Organisation Flashcards
Name 3 types of tissue and give their function
1) Muscular tissue - contracts to move whatever it’s attached to.
2) Glandular tissue - makes and secretes chemicals like enzymes and hormones.
3) Epithelial tissue - covers some parts of the body (e.g. the inside of the gut).
What is a catalyst?
A catalyst (e.g. enzyme) is a substance which increases the speed of a reaction, without being changed or used up in the reaction.
What does the ‘lock and key’ model present?
A substrate fitting and being split apart inside the active site of an enzyme.
How do you calculate the rate of reaction?
Rate = 1000 ÷ Time
Give an example of a carbohydrase, its function and where its made
Carbohydrases (e.g. amylase) break down starch into sugars. They are made in the salivary glands, pancreas and small intestine.
Give an example of a protease, its function and where it’s made
Proteases (e.g. pepsin) convert proteins into amino acids. They are made in the stomach, pancreas and small intestine
Give the function of lipases and state where they’re made
Lipases convert lipids into glycerol and fatty acids. They are made in the pancreas and small intestine.
Give the function of bile and where it’s produced
Bile is produced in the liver. It is stored in the gall bladder before it is released into the small intestine. Bile neutralises stomach acid and emulsifies fat.
Give the function of the salivary glands
These produce the amylase enzyme in the saliva.
Give the function of the liver
The liver is where bile is produced.
Give the function of the gall bladder
The gall bladder is where bile is stored, before it’s released into the small intestine.
Give the function of the large intestine
The large intestine is where excess water is absorbed from the food.
Give the functions of the stomach
1) The stomach pummels the food with its muscular walls.
2) It produces the protease enzyme, pepsin.
3) It produces hydrochloric acid to kill bacteria and to give the right pH (pH 2) for the protease enzyme (pepsin) to work.
Give the function of the pancreas
The pancrease produces protease, amylase and lipase enzymes. It releases these into the small intestine.
Give the functions of the small intestine
The small intestine produces protease, amylase and lipase enzymes to complete digestion. This is also where the digested food is absorbed out of the digestive system into the blood.
Give the function of the rectum
The rectum is where the faeces are stored before they leave through the anus.
What is the Benedict’s Test used to identify?
Sugars
What is the Iodine Solution used to identify?
Starch
What is the Biuret Test used to identify?
Proteins
What is the Sudan III Test used to identify?
Lipids
What is the path that air takes when it enters your body?
The air that you breath in goes trough the trachea. This splits into two tubes called bronchi. The bronchi then split into bronchioles. The bronchioles end at the alveoli.
How does gas exchange happen in the alveoli?
By diffusion
What is the function of the coronary arteries?
To supply oxygenated blood to the heart itself
Which side of the heart pumps oxygenated blood?
The left side
How does the natural pacemaker of the heart work?
The cells in the right atrium wall produce a small electric impulse which spreads to the surrounding muscle cells, causing them to contract.
Describe how the arteries are adapted to carry blood away from the heart
The heart pumps the blood out at high pressure so the artery walls are strong and elastic. The walls are thick compared to the lumen. They contain thick layers of muscle to make them strong and elastic fibres to allow them to stretch and spring back.
Describe how the capillaries are adapted to exchange substances with body cells
They have permeable walls, so substances can diffuse in and out. They supply food and oxygen, and take away waste like carbon dioxide. Their walls are only one cell thick. This increases the rate of diffusion by decreasing the distance over which it occurs.
Describe how the veins are adapted to carry blood back to the heart
The blood is at lower pressure in the veins so the walls don’t need to be as thick as artery walls. They have a bigger lumen than arteries to help the blood flow despite the lower pressure. They also have valves to help keep the blood flowing in the right direction.
Describe red blood cells and their purpose
The job of red blood cells is to carry oxygen from the lungs to all the cells in the body. Their shape is a biconcave disc - this gives a large surface area for absorbing oxygen. They don’t have a nucleus - this allows more room to carry oxygen.
What is haemoglobin?
Haemoglobin is a red pigment in the red blood cells. In the lungs, haemoglobin binds to oxygen to become oxyhaemoglobin. In body tissues, the reverse happens - oxyhameglobin splits up into haemoglobin and oxygen, to release oxygen to the cells.
What is the function of white blood cells?
Some can change shape to gobble up unwelcome microorganisms, in a process called phagocytosis. Others produced antibodies to fight microorganisms, as well as antitoxins to neutralise any toxins produced by the microorganisms.
Describe the purpose of platelets in blood
They help the blood to clot at a wound.
What is plasma?
Plasma is the liquid that carries everything in the blood.
What is coronary heart disease?
Coronary heart disease is when the coronary arteries that supply the blood to the muscle of the heart get blocked by layers of fatty material building up. This causes the arteries to become narrow, so blood flow is restricted and there’s a lack of oxygen to the heart muscle - this can result in a heart attack.
What is the function of stents?
Stents are tubes that are inserted inside arteries to keep the arteries open, making sure blood can pass through to the heart muscles. This keeps the person’s heart beating.
What are statins?
Statins are drugs that can reduce the amount of ‘bad’ cholesterol present in the bloodstream. This slows down the rate of fatty deposits forming.
What are disadvantages of using statins?
Statins must be taken regularly, they can cause negative side effects and they take a while to have an effect.
What are ways to treat cardiovascular diseases?
Artificial heart transplant (heart failure), biological or mechanical valves (damaged valves), artificial blood or a blood transfusion (when loosing blood).
What is the epidermal tissue of a plant?
The tissue that covers the whole plant.
What is palisade mesophyll tissue?
This is the part of the leaf where the most photosynthesis happens.
What is spongy mesophyll tissue?
This is in the leaf, and contains big air spaces to allow gases to diffuse in and out of cells.
What is phloem?
Columns of elongated living cells with small pores in the end walls to allow cell sap to flow through. They transport food substances made in the leaves in both directions to the rest of the plant. This process is called translocation.
What is xylem?
Tubes made of dead cells joined end to end with no walls between them and a hole down the middle. They’re strengthened with lignin. They carry water and mineral ions from the roots to the stem and leaves.
What is meristem tissue?
Tissue found at the growing tips of shoots and roots and is able to differentiate into lots of different types of plant cell, allowing the plant to grow.
What is transpiration?
Transpiration is the loss of water from the plant (mainly through the stomata of leaves).
What factors affect the transpiration rate?
Light intensity, temperature, air flow and humidity.
What is the transpiration stream?
The movement of water from the roots, through the xylem and out of the leaves.
What happens to the stomata when the plant is short of water?
The guard cells lose water and become flaccid, making the stomata close. This helps too much water vapour escaping.
How does one tests for sugars using Benedict’s Test?
5cm3 food sample in test tube
10 drops of Benedict’s solution using a pipette
Place in water bath set to 75C degrees
Blue to Green, yellow or brick-red
How does one test for starch using iodine solution?
5cm3 food sample in test tube
Few drops of iodine solution
Gently shake
Browny-orange to black or blue-black
How does one test for proteins using biuret test?
2cm3 food sample
2cm3 biuret solution
Gently shake
Blue to pink or purple
How does one test for lipids using Sudan III?
5cm3 food sample
3 drops of Sudan III
Gently shake
Bright Red layer on top in test tube
