Chapter 12 Biology Review

Front 1

3 types of fibers in cytoskeleton

Back 1

Microtubules (thickest)

Intermediate filaments

Microfilaments (thinnest, also called actin filaments)

Front 2

Site of synthesis of ribosomes

Back 2

Nucleolus

Front 3

DNA complexed with proteins (called histones)

Back 3

Chromatin

Front 4

How many chromosomes are in a human somatic cell?

Back 4

46

Front 5

How many chromosomes are in a human reproductive (germ) cell?

Back 5

23

Front 6

What proteins complex with DNA to form nucleosome?

Back 6

Histones

Front 7

What is the order of the phases of cell division?

Back 7

Interphase

Prophase

Prometaphase

Metaphase

Anaphase

Telophase

Front 8

What occurs during G1 of Interphase?

Back 8

Initial growth phase. DNA and protein are made. Increase in organelles and cytoskeleton. Cell doubles in size.

Front 9

What occurs during S phase of Interphase

Back 9

DNA replicates

Front 10

What occurs during G2 phase of Interphase?

Back 10

Preparation for division. RNA and protein are made. Apoptosis occurs.

Front 11

What is the purpose of Mitosis?

Back 11

Growth and repair of cells

Front 12

Prophase

Back 12

Chromatin coil to form chromosomes (chromosomes consist of 2 sister chromatids that contain identical DNA)

Nucleoli disappear

Nuclear membrane still intact

Front 13

Centrosomes

Back 13

Organize microtubules of spindle apparatus

Front 14

Centromeres

Back 14

Regions where chromatids are held together

Front 15

Kinetochore

Back 15

Protein structure on chromatids where spindle fibers attach, located on centromere region

Front 16

Prometaphase

Back 16

Nuclear envelope breaks down

Microtubules invade nucleus and interact with chromosomes, which are more condensed

Still 2 sister chromatids

Front 17

Metaphase

Back 17

Chromosomes line up with centromeres in a plane (metaphase plate) in center of spindle apparatus

Chromosomes still consist of 2 sister chromatids

Front 18

Anaphase

Back 18

Sister chromatids separate to opposite poles

Spindle fibers attach to centromere/kinetochore and pull apart chromatids by splitting centromere

Sister chromatids are now called chromosomes

Front 19

Telophase

Back 19

2 daughter nuclei reorganize

Spindle disperses, nuclear envelope and nucleoli reform

Chromatin becomes less tightly coiled

2 genetically identical nuclei are seen, each chromosome has 1 DNA molecule

Cytokinesis is underway

Front 20

Cytokinesis for Animals and Protozoans

Back 20

Pinching in of nuclear membrane forms cleavage burrow

Front 21

Cytokinesis for Plants, Fungi, and Algae

Back 21

Vesicles containing cell wall material fuse along the midline and continues cell wall is formed

Front 22

What is restriction point for cell division?

Back 22

G1 in interphase

Front 23

Cancer cells

Back 23

do not respond to normal regulation of growth and division

Front 24

Benign tumor

Back 24

Not cancerous

Front 25

Malignant Tumor

Back 25

Cancerous, may impair functions of organs

Front 26

Growth factor

Back 26

A proteins released by by certain body cells that stimulates other cells to divide

Front 27

Density-dependent inhibition of cell division

Back 27

Crowded cells usually stop dividing (doesn't happen in cancer cells)