topic b2- organisation

• enzymes denature at

  peaks of graphs, the y axis is reaction time
• enzymes

  • when enzymes and substrates are put together there is an active site between them
  • enzyme and substrate fit together like a lock and key
  • an unchanged enzyme has products that fit inside of it
• cell organisation 


  • cell
  • tissue
  • organ
  • organ system
• cell 


  a basic building block that all living organisms have
• tissue

  a group of similar cells that work together
• organ

  a group of different tissues that work together
• organ systems

  a group of organs working together
• enzymes

  enzymes catalyse (speed up) chemical reactions. each enzyme only catalyses one specific reaction because of its unique shape of it's active site.
• denatured- shown in graphs at peak

  high temperatures and high and low pHs change the shape of the active site so the enzyme no longer works
• digestive enzymes

  • break big molecules down into smaller, soluble ones
  • these can pass through the walls of the digestive system and be absorbed into the blood
• enzyme-breaks down-into-produced in the

  • amylase-starch-maltase and other sugars-salivary glands, small intestine, pancreas
  • protease-protein-amino acids-stomach, pancreas, small intestine
  • lipase-lipid-glycerol and fatty acids- small intestine, pancreas
• bile

  • made in the liver
  • stored in the gall bladder
  • speed up digestion by:
  • emulcifying fat- larger surface area
  • making conditions alkaline so enzymes in the small intestine work better
• food tests

  • benedicts
  • iodine
  • biuret
  • sudan III
• benedit's test- sugars (biscuit, cereal, bread)

  1. prepare a food sample and transfer 5cm cubed to a test tube
  2. prepare a water bath set to 75 degrees celcius
  3. add 10 drops of benedict's solution to the test tube
  4. put the test tube in the water for 5 mins
  5. if it contains sugar the solution will change from blue to green, yellow, brick red
• iodine solution- starch (pasta, rice, potatoes)

  1. prepare a food sample and transfer 5cm cubed to a test tube
  2. add a few drops of iodine solution and shake the tube gently
  3. if it contains starch the solution will change from browny-orange to black or blue-black
• biuret test- proteins (meat, cheese)

  1. prepare a food sample and transfer 2cm cubed to a test tube
  2. add 2cm cubed of biuret solution to the sample and gently shake
  3. if it contains protein it will change from blue to purple
• sudanIII (emulsification test)- lipids (milk, butter)

  1. prepare a food sample and transfer 5cm cubed into a test tube
  2. add 3 drops of sudanIII solution to the test tube and gently shake
  3. if lipids are present it will separate into 2 layers, the top layer being red
• the lungs have

  • trachea- tube at the top
  • lung
  • bronchus- attached to the tube inside the lung
  • alveoli- hanging off bronchus- there are millions of alveoli in the lungs
• gas exchange

  • alveolus- where gases come in and out of
  • capillary- tube where blood passes through
  • air goes in and out of alveolus
  • gases diffuse between the alveolus and the blood
  • blood goes to the rest of the body (lots of 02)
  • blood comes from the rest of the body (lots of 02)
• the heart

  • the circulatory system is made up of the heart, blood vessels and blood
  • in the heart there is:
  • pulmonary artery
  • aorta
  • vena cava
  • pulmonary vein
  • valves- stop blood flowing backwards (bicuspid and tricuspid)
  • right and left ventricles and atriums
  • oxygenated blood flowing through the left sides
  • deoxygenated blood flowing through the right sides
  • pacemaker cells in the right atrium wall control resting heart rate
• blood vessels

  • artery
  • capillaries
  • veins
• rate of blood flow

  volume of blood/ time taken
• artery

  • carry blood away from the heart
  • small lumen
  • thick muscle and elastic layers because blood pressure is high
• capillaries

  • carry blood close to body cells to exchange substances
  • one cell thick
  • thin, permeable walls to allow substances to diffuse in and out easily
• vein

  • carry blood back to the heart
  • valves inside stop blood flowing backwards
  • large lumen
  • thinner walls than arteries because blood pressure is lower
• blood- red blood cells

  • carry oxygen around the body
  • no nucleus- more room for 02
  • contains haemoglobin, which binds to 02
  • biconcave shape=big surface area=lots of 02 absorbed
• blood- white blood cells

  • defend against infection
  • nucleus
  • phagocytosis
  • antitoxins
  • antibodies
• blood- platelets

  • help blood to clot at a wound
  • fragments of cells
• blood- plasma

  • carries everything in the blood
  • amino acids
  • hormones
  • RBC
  • WBC
  • urea
  • glucose
  • antibodies
  • anitoxins
  • proteins
  • platelets
  • co2
• blood

  is a tissue
• cardiovascular disease

  • diseases of the heart of blood vessels, e.g. coronary heart disease
  • normal coronary artery- clear, normal size
  • coronary artery of someone with coronary heart disease:
  • fatty deposit
  • blood flow is restricted so there's a lack of oxygen to the heart muscle- this can cause a heart attack
• treatments for cardiovascular disease

  • statins
  • stent
  • heart transplant
  • artificial heart
  • replacement heart valves
• statins

  • advantages:
  • reduces the amount of LDL cholesterol in the blood
  • which slows down the formation of fatty deposits
  • disadvantages:
  • need to be taken long-term
  • can have side effects
• stent- tube put in artery

  • advantages:
  • keeps coronary artery open for a long time
  • recovery time from surgery is quick
  • disadvantages:
  • surgery can cause bleeding and infection
  • donor hearts can be rejected by immune system
• heart transplant

  • advantages:
  • can treat heart failure
  • donor hearts work better than artificial ones
  • disadvantages:
  • surgery can cause bleeding and infection
  • donor hearts can be rejected by the immune system
• artificial heart

  • advantages:
  • can be used whilst waiting for a donor heart or while the heart is healing
  • disadvantages:
  • artificial devices can lead to thrombosis (blood clots in blood vessels)
• replacement heart valves- biological or mechanical

  • advantages:
  • can treat severe valve damage
  • faulty heart valves can stop blood circulating effectively
  • disadvantages:
  • artificial devices can lead to thrombosis (blood clots in blood vessels)
• cardiovascular system part 1

  1. deoxygenated blood from body carried by vena cavas into right atrium
  2. right atrium contracts, pushing blood through tricuspid valve into right ventricle
  3. right ventricle contracts, pushing blood through pulmonary valve into pulmonary artery
  4. blood travels to lungs, where co2 exchanged for o2 from air
• cardiovascular system part 2

  5. oxygenated blood from lungs carried by pulmonary veins into left atrium

  6. left atrium contracts, pushing blood through bicuspid valve into left ventricle

  7. left ventricle contracts pushing blood through aortic valve into aorta 8. aorta delivers oxygenated blood to body, where used for energy production
• heart rate

  the number of times the heart beats per minute