Chapter 4 Cell division and Reproduction (Defs.)

Question 1

A plant or animal cell that forms the body of the organisms; excludes reproductive cells.

Answer 1

Somatic cell

Question 2

A structure in the nucleus that contains DNA.

Answer 2

Chromosome

Question 3

One of two chromosomes that are genetically identical and held together at the centromere.

Answer 3

Sister chromatid

Question 4

The region where two sister chromatids are held together in a chromosome.

Answer 4

Centromere

Question 5

A microtubule structure that facilitates the movement of chromosomes within a cell.

Answer 5

Spindle fibre

Question 6

A structure that helps to form the spindle fibres.

Answer 6

Centrosome

Question 7

The stage of mitosis during which the cell’s chromatin condenses into chromosomes.

Answer 7

Prophase

Question 7

The stage of the cell cycle during which a cell carries out its normal functions, grows, and makes copies of its genetic material in preparation for the next stage of the cycle.

Answer 7

Interphase

Question 7

The stage of mitosis during which spindle fibres from opposite poles attach to the centromere of each chromosome, guiding the chromosomes to the equator of the cell.

Answer 7

Metaphase

Question 8

Stage of mitosis during which each centromere splits apart and the sister chromatids separate from each other.

Answer 8

Anaphase

Question 9

Stage of mitosis during which the chromosomes start to unwind into strands of chromatin, the spindle fibres break down, the nuclear membrane forms around the new set of chromosomes, and a nucleolus forms within each new nucleus.

Answer 9

Telophase

Question 10

Stage of the cell cycle that begins near the end of mitosis and involves the division of the cell cytoplasm and the creation of a new cell.

Answer 10

Cytokinesis

Question 11

Stage of cell cycle during which a cell’s nucleus and genetic material divide.

Answer 11

Mitosis

Question 12

A structure that forms between the two daughter nuclei during the process of cytokinesis in plant cells; cell walls then form on either side of the cell plate.

Answer 12

Cell plate

Question 13

A spiral shape formed by a DNA molecule.

Answer 13

Double helix

Question 14

The individual units of each strand of DNA; composed of a phosphate group, a sugar group, and a base - either adenine, guanine, thymine, or cytosine.

Answer 14

Nucleotides

Question 15

Nucleotide bases on opposite strands of the DNA backbone that interact in a DNA molecule; adenine pairs with thymine and guanine pairs with cytosine.

Answer 15

Complementary base pairs

Question 16

A permanent change in the genetic material of an organism; the only source of new genetic variation.

Answer 16

Mutation

Question 17

The complete DNA sequence of an organism.

Answer 17

Genome

Question 18

Describes a method of DNA replication that conserves half of the original DNA molecule when producing a new molecule of double-stranded DNA.

Answer 18

Semi-conservative

Question 19

An X or Y chromosome, which determines the genetic sex of an organism.

Answer 19

Sex chromosome

Question 20

A chromosome that is not involved in determining the sex of an organism.

Answer 20

Autosome

Question 21

A chromosome that contains the same sequence of genes as another chromosome.

Answer 21

Homologous chromosome

Question 22

A part of a chromosome that governs the expression of a trait and is passed on to offspring; it has a specific DNA sequence.

Answer 22

Gene

Question 22

One of two or more forms of a gene.

Answer 22

Allele

Question 23

A photograph of pairs of homologous chromosomes in a cell.

Answer 23

Karyotype

Question 24

Reproduction that requires only one parent and produces genetically identical offspring.

Answer 24

Asexual reproduction

Question 25

Reproduction that requires two parents and produces genetically distinct offspring.

Answer 25

Sexual reproduction

Question 26

A male or female reproductive cell.

Answer 26

Gamete

Question 27

A cell formed by the fusion of two gametes.

Answer 27

Zygote

Question 28

In humans, the joining of male and female haploid gametes.

Answer 28

Fertilization

Question 29

A cell that contains half the number of chromosomes as the parent cell.

Answer 29

Haploid

Question 30

A cell that contains pairs of homologous chromosomes.

Answer 30

Diploid

Question 31

The cellular process that produces cells containing half the number of chromosomes as the parent cell.

Answer 31

Meiosis

Question 32

The aligning of homologous chromosomes during prophase I in meiosis I.

Answer 32

Synapsis

Question 33

The process of producing male gametes (sperm) in mammals.

Answer 33

Spermatogenesis

Question 34

The process of producing female gametes (eggs) in mammals.

Answer 34

Oogenesis

Question 35

The exchange of chromosomal segments between a pair of homologous chromosomes.

Answer 35

Crossing over

Question 36

The failure of homologous chromosomes pairs or sister chromatids to separate during meiosis.

Answer 36

Non-disjunction

Question 37

The loss of a chromosome as a result of non-disjunction.

Answer 37

Monosomy

Question 38

The gain of a chromosome as a result of non-disjunction.

Answer 38

Trisomy

Question 39

The process of breeding plants and animals for desirable traits.

Answer 39

Selective breeding

Question 40

The process by which sperm are collected and concentrated before being introduced into the female's reproductive system.

Answer 40

Artificial insemination

Question 41

The process by which an egg that has been fertilized artificially is transferred into a recipient female's uterus.

Answer 41

Embryo transfer

Question 42

The technique used to fertilize egg cells outside the female's body.

Answer 42

In vitro fertilization

Question 43

A process that produces identical copies of genes, cells, or organisms.

Answer 43

Cloning

Question 44

The use of DNA manipulation techniques to produce multiple copies of a single gene or segment of DNA.

Answer 44

Gene cloning

Question 45

A molecule of DNA that includes genetic material from different sources.

Answer 45

Recombinant DNA

Question 46

The process of replacing an egg cell's nucleus with the nucleus from a somatic donor cell to produce a cell line of genetically identical cells.

Answer 46

Therapeutic cloning

Question 47

The process of producing genetically identical organisms.

Answer 47

Reproductive cloning

Question 48

An undifferentiated cell that can develop and become specialized into different cell types of the body.

Answer 48

Stem cell

Question 49

Describes an organism whose genome has been altered by the insertion of a gene from another organisms; a type of genetically modified organisms.

Answer 49

Transgenic

Question 50

An organism whose genome has been altered.

Answer 50

Genetically modified organisms (GMO)