Summary of "GCSE Biology - DNA Part 2 - Alleles / Dominant / Heterozygous / Phenotypes and more! #64"

Main Ideas and Concepts:

Gene Definition: A Gene is a segment of DNA that codes for a specific type of protein.
Alleles: Different versions of the same Gene are called Alleles. Each individual inherits two Alleles for each Gene, one from each parent.
- Homozygous: When both Alleles are the same (e.g., both Alleles for green fur).
- Heterozygous: When the Alleles are different (e.g., one allele for purple fur and one for green fur).
Dominant and Recessive Alleles:
- Dominant Alleles are expressed over recessive Alleles.
- In a Heterozygous situation, the dominant allele will determine the Phenotype.
Phenotype vs. Genotype:
- Genotype: The complete set of Alleles an organism has (e.g., Homozygous dominant, Homozygous recessive, or Heterozygous).
- Phenotype: The observable characteristics resulting from the genotype (e.g., fur color).

Genes are segments of DNA coding for proteins.
Alleles are different forms of a Gene.
Individuals have two Alleles for each Gene:
- Homozygous: Both Alleles are the same.
- Heterozygous: Alleles are different.
Dominant Alleles mask the effect of recessive Alleles in Heterozygous individuals.
Example of fur color in mice:
- A Heterozygous mouse with one purple allele and one green allele will display purple fur if the purple allele is dominant.
- A Homozygous recessive mouse with two green Alleles will display green fur.
Genotype refers to the genetic makeup (e.g., Homozygous dominant, Homozygous recessive, Heterozygous).
Phenotype refers to the physical expression of the genotype (e.g., purple or green fur).