Chapter 8 The Continuity of Life: How Cells Reproduce

Question 1

Anaphase

Answer 1

In mitosis, the stage in which the sister chromatids of each chromosone seperate from one another and are moved to the opposite poles of the cell; in meiosis I, the stage in which homologous chromosones, consisting two sister chromatids, are seperated; in meiosis II, the stage in which the sister chromatids of each chromosome seperate from one another and are moved to opposite poles of the cell.

Question 2

Asexual Reproduction

Answer 2

Reproduction that does not involve the fusion of haploid sex cells. The parent may divide and new parts regenerate, or a new, smaller individual may form as an attachment to the parent, to drop off when complete.

Question 3

Autosome

Answer 3

A chromosone that occurs in homologous pairs in both males and females and that does not bear the genes determining sex.

Question 4

Binary Fission

Answer 4

The process by which a single bacterium divides in half, producing two identical offspring.

Question 5

Cell Cycle

Answer 5

The sequence of evens in the life of a cell, from one division to the next.

Question 6

Cell Division

Answer 6

Splitting of one cell into two; the process of cellular reproduction.

Question 7

Cell Plate

Answer 7

A membrane-bound structure, formed in plant cells during cytokinesis, that becomes the cell seperating two daughter cells.

Question 8

Centriole

Answer 8

In animal cells, a short, barrelshaped ring consisting of nine microtubule triplets; a mircotubule-containing structure at the base of each cilium and flagellum; gives rise to the microtubules of cilia and flagella and is involved in spindle formation during cell division.

Question 9

Centromere

Answer 9

The region of a replicated chromosone at which the sister chromatids are held together until they seperate during cell division.

Question 10

Chiasma (plural, chiasmata)

Answer 10

A point at which a chromatid of one chromosone crosses with a chromatid of the homologous chromosone during photosynthesis; absorbs violet, blue, and red light but reflects green.

Question 11

Chromatid

Answer 11

One of the two identical strands of DNA and protein that forms a replicated chromosone. The two sister chromatids are joined at the centromere.

Question 12

Chromosone

Answer 12

A DNA double helix together with proteins that help to organize the DNA.

Question 13

Clone

Answer 13

Offspring that are produced by mitosis and are therfore genetically identical to each other.

Question 14

Cloning

Answer 14

The process of produicing many identical copies of a gene; also the production of many genetically identical copies of an organism.

Question 15

Crossing Over

Answer 15

The exchange of corresponding segments of the chromatids of two homologous chromosones during meiosis.

Question 16

Cytokinesis

Answer 16

The division of the cytoplasm and organelles into two daughter cells during cell division; normally occurs during telophase of mitosis.

Question 17

Daughter Cell

Answer 17

A cell that is produced as the result of cell division.

Question 18

Diploid

Answer 18

Referring to a cell with pairs of homologous chromosones.

Question 19

Double Helix

Answer 19

The shape of the two-stranded DNA molecule; like a ladder twisted lengthwise into a corkscrew shape.

Question 20

Gamete

Answer 20

The haploid sex cell formed in sexually reproducing organisms.

Question 21

Gene

Answer 21

A unit of heredity that encodes the information needed to specify the amino acid sequence of protiens and hence particular traits; a functional segement of DNA located at a particular place on a chromosone.

Question 22

Haploid

Answer 22

Referring to a cell that has only one member of each pair of homologous chromosones.

Question 23

Homologue

Answer 23

A chromosone that is similar in appearance and genetic information into another chromosone with which it pairs during meiosis; also called homologous chromosone.

Question 24

Interphase

Answer 24

The stage of the cell cycle between cell division; the stage in which chromosones are replicated and other cell functions occur, such as growth, movement, and acquisition of nutrient.

Question 25

Kinetichore

Answer 25

A protein structure that forms at the centromere regions of chromosones; attaches the chromosones to the spindle.

Question 26

Meiosis

Answer 26

In eukaryotes, a type of nuclear division in which a diploid nucleus divides twice to produce four haploid nuclei.

Question 27

Meiotic Cell Division

Answer 27

Meiosis followed by cytokinesis.

Question 28

Metaphase

Answer 28

The stage of mitosis in which, the chromosones, attached to spindle fibers at kinetochores, are lined up along the equator of the cell.

Question 29

Mitosis

Answer 29

A type of nuclear division, used by eukaryotic cells, in which one copy of each chromosone (already duplicated during interphase before mitosis) moves into each of two daughter nuclei; the daughter nuclei are therefore genetically identical to each other.

Question 30

Mitotic Cell Division

Answer 30

Mitosis follwed by cytokinesis.

Question 31

Nucleotide

Answer 31

A subunit of which nucleic acids are composed; a phosphate group bonded to a suger (deoxyribose in DNA), which is in turn bonded to a nitrogen-containing base (adenine, guanine, cytosine, and thymine in DNA). Nucleotides are linked together, forming a strand of nucleic acid, as follows: Bonds between the phosphate of one nucleotide link to sugar of the next nucleotide.

Question 32

Prophase

Answer 32

The first stage of mitosis, in which the chromosones first become visible in the light microscope as thickened, condensed threads and the spindle begins to form; as the spindle is completed, the nuclear envelope breaks apart, and the spindle fibers invade the nuclear region attach to the kinetochores of the chromosomes, Also, the first stage of meiosis: In meiosis I, the homologous chromosomes pair up and exchange parts at the chiasmata; in meiosis II, the spindle re-forms and chromosomes attach to the microctubules.

Question 33

Recombination

Answer 33

The formation of new combinations of the different alleles of each gene on a chromosone; the result of crossing over.

Question 34

Sex Chromosone

Answer 34

One of the pair of chromosones that usually determines the sex of an organism; for example; the X and Y chromosomes in mammals.

Question 35

Sexual Reproduction

Answer 35

A form of reproduction in which genetic material from two parten organisms is combined in the offspring; normally, two haploid gametes fuse to form a diploid zygote.

Question 36

Spindle Microtubule

Answer 36

Microtubules organized in a spindle shape that seperate chromosomes during mitosis or meiosis.

Question 37

Stem Cell

Answer 37

An undifferentiated cell that is capable of diving and giving rise to one or more types of differentiated cell.

Question 38

Telophase

Answer 38

In mitosis, the final stage in which a nuclear envolope re-forms around each new daughter nucleus, the spindle fibers disappear, and the chromosomes relax from their condensed form; in meiosis I, the stage during which the spindle fibers disappear and the chromosomes normally relax from their condensed from; in meiosis II, the stage during which chromosomes relax into their extended state, the nuclear envelopes re-form, and cytokinesis occurs.