Biology

Metabollic rate = Speed at which chemical reactions take place in our bodies.

LDL's = Low density lipoproteins

HDL's = High density lipoproteins

A feature of LDL's is they carry cholesterol from the liver to the cells of the body.

Passive immunity involves receiving antibodies. White blood cells engulf and digest pathogens as well as prodicing antibodies to prevent the virus/bacteria from reproducing. Antibiotics can stop bacteria from reproducing but cannot stop viruses without destroying the host cell. Vaccinations involve injecting an in-active form of the pathogen into the body to trick the immune system into responding and producing the correct antibodies ready for when an active form of the pathogen enters the body.

Oral contraceptives contain oestrogen and progesterone.

FSH and LH are used in fertility treatment.

FSH is produced in the pritruitary gland.

Oestrogen is produced in the overies.

Adrenalin is produced the the Adrenal gland.

Testosterone is produced in the testes.  

Auxin is made in the growing tip of a shoot or root.

 Growing towards the sunlight is positive phototropism, growing downwards is positive gravotropism.

The shaded side of a plant contains more auxin.

 When a root bends in the direction of the force of gravity (gravotropism), the top side grows more than the bottom side.

Alcohol is an example of a depressant.

Depressants slow down the brain activity.

Stimulants speed up heart rate.

 Legal drugs can be purchased in supermarkets, chemists etc, e.g. Paracetamol.

Recreational drugs are used for leisure purposes and can be legal or illegal, e.g. alcohol.

Illegal drugs are very dangerous and most are addictive, e.g. Heroin. 

Interdependance = Mutually dependant on each other

In food chains, the energy is transferred but decreases at each level of consumption. Producers are plants because they produce food for consumers and themselves so they only compete for space, sunlight, water and nutrients. Consumers compete for food, they eat producers and other consumers. Consumers who only eat producers are called herbivores. Humans are at the top of the food chain and are a vital part of the carbon cycle. Everything is made up of carbon atoms. Materials decay because they are digested by microorganisms. Decay happens faster when the conditions are warm and moist.

Organisms that are tolerant to high levels of salt, high temperatures or high pressures are called extremophiles.

Lichens cannot grow in very polluted air so are useful indicators of pollution.

One advantage of using a temperature probe and datalogger rather than a thermometer is that it records the temperature automatically.

Biomass is the amount of biological material.

The nucleus of a cell contains chromosomes which carry genes.

One advantage of taking cuttings from plants is that new, genetically identical plants can be grown quickly and cheaply. Asexual reproduction only needs one parent. Plants and animals can be cloned.

Genetic engineering can create artificial adaptions to plants or animals to benefit humans. It speeds up evolution and is good for scientific research. However, it can harm animals and is seen as unnatural.

Darwin's theory of evolution states that animals and plants evolve and adapt through natural selection. They have to adapt with the changing environment and to compete with other species for food etc otherwise they will not survive to reproduce.

One of the reasons why Lamarck's theory of evolution was discredited is because it could not explain why simple organisms continue to exist on earth.