Resumen De Biologia (Ingles)

Biology summary
Plant nutrition:
Photosynthesis is the process in which plants produce their own food (carbohydrates) from raw materials using light energy. Plants need carbon dioxide, water and light energy to do photosynthesis. The process converts carbon dioxide into organic compounds by absorbing the energy of the sunlight by the chloroplasts in plants. Look at the word equation and atthe diagram of photosynthesis below:

As seen in the diagram above, carbon dioxide enters to plants by the stomata and diffuses into air spaces.
Xylim vessels carry water and minerals absorbed by the roots from the soil to the leaves. They are made up by dead and rigid cells which provide support to the plant.
Pholeom vessels carry nutrients (glucose, water, etc.) around the plant. They aremade up of living cells and are permeable.

Digestion:
Digestion is the breakdown of large food particles into smaller ones, so they can be absorbed into the bloodstream to be carried to the cells for assimilation. Digestion can be summarized into:
Breakdown
AbsorptionAssimilation
Chemical digestion occurs in the mouth (salivary glands), in the stomach and in the duodenum (first portion of the small intestine)
Enzymes involved in chemical digestion:

Transport in Humans:
Blood enters the heart by the right atria throughveins, and leaves the heart by the left ventricle through arteries.

When blood is pushed out of the heart towards the body, blood must be at a very high pressure so that it can move forwards and so it can be sustained throughout its path. Thick muscular walls that will resist the pressure will push the blood forward when contracting and relaxing.

Heart attacks are originated by fat deposits(plaques) on the inner walls of arteries. This may damage the artery walls or block the flow of blood, and blood clots can be formed on the surface of the deposit. Finally for a heart attack to occur; the arteries have to be blocked by fat deposits or by blood clots. Heart muscle cells die without oxygen that is normally supplied by the batteries (as they are now blocked, oxygen cannot pass through).The risk factors of getting attack that cannot be changed are: ages as old people (65+) have more chances of getting one, genders as males have more risk of getting one than females and heredity as people with parents with heart diseases has more chances of getting a heart attack. The risk factors of getting a heart attack that can be changed with by lifestyle changes or medication are:reducing tobacco smoke, controlling blood cholesterol (as cholesterol increases, so does the risk of a heart attack) and controlling blood pressure (high blood pressure increases the heart’s workload, causing the heart to thicken which increases the risk of a heart disease), physical activity and obesity/ overweight(people with an excess on body fat are more likely to develop a heart disease even thoughthey don’t have any other risk).

Tooth decay:

Structure of teeth:
* The enamel (the hardest substance in the body) covers the tooth and provides a tough surface for biting and chewing.
* Dentine is a hard substance that has tiny tubes running from the pulp cavity (hallow region inside the tooth) outwards which are filled with blood vessels to supply it with nutrients. The nervessense things like pressure and pain.
* The pulp is the blood vessels and nerves that keep the tooth a live.
* Cement covers the dentine in the jaw and provides anchorage for tough fibres which hold the tooth in place.

Tooth decay is caused by bacteria which grow on teeth. The bacteria form a sticky substance which helps them stick to the teeth. The bacteria use some of the sugary...