Biology B1,B2,B3

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B2

Photosynthesis

6CO2 + 6H2O ----> C6H1206 + 6O2

Carbon Dioxide + Water ----> Glucose + Oxygen

Respiration = The Equasion Reversed

Parasitic Relationships - Organisms that live off another living thing (Host)

Mutualistic Relationships - Two organisms form a relationship from which both orgnisms benifit.

Plant adaptations- The Cactus -Rounded shape, Thick cuticle reduces water loss

Stores water in thick spongy layer inside stem to reduce drought

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Leaves reduced to spines to reduce water loss and protect

Green stem means it can photosynthesis without leaves

Long roots to reach water

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B2.

Penicillin resistant bacteria

Becomes resistant to penicillin by natural selection as follows-

Variation

Competition

Best adapted

Pass on their genes

Jean-Baptiste Lamarck

Before darwin made his theory lamarck suggested evolution happened by inheritance of acquiring characteristics in the following way

Organisms changing in order to survive

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These changes being passed on to offspring

Rejected as no evidence it could alter their genes

Charles Darwin

All living things produce more offspring than survive, therefor population size remains constant, Variation between species, Characteristics passed through generations.

REMEMBER

Variation, Competition, Adatation And Evolution = Evolution By Natural Selection

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B2..

Acid Rain

When coal or oils are burned sulfur dioxide is produced. Sulfur dioxide gas dissolves to produce acid rain.

Greenhouse Effect

Heat from the sun reaches earth in the form of radiation. Some of this is reflected back out towards space. When it reaches the atmosphere some rays pass through but others are trapped it is these trapped rays that cause the earth to heat up.

However because of the amount of carbon dioxide in the atmosphere has now increase more of the energy id being reflected back. This is known as global warming.

Indicator species tell us about the atmosphere eg. Lichens or Insect larvae.

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B3

Cells

Animal cell- Most chemical reactions take place in the cytplasm

Cell membrane- Controlls movement in and out of the cell

Nucleus- contains the genetic information and what the cell does it has a membrane extending from it which ribosomes are attached (where protein is made)

Mitochondria- Is where respiration takes place

DNA

A- denine

T- hymine

C- ystosine

G - uanine

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A group of three bases represents one animo acid in a protein chain. Each protein has a different shape and function. The liver restructure some amino acids and produce others this is called transamination.

Essential -ones we must get from our diet

First class- contains both essential and non essential

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B3.

Enzymes are proteins which act as a biological catalyst these can be changed by increasing or decreasing the temperature and pH however temperature above the optimum temperature can perminantly damage the enzyme, decreasing or stopping the activity

Diffusion this is how essential substances pass through the cell membrane from the surroundings it is increased when the surface area of the cell membrane is greater, there is a greater difference between concentrations, the particles have a shorter distance to travel.

Diffusion in plants Co2 diffuses through the tiny poress on the bottom of their leaves ,the CO2 moves inside the leaf to lower concentration where Co2 is used up in photosynthesis, O2 diffuses in the opposite direction. At night water is lost by evaporation, diffusing out of cells into spaces in the spongy mesophyll layer(adaptation where they open to icrease the rate of diffussion of CO2 And O2 and close to prevent water loss in drought conditions).

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Diffusion in animals CO2 diffuses from the body tissues --> Blood ---> Lungs ---> Lungs ----> Expelled from body

Lungs ----> CO2 From Blood ---> Alveoli ---> O2 Diffuses from alveoli into blood

Apsorption of digested food

In the intestine the digested soluble molecules diffuse into the blood where they are carried to the body tissues and diffused into cells

Inner surface of small intesting is folded into villi the villi have tiny folds in their membranes called micro villi increasing the surface area for better absorption

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