Biology paper 1

• Amylase, protease and lipase are all enzymes and work with the lock and key mechanism.
• Carl Linnaeus developed taxonomy, the study of grouping living things together.
• Penicillin has saved many millions of lives, but the development of new antibiotics is slow due to the high cost of developing new drugs.
• An evolutionary tree can be drawn to show how closely related different species are to one another.
• Each organism has a two part Latin name developed by Carl Linnaeus.
• Natural selection is a process where random mutations in genes lead to natural variation in a population.
• Bacteria can be passed from person to person or from an animal to person, meaning antibiotic resistant bacteria can spread easily.
• Charles Darwin's theory of natural selection suggests that life, as we know it today, has evolved over the past three billion years from the first life, which were very simple, unicellular organisms.
• Fossils can show us changes that have happened and how different animals are related.
• Bacteria multiply very quickly, allowing single mutations to spread through the population really quickly.
• Evidence for evolution comes from fossils, which show changes that have happened and how different animals are related.
• Enzymes can be used as catalysts for a rate of reaction, causing the reaction to start and end faster.
• There are several enzymes in the digestive system, including Lipase which breaks down fats into fatty acids and glycerol, Protease which breaks down proteins into amino acids, and Amylase which breaks down starch into sugars.
• Diffusion is the movement of gases or any particles that are dissolved in solution moving down a concentration gradient from high concentration to an area of low concentration.
• Active transport is a movement across a membrane from a low concentration to a high concentration against the concentration gradient.
• Osmosis is the movement of water through a partially permeable membrane from the area of high water concentration to an area of low water concentration.
• Enzymes either break apart things or join together things, then release the products and are unchanged, allowing for reuse.
• Enzymes have a limited number of active sites, and once they are full, enzyme activity can't keep increasing.
• Enzyme activity can also be affected by pH, with an optimal pH and denaturation occurring when pH is too high or too low.
• Enzyme activity can be affected by temperature, with a lopsided curve showing that enzymes are most active at the optimal temperature, denature at high temperatures, and are inactive at low temperatures.
• Enzymes have a very specifically shaped active site that can only accommodate one or a few substrates, forming an enzyme substrate complex.
• The three domain system divides everything in life into three groups: Eukaryotes, bacteria and archaea.
• Eukaryotes are things that have nuclei.
• Genetic engineering has brought around some fantastic advances, including the production of insulin, which used to be harvested from pig cells and injected into people, but now is produced by bacteria.
• Selective breeding is the process of breeding an animal for a particular characteristic, which happens with dogs, cows, horses, chickens, etc.
• Dogs and cats are often killed just because they are not cute enough or do not look like the industry standard.
• The desired characteristic can lead to long term health problems for their animals, for example, the pug's large number of folds on their face squashes their little nose and gives them long-term breathing problems.
• Genetic modification can be used to add a gene for a desired characteristic to a plant's DNA, producing genetically modified plants.
• The disadvantages of selective breeding are that if an animal is healthy but does not display desired characteristics, it may be killed.
• The advantages of selective breeding are that your animals which have the desired characteristic are healthy and produce more, which is important commercially.
• The genus is the wide overarching type of thing and the species is exactly what thing it is.
• Exercise is known to have health benefits, but it can lead to heart disease if too many cells die due to lack of oxygen.
• In an epidemiology study, it's not possible to force people to eat a high fat diet or do lots of exercise, but there are people within a wide population that do these things already.
• All drugs have side effects, but since their toxicity is known, it's safe or reasonable to take them without suffering too badly from the side effects.
• Toxicity is the level or the amount of drugs that can be taken before the side-effects are too bad.
• Epidemiology studies look at the levels of health and illness in a population to identify risk factors.
• Risk factors for heart disease include smoking, high blood pressure, having too much salt or fat in your diet, and being overweight or obese.
• Efficacy is how efficient a drug is, for example, if it works better or worse than what's already on the market, or if it's worth developing or taking this drug.
• Dose is how much of a drug needs to be taken for it to be effective.
• Alcohol and smoking are known to increase the risk of various health conditions, but they are also part of a lifestyle for some people.