1. Variation and Sexual Reproduction
Video Notes
Variation and Sexual Reproduction
By: Luis Yescas

2. Variations, Mutations, & Codons
Variations- is a genotype that u could get from either your mom or your dad or maybe even from one of your grandparents, it comes with a phenotype that is either dominant or recessive.
Mutations- is when something goes wrong when DNA tries to copy it’s self, either because it has to much chromosomes or not enough chromosomes a mutation could also occur because the nucleotide basis don’t pair up with the corresponding base. (A-C, C-T)
Codons- these are just the letters that are in your DNA like A-T, C-G for DNA and for RNA it’s A-U, C-G.

3. Sexual Reproduction
Sexual reproduction happens in meiosis. It is when the cell goes through all the steps in meiosis and then goes through telophase and there it reproduces the 4 daughter cells. This could also just be simply known as “two organisms mate to have a child and the child gets a gene from each of the parent”.

4. Chromosomes
Chromosomes are what you inherit from your parents. In the process of mitosis each parent cell has 46 chromosomes, but in meiosis each daughter cell has 23 chromosomes, and that’s because when they combine they make 46. In a cell that has 46 chromosomes there is a ‘x’ and ‘y’ chromosome the ‘x’ being from the man and the ‘y’ from the female.

5. Germ cells, Genotype/Phenotype, Allele, Homologous
Germ cells- is just another name for sex cells. (sperm-male, egg-female)
Genotype- is the trait you get from your parent(s). For example a genotype you could get from your parents is your nose, eyes, hands.
Phenotype- is the description of the genotype. For example if the genotype is eyes the phenotype would be like blue eyes.
Allele- is basically a version of a gene. Ex: Aa- aa
Homologous- I s almost the same but not identical.

6. Crossover
A crossover is just when chromosomes start to mix up and you get genes from both your parents in each one.