Lecture 2 - Foundations for Evolution: Cells & DNA

Vocabulary flashcards covering cells, DNA, chromosomes, meiosis, and protein synthesis from the lecture notes.

Somatic cells

Body cells that form organs, tissues, etc.; genetic changes in somatic cells are not inherited.

Gametes

Reproductive cells (sperm and ova); genetic changes in gametes are inherited.

Nucleus

Organelle containing the cell’s DNA; houses genetic material.

Mitochondria

Organelle containing mitochondrial DNA (mtDNA) and generating cellular energy.

Endoplasmic reticulum

Organelle involved in protein synthesis and other cellular processes.

Ribosomes

Organelle where protein synthesis occurs; reads genetic code.

Deoxyribonucleic acid (DNA)

Molecule that transmits genetic information; exists as nuclear DNA and mitochondrial DNA.

Nuclear DNA (nDNA)

DNA located in the nucleus; codes most genetic information.

Mitochondrial DNA (mtDNA)

DNA located in mitochondria.

Replication

Process by which DNA makes an identical copy of itself.

Mutations

Changes in DNA sequence; important source of genetic variation.

Double helix

Two strands of nucleotides wound into a helical shape.

Nucleotide components

Each nucleotide contains a nitrogenous base (A, T, G, C), a sugar, and a phosphate group.

Nitrogenous bases in DNA

Adenine (A), Thymine (T), Guanine (G), Cytosine (C).

Complementary base pairing

A pairs with T; G pairs with C; enables exact copies during replication.

Adenine–Thymine pairing

A pairs with T in DNA.

Guanine–Cytosine pairing

G pairs with C in DNA.

Chromosome

Physical structure where genes are located; humans have 46 chromosomes (23 pairs).

Autosomes

Non-sex chromosomes (chromosomes 1–22; homologous pairs).

Sex chromosomes

Chromosomes X and Y; determine sex (XY typically male, XX typically female).

Centromere

Constricted region of a chromosome where sister chromatids attach.

Mitosis

Cell division of somatic cells producing two identical diploid daughter cells.

Meiosis

Cell division of germ cells producing four haploid gametes; includes Meiosis I and Meiosis II.

Diploid

Two complete sets of chromosomes (2n).

Haploid

One complete set of chromosomes (n).

Zygote

Fertilized egg formed when egg and sperm unite.

Crossing over

Exchange of chromosome segments during meiosis, creating genetic variation.

Recombination

Process that reshuffles genetic material during meiosis, increasing variation.

Non-disjunction

Failure of chromosomes to separate properly during cell division.

Chromosome anomalies

Abnormal chromosome numbers or structures in gametes/zygotes.

Proteins

Molecules made of amino acids; perform structural, enzymatic, hormonal, transport, antibody, and regulatory roles.

Hemoglobin

A protein example; involved in oxygen transport.

Amino acids

20 building blocks of proteins; proteins differ by number and sequence of amino acids.

Protein synthesis

Process of making proteins; occurs in the cytoplasm at ribosomes.

Transcription

DNA sequence is copied into messenger RNA (mRNA); RNA is single-stranded and uses uracil instead of thymine.

mRNA (messenger RNA)

RNA that carries genetic message from the nucleus to ribosomes.

tRNA (transfer RNA)

RNA that helps assemble a protein by bringing amino acids to the ribosome using the mRNA template.

Translation

Process by which ribosomes decode mRNA to synthesize a protein.

Codon

Three-nucleotide unit of mRNA that specifies a particular amino acid.

Gene

Entire sequence of DNA bases responsible for the synthesis of a protein.