a(i)Complete the table below by stating the type of cell division and the type of set of chromosomes for the listed cells.
| Cell | Type of cell division | set of chromosomes |
| Onion cell | mitosis | |
| Sperm cell | ||
| Pollen grain | ||
| Ovum | ||
| Guard cell | ||
| Cheek cell | diploid |
(ii) What is mitosis?
(b)Explain briefly how parents with blood groups A or B could have an offspring with blood group O.
(c)Explain briefly how genes are involved in the process of evolution.
Explanation
a(i)
| Cell | Type of cell division | set of chromosomes |
| Onion cell | mitosis | diploid |
| Sperm cell | meiosis | haploid |
| Pollen grain | meiosis | haploid |
| Ovum | meiosis | haploid |
| Guard cell | mitosis | diploid |
| Cheek cell | mitosis | diploid |
(ii)Mitosis is a process in which a cell divides into two identical daughter cells. It's a type of cell division that occurs in eukaryotic cells. Mitosis is responsible for growth and replacing worn-out cells. A cell replicates its chromosome and segregates them.
(b) Parents with blood groups A or B can have an offspring with blood group O if both parents are "heterozygous" for their blood type, meaning they carry both the dominant A or B allele and the recessive O allele, and each parent passes on the O allele to the child, resulting in a type O blood group for the offspring; this is possible because the O allele is recessive to both A and B alleles.
(c) Genes are the fundamental unit of inheritance, and their variations, primarily caused by mutations, are the raw material for evolution; meaning that changes in the frequencies of different gene variants within a population over time, driven by natural selection, lead to the observable changes we see as evolution. Genetic variations that alter gene activity or protein function can introduce different traits in an organism. If a trait is advantageous and helps the individual survive and reproduce, the genetic variation is more likely to be passed to the next generation (a process known as natural selection).