Protein Synthesis and Techniques Review

Flashcards created for reviewing key concepts related to protein synthesis, genetic code, techniques in molecular biology, and associated terminologies.

What is the central dogma of molecular biology?

The flow of genetic information from DNA to RNA to protein.

What is transcription?

The process of synthesizing RNA from a DNA template.

What is translation?

The process of synthesizing proteins from mRNA.

What is mRNA?

Messenger RNA, which carries the genetic information from DNA to the ribosome.

What role does tRNA play in protein synthesis?

Transfer RNA serves as an adapter that binds specific amino acids and recognizes the corresponding codon on mRNA.

What is a codon?

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

What is the significance of AUG in translation?

AUG is the start codon that initiates protein synthesis and codes for methionine.

What are stop codons?

Codons that signal the termination of translation.

What is a missense mutation?

A mutation that results in a different amino acid being incorporated into a protein.

What is a nonsense mutation?

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

What are frameshift mutations?

Mutations caused by insertions or deletions of nucleotides, altering the reading frame of the gene.

What is polysome?

A complex of multiple ribosomes translating a single mRNA simultaneously.

What is the role of ribosomal RNA (rRNA)?

Ribosomal RNA forms the core of ribosome's structure and catalyzes peptide bond formation.

How do antibiotics affect protein synthesis?

Antibiotics can inhibit various steps of protein synthesis, affecting bacterial ribosomes.

What is the function of aminoacyl-tRNA synthetases?

They attach the appropriate amino acid to its corresponding tRNA.

What is the wobble hypothesis?

The idea that the third base of a codon can be flexible, allowing fewer tRNAs to pair with multiple codons.

What is post-translational modification?

Chemical changes to a protein after translation that can affect its function and activity.

What is the purpose of the genetic code?

To specify which amino acids will be incorporated into a protein based on the sequence of nucleotides.

What is a silent mutation?

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

What are initiation factors?

Proteins that assist in the initiation of translation by facilitating the assembly of the ribosome.

What is the function of GTP in protein synthesis?

GTP provides energy for the initiation, elongation, and termination phases of protein synthesis.

What are the components of the translation machinery?

Ribosomes, mRNA, tRNA, amino acids, and various initiation, elongation, and termination factors.

How does the structure of prokaryotic ribosomes differ from eukaryotic ribosomes?

Prokaryotic ribosomes are smaller (70S) while eukaryotic ribosomes are larger (80S).

What is gene therapy?

A technique that modifies a person's genes to treat or prevent disease.

What is CRISPR-Cas9?

A genome editing tool that uses a guide RNA to identify a specific DNA sequence for modification.

What is the function of restriction enzymes in molecular biology?

To cut DNA at specific sequences, allowing for cloning and analysis of DNA fragments.

What is the significance of polypeptide folding?

Proper folding is crucial for protein function and activity.

What are the four levels of protein structure?

Primary, secondary, tertiary, and quaternary structures.

What are stem cells?

Cells that can divide and differentiate into various types of specialized cells.

What is the significance of the Shine-Dalgarno sequence?

It is a ribosome-binding site on mRNA in prokaryotes that helps initiate translation.

What role do chaperone proteins play?

They assist in the proper folding of proteins.

What is the fate of the N-terminal methionine in proteins?

It is often removed during post-translational modification.

What is the role of the P-site in the ribosome?

It holds the tRNA carrying the growing polypeptide chain during translation.

What are eukaryotic transcription factors?

Proteins that help regulate the transcription of specific genes by binding to nearby DNA.

What is Southern blotting?

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

What is Northern blotting?

A technique used to study gene expression by detecting specific RNA molecules.

What is Western blotting?

A method to detect specific proteins in a sample.

How do gel electrophoresis techniques work?

They separate nucleic acids or proteins based on size and charge.

What is the purpose of a genomic library?

To store a complete collection of an organism's DNA for research purposes.

What is a cDNA library?

A collection of complementary DNA (cDNA) cloned into vectors.

What is the function of the poly(A) tail in mRNA?

It enhances the stability and translation efficiency of mRNA.

What is reverse transcription?

The process of converting RNA into DNA.

How are proteins usually detected in Western blots?

Using specific antibodies that bind to the target protein.

What defines prokaryotic cells?

They lack a nucleus and have a simpler cell structure.

What are the roles of glycosylation in proteins?

It affects protein folding, stability, and cell signaling.

What is the significance of the poly-A tail in eukaryotic mRNA?

It protects mRNA from degradation and facilitates export from the nucleus.

What is the use of antibodies in protein analysis?

Antibodies are used to detect and quantify specific proteins.

What is polymerase chain reaction (PCR)?

A technique used to amplify specific DNA sequences.

What is the impact of mutations on protein function?

Mutations can alter protein structure and function, potentially causing diseases.

What is the purpose of the initiation complex in translation?

It assembles the ribosome on mRNA and positions the first tRNA.

What is the significance of tRNA's cloverleaf structure?

It allows tRNA to properly recognize and bind to codons in mRNA.

What is peptide bond formation?

The chemical bond that links amino acids together in a protein.

How does GTP hydrolysis contribute to protein synthesis?

It provides the energy required for the elongation and termination phases.

What is transcription initiation?

The stage where RNA polymerase binds to the promoter region of a gene.

What are transfer RNAs (tRNAs)?

Molecules that carry amino acids to the ribosome for protein synthesis.

What distinguishes eukaryotic from prokaryotic gene expression?

Eukaryotic gene expression is compartmentalized; transcription occurs in the nucleus and translation in the cytoplasm.

What is the primary function of ribosomes?

To facilitate the translation of mRNA into a polypeptide chain.

What is the mechanism of action of Diphtheria toxin?

It inhibits protein synthesis by modifying elongation factors.

What is a transgenic organism?

An organism that has been genetically altered to contain a gene from another species.

What kind of modifications can occur during the post-translational modification of proteins?

Phosphorylation, glycosylation, ubiquitination, etc.

What is the role of molecular chaperones?

They assist in the correct folding and assembly of proteins.

What is an operon?

A group of genes regulated together that are transcribed as a single mRNA.

What is a transposable element?

A DNA sequence that can change its position within the genome.

What is the role of ribozymes?

RNA molecules that can catalyze specific biochemical reactions.

What are the key principles of genetic code?

It is universal, degenerate, and non-overlapping.

What is the role of the A-site in the ribosome?

It is the site where the incoming aminoacyl-tRNA binds during translation.

How does the environment influence protein folding?

Proteins fold with the help of chaperones and the surrounding chemical environment.

What is gene knockout technology?

A genetic technique used to inactivate a specific gene to study its effects.

What are the implications of CRISPR technology?

It allows for precise editing of genomic sequences and holds potential for gene therapy.

What is the overall yield of ATP from protein synthesis?

Approximately 1200 NTPs are hydrolyzed per average protein synthesized.

What are the different types of stem cells?

Embryonic stem cells, adult stem cells, and induced pluripotent stem cells.

What is the function of the 5' cap in eukaryotic mRNA?

It protects mRNA from degradation and facilitates ribosome binding.

What is the purpose of the polyadenylation signal in eukaryotic genes?

It signals the addition of the poly(A) tail to the mRNA after transcription.

What is the effect of frameshift mutations on proteins?

Frameshift mutations can drastically alter the protein's amino acid sequence and function.

What distinguishes a benign from a malignant tumor regarding gene mutations?

Malignant tumors often have multiple mutations that drive uncontrolled growth.