DNA Structure, Function, and Gene Expression Study Guide

This set of flashcards encompasses key vocabulary and concepts related to DNA structure and function, gene expression, and the principles of evolution as outlined in the lecture notes.

Hershey & Chase Experiment

Demonstrated that DNA is the hereditary material using bacteriophages.

Base-Pairing Rule

States that adenine (A) pairs with thymine (T) and guanine (G) pairs with cytosine (C).

Semiconservative Replication

Describes DNA replication where each new DNA molecule consists of one original strand and one newly synthesized strand.

Primase

The enzyme that adds RNA primers during DNA replication.

Chargaff’s Rules

Established that the amount of adenine equals thymine, and the amount of guanine equals cytosine, helping Watson and Crick model DNA.

Leading Strand

The DNA strand synthesized continuously in the direction of the replication fork during DNA replication.

Lagging Strand

The DNA strand synthesized in short segments, away from the replication fork, and requires multiple RNA primers.

Telomeres

Protective caps at the ends of chromosomes that prevent degradation; telomerase helps maintain their length during replication.

RNA Polymerase

The enzyme responsible for synthesizing RNA from a DNA template during transcription.

Start Codon

AUG, which codes for the amino acid methionine.

Eukaryotic Transcription

Includes RNA processing, which occurs post-transcription, distinguishing it from prokaryotic transcription.

tRNA

Transfer RNA that carries amino acids to the ribosome during translation.

Alternative Splicing

A process that allows a single gene to code for multiple proteins by including or excluding exons during RNA processing.

Lac Operon

An example of an inducible operon that is activated in the presence of lactose.

Histone Acetylation

A modification that generally results in gene activation by loosening the DNA structure.

Inducible Operon

An operon that is usually off and can be turned on when a specific substrate is present.

Repressible Operon

An operon that is usually on and can be turned off when a specific product accumulates.

Inheritance of Acquired Traits

A concept proposed by Lamarck, suggesting that traits acquired during an organism's lifetime can be passed to offspring.

Hardy-Weinberg Principle

States that allele and genotype frequencies in a population will remain constant in the absence of evolutionary influences.

Disruptive Selection

A type of natural selection that favors extreme values of a trait over intermediate values.

Microevolution Mechanisms

Includes mutation, gene flow, genetic drift, non-random mating, and natural selection.

Homologous Structures

Anatomical features in different species that share a common ancestral origin.

Analogous Structures

Body parts in different species that perform similar functions but do not share a common ancestral origin.

Reproductive Isolation

A mechanism that prevents species from mating successfully and can lead to speciation.

Heterozygous Frequency (2pq)

Represents the frequency of heterozygous individuals in a population under Hardy-Weinberg equilibrium.