Characteristics depends on information carried on a single gene that have two alternative alleles. Many depend on a single that has multiple alleles or POLYGENIC TRAITS: Phenotypic features result from interaction of number of different genes.
DISCONTINUOUS: Whether features present or not
- Blood group or sex
CONTINUOUS: Polygenic inheritance gives rise.
- Height or weight
- GENOTYPE: Alleles expressed in forms of letters
- HOMOLOGOUS PAIRS: Half the chromosomes from male and from the female
- ALLELES: Different versions of the same gene
- HOMOZYGOUS: Both alleles coding for particular characteristics are identical
- HETEROZYGOUS: Two alleles coding for characteristic are different
- GENES: Sequence of bases
- DOMINANT: Effects expressed (upper case letters)
- RECESSIVE: Only expressed in phenotype (lower case letters)
- EPISTASIS: Polygenic traits, one gene effects/alters another
- POLYGENIC: Different alleles interact which affect expression of particular characteristics. More than one gene is involved in influencing phenotype. Gene loci.
Outward expression of a cell or organism.
SIAMESE CAT HAIR:
- Genotype: Gene codes for enzyme which makes dark fur
- Environment: Enzymes at optimum temperature
- Phenotype: Distinctive colouration of body extremeties
LUNG CANCER AND SMOKING:
- Genotype: Presence of enzymes regulating cell cycle
- Environment: Chemical component alters genes
- Phenotype: Cell cycle isn't regulated, the living cells keep dividing which makes a tumour grow.
MONOAMINE OXIDASE A: Enzyme found in the nervous system
MONOAMINE: Transmits nerve impulses across synapse
- High levels of enzymes formed:
Breaks down too many neurotransmitter molecules and functioning of brain affected.
- Low levels of enzymes formed:
Linked to depression and addictive behaviour.
E.COLI: Gut bacteria
Lactose induces E. Coli to produce gut bacteria.
When lactose becomes available, the bacterial cell contains enzymes and molecules.
Lactose binds to repressor which makes it change shape.
X chromosome is inactivated by supercoiling.
Random X chromosomes inactivated by embryonic cells
Cells which descend from that cell have the same inactivated chromosomes.