Cell Reproduction and Cell Cycle Vocabulary

These flashcards cover essential vocabulary and concepts related to cell reproduction, the cell cycle, mitosis, and meiosis.

Prokaryote

A unicellular organism lacking a nucleus; DNA is located in the cytoplasm in a region called the nucleoid.

Eukaryote

An organism whose cells contain a nucleus and membrane-bound organelles.

Chromosome

A tightly coiled DNA molecule with associated proteins that carries genetic information.

Chromatin

Uncoiled, thread-like form of DNA found during interphase.

Chromatid

One of two identical copies of a replicated chromosome joined at the centromere.

Centromere

The region of a chromosome where sister chromatids are attached; site of kinetochore formation.

Kinetochore

Protein structure on the centromere where spindle fibers attach during cell division.

Homologous Chromosomes

Chromosome pairs (one from each parent) that are similar in size, shape, and gene content.

Diploid (2n)

A cell with two sets of chromosomes (somatic cells).

Haploid (n)

A cell with one set of chromosomes (gametes).

Sister Chromatids

Identical copies of a chromosome created during DNA replication.

Cell Cycle

The sequence of growth and division in a cell’s life.

Interphase

Period between cell divisions consisting of G1, S, and G2 phases.

G1 Phase

Cell grows and carries out normal functions; checkpoint ensures conditions are right for DNA replication.

S Phase

DNA replication occurs, forming sister chromatids.

G2 Phase

Cell prepares for division; checks for DNA damage and replication completion.

G0 Phase

Non-dividing resting phase a cell may enter from G1.

M Phase (Mitotic Phase)

Stage of the cell cycle where nuclear and cytoplasmic division occur (mitosis + cytokinesis).

Checkpoint

A control point in the cell cycle where the cell verifies proper progression (e.g., G1/S, G2/M, M).

Apoptosis

Programmed cell death triggered by severe DNA damage or failed checkpoints.

Mitosis

Division of the nucleus that results in two genetically identical diploid cells.

Prophase

Chromosomes condense, spindle forms.

Prometaphase

Nuclear envelope disintegrates; spindle fibers attach to kinetochores.

Metaphase

Chromosomes line up at the metaphase plate.

Anaphase

Sister chromatids separate and move to opposite poles.

Telophase

Nuclear envelopes reform; chromosomes relax back into chromatin.

Cytokinesis

Division of the cytoplasm; forms two daughter cells.

Meiosis

Cell division producing four genetically unique haploid cells from one diploid parent cell.

Meiosis I

Reductional division that halves the chromosome number.

Meiosis II

Equational division similar to mitosis; separates sister chromatids.

Synapsis

Pairing of homologous chromosomes during Prophase I.

Tetrad

Structure formed by two homologous chromosomes (four chromatids) during synapsis.

Crossing Over

Exchange of DNA segments between homologous chromosomes during Prophase I.

Independent Assortment

Random alignment of homologous pairs in Metaphase I, producing genetic variation.

Reductional Division

The first division of meiosis that reduces the chromosome number by half.

Equational Division

The second division of meiosis that separates sister chromatids.

Cohesin

Protein complex that holds sister chromatids together after replication.

Shugoshin

Protein that protects cohesin at the centromere during Meiosis I to prevent premature separation.

Gamete

Haploid reproductive cell (sperm or egg).

Zygote

Diploid cell formed by the fusion of two gametes.

Crossing Over Frequency

Measurement of genetic recombination between homologous chromosomes.

Genetic Diversity

Variation in offspring due to crossing over and independent assortment.

check points in the cell cycle

g1 - is cell ready for DNA synthesis?

g2- is DNA replicated?

metaphase- are all spindle fibers attached?