Jiho biology notes Inheritance

gene is a sequnece of … and controls the production of …. which controls..
it is also a unit of in… on a particular locus of the chromosome ***

gene is a sequnece of nueclotide and controls the production of polypeptides which controls a phenotype
it is also a unit of inheritance on a particular locus of the chromosome

what about allels? alleles are .. forms of the same gene and they occupy.. ***

alleles are different forms of the same gene and occupy the same gene locus on a pair of homologous chromosomes
they control the version sof the same traits and are either dominant or recessive

homologous chromosomes are chomosomes that was from ***

one copy was from the father and one from the mother, to form a zygote.
the homo chromo are similar in shape, length and have EXACT SAME SEQUENCE OF GENE LOCI.

In codominance.. both alleles alleles.. ****

express themselves in the heterozygote, and the phenotype of that character will be intermediate between that of its pure bred parents.

A gene that exists in more than two different forms is said to have ***

multiple allels

explain why observed ratio diff expected ratio **********

The sample size is too small,
the expected ratios are based on mathematical probability
The fertilisations that take place are independent of each other.

sometimes.. it is influenced by environemnet or random mutations

compare continous and discontinuous variations… ***

Continous variations are variations that stem from …

many genes, while discontinous variations is borught about one or few genes.

Discontinous variation:

Distinct phenotype
No influenced by environment
e.g. Blood group, gender

COntinous variation
Many genes
range of phenotypes
Affected by environemntal conditions
e.g. height and skin colour

define mutation *** ( inside syllabus)

a mutation is a random change in the strucutre of a gene or number of chromosomes.

ionising … and chemicals are factors that increase … ****

radiation and mutation

Give an example of mutations, sickle cell anemia.explain.

expressed in homo recessive,
And sickle shaped rbc have lower o2 capacity due to reduced o2 transport

an increase in proton number causes..

down syndrome, extra chromo 21

natural selection is the process where …

organimss with desireable traits better suited to the environemnt survives to their reproductive age to pass their genes to the offspring.

evolution si the gradual cahnge in..

inheritbale characteristics of a population overtime

darwins finches is an example of

evolution, where beaks of finches on the galapagos isalnds were adapted to find specific food sources.