Benedict's or Fehling's Reagent is used to test for glucose but not for sucrose. The test involves heating the sugar with either of the chemicals and observing the colour change of blue to orange.

A chemical test for starch is to add iodine solution (red) and see if it turns blue/black in colour. It is possible to distinguish starch from other carbohydrates using this iodine solution test.

Changes in pH may not only affect the shape of an enzyme but it may also change the shape or charge properties of the substrate so that either the substrate connot bind to the active site or it cannot undergo catalysis. In geneal enzyme have a pH optimum. However the optimum is not the same for each enzyme.

As the temperature increases, so does the rate of reaction. But very high temperatures denature enzymes.The enzyme activity gradually increases with temperature up to around 37ºC, or body temperature.

Vitamin A helps form and maintain healthy teeth, skeletal and soft tissue, mucus membranes, and skin.

Vitamin C is needed for healing wounds, and for repairing and maintaining bones and teeth.

Vitamin D, along with calcium, helps build bones and keep bones strong and healthy.

breaks down food molecules into smaller chunks, increasing the active site for enzymes. Enzymes in the saliva also begin to break down th food

Partial digestion of the food takes place here. The churning action of the stomach muscles physically breaks down the food. The stomach releases acids and enzymes for the chemical breakdown of food.

by this stage, food has been completely broken down and can be absorbed. It has a huge surface area due to villi and micro vili

moves food along, through the pulsing waves of the walls. this is peristalsis

The process of converting oxygen and glucose into CO2 and energy

The opening and closing of the stomata is controlled by the guard cells. In light, guard cells take up water by osmosis and become turgid. Because their inner walls are rigid they are pulled apart, opening the pore. In darkness water is lost and the inner walls move together closing the pore.

The structure of the leaf is adapted for gas exchange. The cells in the spongy mesophyll (lower layer) are loosely packed, and covered by a thin film of water. There are tiny pores, called stomata, in the surface of the leaf. Most of these are in the lower epidermis, away from the brightest sunlight.

Ribs - Curved bones that embrace the lungs, protect them from fatal blows which may damage the lungs

Intercostal muscles - the muscles located in-between the ribs to keep the ribs in place and move the ribs when inhaling or exhaling

Diaphragm - Forms the floor of the thorax, skeletal muscle. When you exhale the diaphragm pushes up onto the lungs to help exhale and vice versa for inhaling

Trachea - This is the separated portion of the throat where air passes through into your lungs

Bronchi -The separation of the bronchus, one main branch in each lung

Bronchioles - further division of the bronchus, contains alveoli at the tips of the bronchiole where gas exchange occur

Pleural Membrane - outer lining of the lung, its spongy and makes a slippery fluid so that there is reduced friction when rubbings against the ribs

they give the lungs a really big surface area

Effects of smoking on the respiratory system. The effects of tobacco smoke on the respiratory system include: irritation of the trachea (windpipe) and larynx (voice box) reduced lung function and breathlessness due to swelling and narrowing of the lung airways and excess mucus in the lung passages.

This is carried out by the skin (sweating), lungs and the kidneys.

The urea is produced in the liver, from excess amino acids (amino acids contain nitrogen, which is toxic to the body if in excess).

The kidneys do this by filtering stuff like urea out of the blood under high pressure, then reabsorbing the useful things. The urea is then added to water to form urine, which travels down the ureters to collect in the bladder.

The hypothalamus detects either too much or too little water in the blood

Pituitary gland releases ADH if there’s too little water, but releases less if there’s too much water

The kidneys maintain the blood water level, or reduce it if it’s too high

If there was previously too little water, less water is lost in urine, but the opposite happens if there’s too much water

the ureter carries the urine to the bladder, which is where the urine’s stored before it leaves the body through the urethra.

