Cell Division, Mitosis, and Meiosis

Flashcards about cell division, mitosis, and meiosis.

Cell Division

The cells of an organism replicate their DNA and split into two cells, leading to reproduction and/or growth.

Binary Fission

Prokaryotes reproduce through this process.

Mitosis

Eukaryotes use this process to break down the nuclear membrane as DNA is divided for the two daughter cells.

Results of Mitosis

Daughter cells are genetically identical to the parent.

Binary Fission Definition

Separation of the body into two new bodies.

Chromosome

A molecule of DNA containing genetic information.

Number of Chromosomes in Humans

Humans have 46.

Centromere

Two chromatids attach together with this during chromosome replication.

Interphase

Longest phase where the cell lives normally, grows, produces proteins and organelles and duplicates each chromosome.

Chromatin

DNA is loosely packed as this during interphase.

Prophase

Chromatin condenses into visible chromosomes, centrosomes move to either end of the cell, and the nuclear membrane breaks down.

Metaphase

Centrosomes release microtubules called spindle fibers that connect to each centromere, pulling chromosomes to align in the center of the cell.

Anaphase

Spindle fibers contract, pulling the sister chromatids apart, and the cell elongates.

Telophase

Nuclear envelope forms around each set of chromosomes, chromosomes decondense, and cytokinesis divides the cytoplasm and organelles evenly.

Mitosis

Clones body cells (diploid to diploid).

Meiosis

Makes distinct gametes (diploid to haploid).

Meiosis

Specialized cell division for the production of sperm & egg cells.

Gametes

Haploid cells produced by meiosis.

Fertilization

Occurs when gametes form a zygote, which grows into an embryo.

Karyotype

A display of chromosome pairs of a cell arranged by size and shape.

Sex of a Human

The last pair of chromosomes determines this.

XX

Female chromosomes.

XY

Male chromosomes.

Errors in Meiosis

Gametes with extra or missing chromosomes.

Interphase

Occurs prior to meiosis; cell grows and replicates its DNA.

Meiosis I

Homologous chromosomes cross over, recombining DNA so each chromatid has some DNA from both parent cells.

Crossing Over

Exchange of genetic material between homologous chromosomes.

Prophase I

Chromosomes condense, and pairs of chromosomes exchange bits of DNA.

Metaphase I

Chromosome pairs line up next to each other along the center equator.

Anaphase I

Pair of chromosomes are pulled apart by spindle fibers.

Telophase I / Cytokinesis

Chromosomes complete their move to opposite poles of the cell, and a membrane forms around each set of chromosomes.

Meiosis II

Sister chromatids condense and migrate to the center of the cells; centromeres cleave as sister chromatids split.

Prophase II

Two daughter cells condense into X shaped structures.

Metaphase II

Chromosomes line up end to end along the equator of the cell.

Anaphase II

Sister chromatids are pulled to opposite poles.

Telophase II / Cytokinesis

Chromosomes complete their move to opposite poles of the cell, and a membrane forms around each set to create four new cells.