BRS Biochemistry_1-231 (1)

Histones nonspecifically repress transcription of genes.

Mutations that occur when the number of bases added or deleted is not a multiple of three, shifting the reading frame.

A point mutation (GAG to GTG) that causes valine to replace glutamate in the β-globin chain.

An elongation factor (EF-Tu in prokaryotes and eEF-1 in eukaryotes) and hydrolysis of GTP.

It binds to the operator, preventing RNA polymerase from binding to the promoter, leading to no transcription.

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

Proteins can be modified by phosphorylation, glycosylation, ADP ribosylation, hydroxylation, and addition of other groups.

The mRNA codon at the A site.

It determines the reading frame for subsequent nucleotides.

To regulate the metabolism of lactose in bacteria.

The peptidyl-tRNA moves from the A site to the P site, and the uncharged tRNA moves to the E site.

A mechanism where the operon is transcribed only when glucose is low.

Transcription continues because the termination structure does not form.

By exocytosis from secretory vesicles.

The binding of aminoacyl-tRNA to mRNA in opposite orientations.

The lac operon is inducible and is induced in the absence of glucose.

Nucleases can degrade mRNAs after synthesis in the nucleus, affecting their stability and translation.

No transcription occurs.

It acts as an inducer that inactivates the repressor.

On ribosomes attached to the rough endoplasmic reticulum (RER).

It is a core promoter element that helps initiate transcription.

It is cleaved from the N-terminus.

They regulate translation of mRNAs for ferritin and transferrin receptor based on iron levels.

Binding of aminoacyl-tRNA to the A site.

The co-repressor binds to the inactive repressor, activating it to bind to the operator and prevent transcription.

A complex of mRNA with multiple ribosomes attached to it.

Highly basic sequences containing arginine and lysine.

siRNA can block translation or induce degradation of target mRNAs, regulating gene expression.

It is the addition of a lipid group to the amino group of N-terminal glycine (gly).

It binds to CAP, facilitating the initiation of transcription by RNA polymerase.

The mammalian genome contains about 1,000 times more DNA than E. coli (10^9 vs 10^6 base pairs).

It is formylated and carried by tRNA f Met.

The Shine–Dalgarno sequence.

Relatively short, repetitive DNA sequences dispersed throughout the eukaryotic genome that do not code for proteins.

It catalyzes the formation of aminoacyl-tRNA by linking an amino acid to tRNA.

It binds to the operator, preventing RNA polymerase from binding and thus inhibiting transcription.

It allows lymphocytes to produce both membrane-bound and soluble forms of IgM antibodies at different developmental stages.

They are required for the movement of peptidyl-tRNA from the A site to the P site.

Apo B-100, which contains more than 4000 amino acids.

The elongation and translocation steps are repeated until termination occurs.

It is a mechanism where cells preferentially use glucose, leading to decreased expression of operons like lac and ara when glucose is present.

They bind to target RNA and ablate its expression.

They can generate siRNA in cells, which holds promise as a therapeutic tool.

Rapid translation of the nascent transcript can lead to the formation of a secondary structure that signals termination of transcription.

Genes can be deleted, amplified, rearranged, or modified (e.g., methylated).

Aminoacyl-tRNA and AMP.

Bromodomains recognize acetylated histones and help bind ATP-driven chromatin remodeling complexes to DNA.

It involves the addition of ADP-ribose to the nitrogen of arginine (arg) and glutamine (gln), and the sulfur of cysteine (cys).

The amino acid sequence KdE1 near the carboxy terminus.

The promoter region and additional gene regulatory sequences, including enhancers and hormone response elements (HRE).

They bind directly to DNA and can act as activators or repressors of transcription for specific genes.

Glucose decreases cAMP levels; when glucose is low, cAMP levels rise.

It binds to a site near the promoter, facilitating the binding of RNA polymerase to the promoter.

In eukaryotes, DNA is complexed with histones, while in prokaryotes, it is not.

The major part of the genome does not code for proteins.

Through an ester bond formed with the 2′- or 3′-hydroxyl of the terminal ribose.

Codon–anticodon interaction.

It binds to and inactivates the repressor, allowing RNA polymerase to bind and initiate transcription.

It modifies the amino group of lysine (lys) and the N-terminus.

Alpha-galactosidase, lactose permease, and transacetylase.

Chloramphenicol inhibits the peptidyl transferase activity of the 50S ribosomal subunit in prokaryotes.

Ricin acts as an N-glycosidase, cleaving a specific adenine base from the 28S rRNA, thereby inhibiting protein synthesis.

It involves the addition of a lipid group to the sulfur of cysteine (cys).

An enzyme-aminoacyl-AMP complex and pyrophosphate (2 Pi).

Serine (ser), threonine (thr), and tyrosine (tyr).

It becomes uncharged and does not contain an amino acid.

They occur when one base in DNA is replaced by another, altering the codon in mRNA.

