Lecture Notes on Protein Synthesis and Techniques in Molecular Biology

These flashcards cover essential concepts in protein synthesis and molecular biology techniques, based on the comprehensive lecture notes.

What is the central dogma of molecular biology?

DNA is transcribed to RNA, which is then translated into protein.

What are the key components of protein synthesis?

Ribosomes, mRNA, tRNA, amino acids, and various factors.

What does mRNA stand for?

Messenger RNA.

What is the function of tRNA?

Transfer RNA transfers amino acids to the ribosome during protein synthesis.

What is the role of ribosomes in translation?

Ribosomes facilitate the decoding of mRNA into a polypeptide chain.

What is meant by the 'wobble hypothesis'?

The third base of a codon can mutate without affecting the amino acid it codes for.

Define missense mutation.

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

Define nonsense mutation.

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

Which amino acid is represented by the codon AUG?

Methionine, which is also the start codon.

What is a polysome?

A complex of multiple ribosomes translating the same mRNA strand.

What is the significance of stop codons?

They signal the termination of translation.

How are proteins post-translationally modified?

Through processes such as phosphorylation, glycosylation, and methylation.

What are the two types of ribosomes found in cells?

Prokaryotic and eukaryotic ribosomes.

What does PCR stand for?

Polymerase Chain Reaction.

What is the purpose of gel electrophoresis?

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

What is the function of restriction enzymes?

To cut DNA at specific sequences.

Define cloning in molecular biology.

The process of creating identical copies of a DNA fragment.

What is the difference between Southern, Northern, and Western blotting?

Southern blots detect DNA, Northern blots detect RNA, and Western blots detect proteins.

What is CRISPR-Cas9 used for?

Genome editing.

What is the genetic code?

A set of rules by which information encoded in DNA is translated into proteins.

What is a codon?

A sequence of three nucleotides that represents an amino acid.

Explain the term 'degenerate code' in genetics.

More than one codon can code for the same amino acid.

What is the role of aminoacyl-tRNA synthetases?

To attach the correct amino acid to its corresponding tRNA.

Define frameshift mutation.

A mutation caused by insertions or deletions of nucleotides, altering the reading frame.

What is the first step in protein synthesis?

Initiation, where the ribosome assembles around the start codon.

List the primary types of RNA involved in protein synthesis.

mRNA, tRNA, and rRNA.

How do antibiotics affect protein synthesis?

They inhibit various steps of translation or transcription.

What are codon-anticodon interactions?

Base-pairing between the codon on mRNA and the anticodon on tRNA.

What does the term 'post-translational modification' refer to?

Changes made to a protein after it has been synthesized.

How many amino acids are encoded by the genetic code?

20 standard amino acids.

What are initiation factors (IFs)?

Proteins that assist in the assembly of the ribosome during the initiation of translation.

What does GTP hydrolysis do during translation?

Provides the energy needed for various steps, including elongation.

Define 'ribozyme.'

An RNA molecule capable of catalyzing biochemical reactions.

Describe the function of release factors (RFs).

Proteins that trigger termination of translation by recognizing stop codons.

What is the significance of the AUG codon?

It is the start codon, signaling the beginning of protein synthesis.

What nutrient deficiencies are proteins responsible for supplying?

Essential amino acids, vitamins, and minerals.

What is a genetic mutation?

A change in the DNA sequence that can affect protein function.

What are the key components required for translation in prokaryotes?

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

What effect do silent mutations have?

They do not change the amino acid sequence of a protein.

What is the purpose of the Shine-Dalgarno sequence?

To help the ribosome identify the start site for translation in prokaryotes.

Define energy metabolism in relation to protein synthesis.

The energy expended during protein synthesis using ATP and GTP.

What role does messenger RNA (mRNA) play?

Carries the genetic information from DNA to the ribosome for protein synthesis.

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

To protect mRNA from degradation and assist in translation.

What is gene therapy?

A technique that modifies a person's genes to treat diseases.

What is the genetic basis for sickle cell anemia?

A mutation in the beta-globin gene causing the substitution of valine for glutamic acid.

Define transgenic organisms.

Organisms that have been genetically modified to contain genes from other species.

What factors influence translation initiation in eukaryotes?

