Patterns of Inheritance Flashcards
What is chlorosis?
When the leaves of a plant look pale or yellow
Why does chlorosis occur?
Cells are not producing the normal amount of chlorophyll, which reduces the ability of the plant to make food by PHS
Give 3 environmental factors that cause chlorosis
1- Lack of light
2- Mineral deficiencies
3- Virus infections
What is a genotype?
The combination of alleles an organism inherits for a characteristic
What is a phenotype?
The observable characteristics of an organism
What is a dominant allele?
The version of the gene that will always be expressed if present in an organism
What is a recessive allele?
Only be expressed if 2 copies of this allele are present in an organism
What does homozygous mean?
They have 2 identical alleles for a characteristic
- Homozygous dominant = DD
- Homozygous recessive = dd
What does heterozygous mean?
They have 2 different alleles for a characteristic, e.g. Dd
What is continuous variation?
- A characteristic that can take any value within a range
- E.g. height and weight
- Genetic and environmental
What is discontinuous variation?
- A characteristic that can only appear in specific (discrete) values
- E.g. blood groups
- Usually only one gene is involved, not environment
What does monogenic inheritance show?
Inheritance of a single gene
What is codominance?
Occurs when 2 different alleles occur for a gene - both of which are equally dominant
What are sex linked genes?
Genes carried on the sex chromosomes
Give an example of a sex-linked genetic disorder
Haemophilia
