BIO 2400 Final Exam Review Flashcards

Organized Question and Answer flashcards covering chromosome structure, genetic modifications, transcription, translation, and operon regulation from BIO 2400.

What is the basic unit of chromatin?

Nucleosome

What is the difference between euchromatin and heterochromatin?

Euchromatin is active/open; heterochromatin is inactive/condensed.

What are polytene chromosomes?

Large chromosomes with many DNA copies and puff regions of active transcription.

What are lampbrush chromosomes?

Large meiotic chromosomes with DNA loops for active transcription.

Why are mitochondria and chloroplasts considered similar to bacteria?

They have circular DNA, no histones, and undergo independent replication.

What is the effect of histone acetylation on chromatin structure?

It loosens chromatin and increases transcription.

What is the typical function of DNA methylation?

It represses gene expression.

What are STRs/VNTRs used for in biological science?

DNA fingerprinting/forensics.

What are LINEs and SINEs?

Transposable repetitive DNA elements.

What is the start codon in the genetic code?

AUG

What are the three stop codons in the genetic code?

UAA, UAG, UGA

Which enzyme performs the process of transcription?

RNA polymerase

What does it mean for the genetic code to be degenerate?

Multiple codons can code for the same amino acid.

What is the wobble hypothesis?

The idea that third codon base pairing is less strict.

Does RNA polymerase require a primer to initiate transcription?

No

What components are removed from the pre-mRNA during splicing?

Introns

What segments of the mRNA remain after the splicing process is complete?

Exons

What is alternative splicing?

A process where one gene can make multiple proteins.

What is the function of the 5' cap on mRNA?

It protects mRNA and helps ribosome binding.

What is the function of the poly-A tail?

It stabilizes mRNA and prevents degradation.

What are enhancers in eukaryotic transcription?

DNA elements that increase transcription.

What are the functions of the ribosome A, P, and E sites?

A = Arrival, P = Peptide, E = Exit

What enzyme is responsible for charging tRNA with the correct amino acid?

Aminoacyl-tRNA synthetase

What molecules recognize stop codons to terminate translation?

Release factors

What specific cargo does tRNA carry for translation?

Amino acids

What is an anticodon?

A tRNA sequence complementary to an mRNA codon.

What are the four levels of protein structure?

Primary, secondary, tertiary, quaternary

What are polyribosomes?

Many ribosomes translating one mRNA at once

What is the role of chaperone proteins?

They help proteins fold correctly.

Which diseases are linked to protein misfolding?

Alzheimer’s, Parkinson’s, and prion diseases

Is the lac operon classified as inducible or repressible?

Inducible

Under what conditions is the lac operon turned ON?

When lactose is present and glucose is low.

What protein does the lacZ gene code for?

$$\beta\text{-galactosidase}$$

What is the consequence of a lacI- mutation?

The operon is always ON.

What is catabolite repression in the context of the lac operon?

Glucose inhibits lac operon expression.

What is the role of CAP-cAMP?

It activates the lac operon when glucose is low.

Is the trp operon classified as inducible or repressible?

Repressible

When is the trp operon turned OFF?

When tryptophan is present.

What is a corepressor?

A molecule that activates the repressor.

What is chromatin remodeling?

The repositioning of nucleosomes to allow access to DNA.

What are general transcription factors?

Proteins required for RNA polymerase II binding.