Inheritance

Question 1

Inheritance

Answer 1

transmission of genetic information from generation to generation

Question 2

Chromosome

Answer 2

A thread-like structure of DNA, carrying genetic information in the form of genes

Question 3

Gene

Answer 3

Length of DNA that codes for a protein

Question 4

haploid nucleus

Answer 4

A nucleus contains single set of unpaired chromosomes (sperm or egg cell)

Question 5

Diploid nucleus

Answer 5

a nucleus containing two sets of chromosomes (body cells)

Question 6

homologous Chromosomes

Answer 6

The chromosomes which are structurally and functionally similar

Question 7

Mitosis

Answer 7

Nucleus division giving rise to genetically identical cells (1 cell divides into 2 identical cells, have equal number of chromosomes)

Question 8

Role of mitosis in growth, repair of damaged tissues, replacement of cells and asexual reproduction

Answer 8

Mitosis is used to create new cells in the body to repair and replace old damaged tissues, as well as allowing growth of organisms and playing a role in Asexual reproduction.

Question 9

State that during mitosis, the copies of chromosomes separate, maintaining the chromosome number

Answer 9

Mitosis involves splitting of chromosomes, into their two halves, each of which are know was chromatid.

1. Before replication occur, chromatid in parent cell replicates to produce identical copies of themselves which pair as chromosomes.
2. Chromosomes line up along nucleus
3. chromosomes separate so that each identical chromatid is pulled is pulled to opposite poles of the cell.
4. Cell membrane constricts in the middle, nucleus is separated as cell splits into two new daughter cells. each cell contain sets of chromatids, which replicates themselves to produce new chromosomes.

Question 10

Stem cells

Answer 10

Found in embryos of bone marrow, they are unspecialized cells and divide by mitosis to produce daughter cells, which specialise to have variety of functions.

Question 11

Meiosis

Answer 11

Reduction division in which the chromosome number is halved from diploid to haploid resulting in genetically different cells

-Meiosis is involved in the production of gametes

Question 12

How meiosis produces variation by forming new combinations of maternal and paternal chromosomes

Answer 12

During meiosis, chromosome Is halved, diploid cell divides to produce 4 haploid cells. As each gamete produced is genetically unique, each offspring will also be unique. Beneficial for species as it produces genetic variation.

Question 13

Genotype

Answer 13

the genetic make-up of an organism in terms of the alleles present

Question 14

Phenotype

Answer 14

the observable features of an organism

Question 15

Homozygous

Answer 15

Having two identical alleles of a particular gene

Question 16

Pure-breeding

Answer 16

• When two identical homozygous individuals that breed together
• Heterozygous individual will not be pure-breeding

Question 17

Heterozygous

Answer 17

Having two different alleles of a particular gene

Question 18

Dominant

Answer 18

an allele that is expressed if it is present

Question 19

Recessive

Answer 19

an allele that is only expressed when there is no dominant allele of the gene present

Question 20

Co-dominance

Answer 20

Some alles are co-dominant, meaning neither is recessive, both displayed in the phenotype. Example: Blood groups. Possible groups for blood group is A, B, and O, where A, and B alles are co-dominant, leads to AB blood group. blood group O is recessive, thus is only displayed in phenotype if both parents have O blood groups.

Question 21

Sex-linked characteristic

Answer 21

• A characteristic in which the gene responsible
  is located on a sex chromosome and that this makes it more common in one sex than in the other
• Example: colour blindness, recessive characteristic found on X chromosome.