Biology topic 2: organisation

• What are cells?


  Cells are the basic building blocks of all living organisms
• What is a tissue?

  A tissue is a group of cells with a similar structure and function
• What is an organ?

  Organs are aggregations of tissues performing specific functions.
• What is an organ system?

  Organs are organised into organ systems, which work together to form organisms.
• What is the digestive system?

  The digestive system is an example of an organ system in which several organs work together to digest and absorb food
• What is the relationship between enzymes and metabolism?

  the enzyme helps to increase or decrease the rate of metabolism in the body.
• What is a carbohydrase?

  Carbohydrases convert carbohydrates into simple sugars
• What is a specific example of a carbohydrase?

  Amylase is a carbohydrase which breaks down starch into maltose?
• What is protease?


  Protease convert proteins into amino acids
• What is lipase?


  Lipases convert lipids into fatty acids and glycerol
• What are the products of digestion used for?

  The products of digestion are used to build new carbohydrates, lipids and proteins. Some glucose is used in respiration
• What is an enzyme?

  -Enzymes are biological catalysts which increases the rate of reaction without being used

  (protein molecules)
• What is the lock and key theory?

  - the active site of each enzyme is a different shape.

  -It is a perfect match to the shape of the substrate molecule, or molecules.

  -One enzyme is therefore specific to one substrate (complementary)
• How does temperature affect enzyme activity?

  -At low temperatures, the number of successful collisions between the enzyme and substrate is reduced because their molecular movement decreases. The reaction is slow

  -Higher temperatures disrupt the shape of the active site, which will reduce its activity, or prevent it from working. The enzyme will have been denatured.

  -Enzymes therefore work best at an optimum temperature. (37)
• How does pH affect enzyme activity?

  -If the Ph is to high or too low, the forces that hold the amino acid chains that make up the protein will be affected?

  -This will change the shape of the active site, so the substrate can no longer fit in

  - the enzyme is said the be denatured and can no longer work.
• Where are Carbohydrases/ amylases found?

  - salivary amylase is found in the salivary glands

  - pancreatic amylase is found in in the pancreas

  - amylase is found in the small intestine ( ileum)
• Where is protease found?

  - pepsin is found in the gastric glands in the stomach

  - trypsin is found in the pancreas

  - peptidase is found in the small intestine
• Where is lipase found?

  - pancreas and small intestine
• What is the role of a digestive enzyme?

  Digestive enzymes convert food into small soluble molecules that can be absorbed into the bloodstream.
• What is the role of bile in digestion?

  -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 heart?

  -The heart is an organ that pumps blood around the body in a double circulatory system.

  
• What is pulmonary circulation and what happens to the gases?

  The pulmonary circulation transports blood to the lungs. At the lungs:

  -oxygen diffuses into the blood from the alveoli - the blood becomes oxygenated

  -carbon dioxide diffuses from the blood into the lungs

  - low pressure ( optimum for diffusion of gases).
• What is One way flow?

  Blood must flow one way only through the circulatory system. Valves in the heart, aorta and veins ensure this one-way flow.

  Closure of a valve prevents back flow
• What is a Faulty Heart Valve?


  Heart valves may become faulty. A valve may not:

  
  

  -open as wide as it should, restricting blood flow through the heart - this means less blood reaches the body, pressure builds up and the lungs can swell with fluid

  -doesn't close properly and allow blood to leak back through into the atrium
• CHD: Faulty heart valve solution?

  -with a biological valve from a human donor or made from animal tissue from a pig or cow

  -with a mechanical valve made from strong, durable materials

  -The operation is usually successful.evaluation

  -Mechanical valves last longer, but blood can clot on them.

  - A patient may need long

  -term medication that prevents blood clots developing.

  -Biological valves are more likely to wear out.

  - Infection
• What controls the natural resting heart rate?

  -Specialised cells in the right atrium generate electrical signals that make the heart contract independently

  - These specialised cells act as a natural pacemaker.

  -A wave of contraction spreads across the heart - to the left atrium and then to the ventricles. This enables the ventricles to contract together.
• what is an Artificial pacemakers ?


  -An artificial pacemaker is a small, battery-operated electronic device implanted in a person's chest that sends out regular, adjustable electrical impulses to produce normal contractions of the heart.
• What are The types of blood vessels?

  -Blood is transported in arteries, veins and capillaries.
• What are Arteries and their features?

  -Always carry blood away from the heart-Carry blood under high pressure-Have thick muscular and elastic walls to pump and accommodate blood-connective tissue provides strength-narrow lumen
• What are Veins and their features?

  Always carry blood to the heart-Carry blood under low or negative pressure-Have thin walls - have less muscular tissue than arteries-Have less connective tissue than arteries-Have a wide lumen
• What are Capillaries and their features?

  -Capillaries connect the smallest branches of arteries and veins

  -The walls of capillaries are just one cell thick. -allow the exchange of molecules between the blood and the body's cells - molecules can diffuse across their walls. This exchange of molecules is not possible across the walls of other types of blood vessel.
• What does Blood contain?

  Blood is a tissue consisting of plasma, in which the red blood cells, white blood cells and platelets are suspended.
• What is the role of Red blood cells?

  -Red blood cells transport the oxygen required for aerobic respiration in body cells
• What is the role of White blood cells?

  produces antibodies specific to an antigen
• What are Platelets?


  -they have proteins on their surface that enable them to stick to breaks in a blood vessel and clump together

  -they secrete proteins that result in a series of chemical reactions that make blood clot, which plugs a wound.
• What is Coronary heart disease?

  -The coronary arteries may become blocked by a build-up of fatty material, caused by certain kinds of 'bad' cholesterol. As the fatty material increases, one or more coronary arteries narrow, and can become blocked.

  - the amount of oxygen reaching the heart muscle is reduced. -A person will develop chest pain, and if left untreated, a heart attack is the result.

  -can lead to death of heart muscle or heart failure
• How do we treat coronary heart disease with statins? ( ad & dis)


  -Statins are drugs that help to lower cholesterol in the blood. They do this by lowering its production in the liver.

  dis -Statins are not suitable for everyone - they should not be prescribed for people with liver disease, or pregnant or breast feeding women.

  dis -Some patients taking statins often experience side-effects such as headaches and memory loss.

  dis -There have been reports of statins being linked with type 2 diabetes and liver damage.

  ad -They may protect against other conditions such as Alzheimer's disease, but further research is needed.

  dis- inconvenient

  ad- reduce risk of strokes and heart attacks
• How can we treat coronary heart disease with anti-plasty stent? ( ad& dis)

  -Coronary arteries that are blocked or have become narrow can be stretched open and a stent inserted to restore and maintain blood flow.

  ad-They can be used in instances where drugs are less effective, and offer a longer term solution.

  ad -Stents are made from metal alloys and do not lead to an immune response in the patient.

  dis: risks: catching an artery, blood clot, infection due to surgery.
• How can we treat coronary heart disease with an artificial heart? ( ad & dis)

  In the case of heart failure a donor heart, or heart and lungs can be transplanted. Artificial hearts are occasionally used to keep patients alive whilst waiting for a heart transplant, or to allow the heart to rest as an aid to recovery

  dis: infection

  ad: less likely to be rejected by immune system

  dis: mechanical failure

  dis: blood clots leading to stroke ( blood thinners are then taken)
• What is health defined as?

  Health is the state of physical and mental well-being.

  Diseases, both communicable and non-communicable, are major causes of ill health.

  Other factors including diet, stress and life situations may have a profound effect on both physical and mental health.