Overview

• Sexual reproduction is beneficial as it allows for genetic variation, enabling organisms to adapt to changes in the environment.
• Asexual reproduction is quick and easy to replenish the population, but produces genetically identical organisms which can be more susceptible to disease.
• Meiosis is a type of cell division that creates the gametes or sex cells.
• During meiosis, the cell duplicates its chromosomes, creating eight chromosomes and eight chromatids.
• Brown eyes are a dominant trait, so if both brown alleles are passed down, the phenotype will be brown.
• Punnett squares can be used to predict the alleles that will come together.
• Cystic fibrosis is a recessive disease, so people with two recessive alleles will have the disease.
• Mendel used pea plants to study different genes, noticing that the offspring of a short paper and a tall pea plant were all tall.
• Mendel then bred these plants again and realized that they produced three tall plants and one short plant.
• Mendel concluded that these plants must have had different genes to pass this on.
• The chromosomes move to each end of the cell during the first division of meiosis.
• After the first division of meiosis, the chromatids move to each end of the cell.
• The cell divides into two cells during the second division of meiosis, resulting in four chromosomes and eight chromatids in each of the four cells.
• Meiosis is a reduction division as it starts with eight chromosomes and ends with four chromosomes.
• DNA stands for deoxyribose nucleic acid and the DNA is stored as chromosomes in the nucleus of our cells.
• DNA has a double helix shape.
• DNA is a giant polymer, almost like a chain made up of different parts, each part of the DNA is called a nucleotide.
• A nucleotide is made up of a phosphate, a sugar called deoxyribose, and a base.
• The order of these bases is unique to every single person and these are coded instructions that tell your body to make different proteins to then show different characteristics.
• The process of making these proteins is called protein synthesis, which has two parts: transcription and translation.
• Transcription, which happens in the nucleus, is when a molecule called MRNA comes up under the DNA to make a copy of the order.
• Translation, which happens outside the nucleus, is when a molecule called TRNA reads these bases in groups of three and brings an amino acid with it.
• These amino acids build up to form a long chain which then creates a protein.
• A gene is a section of DNA and it usually goes for a certain characteristic, an allele is a different version of a gene.
• Alleles can either be homozygous or heterozygous, homozygous means you have the same two alleles, while heterozygous means you have different alleles.
• Dominant alleles override recessive, if a person has one dominant allele and one recessive allele, the dominant allele will overpower the recessive one.
• If a person has two recessive alleles, they work together and mean that the recessive trait is thrown.
• DNA is your genotype and the alleles that show is your phenotype.