Topic 2 (Organisation) Flashcards
Cell organisation
Cells-Tissues-Organs-Organ Systems
What is a catalyst
A catalyst is a substance which increases the speed of a reaction without being changed or used up
What is an enzyme
Enzyme are large proteins made up of chains of amino acids
When do enzymes work best
At the optimum temperature and optimum ph level
Rate of reaction equation
Rate of reaction =
1000/
Time
What do digestive enzymes do
Break down big molecules such as starch proteins and fats
What breaks down carbohydrates
Amylase is an example of carbohydrate, it breaks down starch. It is made in the salivary glands, pancreas and small intestine
What breaks down protein
Protease breaks down protein into amino acids, it is produced in the stomach, pancreas and the small intestine
What breaks down lipids
Lipase breaks down lipids into glycerol and fatty acids. It is produced in the pancreas and the small intestine
What does bile do
•Bile, produced in the liver, is stalled in the gall bladder before it’s released into the small intestine
•The hydrochloric acid in the stomach makes the ph too acidic for enzymes in the small intestine to work properly. Bile is alkaline, it neutralises the acid and makes conditions alkaline which is ideal for the enzymes in the small intestine
•It emulsifies fats, in other words, breaks fats down into tiny droplets to create a much bigger surface area of fat for lipase to work on which make digestion faster
What is the catalyst for digestion
Enzymes are natural catalysts
What tests for sugars
Benedict’s solution
Blue to brick red
What tests for starch
Iodine
Orange to black
What tests for proteins
Bitters reagent
Blue to purple
How does blood flow around the heart
Deoxygenated blood enters the heart through the vena cava. The right atrium contracts pushing blood into the right ventricle. The blood flows through the pulmonary artery out of the heart to the lungs where gaseous exchange takes place and the blood becomes oxygenated. The oxygenated blood travels through the pulmonary vein to the left atrium. The left atrium contracts at the same time as the right atrium, this pushes blood into the left ventricle. The oxygenated blood leaves the heart through the aorta where it goes to the rest of the body.
What are the three types of blood vessels
•Arteries-Carry blood away from the heart
•Veins-Carry blood towards the heart
•Capillaries-Involved in exchange of materials at the tissues
Properties of arteries
•Thick, strong elastic walls to withstand the high blood pressure in which the blood is pumped through them
•Narrow lumen
•Walls contain elastic fibres which allow them to stretch and spring back
Properties of veins
•Thin walls as blood pressure is lower in the veins
•Wide lumen to help blood flow despite lower pressure
•Have valves to prevent back flow of blood
Properties of capillaries
•Extremely small, one cell thick
•Permeable walls, can exchange substances
Red blood cells
Biconcave shape giving them a large surface area, no nucleus so they have more room to carry oxygen. They contain haemoglobin which binds to oxygen to form oxyhaemoglobin. There main function is to transport oxygen around the body
White blood cells
Defend against pathogens. Phagocytes engulf pathogens whilst others produce antibodies to fight microorganisms aswell as antitoxins to neutralise any toxins produced by microorganisms
Platelets
Small fragments of cells with no nucleus.
Help blood clot at a wound to stop infection. Lack of platelets can cause excessive bruising and bleeding
Plasma
Pale straw coloured liquid which carries everything around. It carries:
•Red and White blood cells
•Platelets
•Nutrients like glucose and amino acids
•Carbon Dioxide
•Urea
•Hormones
•Proteins
•Antibodies and Antitoxins
What is Coronary Heart Disease
CHD is when the coronary arteries which supply blood to the heat get blocked by a build up of fatty material. This causes the arteries to become narrow, restricted blood flow can lead to lack of oxygen and therefore heart failure
