two types of chromosomes Correct Ans-- the chromosome types are divided into two
categories, autosomes and sex chromosome
- XX = female
- XY = male
autosomes Correct Ans-- are structures that contain the hereditary information
- they do not contain information related to reproduction and sex determination
- they are identical in both sexes, i.e., male and female species of humans
- there are 46 (2n) chromosomes in humans
- of these 46 chromosomes, there are 44 pairs of autosomes and contain information related
to the phenotypic characters
> physical features
, BIOS 256: week 6 Questions and Answers 100% Solved
allosomes/heterosomes Correct Ans-- are sex chromosomes that are different from
autosomes in form, behavior and size
- there are two allosomes in humans
> the X chromosomes are present in the ovum and either the X or Y chromosome can be
present in the sperm
- these chromosomes help in determination of sex of the progeny
- if the offspring receives X chromosome from the mother as well as father, it results in a
female child (XX)
- if the offspring receives one X and one Y chromosome from the parents, it results in a male
child (XY)
- in simple words, it is the donation of X or Y chromosome by the father that helps the
determination of the sex of the child
sperm Correct Ans-- male sex cells
, BIOS 256: week 6 Questions and Answers 100% Solved
oocytes Correct Ans-- also called eggs
- female sex cell
sex cell production Correct Ans-- sex cells have 1 set of genetic instructions found on 23
chromosomes, compared to 2 sets of 46 chromosomes in other body cells
- when the sperm and egg unite at fertilization, the genetic information carried on 46
chromosomes is restored
- sex cells are produced by a special type of cell division called meiosis
meiosis Correct Ans-- includes 2 successive divisions, called the first (meiosis I) and second
(meiosis II) meiotic divisions
- prior to meiosis, each chromosomes replicates and contains 2 DNA strands, called
chromatids, connected by a centromere
somatic cells Correct Ans-- diploid cells