Chapter 10 — Cell Division

What are the two main functions of cell division?

Growth maintenance and repair in multicellular organisms reproduction in single-celled organisms

What is a genome?

The complete set of an organism's DNA

What is a plasmid?

A small extra loop of DNA that may carry useful genes in prokaryotes

What is a chromosome?

A DNA molecule packaged with proteins

What is a karyotype?

Chromosomes arranged by size and other features

What are homologous chromosomes?

A chromosome pair with corresponding genes one inherited from each parent

What are somatic cells?

Body cells that are typically diploid (2n)

What are gametes?

Reproductive cells such as eggs and sperm that are haploid (1n)

What is a nucleosome?

DNA wrapped around a core of eight histone proteins

What is chromatin?

DNA and associated proteins that make up chromosomes

What are the two major phases of the cell cycle?

Interphase and the mitotic phase

What happens during G1?

The cell grows and carries out normal biochemical activities

What happens during S phase?

DNA is replicated producing sister chromatids

What happens during G2?

The cell prepares for division and replenishes resources

What is mitosis?

Division of the nucleus and its duplicated chromosomes

What is cytokinesis?

Division of the cytoplasm to form two daughter cells

What happens during prophase?

Chromosomes condense the spindle forms and the nuclear envelope breaks down

What happens during prometaphase?

Spindle microtubules attach to chromosome kinetochores

What happens during metaphase?

Chromosomes line up at the cell's equator

What happens during anaphase?

Sister chromatids separate and move to opposite poles

What happens during telophase?

Chromosomes reach opposite poles decondense and new nuclear envelopes form

How does cytokinesis differ in animal and plant cells?

Animals form a cleavage furrow plants form a cell plate

What are the three major cell-cycle checkpoints?

G1 checkpoint G2 checkpoint and M (spindle) checkpoint

What does the G1 checkpoint check?

Cell conditions size resources and DNA damage before S phase

What does the G2 checkpoint check?

Whether DNA replication is complete and DNA is undamaged

What does the M checkpoint check?

Whether chromosomes are correctly attached to spindle microtubules

What is G0?

A state in which a cell exits the active cell cycle and waits

What are cyclins and Cdks?

Proteins that work together to regulate cell-cycle progression

What do negative cell-cycle regulators do?

Stop or slow the cell cycle when conditions are unfavorable

What are p53 p21 and Rb?

Negative regulators involved in controlling cell-cycle progression

What is cancer?

Uncontrolled cell growth caused by changes affecting cell-cycle regulation

What are proto-oncogenes?

Normal genes that encode positive cell-cycle regulators

What are oncogenes?

Mutated or abnormally activated genes that can promote uncontrolled division

What are tumor suppressor genes?

Genes that encode proteins that help prevent uncontrolled cell division

How do prokaryotes divide?

By binary fissio