B3 Revision

James Pugh
Mind Map by James Pugh, updated more than 1 year ago
James Pugh
Created by James Pugh about 5 years ago


Mind Map on B3 Revision, created by James Pugh on 02/28/2015.

Resource summary

B3 Revision
1 Meiosis & Mitosis
1.1 Are 2 different ways in which cells reproduce
1.2 In mitosis a cell splits to create two identical copies of the original cell.
1.3 In meiosis cells split to form new cells with half the usual number of chromosomes, to produce gametes for sexual reproduction.
1.3.1 Gametes are sex cells. The male gametes are the sperm, and the female gametes are the eggs. Gametes contain one set of genetic information, while body cells contain two sets of genetic information. Fertilisation is when the male gamete (sperm) and the female gamate (egg) join
2 Anearobic & Arobic Respiration
2.1 Aerobic respiration is used to help mammals maintain a constant body temperature, they do this through the use of Aerobic Respiration
2.1.1 Aerobic respiration needs oxygen. It is the release of a relatively large amount of energy in cells by the breakdown of food substances in the presence of oxygen: word equation: glucose + oxygen → carbon dioxide + water chemical equation: C6H12O6 + 6O2 → 6CO2 + 6H2O Aerobic respiration happens all the time in animals and plants. Note that respiration is different to breathing (ventilation). Most of the reactions in aerobic respiration happen inside mitochondria in cells (cells which provide energy)
2.2 Unlike aerobic respiration, Anaerobic respiration does not need oxygen.. It is the release of a relatively small amount of energy in cells by the breakdown of food substances in the absence of oxygen.
2.2.1 Anaerobic respiration occurs during hard excersize word equation: glucose-->lactic acid chemical equation: 6H12O6 → 2C3H6O3 Glucose is not completely broken down, so much less energy is released than during aerobic respiration. There is a build-up of lactic acid in the muscles during vigorous exercise. The lactic acid needs to be oxidised to carbon dioxide and water later. This created an oxygen debt, and just like money, debt must be repaid. (This is why we breathe deeply after exercise)
2.2.2 Anaerobic Respiration also takes place in plants and yeast Anaerobic respiration also happens in plant cells and some microorganisms. Anaerobic respiration in yeast is used during brewing and bread-making: glucose → ethanol + carbon dioxide C6H12O6 → 2C2H5OH + 2C02 Ethanol is the alcohol found in alcoholic drinks like beer and wine. In bread-making, bubbles of carbon dioxide gas expand the dough and help the bread rise.
3 The circulatory system
3.1 Also known as the cardiovascular system, your heart, blood vessels and blood itself are three essential components the body needs to survive. The circulatory system consists of two circuits that blood travels through; pulmonary and systemic. Exercise affects these systems, causing the heart to pump blood faster around the body, which in turn allows you to exercise for longer!
3.1.1 The pulmonary circuit carries blood to the lungs to be oxygenated and then back to the heart. In the lungs, carbon dioxide is removed from the blood, and oxygen taken up by the haemoglobin in the red blood cells.
3.1.2 The systemic circuit carries blood around the body to deliver the oxygen and returns de-oxygenated blood to the heart. Blood also carries nutrients and waste.
4 Enzymes, Amino Acids & Proteins
4.1 Proteins are made from long chains of smaller molecules called amino acids. These long chains are folded into particular shapes. This is important in relation to how antibodies and enzymes work.
4.1.1 Different proteins The long chains of amino acids fold to give each type of protein molecule a specific shape. Proteins act as: Structural components of tissues (such as muscles) Hormones (such as insulin) Antibodies (part of the body's immune system) Biological catalysts (enzymes) They are shape specific
4.2 Enzymes are biological catalysts. There are optimum temperatures and pH values at which their activity is greatest. Enzymes are also proteins. If the shape of an enzyme changes, it may no longer work (it is said to have been 'denatured').
4.2.1 There are only about 20 different naturally occurring amino acids. However, each protein molecule has hundreds, or even thousands, of them joined together in a unique sequence. This gives each protein its own individual properties.
5.1 A double helix has 4 bases
5.1.1 A goes to T C goes to G
5.2 deoxyribose nucleic acid
5.2.1 Chromosones are made from DNA Genes are short sections of DNA
5.3 Your DNA is the code that makes you, you!
6 Mutations
6.1 The word mutation means a change in the genetic composition of a cell. Mutations can be divided into two main groups. The first group is gene mutations. These are chemical changes in the DNA of the cell.
6.1.1 A gene mutation is a change in the order of bases on a strand of DNA.
6.1.2 Chromosome mutations are due to change in either the chromosome structure or the chromosome number of a cell.
7 Cloning
7.1 Plants can make identical copies of themselves by asexual reproduction, for example by tubers and runners. Humans have been cloning plants for years and have recently started to develop techniques to clone animals.
7.1.1 Asexual Reproduction involves only one parent
7.1.2 Advantages: Can produce lots of the same plant, even if the seed is rare Disadvantages: If a disease knocks out one plant, it will knock all of them out because they are genetically identicle
7.2 However, animal cloning raises ethical issues about how far humans should interfere in the production of new life.
8 Stem Cell Research
8.1 Stem Cells can be used to grow any part of a human body
8.2 There are two types of stem cell: Emboyonic and Bone Marrow
8.2.1 Many people disagree with Emboyonic stem research as an embroyo is a living thing
8.3 Can be used to cure Parkinsons, rebuild bones and body parts, repairing damages immune systems.
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