b2

• 4 parts of the blood:

  plasma, WBC, RBC, platelets
• Benign tumour: tumour that does not spread

  encased in a membrane so it has limited growth

  made up of cells that are more similar to normal cells
• Malignant tumour: tumour that can spread to neighbouring tissue

  cells break off and invade healthy cells forming secondary tumours

  result from changes in cell, uncontrolled cell division

  travel up the blood
• arteries:

  thick muscular walls, thick elastic fibres, narrower lumen

  blood needs to be pumped at high pressure
• veins:

  thinner walls, larger lumen, has valves

  blood needs to be pumped at low pressure
• cappillaries:

  1 cell thick (for quick gas exchange), permeable walls (substances can diffuse in and out)
• blood circulation is needed to:

  move glucose, co2, o2, hormones and urea, to and from cells

  help fight disease

  regulate body temp
• coronary artery:

  found on the outside of heart muscle

  supplies heart with co2 and oxygen

  muscle tissue needs enough oxygen for respiration so that they can have enough energy for muscle contraction
• enzymes:

  biological catalysts

  large proteins made of amino acids

  specific to one substrate (has a specific active site)
• factors effecting enzymes:

  pH (7), temperature(37)- can cause enzymes to denature if theyre too high

  surface area

  pressure
• coronary heart disease:

  coronary arteries are blocked by layers of fatty material, found on the outside of heart material, supply heart with o2

  = arteries become narrower

  = blood is restricted

  = lack of oxygen to muscle heart

  = cannot respire

  needs respiration so muscles have enough energy to contract

  heart begins respiring anaerobically so produces lactic acid, keeping muscles contracted
• stents:

  metal tubes that are inserted into the arteries to keep them open so more blood can flow through

  side effects: infections, blood clots
• statins:

  reduce cholesterol in the blood, lowering the risk of heart disease

  side effects: kidney failure, liver damage
• cancer risk factors:

  smoking, obesity, uv exsposure
• phloem (translocation)

  living cells, transports sugars made in the leaf (for storage), goes both ways
• xylem (transpiration)

  dead cells, carries water/minerals from the roots to leaves, goes one way
• transpiration stream: water moves from the roots to the leaves through the xylem
• rate of transpiration:

  high light intensity: increases (no light = no photosynthesis = closed stomata = little water escapes)

  high temperature: increases (particles have more energy to diffuse out of the stomata)

  good air flow: increases (water vapour swept away maintaining low conc of water outside the leaf = quicker diffusion)

  low humidity = increases (low conc of water outside leaf = quicker diffusion)
• organisation in plants:

  upper epidermal tissue -covered in waxy cuticle to reduce water loss, transparent to let light through

  palisade mesophyll - lots of chloroplasts, more light = more photosynthesis

  spongy mesophyll

  lower epidermal

  stomata - lets co2 diffuse into the cell

  guard cell - opens and closes stomata
• test for starch

  1. add sample of food to test tube
  2. add 2 drops of iodine
  3. if starch is present, it will turn blueblack
• protein

  • produced by pancreas, small intestine
  • tested by biuret solution - turns from light blue to light purple
  • enzyme: protease
  • product: amino acids
• starch

  • produced by pancreas, stomach, salivary glands
  • tested by iodine solution - turns from orange red to blue black
  • enzyme: amylase
  • product: glucose, maltose
• lipids

  • produced by pancreas, stomach, small intestine
  • tested by ethanol solution - turns from colourless to cloudy white (add half filled test tube with water)
  • enzyme: lipase
  • product: fatty acids, glycerol
• sugar is tested by blue benedicts solution, blue colour to brick red (heat in a water bath)
• pace makers - produce small electric impulse
• cappillaries

  • one cell thick for quick gas exchange via diffusion (decreases distance)
  • permeable walls so substances can diffuse in and out
• The pituitary gland is in the brain. It produces several hormones which act upon other glands to stimulate further hormones to be produced. It is called the ‘master gland’.
• The adrenal glands are found above your kidneys. They release the hormone adrenaline which increases your heart rate for a flight, flight or freeze response.
• The thyroid gland is in the throat. This produces the hormone thyroxine which controls your metabolism.
• The pancreas is found in the abdomen. It produces insulin and glucagon which regulate blood sugar.
• lungs are adapted for efficient gas exchange

  • alveoli have a large surface area to absorb oxygen
  • alveoli walls are one cell thick to provide a short diffusion pathway for absorbing oxygen
  • alveoli have moist lining
  • capillaries have a good blood supply to maintain the concentration gradient
  • lungs are well ventilated to absorb oxygen and release co2
• liver - bile is produced, bile neutralises stomach acids and emulsifies fat

  bile is stored in the gall bladder before it is released in the small intestine
• stomach - produces the protease enzyme, pepsin

  pummels the food with its muscular walls
• blocked duct from pancreas to small intestine

  fewer digestive enzymes enter small intestine

  enzymes break down/digest less food

  less absorption of nutrients

  less glucose can enter the bloodstream

  less glucose available for respiration

  fewer amino acids can enter the bloodstream - less protein is made (for growth)
• blocked tubes leading to alveoli

  • less oxygen to blood steam
  • less oxygen available to respiration
  • less energy/glucose made for growth/proteins
• pancreas produces protein, starch and lipids
• small intestine produces protein and lipids
• salivary glands produces starch
• stomach produces starch, lipids
• lock and key

  substrate collides with enzymes active site that is complimentary to its shape

  the enzyme catalyses the breakdown of the substrate

  the products are released from the active site, and the enzymes remains unchanged so it can be reused