DNA and Protein Synthesis

What is the role of helicase in DNA replication?

Helicase unwinds the double-stranded DNA by breaking hydrogen bonds.

What does DNA Polymerase III do during DNA replication?

DNA Polymerase III extends RNA primers to form new strands of DNA.

What is the difference between leading strand and lagging strand synthesis?

Leading strand synthesis is continuous toward the fork, while lagging strand synthesis is discontinuous, forming Okazaki fragments.

What are Okazaki fragments?

Short segments of DNA synthesized on the lagging strand during DNA replication.

What is the function of primase in DNA replication?

Primase synthesizes a short RNA primer that provides a 3′-OH group for DNA polymerase to extend.

What is the significance of the origin of replication?

It is the specific DNA sequence where replication begins.

How does DNA polymerase I function in the replication process?

DNA polymerase I removes RNA primers and replaces them with DNA nucleotides.

What is the role of ligase in DNA replication?

Ligase seals adjacent DNA fragments by forming phosphodiester bonds.

What is transcription in the context of protein synthesis?

Transcription is the process of converting DNA sequence into an mRNA sequence.

What enzyme is responsible for synthesizing mRNA during transcription?

RNA polymerase reads the DNA and synthesizes mRNA.

What is alternative splicing?

Alternative splicing allows one gene to code for multiple proteins by combining different exons.

What is the role of tRNA in translation?

tRNA brings amino acids to the ribosome and has anticodons that are complementary to mRNA codons.

What happens when a stop codon is reached during translation?

No tRNA binds; a release factor binds instead, causing the ribosome and mRNA to disassemble and the new protein to be released.

What are point mutations?

Point mutations occur when only one base pair is changed in the DNA sequence.

What are the types of point mutations?

Substitution, silent, missense, and nonsense mutations.

What is a frameshift mutation?

A frameshift mutation occurs when a base is inserted or deleted, shifting the reading frame of the genetic code.

What are the potential effects of frameshift mutations?

Frameshift mutations can lead to missense or nonsense outcomes, as the entire amino acid sequence can be read incorrectly.

What is the importance of the G-cap in mRNA?

The G-cap protects mRNA from degradation and helps ribosomes recognize and bind to it.

What does the term 'stop codon' refer to?

Stop codons (UAA, UAG, UGA) signal the end of protein synthesis during translation.