Molecular Biology Quiz & Flashcards

tRNA carries amino acids to the ribosome, while mRNA and rRNA have different roles in protein synthesis.

DNA polymerase synthesizes new DNA strands during replication, while other enzymes perform the other functions.

Transcription is the process where RNA is synthesized from a DNA template, unlike translation and replication.

The genetic code is redundant, meaning multiple codons can code for the same amino acid.

Helicase unwinds the DNA double helix, whereas ligase joins DNA fragments and topoisomerase prevents overwinding.

A promoter is a DNA sequence that signals the start of transcription by binding RNA polymerase.

rRNA is a component of ribosomes, while mRNA and tRNA have different roles in protein synthesis.

A point mutation is a change in a single nucleotide, unlike larger chromosomal alterations.

Frameshift mutations shift the reading frame, affecting the entire amino acid sequence downstream.

Translation is the process of synthesizing proteins from mRNA, not transcription or replication.

A spliceosome removes introns and joins exons in pre-mRNA, unlike other processes like cutting DNA.

An operon is a cluster of genes transcribed together, unique to some prokaryotic organisms.

Introns are removed during RNA processing, while exons are expressed.

A plasmid is a small circular DNA molecule found in bacteria, not a protein or RNA.

Epigenetic modifications change DNA accessibility, not the sequence itself, affecting gene expression.

Ligase seals nicks between Okazaki fragments, while other enzymes perform synthesis and unwinding.

A nonsense mutation introduces a premature stop codon, leading to truncated proteins.

The poly-A tail protects mRNA from degradation, aiding in its stability and transport.

RNA polymerase synthesizes RNA during transcription, unlike DNA polymerase and ligase.

Telomeres protect the ends of chromosomes from degradation, not involved in replication or coding.

DNA methylation generally silences genes by preventing transcription factor binding.

A missense mutation results in a change in one amino acid due to a single codon alteration.

MicroRNAs regulate gene expression by binding to mRNA, not involved in DNA replication or protein synthesis.

PCR is used to amplify DNA segments, whereas transcription and translation are different processes.

Histones help package DNA into chromatin, not directly involved in RNA stabilization or DNA replication.

The lac operon activates in the absence of glucose to metabolize lactose in bacteria.

Topoisomerase prevents DNA overwinding, unlike helicase which unwinds DNA.

Alternative splicing allows multiple proteins to be produced from a single gene due to exon rearrangement.

Silent mutations do not change the amino acid sequence and are least likely to affect protein function.

Chromatin remodeling modifies DNA accessibility, influencing gene expression without altering the sequence.

Ribosomes are responsible for protein synthesis, whereas other organelles have different functions.

Signal peptides direct newly synthesized proteins to specific locations within or outside the cell.

DNA polymerase synthesizes Okazaki fragments on the lagging strand during replication.

rRNA forms the core of ribosomes and catalyzes protein synthesis, not involved in carrying genetic info.

The central dogma describes the flow of genetic information as DNA to RNA to protein.

Gel electrophoresis separates DNA fragments by size, unlike PCR which amplifies DNA.

A transgenic organism contains a gene from another species, introduced through genetic engineering.

Repressor proteins bind to operators to prevent transcription of certain genes.

DNA is the primary molecule responsible for carrying genetic information in cells.

mRNA carries genetic information from DNA to the ribosome for protein synthesis.

Transcription factors regulate gene expression by binding to specific DNA sequences.

A genome is the complete set of genetic material in an organism.

Histones form the core structure of chromatin by packaging DNA into nucleosomes.

Topoisomerase prevents DNA overwinding ahead of the replication fork.

Silent mutations do not alter the amino acid sequence and usually have no effect on protein function.

Chromatin remodeling alters DNA accessibility, influencing gene expression.

A genetic codon is a sequence of three nucleotides that codes for a single amino acid.

A nonsense mutation introduces a premature stop codon, leading to truncated proteins.

DNA contains the genetic instructions for protein synthesis, which are transcribed and translated.

The start codon is crucial for initiating the translation process at the ribosome.