science - booklet I

food and digestion

humans need to concume a balanced diet which contains a variety of difrent types of food.

carbohydrates for energy  proteins for growth and repair  fats to store energy vitamins and minerals to keep the body helthy

carbohydrate molecules called starch contain sugar molecules  proteins are made up of chains of small molecules called amino acids  fats are made up of fat molecules which contain fatty acids and glycerol

enzymes

enzymes are chemicals that break down large insoluble molecules to small soluble molecules so the body can absorb.  

carbohydrate enzyme = amylase  protein enzyme = protease fat enzyme = fat enzyme

mouth => food chewd and mixed with saliva, then swallowed gullet => a straight muscular tube going to the stomach.  stomach => the acid bath! digestive juices and acid are added. food is churned. small intestine => more juices added from the liver and the pancreas to finish digestion food then passes into the blood  large intestine => fiber and food that can't be digested are removed through the anus water is taken back here.

digestion 

chemical elements

atoms are the smallest part of any substance. they make up solids, liquids and gasses. 

all substances are made up of small particles called atoms. substances which contain only one type of element. elements can't be broken down into anything sympler. when these combine together, they make compounds.

simple periodic symbols.

c - carbon cu - copper o - oxygen n - nitrogen ca - calcium fe - iron na - sodium cl - chlorine mg - magnesium s - sulfur

geology

rocks over time

rocks can be broken down into smaller pieces. this is called erosion. 

rocks crumble into small particles. the particles are carried away by rivers or wind. the particles in another place form larger by joining together and form a layer. more layers form on top of it. the lower layers get pressed together. water is sqweezed out. the preasure and the material cement the particles together. 

A river carries, or transports, pieces of broken rock as it flows along. When the river reaches a lake or the sea, its load of transported rocks settles to the bottom. We say that the rocks are deposited. The deposited rocks build up in layers, called sediments. This process is called sedimentation.

The inside of the Earth is very hot - hot enough to melt rocks. Molten (liquid) rock forms when rocks melt. The molten rock is called magma. When the magma cools and solidifies, a type of rock called igneous rock forms.

Sedimentary rocks

Igneous rocks

Metamorphic rocks

Earth movements can cause rocks to be deeply buried or squeezed. As a result, the rocks are heated and put under great pressure. They do not melt, but the minerals they contain are changed chemically, forming metamorphic rocks.

ecology

classifying plants

plants are very different to animals because they make their own food. plants are often known as producers, whilst animals are known as consumers. 

live in damp places  thin leaves that easily lose water. make spores instead of seeds.

mosses

ferns

strong stems make spores tubes for water called Xylems.

conifers

evergreen xylem tubes seeds produced in cones.

flowering plants

produce flowers. xylem tubes. seeds in fruits or berries.

competition

in nature, living things compete for resources that are in short supply. those that compete successfully will survive to breed.

animals compete for:

territory food / water mates.

plants compete for:

space light water 

different habitats.

a habitat is a place an animal or plant lives. 

population growth

first there are few rabbits, and plenty of food. many will survive to breed their numbers to increase. at first there are no predators. to keep their numbers down.soon each generation id double the size as the last one. but this can only take place under ideal habitat conditions.the rabbit population can not go on increasing for ever, because not all of them will survive.  some factors will start to limit  the population growth, such as lack of food or being eaten by a predator. 

people often think of population as only being plants and animals. but you can have populations of microbes too.  

pyramids

food chains cannot show how food pass from one living thing to another.

you can show food chains in a pyramid of numbers. the area of each box tells us how big the numbers are.  

MICROBES AND DISEASE

in the olden days people dint know why food went bad. now we know that microbes are to blame.

microbes include BACTERIA, FUNGI and VIRUSES. many are so small that you need a microscope to see them.

SUGAR + OXYGEN => CARBON DIOXIDE WATER +  ENERGY

Your skin acts like a barrier to microbes. Bacteria and viruses are a common cause of disease. the symptoms of a disease are the body's response to waste chemicals made by the microbes 

points of entry:

air food touch water animals

self - defence

bacteria enter your body through a cut or any other point of entry.  your body makes antibodies to fight the invaders. the bacteria are destroyed by the antibodies antibodies stand by  ready to fight off any future attacks. the body is immune.

food and digestion

atoms and elements

geology

ecology

microbes and disease