General

Question 1

define meiosis

Answer 1

reduction division wherby chromosoma number is halved from diploid to haploid for the production of gametes

Question 2

Chromosome characteristics?

Answer 2

single stranded dna molecules around histone protein in chromatin network

Question 3

Explain the formation of a homologous pair and what it is?

Answer 3

Homologous is a pair of chromosomes with same structure and purpose
Interphase dna replication occurs double the number of chromosomes in the form of two chromatids joined by centromere

Question 4

Autosomes vs Gonosomes?

Answer 4

autosomes are chromosomes that determine features first 22
gonosomes determine sex and is 23rd pair
xx female
xy male

Question 5

Why are haploid gametes required?

Answer 5

overcome the doubling effect of fertilization

Question 6

Importance of Meiosis (3)?

Answer 6

1- overcome doubling effect
2- keep chromosomal number constant through generations
3- genetic variance through crossing over and random assortment to ensure survival through evolution

Question 7

Explain Downs Syndrome

Answer 7

Abnormal meiosis and chromosomes during oogenesis don’t split properly in anaphase 1
This is a form of anuploidy as there will be an extra chromosome in the daughter cell
where one has two on chromosome 21
fertilization occurs and a zygote is formed wherby 23+24=47 and this results in extra pair of chromosome
hence trisomy-21
effect feature- flat face, retard and heart defects

Question 8

what is a bivalent

Answer 8

paternal and maternal chromatids that lie next to each other from two chromosomes as a result of synapsis

Question 9

define karyotype
and what does it show

Answer 9

computer diagram of chromosomes during metaphase organized by size and shape
show sex and abnormalities