(a) List four characteristics which can be genetically transmitted in humans. (b)(i) Name two sites eac• in plants and animals where meiosis occurs. (ii) State two differences between meiosis and mitosis (c) A woman with blood group 'A' (heterozygous) claimed that her son who has blood group '0' was fathered by Mr. James who has blood group 'A' (homozygous). With the aid of suitable genetic diagrams (i) prove or disprove the woman's claim (ii) give reasons to support your answer.
Explanation
(a) Inheritable characters: - Skin/hair/eye colour - Blood Group - voice Height/structure - Haemophilia Albino/albinism Weight Size - Sickle cell anaemia Colour blindness Size - Tongue rolling Intelligence - baldness (b)(i) Sites of Meiosis: - In plants:
Number of chromosomes remain the same after division. Diploid
Number of chromosomes is halved after division. Haploid
Homologous chromosomes do not associate
homologous chromosome associate to form bivalents
chiasmata are never formed
chiamata are formed
crossing over never occurs / no exchange of genetic material
crossing over occurs/exchange of genetic material occurs
Daughter cells identical to parents cells
daughter cell generally different from parent cell
Two daughter cells are formed
four daughter cells are formed
chromosomes form single role at the equator
chromosomes form double role at the equator
Occurs in somatic cell
occurs in reproductive cell
occurs in asexual reproduction
occurs in sexual reproduction
The woman's claim is wrong.Reasons (ii) Half their children are heterozygous blood group A and Half homozygous blood group A (iii) No child is group 0.
