Chapter
4 – Genetics
1.
Explain the following terms: heredity and genetics.
- Genes,
chromosomes
- dominant
and recessive
- homozygous
(pure-breeding or true-breeding) and heterozygous (or hybrid).
2.
What conclusions did Mendel draw from his experiment?
3.
How many chromosomes do humans have in normal body cells?
In gametes?
4.
Explain why the number of chromosomes in normal cells differ
from those in the gametes.
5.
What is meant by the term allele?
6.
Explain the meaning of the terms genotype and a phenotype
using examples.
7. Explain the difference
between a heterozygous and a homozygous genotype?
8.
Draw a Punnet square to show the ratio of phenotypes and
genotypes when two heterozygous red flowered pea plants are crossed
(the recessive character is white).
9. In guinea pigs black colour
is dominant to white. Draw a Punnett square to show the possible
offsprig that would resulf from a cross between a pure black guinea
pig and a pure white guinea pig.
10. What are the genotypes
and pheotypes of the offspring?
11. Show the expected ratio
of genotypes and phenotypes when two heterozygous black gunea pigs
are crossed.
12. In guppies straight tail is dominant to curly tail and blotching is dominant to stripes.
If a double heterozygous straight tailed blotchy male is mated with
a curly tailed blotchy female (who is heterozygous for that trait), what are the phenotypes and genotypes
that would be expected in the offspring?
13.
Explain
what is meant by incomplete dominance. 14. When a pure breeding white bull is crossed with a pure-breeding red cow, the offspring are all roan. this is an example of incomplete dominance. Predict the ratio of genotypes and phenotypes when a roan cow is crossed with a roan bull.
15.
The
ability to taste sour foods is dominant and non-tasting is recessive.
Write down the phenotypes and genotypes for the following family.
Shaded individuals are non-tasters. 
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