MEIO
Structure of chromosomes:
SIS
Nucleus = nuclear membrane with nuclear pores and nucleoplasm – contain
chromatin network/ threads.
Beginning of cell division
Chromatin network unwinds to form separate chromosomes.
Chromosome – made up of long strand of DNA which is tightly wrapped by outer
protein covering.
Short sequence of nucleotides carries genetic code for development of characteristic
or trait = gene
Non-coding DNA = nucleotides are non-functional
Chromosomes in Somatic and Sex cells
, Somatic cells – body cells and sex cells - gametes
Humans have 46 chromosomes in body cells or somatic cells
Chromosomes arranged in pairs- 23 pairs of chromosomes (Karyotype)
22 autosomes and a pair of sex chromosomes/gonosomes
The two chromosomes making up each pair are identical to each other in autosomes
(same shape, size and gene structure)
Females: XX and Males: XY sex chromosomes are genetically different to each
other and come from maternal and paternal origin.
2 sets of 23 different kinds of chromosomes in each somatic cell- cells have diploid
no. of chromosomes. (2n)
Structure of chromosomes:
SIS
Nucleus = nuclear membrane with nuclear pores and nucleoplasm – contain
chromatin network/ threads.
Beginning of cell division
Chromatin network unwinds to form separate chromosomes.
Chromosome – made up of long strand of DNA which is tightly wrapped by outer
protein covering.
Short sequence of nucleotides carries genetic code for development of characteristic
or trait = gene
Non-coding DNA = nucleotides are non-functional
Chromosomes in Somatic and Sex cells
, Somatic cells – body cells and sex cells - gametes
Humans have 46 chromosomes in body cells or somatic cells
Chromosomes arranged in pairs- 23 pairs of chromosomes (Karyotype)
22 autosomes and a pair of sex chromosomes/gonosomes
The two chromosomes making up each pair are identical to each other in autosomes
(same shape, size and gene structure)
Females: XX and Males: XY sex chromosomes are genetically different to each
other and come from maternal and paternal origin.
2 sets of 23 different kinds of chromosomes in each somatic cell- cells have diploid
no. of chromosomes. (2n)
