2. Mitosis and Meiosis - Lecture Notes

35 vocabulary-style flashcards covering key genetics terms from the video notes.

DNA

The molecule that carries genetic information; two long chains in a double helix; built from nucleotides A, T, C, G.

Gene

A discrete unit of inheritance; a nucleotide sequence that encodes the info to produce a protein.

Allele

Different forms of a gene with potentially different DNA sequences and functions.

Mutation

Random changes in the DNA sequence; can be substitutions, insertions, or deletions.

Nucleotide

The basic building block of DNA; four types: A, T, C, G.

Chromosome

A DNA molecule packaged with proteins; carries many genes.

Homologous chromosomes

Pairs of chromosomes that are similar in length and gene location; carry the same genes in the same places.

Diploid (2n)

Cells with two sets of chromosomes, one from each parent.

Haploid (n)

Cells with a single set of chromosomes; gametes are haploid.

Sister chromatids

Two identical copies of a chromosome produced during DNA replication and held together at the centromere.

Centromere

Region where sister chromatids are held together and where spindle fibers attach during division.

Chromatid

One of the two identical copies of a chromosome that result from replication.

Mitosis

Cell division that creates two genetically identical diploid daughter cells; includes prophase, metaphase, anaphase, and telophase.

Meiosis

Cell division that yields four haploid gametes and introduces genetic variation.

Meiosis I

First division; separates homologous chromosomes (reductional division).

Meiosis II

Second division; separates sister chromatids (equational division).

Crossing over

Exchange of genetic material between non-sister chromatids during prophase I; creates recombinants.

Chiasmata

Sites where crossing over occurs between homologous chromosomes.

Independent assortment

Random orientation and separation of different pairs of homologous chromosomes during meiosis.

Recombinant chromosomes

Chromosomes that contain new combinations of alleles created by crossing over.

Gamete

A haploid reproductive cell (sperm or egg).

Zygote

Diploid cell formed when a sperm fertilizes an egg.

Fertilization

Union of gametes forms a zygote.

Genotype

The two alleles an individual has for a gene (e.g., HH, Hh, hh).

Phenotype

The observable traits expressed by the organism.

Transcription

Process of copying a DNA sequence into RNA.

Translation

Process of decoding mRNA to build a protein.

mRNA

Messenger RNA; carries genetic information from DNA to the ribosome.

Protein

Molecule that performs cellular functions and is encoded by genes.

Interphase

Non-dividing phase of the cell cycle where growth and DNA replication occur.

G1

Gap 1: primary growth phase of the cell.

S-phase

DNA synthesis; replication of the DNA.

G2

Gap 2: organelles replicate and microtubules organize.

Cytokinesis

Division of the cytoplasm to form two separate cells; animal cells form a cleavage furrow; plant cells form a cell plate.

Gene expression

Process of converting information from a gene into a cellular product.

Independent/random Assortment

Random separation of homologous chromosome pairs during meiosis, increasing genetic diversity.