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| Name | Genes and Inheritance | 9-1 GCSE Science Biology | OCR, AQA, Edexcel |
| Video Uploader | Video From SnapRevise |
| Upload Date | This Video Uploaded At 01-09-2018 00:27:06 |
| Video Discription | https://goo.gl/rfg21j to unlock the full GCSE Biology & Combined Science videos series for the new 9-1 OCR, AQA and Edexcel specifications. They key points covered in this video include: 1. Genes and phenotypes 2. Alleles 3. Dominant and Recessive Alleles Genes and Phenotypes We can inherit characteristics from our parents. This is because we inherit their genes. Genes are sections of DNA that code for a specific protein. Different genes control different characteristics. These characteristics, like hair and eye colour are called phenotypes. Most characteristics are controlled by multiple genes interacting. Some characteristics are coded by a single gene - this includes red-green colour blindness. Alleles Our bodies have different variants of the same genes - these are called alleles. Alleles code for different proteins - this determines what characteristics (or phenotypes) you have. Gametes have one allele for each gene - normal body cells have two. There is one allele on each chromosome. We inherit one chromosome from the mother and one chromosome from the father. This means we get one allele from the mother and one from the father. Heterozygous individuals have two different alleles for the same gene - homozygous individuals have two of the same alleles. Dominant and Recessive Alleles Alleles are represented by letters. The genotype is the combination of alleles you have. Alleles can either be dominant or recessive. The recessive allele only controls the characteristic if there are two of them - these are represented by a lowercase letter. We say they are homozygous for this characteristic. Dominant alleles are represented by a capital letter. The allele b codes for blue eyes and the allele B codes for brown eyes. You only have blue eyes if you inherit two copies of the b allele from your parents. The dominant allele controls the characteristic if there is one dominant allele present. This is because the dominant allele overrules the recessive allele if the organism is heterozygous. For example, if you inherit an allele for brown eye colour from either or both of your parents you will have brown eyes. Some dominant human characteristics are the ability to roll your tongue and dark hair. Some recessive human characteristics include not being able to roll your tongue and blonde hair. Summary 1. Alleles are different versions of genes 2. Different alleles code for different characteristics - these characteristics are called phenotypes 3. If an organism is homozygous it has two copies of the same allele 4. If the organism is heterozygous it has two different alleles 5. Alleles can be dominant or recessive [1zsh-PGJcQo] |
| Category | People & Blogs |
| Tags | snaprevise | gcse | biology | gcse biology | combined science | ocr | aqa | edexcel | 9-1 gcse | gene | phenotype | allele | dominant | recessive | inherit | DNA | code | protein | gamete | chromosome | heterozygous | homozygous | characteristics |
