Chromosomes

Question 1

chromosome function

Answer 1

faithful transmission of genetic material, appropriate expression of genetic material
every chromosome has a different nucleotide sequence, hence unique set of genes, unique length

Question 2

chromatid definition

Answer 2

identical halves of a chromosome

Question 3

telomere

Answer 3

constricted G-rich ends of the chromosome, protect DNA from degenerating

Question 4

centromere

Answer 4

constricted region of chromosome that holds both sister chromatids together

Question 5

p and q arm

Answer 5

short and long arm of chromosome

Question 6

chromosome nomenclature conventions

Answer 6

1 to 22 autosomes, arranged based on biggest to smallest and X/Y chromosomes
regions in chromosome are labelled
np/qn
chromosome number, which region from centromere

Question 7

types of chromosomes

Answer 7

metacentric: centromere in the centre, both arms approx equal length
submetacentric: centromere slightly offset from centre, slight asymmetry between arms
acrocentric: centromere severely offset from centre, one very long one very short arm
telocentric: centromere at end of chromosome

Question 8

DNA content

Answer 8

mass of DNA in a cell (3.5pg)

Question 9

ploidy (n)

Answer 9

number of copies of chromosome sets they have
haploid: single chromosome set
diploid: two copies of chromosome sets
polypoint: more than 2 copies of chromosome sets

Question 10

chromatin

Answer 10

uncondensed and more acessible form of chromosome (combination of DNA and protein made up of repeating nucleosomes)
euchromatin: more accessible, less densely packed
heterochromatin: less accessible, more densely packed
condenses in metaphase

Question 11

karyotype

Answer 11

species specific number, size, shape, centromere position of chromosome

Question 12

karyogram

Answer 12

visual profile of karyotype sorted by size shape, centromere location

Question 13

homologous pairs

Answer 13

pair of chromosomes carrying genetic information for same set of hereditary structures

Question 14

cytogenetics

Answer 14

alternating light and dark regions, reflecting composition of AT CG pairs
produced after staining with a dye that binds to DNA
some dyes preferentially bind to AT/CG

Question 15

histone structure

Answer 15

H1 H2A H2B H3 H4
high % of arginine and lysine residues, postively charged
attracts negatively charged phosphates of DNA

Question 16

nucleosome

Answer 16

2 turns of DNA wrapped around histone octamer

Question 17

genes

Answer 17

functional parts of chromosomes made with double stranded DNA, some genes encode for protein AA sequence