change in amino acid * Missense mutation: Changes one amino acid * Nonsense mutation: Creates a stop codon prematurely

Question 30

What is a mutagen?

Answer 30

An agent that causes mutations in DNA.

Question 31

What is the significance of the one gene-one enzyme hypothesis?

Answer 31

It suggests that each gene encodes a specific enzyme, but is better termed as one gene-one polypeptide.

Question 32

What is the function of RNA polymerase in transcription?

Answer 32

It synthesizes RNA by adding RNA nucleotides complementary to the DNA template.

Question 33

How does complementary base pairing facilitate DNA replication?

Answer 33

It ensures accurate pairing of nucleotides, guiding synthesis of new strands.

Question 34

What bond holds the two DNA strands together?

Answer 34

Hydrogen bonds between complementary nitrogen bases.

Question 35

What is nucleotide excision repair?

Answer 35

A process where damaged DNA is cut out and replaced.

Question 36

What is the final error rate in DNA replication?

Answer 36

One error per billion nucleotides.

Question 37

What are the three key components of a nucleotide?

Answer 37

Phosphate group, deoxyribose sugar, nitrogenous base (Adenine, Guanine, Cytosine, Thymine).

Question 38

What makes up the backbone of DNA?

Answer 38

The sugar and phosphate groups form the backbone of DNA.

Question 39

What is the shape of DNA, and how do the strands run?

Answer 39

DNA has a double helix shape, and the two strands run antiparallel to each other.

Question 40

How do nitrogenous bases pair in DNA

Answer 40

Adenine (A) pairs with Thymine (T), and Guanine (G) pairs with Cytosine (C).

Question 41

Why is DNA replication considered semi-conservative?

Answer 41

Because each new DNA molecule consists of one original (parent) strand and one newly synthesized strand.

Question 42

What is the role of Helicase in DNA replication?

Answer 42

Helicase unwinds the DNA double helix during replication.

Question 43

What is the function of DNA polymerase in DNA replication?

Answer 43

DNA polymerase adds complementary nucleotides to the growing DNA strand.

Question 44

What is an Okazaki fragment, and why is it important

Answer 44

Okazaki fragments are short DNA segments synthesized on the lagging strand, which are later joined by ligase.

Question 45

Where does transcription occur, and what is its purpose?

Answer 45

Transcription occurs in the nucleus, where a segment of DNA is copied into RNA.

Question 46

What are the steps of transcription?

Answer 46

Initiation (RNA polymerase binds to the promoter), Elongation (RNA polymerase synthesizes RNA), Termination (RNA transcript is released).

Question 47

What is RNA splicing, and what happens during it?

Answer 47

RNA splicing removes introns and joins exons to form a mature mRNA.

Question 48

What is the function of tRNA during translation?

Answer 48

tRNA brings amino acids to the ribosome and matches its anticodon with the codon on mRNA.

Question 49

What is a codon?

Answer 49

A codon is a three-nucleotide sequence on mRNA that codes for a specific amino acid.

Question 50

What is the role of the ribosome during translation?

Answer 50

The ribosome reads mRNA codons and assembles amino acids into a polypeptide chain.

Question 51

What is a mutation in DNA, and how can it affect proteins?

Answer 51

A mutation is a change in the DNA sequence that can affect protein structure and function by altering the amino acid sequence.

Question 52

What is the difference between missense and nonsense mutations?

Answer 52

A missense mutation results in a change in one amino acid, while a nonsense mutation introduces a premature stop codon.

Question 53

What is the central dogma of molecular biology

Answer 53

The central dogma states that information flows from DNA to RNA to protein.

Question 54

What is the significance of the start codon AUG in translation?

Answer 54

The start codon AUG codes for the amino acid methionine and signals the beginning of translation.

Question 55

What is a frameshift mutation?

Answer 55

A frameshift mutation is caused by the insertion or deletion of nucleotides, shifting the reading frame of the codons.

Question 56

What does PCR stand for, and how does it relate to DNA replication

Answer 56

PCR stands for Polymerase Chain Reaction, and it uses DNA polymerase to amplify DNA sequences in vitro, mimicking DNA replication.