Chapter 6: Cell Division Flashcards Preview

Barron's AP Biology > Chapter 6: Cell Division > Flashcards

Flashcards in Chapter 6: Cell Division Deck (21):
1

Mitosis

Cell division that produces genetically identical daughter cells. Involves prophase, metaphase, anaphase, and telophase.

2

Meiosis

Cell division that occurs in sexually reproducing organisms, and produces haploid cells. Produces gametes, and the nucleus divides twice.

3

Sister Chromatids

Makes up a replicated chromosome.

4

Centromere

The center of a chromosome that holds two chromatids together.

5

Kinetochore

The disc shaped protein on the centromere that attaches the chromatid to the mitotic spindle during division.

6

Cell Cycle

The sequence of growth and cell division.

Two important factors that limit cell growth and promote cell division: Surface area to volume ratio, and the capacity of the nucleus to control the whole cell.

7

Phases of the Cell Cycle

G1: Growth and biochemical activity.
S: Synthesis, DNA replication.
G2: Growth and preparation for mitosis.
Mitosis: The actual splitting of the nucleus.
Cytokinesis:

8

Prophase

- Nucleolus disappears.
- Nuclear envelope disintegrates.
- Chromatin begins to condense.
- Mitotic spindles begin to form.

9

Metaphase

- Chromosomes line up along the equator.
- Centrosomes are situated on opposite sides of the cell.
- Mitotic spindles connect the centrosomes through the kinetochores.

10

Anaphase

- Centrosomes begin to pull the chromosomes and the cell in opposite directions.

11

Telophase

- Centrosomes and chromosomes cluster at their respective ends.
- Chromosomes begin to uncondense to their pre-mitosis state.
- When the individual nucleolus reappear, mitosis is complete.

12

Cytokinesis

The division of the cytoplasm. In animals, a cleavage furrow develops and pinches the cytoplasm, and in plants, a cell plate appears and creates a middle lamella.

13

Density-dependent Inhibition

Cells usually divide until they become too crowded. Cancer cells defy this, however.

14

Anchorage Dependence

Cells must be anchored to something to divide, such as a Petri dish or extracellular membrane. Cancer cells also defy this.

15

Meiosis I

Where the homologous chromosomes separate. Involves synapsis and crossing over.

16

Prophase I

- Crossing over (nonsister chromatids exchanging genetic material).
- Synapsis (pairing of homologues).
- Chiasmata

17

Metaphase I

- Chromosomes line up double file along the equator of the cell.
- Spindle fibers connect at the kinetochores.

18

Anaphase I

- Homologous chromosomes are separated as they are pulled in opposite directions by the spindle fibers.

19

Telophase I and Cytokinesis I

- Chromosomes are pulled apart until they reach the opposite ends of the cell.
- Cytokinesis I usually occurs simultaneously with Telophase I, and splits the cell into two haploid.

20

Three Types of Genetic Variation

1. Independent Assortment of Chromosomes: each chromosome has two ways it can line up at the metaphase plate during meiosis I, which is randomly decided.
2. Crossing Over: the chromosomes randomly trade DNA segments.
3. Random Fertilization: the ovum and sperm have millions of chromosome options.

21

Apoptosis

Programmed cell death.