Organisation

• What are cells?


  The basic building blocks of all living organisms.
• What is a tissue?

  A tissue is a group of similar cells that work together to carry out a particular function.
• What is an organ?


  A group of different tissues working together to perform a certain function.
• What is an organ system?

  A group of different organs working together to perform a particular function.
• What do organ systems form?

  Organisms
• What are enzymes?


  Biological catalysts.
• What are catalysts?


  It is a substance which increases the speed of a reaction without being changed or used up in a reaction.
• How do catalysts speed up the rate of reaction?

  Lock and key model.

  
• Why can different substances only react with specific enzymes?

  Because the active site has a specific shape. Therefore, only substances that fit in the enzyme can react with it.
• What happens to enzymes when the temperature is too high or the pH is too high or low?

  Some of the bonds holding the enzyme together break which changes the shape of the active site. The enzyme is denatured.See an expert-written answer!We have an expert-written solution to this problem!
• How do you calculate rate of reaction?

  1000/time

  or

  change/time
• Amylase


  Carbohydrase.

  Breaks down starch into simple sugars e.g. maltose

  Made in the salivary glands, pancreas and the small intestine.
• Protease


  Breaks down proteins into amino acids.

  Made in the stomach, pancreas and the small intestine.
• Lipase


  Breaks down lipids into glycerol and fatty acids.

  Made in the pancreas and the small intestine.
• What are the products of digestion used for?

  Used to build new carbohydrates, lipids and proteins.

  Some glucose is used in respiration.
• Bile


  Made in the liver and stored in the gall bladder.

  It is alkaline to neutralise hydrochloric acid from the stomach.

  It also emulsifies fat to form small droplets which increases the surface area.

  The alkaline conditions and large surface area increase the rate of fat breakdown by lipase.
• What is the order of organs in the digestive system?

  Salivary glands

  Oesophagus

  Stomach

  Pancreas

  Small intestine

  Large intestine

  Rectum
• Describe the food test for starch.

  Add iodine solution to the food sample.

  If there is starch present, it will change from brown/orange to black.
• Describe the food test for proteins.

  Add biuret solution to the food sample.

  If there are proteins present, it will change from blue to pink
• Describe the food test for lipids.

  Add Sudan III stain solution to the food sample.

  If there are lipids present, a red-stained layer will form on top.
• Describe the structure of the lungs.

  The air you breathe in goes through the trachea.

  The trachea is split into two tubes called bronchi, one going into each lung.

  The bronchi split into smaller tubes called bronchioles.

  The bronchioles end at small bags called alveoli

  The lungs are a pair of spongy, air-filled organs located on either side of the chest.
• Humans have what kind of circulatory system?

  Double circulatory system
• Describe the structure of the heart.

  Left: left atrium, left ventricle, aorta, pulmonary vein

  Right: right atrium, right ventricle, vena cava, pulmonary artery

  The heart has valves to make sure that blood flows in the right direction.

  Your pacemaker is in the right atrium wall.

  Coronary arteries branch off the aorta and surround the heart, making sure it gets all the oxygenated blood it needs.

  
• How does the heart pump blood around the body?

  Deoxygenated blood flows into the right atrium through the vena cava. The atrium contracts pushing the blood into the right ventricle. The right ventricle pushes the blood out of the pulmonary artery to the lungs to get oxygen.

  
  

  Oxygenated blood flows into the left atrium through the pulmonary vein. The atrium contracts, pushing the blood into the left ventricle. The left ventricle pushed the blood out of the aorta to the rest of the body.

  
  

  Coronary arteries branch off the aorta and surround the heart, making sure it gets all the oxygenated blood it needs.
• What is the natural resting heart rate controlled by?

  A group of cells in the right atrium wall act as a pacemaker. These cells produce a small electric impulse which spreads to the surrounding muscle cells, causing them to contract.
• How can you fix an irregular heartbeat?

  By using an artificial pacemaker.

  It is a device that's implanted under the skin and has a wire going to the heart. It produces an electric current to keep the heart beating regularly.
• What are the three types of blood vessel?

  Arteries

  Capillaries

  Veins
• What is the structure of an artery and has does this relate to its function?

  Arteries carry blood away from the heart at a high pressure.

  Small lumen.

  The walls contain thick layers of muscle to make them strong and elastic fibres to allow them to stretch and spring back. This accommodates the high pressure of the blood.
• What is the structure of a capillary and has does this relate to its function?

  Capillaries allow the exchange of substances.

  Very small lumen

  Permeable walls so that substances can diffuse in and out.

  Walls that are one cell thick. This increases the rate of diffusion by decreasing the distance over which it occurs.
• What is the structure of a vein and has does this relate to its function?

  Veins carry blood to the heart at a low pressure.

  Have thin walls which allows for a large lumen to help the blood flow despite the low pressure.

  Have valves to help keep the blood flowing in the right direction.
• What makes up the blood?

  Red blood cells

  White blood cells

  Platelets

  Plasma
• Red Blood Cells


  They carry oxygen from the lungs to the cells.

  They are a biconcave disc which gives a large surface area for absorbing oxygen. They also don't have a nucleus which allows more room for carrying oxygen.

  Contains haemoglobin.

  The oxygen binds to the haemoglobin and is carried to the cells. At the cells, the oxygen splits from the haemoglobin and goes into the cell.
• White Blood Cells


  They defend against infection.

  They have a nucleus

  Phagocytes undergo phagocytosis.

  Lymphocytes produces antibodies and antitoxins.
• Platelets


  Help blood clot- stop blood pouring out and microorganisms getting in at a wound.

  They are small fragments of cells and have no nucleus.
• Plasma


  A liquid that carries:

  Red blood cells

  White blood cells

  Platelets

  Glucose

  Amino acids

  Carbon Dioxide

  Urea

  Hormones

  Proteins

  Antibodies

  Antitoxins
• What is coronary heart disease?

  In coronary heart disease, layers of fatty material build up inside the coronary arteries, narrowing them.

  This reduces the flow of blood through the coronary arteries, resulting in a lack of oxygen for the heart muscle.
• How can you treat coronary heart disease?

  Stents

  Statins
• What are stents?


  They are tubes that are inserted inside arteries. They keep them open, making sure blood can pass through to the heart muscles. This keeps the person's heart beating.
• What are the advantages and disadvantages of stents?

  A: effective for a long time and the recovery time from surgery is relatively quick.

  
  

  D: risk of complications and infection from surgery and a risk of developing a blood clot near the stent.
• What are statins?


  Statins are drugs that are widely used to reduce blood cholesterol levels which slows down the

  rate of fatty material deposit.