Genetics and Evolution

Uterus: Where menstruation takes place and baby grows. Cervix: Ring of muscle at the entry of the uterus Ovaries: Eggs are made here Oviducts: Carries eggs from ovary to uterus, fertilisation occurs here. Vagina: Entry to uterus.

Scrotum: A bag of skin that protects and helps heat the testes. Testes: Sperm is made here Sperm ducts: Carries sperm from testes to penis. Prostate gland: Urethra: Also carries sperm out of the body. Penis: Carries sperm out of the body.

Gametes are reproductive and sex cells. During fertilisation the male and female gametes fuse together and create a zygote (egg).

A zygote splits into an embryo and placenta, the embryo then develops into a foetus 8 weeks after.

Haploid: - Contains one set of chromosomes (n) - Goes through the process of meiosis - Example: gametes Diploid: - Contains two sets of chromosomes (2n) - Goes through the process of mitosis. - Example: skin and blood cells

Chromosomes carry DNA in cells. DNA is responsible for building and maintaining your human structure. Genes are segments of your DNA, which give you physical characteristics that make you unique

DNA and genes are located in the cell nucleus.

Known as a double helix, DNA is made up of simple repeating units called nucleotides. The nucleotides are comprised of a sugar, a phosphate and a base. They have complementary base pairings, such as adenine pairs with thymine (curved) and cytosine with guanine (straight).

The genome isthe entire set of DNA instructions found in a cell.

Deoxyribonucleic acid

Cells must replicate their DNA before they can divide. Thisensures that each daughter cell gets a copy of the genome, and therefore, successful inheritance of genetic traits.

Mutation is a change in genetic code

Alzheimers disease, cystic fibrosis

Mutations can result fromerrors in DNA replication during cell division, exposure to mutagens or a viral infection.

Useful: • Essential for evolution • Increase an organism’s changes of surviving or reproducing • Becomes more common over time Harmful: • May cause genetic disorders or cancer • frameshift mutation; the deletion or insertion of a sequence

Genotype: the genetic makeup of an organism, an organism’s complete set of genes. Phenotype: an individual’s observable traits (e.g eyes, height etc), which can both be by their genotype or environmental factors.

All cells except gametes have 2 genes/alleles for each characteristic.

Dominant genes: The gene physically expressed that overshadows recessive. Recessive genes: The gene not expressed because of the dominant gene.

Variation is any difference between cells, individual organisms, or groups of organisms caused bygenetic differences (genotypic variation) or effect of environmental factors (phenotypic variation).

Continuous: A complete range of measurements from one extreme to the other. e.g height, weight Discrete: when characteristics fall into a number of distinct categories. e.g attached vs detached earlobes, finger prints, eye colour, and blood groups

(normal cell division) The process of a cell replicating its chromosomes and then segregating them, producing two identical nuclei in preparation for cell division. They are genetically identical.

Cell division in sexually reproducing organisms that reduces the number of chromosomes in gametes (sex cells).

Haploid: - Contains one set of chromosomes (n) - Goes through the process of meiosis - Example: gametes Diploid: - Contains two sets of chromosomes (2n) - Goes through the process of mitosis. - Example: skin and blood cells

The process of species adapting over time due to the changing environment.