Core Terminology 2: Cell division

Question 1

Gene

Answer 1

basic unit of a chromosome that controls a specific characteristic/trait

Question 2

Chromatin network

Answer 2

chromosome material inside the nucleus when cells are NOT dividing (tangled mass)

Question 3

Chromosome

Answer 3

linear collection of genes, made up of 2 chromatids joined by a centromere

Question 4

Chromatid

Answer 4

individual strand of a chromosome

Question 5

Centromere

Answer 5

joins 2 chromatids together

Question 6

Homologous chromosome

Answer 6

pair of identical chromosomes, one from father (paternal) & one from mother (maternal)

Question 7

Bivalent

Answer 7

2 homologous chromosomes intertwined

Question 8

Diploid chromosome number (2n)

Answer 8

Double set of chromosomes that appear in each somatic cell

Question 9

Haploid chromosome number (n)

Answer 9

Chromosome number of a gamete

Question 10

Autosomes

Answer 10

normal body chromosomes (22pairs)

Question 11

Gonosomes (2)

Answer 11

sex chromosomes; X and Y Male = XY Female = XX

Question 12

Karyotype

Answer 12

complete set of chromosomes arranged in homologous pairs, according to size, number and shape

Question 13

Genome

Answer 13

complete set of chromosomes with all the genes of an organism

Question 14

Fertilisation

Answer 14

process where a sperm(n) fuse with an egg cell (n) to produce a zygote (2n)

Question 15

Zygote

Answer 15

diploid fusion of sperm and egg

Question 16

Mitosis

Answer 16

type of cell division where 2 identical cells are formed; chromosome number remains the same

Question 17

Meiosis

Answer 17

reduction division; where gametes are formed

Question 18

Crossing over

Answer 18

process for the exchange of genetic material between homologous chromosomes

Question 19

Chiasma (ta)

Answer 19

point where homologous chromosomes overlap to exchange genetic material

Question 20

Cytokinesis

Answer 20

division of the cytoplasm

Question 21

Karyokinesis

Answer 21

division of nucleus

Question 22

Mutations

Answer 22

change in genetic composition (DNA) of an organism

Question 23

Down syndrome

Answer 23

• genetic disorder where chromosome pair 21 consist of an extra chromosome,
• 47 instead of 46 chromosomes in cell
• chromosomal mutation

Question 24

Somatic cells

Answer 24

normal body cells; contains 46 chromosomes

Question 25

Gametes

Answer 25

• sex cells;
• sperm(males); ova (female)
• Plants: pollen = male gametes Ovules = female gametes

Question 26

Gonads

Answer 26

• sex organs that produces the gametes;
• males testes;
• females ovaries;
• Plants: anther = male ovaries = female

Question 27

Non-disjunction

Answer 27

when homologous chromosomes in a bivalent do not separate during Anaphase I

Question 28

Centrosome

Answer 28

An organelle that is the main place where cell microtubules are organized.

Question 29

Centriole

Answer 29

A bound pair of centrioles makes up a centrosome. Important in forming the spindle fibres for cell division.