GCSE biology b1

important thing in B1

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FIT FO LIFE

aerobic respiration  glucose+oxygen~~>carbon dioxde+water+ energy

anaerobic respiration glucose~~> lactic acid+ energy

when lactic acid is produced it collects in the muscles and it casues pain and fatigue

After excercise  heart rate and breathing take time to return to normal. The fitter someone is the faster they turn to normal.

Cardio-vascular efficiency, strenght, stamina, agility, speed and flexabilty are ways of measuring fitness.

 

 

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Blood pressure has 2 measurments:

-systolic pressure is the maximum pressure the heart produces

-diastolic pressure is the blood pressure between  heart beats

high blood pressure would increas the risk of blood vessals bursting and brain damage, stokes and kidney damage.

low blood pressure can cause problems such as poor circulation, dizziness and fainting

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keeping healthy

Mosquitoes are called vectors and carry nad carry microorganisims that cause malaria. Knowlegde of a vector's life cycle is useful in preventing the spread of disease. The mosquito larva (young stage) lives in water. Draining stagnant water kills them. Spraying insecticide can kill the adult mosquito.

-Benign tumuor cells, are slow to divide and harmless

-Malignant tumuors are caner cells, which divide out of control and spread around the body.

Active immunity happens when a pathogen ivades the body a second time. The white blood cells recognise it and make antibodies quickly destroying the pathogen before the symptoms occour. Can last a lifetime.

passive immunty only last a short timeand you are given antibodies ina vaccine.

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keeping in touch

Binocular vision helps us to judge the distance because the range from 2 eyes overlap. However, it only gives a small range of vision compared to monocular vision.

The conjunctiva is at the very front of the eye, covering the cornea. Behind this is the pupil, then the lens. The ciliary muscle and suspensory ligaments are attached to the lens. At the back of the eye are the sclera, retina, fovea and opitc nerve (http://www.bbc.co.uk/schools/gcsebitesize/science/images/bieyestructure.gif)

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PartDescriptionFunction Cornea Front part of the tough outer coat, the sclera. It is convex and transparent. refracts light - bends it as it enters the eye

Iris

Pigmented - decides the colour of your eyes - so light cannot pass through. Its muscles contract and relax to alter the size of   its central hole or pupil. controls how much light enters the pupil

Lens

Transparent, bi-convex, flexible disc behind the iris attached by  the suspensory ligaments to the ciliary muscles. focuses light onto the retina Retina  The lining of the back of eye containing two types of   photoreceptor cells - rods - sensitive to dim light and black and white - and cones - sensitive to colour. A small area called the fovea in the middle of the retina has many more cones than rods. contains the light receptors Opticnerve        Bundle of sensory neurones at back of eye. carries impulses from the eye to the brain

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Stereoscopic vision

Because our eyes sit side by side, each eye captures a slightly different view. This is called stereoscopic vision. When signals from the two eyes reach the brain, they are superimposed and processed into a single picture with depth. As a result, we get a 3D picture and are able to judge distances well.

Most birds and lizards have monocular vision - their eyes are on each side of their head. This gives them a greater field of view, which is useful for spotting predators. However, they have poor depth perception.

 

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Short-sight

Someone with short-sightedness can see near objects clearly, but cannot focus properly on distant objects. This is because the lens focuses the sharpest image in front of the retina, instead of on i

Myopia - short-sight

t. the focus is in front of the retina (http://www.bbc.co.uk/schools/gcsebitesize/science/images/sight_myopia.gif)

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Long-sight

 Someone with long-sightedness can see distant objects clearly, but cannot focus properly on near objects. This is because the lens focuses the sharpest image behind the retina, instead of on it.

Hypermetropia - long-sight

 The focus is behind the retina (http://www.bbc.co.uk/schools/gcsebitesize/science/images/sight_hypermetropia.gif)

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Comments

Al

Well done Fatima. Very good work.

Al

Numerous spelling and grammar mistakes :S  you can delete, fix, then re-publish on this fantasic site :)

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