Study Guide: DNA, RNA, and Evolution Concepts

DNA

Contains genetic instructions.

RNA

Acts as a messenger to translate genetic instructions.

Proteins

Synthesized based on the genetic code through transcription and translation.

Erwin Chargaff

Discovered that the amount of adenine (A) equals thymine (T) and cytosine (C) equals guanine (G).

Chargaff's Rules

A=T and C=G.

James Watson and Francis Crick

Discovered the double helix structure of DNA using X-ray crystallography images.

Rosalind Franklin

Provided crucial X-ray diffraction images contributing to Watson and Crick's discovery.

DNA Structure

Double-stranded, deoxyribose sugar, bases include A, T, C, G.

RNA Structure

Single-stranded, ribose sugar, bases include A, U (uracil), C, G.

DNA vs. RNA

DNA is double-stranded and stable, RNA is single-stranded and temporary.

Transcription

The synthesis of mRNA from DNA.

Translation

The synthesis of proteins from RNA.

Codons

Three-nucleotide sequences on mRNA.

Anticodons

Complementary sequences on tRNA.

Introns

Non-coding regions removed during RNA processing.

Exons

Coding regions of a gene.

rRNA

Forms ribosomes.

mRNA

Carries genetic information.

tRNA

Transports amino acids.

Gene

Consists of coding sequences (exons) and non-coding sequences (introns).

Protein

A chain of amino acids folded into a functional shape.

Gene Mutation

A change in a single gene (e.g., point mutation).

Chromosomal Abnormality

Larger changes affecting entire chromosomes (e.g., deletions, duplications).

Base Substitution

A single nucleotide change may result in a different amino acid.

Frameshift Mutation

Insertions or deletions shift the reading frame, often causing nonfunctional proteins.

Non-Random Mating

A mating system in which individuals select partners based on specific traits, leading to a higher likelihood of certain genotypes and phenotypes.

Natural Selection

Favorable traits increase reproductive success.

Genetic Drift

Changes in allele frequencies due to random events.

Gene Flow

Movement of genes between populations.

Mutation

Introduction of new genetic variations.

Artificial Selection

Humans select for desired traits.

Speciation Mechanisms

Geographic isolation, reproductive isolation, and genetic divergence can lead to new species.

Anatomical Evidence

Homologous structures suggest common ancestry.

Developmental Evidence

Similar embryonic stages indicate evolutionary relationships.

Genetic Evidence

DNA and protein similarities reveal evolutionary links.