Chapter 2

Question 1

Prokaryote

Answer 1

A cell that lacks a cellular membrane and doesn’t possess membrane-bound organelles

Question 2

Eukaryote

Answer 2

A complex cell that contains a nucleus and membrane-bound organelles

Question 3

Nucleus

Answer 3

Located in eukaryotes. It separates the DNA from other cellular contents

Question 4

Histone

Answer 4

A special class of proteins. They limit enzymes and proteins that copy/read DNA but they allow the DNA to fit into the nucleus. The DNA must separate from the histones before the genetic information can be accessed.

Question 5

Chromatin

Answer 5

Made up of DNA and histones. Chromatin makes up chromosomes.

Question 6

Homologous pair

Answer 6

A pair of chromosomes that are alike in size, structure, and carry information for the same chromosomes. They aren’t necessarily identical.

Ex: may both code for hair color, but may code for different colors

Question 7

Diploid

Answer 7

Calls that carry two sets of genetic information

Question 8

Haploid

Answer 8

Cells with a single set of chromosomes (only one copy of each gene).

Question 9

Telomere

Answer 9

The natural ends of a linear chromosome. They protect and stabilize the ends of the chromosomes.

Question 10

Centromere

Answer 10

The attachment point for the spindle micro tubules.

Question 11

Origin of replication

Answer 11

The site where DNA synthesis begins.

Question 12

Sister chromatid

Answer 12

Two initial identical copies after cell division. They a held together at the centromere

Question 13

Cell cycle

Answer 13

The life of a cell. A new cycle begins after a cell has divided and produced 2 new cells. There are two main phases: Interphase and M phase.

Question 14

Interphase

Answer 14

The period in between cell divisions in which the cell grows, develops, and functions.

Question 15

M phase

Answer 15

Mitotic Phase. The period of active cell division.

Question 16

Mitosis

Answer 16

The separation of chromosomes in the division of somatic (non-sex) cells (nuclear division).

Question 17

Meiosis

Answer 17

The pairing and separation of chromosomes in the division of sex cells to produce gametes (reproductive cells). The chromosome number is reduced by half. It produces genetically variable cells.

Question 18

Cytokinesis

Answer 18

Cytoplasmic division

Question 19

Checkpoint

Answer 19

ensure that all cellular components are present and functional before moving on to the next stage. Defects in checkpoints can lead to unregulated cell growth.

Question 20

Prophase

Answer 20

Contains two chromatids attached at the centromere; mitotic spindle forms; chromosomes condense

Question 21

Metaphase

Answer 21

chromosomes line up on the metaphase plate; centrosomes go to the opposite ends of the cell and align chromosomes; no nuclear membrane at this point

Question 22

Anaphase

Answer 22

Sister chromatids separate and move towards opposite centrosomes; now there is a total of 8 chromosomes

Question 23

Telophase

Answer 23

chromosomes arrive at spindle poles; the nuclear membrane reforms and the chromosomes relax; 4 chromosomes in each daughter cell. 2N=4

Question 24

Gametogenesis

Answer 24

?

Question 25

Fertilization

Answer 25

Two haploid gametes fuse and restore chromosome number to it’s original diploid value.

Question 26

Prophase I

Answer 26

chromosomes contract and become visible (leptotene); chromosomes continue to condense (zygotene); chromosomes become shorted and thicker (pachytene); homologous chromosomes exchange genetic information (crossing over)

Question 27

Synapsis

Answer 27

pairs the homologous chromosomes; creates a tetrad

Question 28

Bivalent

Answer 28

four chromatids (a.k.a tetrad)

Question 29

Tetrad

Answer 29

Four chromatids (a.k.a bivalent)

Question 30

Crossing Over

Answer 30

When homologous chromosomes exchange genetic information. It generates genetic variation and is essential for the proper alignment and separation of homologous chromosomes.

Question 31

Metaphase I

Answer 31

When homologous pairs of chromosomes line up on the metaphase plate. Can NOT be somatic cells.

Question 32

Anaphase I

Answer 32

The 2 chromosomes (each containing 2 chromatids) of each homologous pair separate and move toward opposite poles. Diads.

Question 33

Telophase I

Answer 33

Chromosomes arrive at spindle poles and the cytoplasm divides. N=2, haploid cells.

Question 34

Interkinesis

Answer 34

The period between meiosis I and meiosis II. The nuclear membrane re-forms around the chromosomes at each pole, the spindle breaks down, and the chromosomes relax.

Question 35

Prophase II

Answer 35

The chromosomes (now diads) re-condense. There is one set of chromosomes in each daughter cell.

Question 36

Metaphase II

Answer 36

Individual chromosomes line up on the equatorial plate.

Question 37

Anaphase II

Answer 37

Sister chromatids separate and move toward opposite poles.

Question 38

Telophase II

Answer 38

Chromosomes arrive at the spindle poles and the cytoplasm divides. N=2.

Question 39

Recombination

Answer 39

Creating new combinations of alleles on a chromatid. Produces genetic variation.

Question 40

Cohesion

Answer 40

A protein that holds the chromatids together in the S phase, G2 phase, and early mitosis.

Question 41

Spermatogenesis

Answer 41

The production of gametes in a male animal. Takes place in the testes. Diploid germ cells divide mitotically to produce diploid cells called spermatogonia.

Question 42

Oogenesis

Answer 42

The production of gametes in a female animal. Diploid germ cells divide mitotically to produce oogonia.

Question 43

Oocyte

Answer 43

Diploid cells. (?)