MODULE C1: Genes and Chromosomes: Management and Expression of Genetic Information

These flashcards cover the key concepts regarding genes, chromosomes, and the management of genetic information, as discussed in the lecture.

What is the key concept behind the Central Dogma of Molecular Biology?

Information flows from DNA to RNA to protein.

Who proposed the Central Dogma and when?

Francis Crick proposed the Central Dogma in 1956.

What does DNA replication accomplish?

DNA replication copies parental DNA to daughter DNA with high fidelity.

How is RNA synthesized during transcription?

RNA is synthesized using DNA as a template.

How is genetic information transferred from RNA to protein?

Proteins are synthesized based on information stored in ribonucleotide triplets in RNA.

Describe the typical organization of eukaryotic DNA.

Eukaryotic DNA is organized into multiple chromosomes and associated with proteins to form chromatin.

What is a chromosome composed of?

A chromosome consists of one covalently connected DNA molecule and associated proteins.

How many chromosomes do humans typically have?

Humans typically have 46 chromosomes.

What role do telomeres play in chromosomes?

Telomeres cap the ends of linear chromosomes and are necessary for successful cell division.

What happens to telomeres during cellular replication?

Telomeres shorten after each round of replication, leading to cellular aging.

What is the significance of introns in eukaryotic genes?

Introns do not encode for polypeptide sequences and are removed during mRNA processing.

How do topoisomerases function?

Topoisomerases change the linking number of DNA, aiding in unwinding and rewinding during transcription and replication.

What is the effect of supercoiling on DNA?

Supercoiling organizes DNA to allow compact storage and access for protein interactions.

What percentage of the human genome encodes for proteins?

Only about 1.5% of the human genome encodes for proteins.

Why is the correlation between genome size and organism complexity weak?

Most eukaryotic DNA is non-coding, which does not correlate with perceived biological complexity.

What is the role of messenger RNA (mRNA) in protein synthesis?\n\n

mRNA carries genetic information from the nucleus to the ribosome for protein synthesis.\n\n

What is transcription?\n\n

Transcription is the process of synthesizing RNA from a DNA template.\n\n

What is translation in the context of molecular biology?\n\n

Translation is the process by which ribosomes synthesize proteins using mRNA as a template.\n\n

What are ribosomes made of?\n\n

Ribosomes are composed of ribosomal RNA (rRNA) and proteins.\n\n

What is the function of transfer RNA (tRNA)?\n\n

tRNA transports specific amino acids to the ribosome during protein synthesis.\n\n

Explain the significance of codons.\n\n

Codons are triplets of nucleotides in mRNA that specify particular amino acids during translation.\n\n

What is a mutation?\n\n

A mutation is a change in the DNA sequence that can affect protein synthesis and function.\n\n

How do mutations affect proteins?\n\n

Mutations can lead to changes in amino acid sequences, potentially altering protein function or stability.\n\n

What are exons and introns?\n\n

Exons are coding sequences in RNA that remain after splicing, while introns are non-coding sequences removed during mRNA processing.\n\n

What process do ribosomes perform during translation?\n\n

Ribosomes facilitate the assembly of amino acids into polypeptides by reading the mRNA sequence and utilizing tRNA.\n\n

What is genetic code?\n\n

The genetic code is a set of rules by which information encoded in mRNA is translated into proteins, consisting of codons that represent specific amino acids.\n\n

What are the main types of RNA involved in protein synthesis?\n\n

The main types of RNA are messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA), each playing specific roles in the process.\n\n

How does the ribosome know when to start translation?\n\n

Translation begins at a specific start codon (AUG) on the mRNA, which signals the ribosome to assemble and begin protein synthesis.\n\n

What is the significance of the AUG codon?\n\n

The AUG codon is the start codon that not only signals the beginning of translation but also codes for the amino acid methionine.\n\n

What is the difference between synonymous and nonsynonymous mutations?\n\n

Synonymous mutations do not change the amino acid sequence, while nonsynonymous mutations result in a change to the amino acid sequence in a protein.\n\n

What is RNA splicing?\n\n

RNA splicing is the process of removing introns from pre-mRNA and joining exons together to form mature mRNA.\n\n