The 5’ cap of mRNA, initiation factors, and the ribosome's small subunit.

What is the significance of protein folding?

Proper folding is crucial for a protein's function.

What does 'energy coupling' refer to in translation?

Using the energy from ATP and GTP hydrolysis to drive the protein synthesis process.

Define the term 'genomic library.'

A collection of cloned DNA fragments that represent the entire genome of an organism.

What is the steady-state level of a protein?

The balance between protein synthesis and degradation.

What is the difference between primary, secondary, tertiary, and quaternary protein structures?

Different levels of organization in protein folding, from linear chain to complex assemblies.

Describe the function of antibodies in western blotting.

Antibodies are used to specifically detect target proteins in a sample.

What does Northern blotting detect?

RNA molecules.

What does Southern blotting detect?

DNA sequences.

What is mass spectrometry used for in protein analysis?

To identify and quantify proteins based on their mass-to-charge ratio.

What are the implications of using CRISPR technology?

It allows for precise edits to DNA, with applications in medicine, agriculture, and research.

Define DNA hybridization.

The process of joining two complementary strands of DNA or RNA.

What is a selectable marker in genetic engineering?

A gene introduced into an organism that allows for the identification of cells that have successfully integrated a new gene.

What does PCR amplify?

Specific DNA sequences.

What is the purpose of a plasmid in molecular biology?

To serve as a vector for gene cloning.

What does the term 'sickle cell trait' mean?

A person who carries one copy of the sickle cell gene and is generally asymptomatic.

What are stem cells?

Undifferentiated cells that can develop into various cell types.

What is the role of eIFs in translation?

Eukaryotic initiation factors facilitate the initiation of protein synthesis.

Define termination in the context of protein synthesis.

The process of completing translation when a stop codon is reached.

What are the components of an active ribosome?

Large and small subunits, mRNA, tRNA, and the growing polypeptide chain.

What is a hybridoma?

A hybrid cell used to produce antibodies.

When is mRNA translated?

When it has been fully processed and transported to the cytoplasm.

What is the cleavage process in insulin maturation?

The removal of the C-peptide to activate insulin.

What is the Zika virus attack mechanism on host cells?

Disrupts protein synthesis, affecting immune response.

What does 'effector' mean in gene editing?

The protein machinery or function that executes the desired changes.

What are integrative and non-integrative techniques in gene therapy?

Integrative techniques alter the genome; non-integrative techniques utilize episomal expressions.

Define the importance of insulin regulation.

Maintains glucose homeostasis and energy balance within the body.

What does a cDNA library contain?

Complementary DNA synthesized from mRNA transcripts.

What do functional assays in molecular biology test?

The activity of genes or gene products.

How do release factors (RFs) function in termination?

They bind to stop codons, facilitating the disassembly of the translation complex.

Describe the purpose of eukaryotic gene expression regulation.

To control when and how much protein is produced from a gene.

Identify one application of stem cell technology.

Tissue regeneration in regenerative medicine.

What roles do the cap and tail structures play in eukaryotic mRNA?

They protect mRNA from degradation and assist in ribosome binding.

What can result from disorders in the protein synthesis pathway?

Various diseases, including genetic disorders and cancers.

What is the significance of amino acid activation?

It ensures the correct amino acid is added to the growing polypeptide chain.

Define the systematic naming of amino acids.

Using three-letter and one-letter codes for amino acid identification.

What challenges does gene therapy face?

Delivery methods, immune responses, and long-term expression.

What types of bonds are found in the tertiary structure of proteins?

Hydrogen bonds, ionic bonds, hydrophobic interactions, and disulfide bridges.

What is protein synthesis energetically costly?

It requires energy in the form of ATP and GTP for multiple steps.

What transformation occurs during ribosome assembly?

Single components combine to form functional ribosomal units.

How can mutations affect the structure of proteins?

They can lead to misfolded proteins, impacting function.

What are some ways to identify mutations in genes?

Sequencing, RFLP analysis, and functional assays.

What factor differentiates prokaryotic from eukaryotic translation?

Prokaryotic translation occurs simultaneously with transcription, while eukaryotic translation is separated in time and space.

What strategies are employed for cancer treatment related to proteins?

Targeted therapies that aim to correct or inhibit specific protein functions.