DNA, Genes & Protein Synthesis (Chapter 8) Flashcards
What is the structure of DNA?
DNA is a double helix composed of two strands of nucleotides.
What are the four nitrogenous bases in DNA?
Adenine (A), Thymine (T), Cytosine (C), and Guanine (G).
Which nitrogenous bases pair together in DNA?
Adenine pairs with Thymine, and Cytosine pairs with Guanine.
True or False: DNA is made up of amino acids.
False.
What is a gene?
A gene is a sequence of DNA that codes for a specific protein.
What is the function of mRNA?
mRNA (messenger RNA) carries the genetic information from DNA to the ribosomes for protein synthesis.
Fill in the blank: The process of copying DNA into RNA is called __________.
transcription.
What is the role of tRNA in protein synthesis?
tRNA (transfer RNA) brings amino acids to the ribosome during translation.
What is the central dogma of molecular biology?
DNA -> RNA -> Protein.
What are introns and exons?
Introns are non-coding regions of a gene, while exons are coding regions that are translated into protein.
True or False: All mutations are harmful.
False.
What is a point mutation?
A point mutation is a change in a single nucleotide in the DNA sequence.
What is the role of RNA polymerase?
RNA polymerase synthesizes RNA from a DNA template during transcription.
Define ‘codon’.
A codon is a sequence of three nucleotides that corresponds to a specific amino acid.
What are the three stages of translation?
Initiation, elongation, and termination.
Fill in the blank: The genetic code is __________.
degenerate.
What is the difference between DNA and RNA?
DNA is double-stranded and contains deoxyribose, while RNA is single-stranded and contains ribose.
What is a silent mutation?
A silent mutation is a change in the nucleotide sequence that does not alter the amino acid sequence of a protein.
What is a frameshift mutation?
A frameshift mutation is caused by insertions or deletions of nucleotides that change the reading frame of the gene.
What is the role of ribosomes in protein synthesis?
Ribosomes are the sites where translation occurs, synthesizing proteins from amino acids.
True or False: All genes are expressed all the time.
False.
What is the purpose of the promoter region in a gene?
The promoter region is a sequence that initiates transcription of a gene.
What is a poly-A tail?
A poly-A tail is a stretch of adenine nucleotides added to the 3’ end of mRNA for stability and transport.
What is the significance of the start codon?
The start codon (AUG) signals the beginning of translation and codes for methionine.
What is a stop codon?
A stop codon is a codon that signals the termination of protein synthesis.
What is the process of DNA replication?
DNA replication is the process by which a DNA molecule is copied to produce two identical molecules.
What enzyme is responsible for DNA replication?
DNA polymerase.
What is the role of ligase in DNA replication?
Ligase joins Okazaki fragments on the lagging strand during DNA replication.
What is the difference between leading and lagging strands during DNA replication?
The leading strand is synthesized continuously, while the lagging strand is synthesized in short segments.
What is a mutation?
A mutation is a change in the DNA sequence that can lead to changes in protein function.
What is gene expression?
Gene expression is the process by which information from a gene is used to synthesize a functional gene product, usually a protein.
What is epigenetics?
Epigenetics is the study of heritable changes in gene expression that do not involve changes to the DNA sequence.
True or False: All proteins are enzymes.
False.
What is the role of chaperone proteins?
Chaperone proteins assist in the proper folding of other proteins.
What is the significance of alternative splicing?
Alternative splicing allows a single gene to produce multiple protein isoforms.
What is a transcription factor?
A transcription factor is a protein that binds to specific DNA sequences to regulate gene expression.
What is a plasmid?
A plasmid is a small, circular piece of DNA found in bacteria that can replicate independently of chromosomal DNA.
What is the role of the operator in an operon?
The operator is a segment of DNA that a repressor protein binds to, blocking transcription.
What is the significance of the 5’ cap on mRNA?
The 5’ cap protects mRNA from degradation and assists in ribosome binding during translation.
True or False: All cells in an organism express the same genes.
False.
What is the purpose of gene regulation?
Gene regulation ensures that the right genes are expressed at the right times and in the right amounts.
What is a genetic disorder?
A genetic disorder is a disease caused by abnormalities in an individual’s DNA.
What is the role of telomeres?
Telomeres protect the ends of chromosomes from deterioration or fusion with neighboring chromosomes.
What is recombinant DNA technology?
Recombinant DNA technology involves combining DNA from different sources to create new genetic combinations.
What is gene therapy?
Gene therapy is a technique that modifies a person’s genes to treat or prevent disease.
What is CRISPR technology?
CRISPR is a gene-editing technology that allows for precise modifications to the DNA of organisms.
True or False: DNA can be found in both the nucleus and the cytoplasm of eukaryotic cells.
False.
What is a phenotype?
A phenotype is the observable physical or biochemical characteristics of an organism, determined by its genotype.
What is a genotype?
A genotype is the genetic constitution of an organism, specifically the alleles it carries.
What is the difference between dominant and recessive alleles?
Dominant alleles express their traits even when only one copy is present, while recessive alleles require two copies to express their traits.
