Protein Synthesis and Techniques Review

This set of flashcards is designed to help students review key concepts, terms, and processes related to protein synthesis and molecular biology techniques in preparation for exams.

What is the central dogma of molecular biology?

It describes the flow of genetic information from DNA to RNA to proteins.

What are the three types of RNA involved in protein synthesis?

mRNA (messenger RNA), tRNA (transfer RNA), and rRNA (ribosomal RNA).

What does transcription refer to in molecular biology?

The process of copying a segment of DNA into RNA.

What is the genetic code?

A set of rules that determines how the sequence of nucleotides in DNA is translated into the sequence of amino acids in proteins.

What is a codon?

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

Define missense mutation.

A mutation that changes one amino acid in a protein sequence.

Define nonsense mutation.

A mutation that creates a premature stop codon, truncating the protein.

What is a frameshift mutation?

A mutation caused by insertions or deletions, shifting the reading frame of codons.

What is polysome?

A complex of several ribosomes translating a single mRNA simultaneously.

What role does the ribosome play in protein synthesis?

It serves as the site where mRNA is translated into a polypeptide chain.

What are initiation factors?

Proteins that help initiate the process of translation.

What is the significance of the Shine-Dalgarno sequence?

It is a ribosomal binding site in bacterial mRNA that helps initiate translation.

What is post-translational modification?

The chemical modification of a protein after it has been synthesized.

How does tRNA function in translation?

tRNA carries specific amino acids to the ribosome and pairs its anticodon with the corresponding codon on mRNA.

What is the importance of the AUG codon?

It is the start codon that signals the beginning of protein synthesis.

Describe the role of aminoacyl-tRNA synthetase.

It attaches the correct amino acid to its corresponding tRNA, ensuring accurate protein synthesis.

What does the term 'wobble pairing' refer to?

It describes the flexibility in base pairing at the third position of a codon, allowing for more than one codon to code for the same amino acid.

What is the purpose of gel electrophoresis?

To separate nucleic acids or proteins based on their size and charge.

Define Southern blotting.

A technique used to detect specific DNA sequences in DNA samples.

Define Northern blotting.

A technique used to detect specific RNA sequences in a sample.

Define Western blotting.

A method used to detect specific proteins in a sample using antibodies.

What is CRISPR-Cas9?

A revolutionary genome-editing technology that allows for precise modifications to DNA.

What is the function of restriction enzymes?

They cut DNA at specific sequences, allowing for DNA fragmentation and recombination.

What is the role of the ribosome's E, P, and A sites?

The E site is for exiting tRNA, the P site holds the growing polypeptide, and the A site is where new tRNA enters.

What is the primary energy source for translation?

GTP (Guanosine Triphosphate) is the main energy currency used.

What is the result of a silent mutation?

A mutation that does not change the amino acid sequence of a protein.

Describe the concept of 'degenerate code' in genetics.

The genetic code is degenerative because multiple codons can encode the same amino acid.

What role does ATP play in protein synthesis?

ATP provides energy for the activation of amino acids and the initiation of translation.

What is the role of release factors in translation?

Release factors recognize stop codons and promote the release of the synthesized polypeptide from the ribosome.

What types of structural modifications occur in proteins after translation?

Common modifications include phosphorylation, glycosylation, and ubiquitination.

How does the ribosome achieve peptide bond formation?

The ribosomal RNA catalyzes the peptidyl transferase reaction.

What are the basic steps of translation?

Initiation, elongation, and termination.

What is gene therapy?

A technique that uses genes to treat or prevent disease.

Define the Sickle Cell Disease mutation.

A single nucleotide substitution in the HBB gene that causes a change from Glu (GAG) to Val (GUG), leading to sickle-shaped red blood cells.

What is the significance of eIFs in eukaryotic translation?

They are initiation factors essential for starting translation in eukaryotes.

What does a cDNA library contain?

cDNA libraries contain complementary DNA generated from mRNA, reflecting the expressed genes of a cell.

What is the function of the poly-A tail in mRNA?

It stabilizes mRNA and facilitates its export from the nucleus and translation efficiency.

What is the significance of the 5' cap on mRNA?

It protects mRNA from degradation and assists in ribosome binding during translation.

How are disulfide bonds formed in proteins?

They are formed between cysteine residues, stabilizing protein structure.

What is mass spectrometry used for in molecular biology?

It measures the mass-to-charge ratio of ions to identify and quantify proteins.

What is the purpose of DNA hybridization?

To identify specific DNA sequences by base pairing with complementary probes.

What is the wobble hypothesis, and how does it relate to tRNA?

It explains how tRNA can recognize more than one codon due to flexible pairing at the third base.

What is the function of the Translational Control Mechanisms?

To regulate the rate and efficiency of protein synthesis.

How does the heme synthesis process relate to RBC maturation?

Heme is synthesized in the liver and is essential for red blood cell function and maturation.

What are transgenic animals?

Animals that have had genes from other species inserted into their genomes.

What is the importance of insulin's structure?

Insulin consists of two polypeptide chains that regulate blood sugar levels.

What challenges are introduced by working with RNA instead of DNA?

RNA is more unstable and cannot be directly manipulated with restriction enzymes as DNA can.

How can CRISPR technology treat genetic diseases?

By specifically editing or correcting mutations in the DNA.

What are the functions of different amino acids in proteins?

Amino acids determine protein structure and function based on their properties.

What is the role of ribosomal RNA (rRNA) in the ribosome?

It forms the core of the ribosome's structure and catalyzes protein synthesis.

What is the outcome of antibiotic inhibition on prokaryotic translation?

It prevents bacteria from synthesizing proteins, effectively stopping their growth.

How does recruitment of proteins to the ribosome occur during translation initiation?

Initiation factors help assemble ribosomal subunits, mRNA, and the first tRNA at the start codon.

What is the function of the D loop in tRNA?

It is involved in the recognition of correct aminoacyl-tRNA synthetases.

What does the term gene expression refer to?

The process by which information from a gene is used to synthesize a functional gene product, often a protein.

What is the result of a mutation that affects the promoter region of a gene?

It can lead to reduced transcription and thus lower levels of the gene product.

What types of post-translational modifications are possible?

Modifications include methylation, phosphorylation, glycosylation, and ubiquitination.

What is the importance of the 3' end of mRNA?

It plays a role in the polyadenylation process and regulation of mRNA stability.

Describe the main difference between prokaryotic and eukaryotic ribosomes.

Prokaryotic ribosomes are smaller (70S) compared to eukaryotic ribosomes (80S).

What is the significance of codon-anticodon pairing during translation?

It ensures the correct incorporation of amino acids into the growing polypeptide chain.

How do mutations affect protein function?

Mutations can alter amino acid sequences, impacting protein folding and function.

What techniques are used in proteomics?

Techniques include mass spectrometry, protein microarrays, and two-dimensional gel electrophoresis.

What is the purpose of an initiation codon?

It signals the start of translation and specifies the first amino acid in the protein.

What are the characteristics of hydrophilic amino acids?

They are typically polar or charged and interact favorably with water.

Define hydrophobic amino acids.

Amino acids with non-polar side chains, often found in the interior of proteins.

What does 'gene expression regulation' entail?

The mechanisms that cells use to increase or decrease the production of specific proteins.