O-glycosylation involves the hydroxyl groups of serine (ser), threonine (thr), and tyrosine (tyr), while N-glycosylation involves the amino group of asparagine (asn).

It is the process whereby a corepressor inhibits the transcription of an operon.

A mutation that results in a premature termination of the growing polypeptide chain.

By highly specific enzymes known as aminoacyl-tRNA synthetases.

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

The large ribosomal subunit binds.

Inducers cause proteins to bind to DNA sequences and stimulate transcription of specific genes.

Transcription factors often have histone acetylase activity, facilitating the removal of histones from DNA for transcription.

The amino acid sequence SKL at the carboxy terminus.

It is the addition of a lipid group to the internal sulfur of cysteine (cys).

It is a mechanism that inhibits the expression of the lac operon in the presence of glucose.

Apo B-48, which contains only 48% of the amino acids of Apo B-100.

RNA editing, specifically the conversion of a C to a U.

Calcitonin.

By modification of DNA, transcription, mRNA processing, or translation.

It involves alternative start sites for transcription, alternative splice sites for intron removal, alternative polyadenylation sites, and RNA editing.

Histone acetylation facilitates transcription by allowing chromatin remodeling and nucleosome displacement.

Alternative splice sites can produce different mRNAs, leading to the production of different proteins from the same gene.

Allolactose, a metabolite of lactose.

Streptomycin binds to the 30S ribosomal subunit and causes misreading of mRNA, preventing the formation of the initiation complex.

A mutation that results in one amino acid being replaced by another.

A hydrophobic signal sequence at the N-terminus.

Diphtheria toxin inhibits translocation in eukaryotes by catalyzing the ADP-ribosylation of EF-2.

Puromycin binds at the A site, forms a peptide bond with the growing peptide chain, and prematurely terminates synthesis.

An imbalance in the synthesis of globin proteins, resulting in an excess of α subunits.

Methionyl-tRNA i Met binds to the small ribosomal subunit.

It processes pre-miRNA into double-stranded miRNA and selects the guide strand for RISC.

Eukaryotic genes contain introns, while bacterial genes do not.

Three initiation factors (IF-1, IF-2, IF-3).

It determines whether the genes are expressed or not by interacting with repressor proteins.

It is a modified amino acid derived from proline.

Peptidyl transferase, which is an activity of the rRNA in the large ribosomal subunit.

Mutations can be transcribed into mRNA, causing changes in the encoded protein.

RNA editing involves the alteration of bases in mRNA after transcription, potentially changing the protein produced.

Mannose 6-phosphate.

They contain promoter regions that facilitate or inhibit RNA polymerase binding.

Factors such as sigma that bind to core RNA polymerase to increase its binding ability to specific promoters.

Some eukaryotic genes are unique, while others have many copies in the genome.

Increased methylation generally reduces the transcriptional activity of a gene.

Histones are proteins that associate with DNA in eukaryotes and act as nonspecific repressors.

Glutamic acid (glu).

Release factors cause the newly synthesized polypeptide to be hydrolyzed from the tRNA and released from the ribosome.

Tryptophan itself acts as the corepressor.

It represses the operon since the cell does not need to synthesize tryptophan when it is already present.

It refers to mechanisms that activate transcription, such as the binding of arabinose to the repressor of the ara operon, turning it into an activator.

It contains RNA polymerase and general transcription factors, binding to the TATA box to initiate gene transcription.

It is the process by which the same transcript can be spliced differently to produce different protein products.

Attenuation.

Calcitonin gene-related protein (CGRP).

The first AUG codon.

By preventing the phosphorylation and inactivation of eIF-2, a factor involved in initiation.

It stimulates the phosphorylation of eIF-2, causing inhibition of initiation.

Most mammalian cells are diploid.

P (peptidyl), A (acceptor), and E (ejection) sites.

Bacterial genes are organized in operons, controlled by a single promoter.

80S ribosome (40S and 60S subunits).

Heterochromatin is transcriptionally inactive, while euchromatin is transcriptionally active.

Tetracycline binds to the 30S ribosomal subunit and inhibits the binding of aminoacyl-tRNA to the A site.

Polycistronic mRNA.

It leads to either degradation of the mRNA or inhibition of translation.

Eukaryotic cells undergo differentiation and have separated transcription and translation, while prokaryotes perform both simultaneously.

They are co-activators or co-repressors that interact with specific transcription factors and general transcription factors.

They control the expression of genes that produce proteins, including the basal promoter, enhancers, and silencers.

Through the degradation of mRNA by silencing RNA (miRNAs).

A set of genes that are adjacent in the genome and are coordinately controlled.

An inducer stimulates the transcription of an operon by inactivating the repressor.

70S ribosome (30S and 50S subunits).

Initiation factors, ATP, and GTP.

Genes can be lost or partially lost, preventing the production of functional proteins.

It causes amplification of the gene for dihydrofolate reductase, leading to drug resistance.

A single mRNA that codes for all the proteins of an operon.

Inducers enter cells, bind to receptors, and activate specific genes by interacting with chromatin.