What are ribozymes?\n\n

Ribozymes are RNA molecules that can catalyze biochemical reactions, including those involved in RNA splicing.\n\n

What are the roles of chaperone proteins?\n\n

Chaperone proteins assist in the folding and assembly of polypeptides into functional proteins, helping to prevent misfolding.\n\n

What determines the specificity of tRNA?\n\n

The specificity of tRNA is determined by its anticodon, which pairs with the corresponding codon on mRNA during translation.\n\n

What is the role of aminoacyl-tRNA synthetase?\n\n

Aminoacyl-tRNA synthetase is an enzyme that attaches the appropriate amino acid to its corresponding tRNA, ensuring accuracy in protein synthesis.\n\n

What is the function of RNA polymerase?\n\n

RNA polymerase is the enzyme responsible for synthesizing RNA from a DNA template during transcription.\n\n

What are processing events that occur to mRNA before it is ready for translation?\n\n

Processing events include 5' capping, addition of a poly-A tail, and splicing out of introns.\n\n

What is the purpose of the 5' cap on mRNA?\n\n

The 5' cap protects mRNA from degradation and helps in ribosome binding during translation.\n\n

What does the poly-A tail do for mRNA?\n\n

The poly-A tail aids in the stability and export of mRNA from the nucleus to the cytoplasm.\n\n

What is the genetic code's redundancy?\n\n

The genetic code's redundancy means that multiple codons can code for the same amino acid, providing a buffer against mutations.\n\n

How do introns affect gene expression?\n\n

Introns can play roles in regulating gene expression and alternative splicing, which generates varied mRNA products.\n\n

What is the role of siRNA in the cell?\n\n

siRNA (small interfering RNA) is involved in RNA interference, regulating gene expression by degrading mRNA transcripts.\n\n

What are the characteristics of prokaryotic transcription?\n\n

Prokaryotic transcription occurs in the cytoplasm, lacks a nucleus, and does not involve extensive RNA processing.\n\n

How do eukaryotic and prokaryotic ribosomes differ?\n\n

Eukaryotic ribosomes are larger (80S) and more complex than prokaryotic ribosomes (70S).\n\n

What is the significance of the Shine-Dalgarno sequence?\n\n

The Shine-Dalgarno sequence is a ribosomal binding site in prokaryotic mRNA, crucial for the initiation of translation.\n\n

What is the function of the promoter in gene expression?\n\n

The promoter is a region of DNA where RNA polymerase binds to initiate transcription of a gene.\n\n

What is the difference between prokaryotic and eukaryotic gene expression?\n\n

Prokaryotic gene expression occurs in the cytoplasm without introns, while eukaryotic gene expression involves extensive RNA processing and occurs in the nucleus.\n\n

What role do transcription factors play in gene expression?\n\n

Transcription factors are proteins that bind to specific DNA sequences to regulate the transcription of target genes.\n\n

How is gene silencing achieved?\n\n

Gene silencing is achieved through mechanisms like RNA interference (RNAi) and the methylation of DNA, which inhibit gene expression.\n\n

What is the role of the 3' untranslated region (3' UTR) in mRNA?\n\n

The 3' UTR is involved in the regulation of mRNA stability, localization, and translation efficiency.\n\n

What are enhancers in gene regulation?\n\n

Enhancers are DNA sequences that increase the likelihood of transcription of a particular gene by binding transcription factors.\n\n

What is the role of RNA editing in gene expression?\n\n

RNA editing is a post-transcriptional process that alters RNA molecules, potentially affecting protein coding and expression.\n\n

What is the significance of alternative splicing?\n\n

Alternative splicing allows a single gene to produce multiple protein isoforms, increasing protein diversity and function.\n\n

How does the ribosome ensure accurate translation?\n\n

The ribosome ensures accurate translation by pairing tRNA anticodons with mRNA codons, verifying correct matches based on codon sequence.\n\n

What are terminators in transcription?\n\n

Terminators are sequences in DNA that signal RNA polymerase to stop transcription, leading to the release of the newly synthesized RNA.\n\n