Selective reabsorption of glucose etc. happens in the proximal convoluted tubule #

Blood from the renal artery flows through glomerulus (which is a bundle of capillaries at the start of the nephron)

The high pressure that’s built up squeezes the water, urea, salts and glucose outof the blood, and into the bowman’s capsule

Membranes between blood vessels in glomerulus and bowman’s capsule act like filters

Big molecules (like proteins and blood cells) aren’t squeezed out (they stay in the blood)

The filtered liquid in bowman’s capsule is called glomerular filtrate

As the filtrate flows through the nephron, useful substances get selectively reabsorbed back into the body:

All glucose is reabsorbed from the proximal convoluted tubule (using active transport, against a concentration gradient)

Sufficient water is reabsorbed from the collecting duct into the blood stream

ADH is made in the pituitary gland (in the brain), and its role is to control water content, by increasing the permeability of kidney tubules to water.

So if there’s too little water, more ADH is released, so more water can be reabsorbed back into the blood.

The Opposite: diuretics. These increase the production of urine, as they make the collecting duct less permeable, so less water is reabsorbed into the blood.

Urine contains water, urea and salts, which must be removed, or they may interfere with chemical reactions, or damage cells because of increased concentration.

Living things must have receptors to be able to detect the change and effectors to be able to carry out a response.

For example osmoregulation is the control of water levels in the body.

emperature regulation also needs to take place (as body process work best at 37 degrees) it is called thermoregulation.

A stimulus- a change in the internal or external environment- is needed to prevoke a response.

A receptor is needed to detect a stimulus, so that it can send messages to a coordinator to

Roots always carry out posotive geo-tropism, towards gravity/ down.

Shoots always carry out negative geo-tropism, away from gravity/ up.

Stems experience positive photo-tropism, this means they always grow towards light.

In a place where light shines there will be fewer auxins (growth hormones) this encourages the stem to bend towards the source of light.

Hormones do this with chemicals which travel, a little slower, at the speed of the blood stream they are travelling in.

eceptors in sense organs (eg eyes or skin) send messages through nerves to the CNS- either to you brain or spinal chord- it creates a response which it will send in electrical impulses down nerves to effectors to carry out the response.

A reflex is an automatic reaction, for example removing your hand from extreme heat. A reflex arch is the path of the reaction.

his makes an effector carry out a response e.g muscle contracts to bring finger away from heat.

The eye is a receptor of light, it has light receptor cells in its retina. These cells turn stimuli into electrical impulses.

In response to increased light you pupil will shrink, in dim light your pupil will dilate (grow bigger). This happens because you iris will contract to make the pupil smaller or relax to make it bigger. Radial muscles also make the pupil bigger by contracting.

If an object is far, ciliary muscles will relax making the suspensory ligaments tight so they pull the lens thin.

when too hot, glands under the skin secrete sweat, this increases heat loss by evaporation.

blood vessels by the skin shrink, this reduces the blood which runs by the surface meaning less heat can be lost to the air.

blood vessels by the skin grow, this means that more blood, and so more heat, is travelling near the surface of your body, in this way heat will be lost as it is conducted by the air.

Lack of water is detected by the hypothalamus in the brain, it causes the pituitary gland to produce Anti-diuretic hormone, or ADH. This makes the kidneys to reabsorb more water- so less is lost from the body.

Produced in the adrenal glands in stressful situations. Heart rate quickens to increase the flow of blood to muscles- this means that they can respire more (as there is more oxygen available) to provide energy if you need to 'fight or flee'.

Produced in the pancreas when there is too much glucose in the blood. It stimulates cells to convert the glucose into glycogen which is a from that can be stored. This means that you always have the right amount of glucose in your blood.

Produced in ovaries in girls and testicles in boys. Plays a key role in puberty, developing sex organs and inspiring hair growth.

Produced in the ovaries it maintains the lining ready for pregnancy, and continues to do so if the egg is fertilised.

Produced in the ovaries, it is controls other hormones to regulate the menstrual cycle. It stops the production of FSH and starts the production of LH.

If an object is near, ciliary muscles will contract which relaxes the suspensory ligaments so that the lens is fat;