DNA Structure
How many rings are found in the structure of a purine?
2
The _____ strand is synthesized continuously toward the replication fork.
Leading
Transcription is he process of using information from ________ to synthesize __________.
DNA, RNA
mRNA nucleotide triplets that code for specific amino acids are called _____.
Codons
In an operon, where does RNA polymerase attach to begin transcription?
Promoter
What does it mean that DNA strands are 'antiparallel'?
The two strands run in opposite directions (5' to 3' and 3' to 5').
The lagging strand is synthesized discontinuously in short segments called _____.
Okazaki Fragments
Which molecule carries genetic information from the DNA in the nucleus to the ribosome?
mRNA
What is the universal start codon for translation?
AUG
A _____ operon is usually ON but can be turned OFF by a repressor (e.g., the trp operon).
repressible
Prokaryotic organisms typically have _____ chromosomes, while eukaryotic organisms have multiple linear chromosomes.
Circular
Which enzyme is responsible for unwinding the DNA strands at the replication fork?
Helicase
In eukaryotic cells, where does transcription occur?
Nucleus
What is the function of Transfer RNA (tRNA)?
Binds specific amino acids and uses its anticodon to pair with mRNA during translation.
What is the inducer molecule for the lac operon?
Allolactose
Small extrachromosomal, double-stranded, circular DNA molecules found in prokaryotes and some eukaryotes.
Plasmids
Which enzyme initiates DNA synthesis by adding short segments of RNA?
Primase
During RNA splicing, _____ are removed and exons are joined together.
Introns
The _____ site of a ribosome holds the tRNA carrying the growing polypeptide chain.
P (Peptidyl)
How does histone acetylation affect gene expression?
It loosens chromatin structure, making DNA more accessible for transcription.
In a DNA molecule, how many hydrogen bonds form between Adenine and Thymine?
2
What is the role of DNA Polymerase III in replication?
Attaches to primers and adds nucleotides to the new strand in the 5' to 3' direction.
What are the three non-coding modifications made to eukaryotic pre-mRNA before it leaves the nucleus?
Addition of a 5' GTP cap, addition of a 3' Poly-A tail, and RNA splicing.
What happens during the translocation step of translation elongation?
The tRNA in the A site moves to the P site, and the tRNA in the P site moves to the E site to exit.
What role do microRNAs (miRNAs) and small interfering RNAs (siRNAs) play in gene regulation?
They can bind to mRNA to block translation or cause mRNA degradation.