Synthesis of DNA, RNA, and Proteins

These flashcards cover key concepts related to the synthesis of DNA, RNA, and proteins, as explained in the lecture notes.

What are the monomers of DNA?

Nucleotides.

What is the Central Dogma of molecular biology?

DNA is transcribed to RNA, which is translated into proteins.

What are the names of the four nitrogenous bases in DNA?

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

What process synthesizes RNA from DNA?

Transcription.

What type of RNA carries the genetic information from DNA to the ribosome?

Messenger RNA (mRNA).

What are the three main types of RNA and their functions?

mRNA (carries genetic information), tRNA (transfers amino acids), rRNA (component of ribosomes).

What is the role of RNA polymerase in transcription?

It binds to the promoter region of DNA and synthesizes RNA.

Define the term 'codon'.

A sequence of three nucleotides on mRNA that codes for a specific amino acid.

What is the purpose of the 5' cap and 3' poly-A tail on mRNA?

They protect mRNA from degradation and assist in its export from the nucleus.

What is translation in the context of protein synthesis?

The process of synthesizing proteins from mRNA by ribosomes.

Why is DNA replication described as semi-conservative?

Each new DNA molecule consists of one old strand and one new strand.

What is the significance of the stop codons in mRNA?

They signal the termination of protein synthesis.

How does base pairing work in DNA replication?

Adenine pairs with Thymine, and Guanine pairs with Cytosine.

Which enzyme is responsible for adding new nucleotides during DNA replication?

DNA polymerase.

What is the difference between transcription and translation?

Transcription is the synthesis of RNA from DNA, while translation is the synthesis of proteins from mRNA.

What role do ribosomes play in translation?

Ribosomes read mRNA sequences and facilitate the assembly of amino acids into polypeptides.

What is the function of tRNA during translation?

tRNA brings the appropriate amino acid to the ribosome according to the codon in the mRNA.

What type of bond forms between amino acids during protein synthesis?

Peptide bonds.

Define ‘exon’ and ‘intron’.

Exons are coding regions of a gene, while introns are non-coding regions that are removed from pre-mRNA during splicing.

What is the purpose of post-transcriptional processing?

To convert the primary RNA transcript into a mature mRNA by adding a cap, tail, and splicing.

What can you infer about the genetic code based on its universality?

It suggests that all living organisms share a common evolutionary ancestor.

What is the role of ribonucleic acid (RNA) in cells?

RNA plays crucial roles in coding, decoding, regulation, and expression of genes.

What is the difference between a nucleotide and a nucleoside?

A nucleotide consists of a sugar, a phosphate group, and a nitrogenous base, while a nucleoside consists only of the sugar and the nitrogenous base.

What are the three stages of transcription?

Initiation, elongation, and termination.

What is the function of the promoter region in DNA?

The promoter region is the site where RNA polymerase binds to initiate transcription.

What are ribozymes?

Ribozymes are RNA molecules that can catalyze chemical reactions, similar to protein enzymes.

What is DNA replication and when does it occur?

DNA replication is the process of copying the DNA molecule, occurring during the S phase of the cell cycle before cell division.

What is the function of helicase in DNA replication?

Helicase unwinds the DNA double helix, separating the two strands to allow replication to occur.

What are the leading and lagging strands in DNA replication?

The leading strand is synthesized continuously in the direction of the replication fork, while the lagging strand is synthesized in short segments away from the fork.

What is the role of ligase in DNA replication?

Ligase joins Okazaki fragments on the lagging strand, sealing the gaps between them.

What is the significance of telomeres?

Telomeres are repetitive nucleotide sequences at the ends of chromosomes that protect them from deterioration and prevent loss of important DNA during replication.

What are the major differences between prokaryotic and eukaryotic DNA replication?

Prokaryotic DNA replication occurs in the cytoplasm and is usually circular, while eukaryotic replication occurs in the nucleus, involving linear chromosomes and multiple origins of replication.

What role do origins of replication play in DNA replication?

Origins of replication are specific sequences in DNA where replication begins, allowing for multiple sites of duplication.

What are histones and how do they relate to DNA?

Histones are proteins around which DNA winds, forming nucleosomes that help package DNA into a compact structure within