Biology Exam 4 Review

Flashcards based on key concepts from the biology exam notes covering DNA structure, replication, and protein synthesis.

Frederick Griffith's Experiment

Demonstrated that a living S strain (virulent) could transform a nonvirulent R strain into a virulent form.

Avery Experiment

Identified DNA as the genetic material by proving it may be taken up and active in bacterial cells.

Hershey & Chase Experiment

Used bacteriophages to demonstrate that DNA, not protein, is the genetic material.

Semiconservative Replication

Each parent strand serves as a template for a new strand, resulting in one old and one new strand in each DNA molecule.

DNA Structure

Features include double stranded helix, right-handed helix, antiparallel strands, complementary base pairing, and sugar-phosphate backbone.

Covalent Bonds in DNA

Link nucleotides within each strand, while hydrogen bonds hold the two strands together between base pairs.

Primase

Enzyme that synthesizes a short RNA primer, complementary to the DNA template, to initiate DNA synthesis.

Leading Strand

Strand of DNA synthesized continuously in the same direction as the replication fork opens.

Lagging Strand

Strand of DNA synthesized discontinuously in Okazaki fragments, requiring multiple primers.

Telomeres

Repetitive nucleotide sequences at the ends of eukaryotic chromosomes, protecting genetic information.

Telomerase

Enzyme that adds lost telomeres, helping maintain chromosome length during replication.

Proofreading by DNA Polymerase

DNA polymerase checks and corrects errors as nucleotides are added during DNA replication.

Central Dogma of Molecular Biology

The process of DNA transcribing to RNA and then translating into protein, which cannot be reversed.

mRNA

Messenger RNA, a complementary strand to DNA that carries genetic information from the nucleus to the cytoplasm.

Codon

A sequence of three bases on mRNA that corresponds to a specific amino acid.

Start Codon

AUG, the initiation signal for translation, coding for methionine.

tRNA

Transfer RNA that brings amino acids to ribosomes and has an anticodon that pairs with mRNA codons.

Ribosome Binding Sites

A site (binds anticodon of tRNA), P site (where amino acids are added), and E site (exit site for tRNA).

Protein Modifications

Processes such as proteolysis (cutting), glycosylation (adding carbohydrates), and phosphorylation (adding phosphates) after translation.

Transcription Steps

Include initiation, elongation, and termination, occurring in the nucleus.