DNA
What molecule carries genetic information in all living organisms?
DNA
Which nitrogenous base does RNA contain instead of thymine?
Uracil (U)
What is transcription?
The process of making RNA from DNA.
What is the process of converting the genetic information in mRNA into a polypeptide called?
translation
What is DNA replication?
The process by which a DNA molecule is duplicated.
What are the building blocks of DNA called?
nucleotides
What sugar is found in RNA?
Ribose
Which DNA strand is used to synthesize mRNA?
Template strand
What is a codon, and how many nucleotides does it contain?
Three consecutive, non-overlapping nucleotides that specify an amino acid.
Why must DNA replicate before a cell divides?
So each daughter cell receives a complete set of chromosomes.
Which two nitrogenous bases pair together in DNA besides adenine and thymine?
Cytosine and guanine (C–G)
Is RNA usually single-stranded or double-stranded?
Single stranded
During transcription, which RNA nucleotide pairs with adenine (A) in the DNA template?
Uracil (U)
What is the start codon for translation?
AUG
How does DNA's double-stranded structure help replication?
Each separated DNA strand serves as a template for a new complementary strand.
What are the three components of a DNA nucleotide?
A phosphate group, a sugar, and a nitrogenous base
What is the primary function of mRNA?
It encodes proteins and carries genetic information used to make proteins.
If the DNA template sequence is 3′-ACCTGCT-5′, what is the mRNA sequence?
5′-UGGACGA-3′
What are the three sites of the large ribosomal subunit, and what does each do?
A site accepts incoming tRNA; P site is where the polypeptide chain is synthesized; E site is where discharged tRNA exits.
What enzyme facilitates DNA replication and helps correct errors?
DNA Polymerase
How do weak hydrogen bonds between DNA base pairs help DNA function?
They allow the two strands to separate during replication and transcription.
How do the functions of mRNA and tRNA differ?
mRNA encodes proteins, while tRNA carries amino acids.
Why does transcription not require a change in genetic “language,” unlike translation?
Because transcription converts one nucleotide sequence (DNA) into another nucleotide sequence (RNA).
What happens when a stop codon reaches the ribosome's A site?
A release factor binds, causing the polypeptide to detach, and the translation complex comes apart.
What are replication origins and why does replication proceed in both directions?
Replication begins at origins of replication and proceeds outward through two replication forks. Eukaryotic DNA has multiple origins.