KS3 Genetics and Inheritance Flashcards
Not sure if complete (probs good for revision anyways)
What are chromosomes?
Thread-like structures composed of proteins and a single molecule of deoxyribonucleic acid (DNA).
Where are chromosomes located (eukaryotes and prokaryotes)?
- Eukaryotes: inside the nucleus.
- Prokaryotes: inside the nucleoid.
What is DNA?
A polymer that contains biological instructions (genes) - makes each species unique.
What is a gene?
A segment of DNA which encodes for a particular type of protein.
What are alleles?
Different forms of a particular gene.
What are dominant alleles?
Alleles whose characteristics are always expressed.
What are recessive alleles?
Alleles whose characteristics are only expressed when inherited from both parents.
What is a genotype?
The genetic makeup of an individual.
(It is also known as the collection of alleles that an individual has).
Do we have different or similar genotypes? Why?
Everyone has different genotypes because everyone has different alleles and different genetic codes.
What is a phenotype?
The physical appearance of the characteristics.
(It is also known as the characteristics an organism has as a result of their genotype).
Do we have different or similar phenotypes?
It depends:
- Having the same physical characteristics = same phenotypes.
- Having different physical characteristics = different phenotypes.
e.g. A blue eyed person and a brown eyed person have different phenotypes.
What is a homozygote?
An individual who has identical alleles for a particular gene; a homozygous individual.
What is a heterozygote?
An individual who has different alleles for a particular gene; a heterozygous individual.
What is genetic variation?
The difference in DNA sequences between individuals within a population.
How many chromosomes are in skin cells?
46
How many chromosomes are in gametes? Why?
23; When the sperm cell fuses with the ova, the chromosomes from both gametes add up to equal 46, allowing a new cell (zygote) to be formed (aka, you).
What is monohybrid inheritance?
The inheritance of a characteristic that is controlled by a single gene or a pair of allele.
What is fertilisation?
The fusion of a male and female gamete.
What is a gamete?
The reproductive cell of an organism.