Cell Division Terminology

Question 1

Chromosomes

Answer 1

Made of DNA + histone proteins.

Chromosomes only become visible when chromatin condenses prior to cell division.

Question 2

Define a centromere

Answer 2

Part of a chromosome where 2 chromatids join + where microtubules of the spindle attach at cell division.

Question 3

Define chromatin

Answer 3

Complex of DNA and protein found in eukaryotic cells

Question 4

Define a tumour

Answer 4

Irregular mass of cells

Question 5

Define the chiasma

Answer 5

Point of crossing over in prophase 1 in meiosis.

Question 6

Define a bivalent

Answer 6

Pair of homologous chromosomes

Question 7

Define a synapsis

Answer 7

Each homologous pair of chromosomes comes together to form a bivalent.

Question 8

Define a centrosome

Answer 8

Organelle near nucleus of a cell containing centrioles and where the spindle fibres develop in cell division.

Question 9

Define a chromatid

Answer 9

1 of the 2 identical copies of a chromosome joined at the centromere prior to cell division.

Question 10

How many chromosomes does a normal human body cell have?

Answer 10

46

23 pairs

Question 11

Define the haploid number

Answer 11

No. of chromosomes in a complete set.

Organisms receive 1 complete set of chromosomes from each parent + so chromosomes occur in matching pairs = homologous pairs.

Question 12

Define ploidy level

Answer 12

No. of complete sets of chromosomes in an organism.

i.e human body cells are diploids due to having 2 chromosome sets.