GCSE Biology - DNA Part 2 | Alleles | Phenotype vs Genotype

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** WHAT'S COVERED **
1. The role of genes in determining characteristics.
Genes as segments of DNA coding for proteins.
Characteristics determined by single or multiple genes.
2. The definition of alleles.
Alleles as different versions or forms of the same gene.
3. The concepts of dominant and recessive alleles.
How dominant alleles are always expressed when present.
How recessive alleles are only expressed when two copies are present.
4. The distinction between homozygous and heterozygous conditions.
Homozygous meaning having two identical alleles for a gene.
Heterozygous meaning having two different alleles for a gene.
5. The difference between genotype and phenotype.
Genotype referring to the combination of alleles an organism possesses.
Phenotype referring to the observable characteristics resulting from the genotype.

** CHAPTERS **
0:00 Introduction & Recap of Genes
0:30 What is a Gene?
0:47 How Characteristics are Determined (Single vs Multiple Genes)
1:13 Alleles: Different Versions of Genes
1:39 Homozygous vs Heterozygous
2:03 Dominant vs Recessive Alleles
3:04 Genotype vs Phenotype

** PLAYLISTS **
   • GCSE Maths (9-1)  

   • GCSE Biology (9-1)  

   • GCSE Chemistry (9-1)  

   • GCSE Physics (9-1)  

   • Alevel Biology  

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