9.+Genes,+chromosomes+and+patterns+of+inheritance

media type="custom" key="26975340" All prokaryotes reproduce **asexually**, without the formation and fusion of gametes. Many plants and fungi also reproduce asexually, meaning that they are genetically identical to their parent. Types of asexual reproduction include: This week we will begin to study molecular genetics – the foundations of ‘who we are’, before environmental factors play a role. Half your DNA comes from your mother (eggs produced in the ovaries) and half from your father (sperm produced in the testes). This DNA contains genes and genes code for proteins, so the **gametes** (eggs and sperm) contain the genetic instructions that cross the generation gap, giving you the characteristics that you share with your biological parents. The genetic instructions in an organism make up it’s **genotype**, which is expressed visually as the **phenotype** (physical, biochemical and physiological traits). Humans have 23 pairs of chromosomes, often referred to as the diploid number or 2n=46. The image above is called a **karyotype**, used to assist with chromosomal analysis – is this one from a male or female? Chromosomes can be distinguished by their relative size, position of the **centromere** and the patterns of light an dark bands. Matching pairs are said to be **homologous.** A human male has **non-homologous** sex chromosomes (XY).
 * Binary fission (bacteria)
 * Budding (yeast)
 * Vegetative reproduction (strawberry runners, aloe)
 * Sporulation (fungi, algae, ferns)
 * Fragmentation (annelids, sea-stars)
 * Parthenogenesis (some lizards, sharks and stick-insects)

Gregor Mendel (1822-1884) was an Austrian monk who is known as the father of modern genetics due to his experimental work with plant hybridization. It was Mendel who first coined the terms “dominant” and “recessive” and he formulated generalizations that have become known as “Mendel’s Laws of Inheritance”. “Mendel’s Pea Genetics – Experiments that changed the world” is a twenty-five minute documentary that describes his life. Complete the following three activities:
 * DNA Learning Centre – Gregor Mendel and Pea Plants
 * Information about the basic principles of genetics – Mendel’s Genetics, including a practice quiz.
 * An online, interactive task (a ”web lab”) that allows you to learn about Mendel’s experiments with peas – Mendel’s Peas.

**More Resources for this Unit:**
 * [|Douchy’s videos]
 * [|Douchy’s podcasts]
 *  [|The Biology Place] – some good animations.
 * <span style="background-color: #ffffff; color: #333333; font-family: Georgia,'Times New Roman',Times,serif; font-size: 14.3999996185303px;"> [|Biology animations] – more animations.
 * <span style="background-color: #ffffff; color: #333333; font-family: Georgia,'Times New Roman',Times,serif; font-size: 14.3999996185303px;"> [|Click4Biology] – Comprehensive information.
 * <span style="background-color: #ffffff; color: #333333; font-family: Georgia,'Times New Roman',Times,serif; font-size: 14.3999996185303px;">[|Biology Interactive tutorials]
 * <span style="background-color: #ffffff; color: #333333; font-family: Georgia,'Times New Roman',Times,serif; font-size: 14.3999996185303px;"> [|Educator AP Biology] – animated videos
 * <span style="background-color: #ffffff; color: #333333; font-family: Georgia,'Times New Roman',Times,serif; font-size: 14.3999996185303px;"> [|Biology4kids] – simplified definitions of conccepts
 * <span style="background-color: #ffffff; color: #333333; font-family: Georgia,'Times New Roman',Times,serif; font-size: 14.3999996185303px;"> [|i-Biology] – a list of great resources, particularly for IB Biology