Organisation- CHAPTER 2

• cells

  basic building blocks that make up a living organism
• tissue

  group of similar cells that work together to perform a particular function
• muscular tissue

  contract to move whatever its attached to
• glandular tissue 


  makes and secretes chemicals like enzymes and hormones
• epithelial tissue

  covers parts of the body
• organ

  a group of different tissue working together to perform a certain function
• organ system

  group of organs working together to perform a particular function
• enzymes

  large proteins made up of chains of amino acids. biological catalyst that speeds up reaction
• catalyst

  substance that speeds up reaction without being used up or changed in the process
• active site


  every enzyme has an active site (special region that binds to the substrate) with a unique shape that fits into the substance involved in the reaction
• active site is complementary to the substrate
• lock and key model


  scientist thought that the substrate had to fit perfectly into the active site
• induced fit model

  enzyme changes shape slightly as it binds to the substrate
• how does temperature affect enzymes

  changing the temperature changes the rate of reaction of an enzyme-catalyst reaction. like with any temperature, a higher temperature increases the rate at first. but if it gets too hot some off the bonds holding the enzymes together break which changes the shape of the enzyme, so the substrate won't fit anymore. The enzyme is said to be denaturing. All enzymes have an optimum temperature that they work best at.
• how does PH affect enzymes

  if the PH is too high or two low it interferes with the bonds holding the enzyme together. This changes shape of the active site and denatures the enzyme. All enzymes have an optimum Ph that they work best at, which is often PH neutral 7 but not always
• what does amylase break down into ?

  Amylase breaks down carbohydrates into simple sugars and starch
• where is amylase found in the body

  small intestines, pancreas, salivary glands
• what does protease break down into ?

  protease converts proteins into amino acids
• where is protease found in the body

  stomach, pancreas, small intestine
• what lipase break down into ?

  lipase converts lipids into 1 glycerol and 3 fatty acids
• where is lipase found in the body

  pancreas and small intestine
• bile is produced in the liver, stored in the gall bladder and released into the small intestine
• what does bile do

  Bile is alkaline and therefore neutralise acids. It emulsifies fats which gives them a bigger surface area for digestive enzymes to work on.
• Gas exchange

  blood next passing to the alveoli has just returned to the lungs from the rest of the body and contains lots of carbon dioxide ( transported around the body in blood plasma) and very little oxygen. Oxygen diffuses out of the alveolus (high concentration) into the blood (low concentration). Carbon dioxide diffuses out of the blood (high concentration) into the alveolus (low concentration) to be breathed out
• After Gas Exchange

  Blood reaches the body cells and oxygen is released from red blood cells were there is a high concentration and diffuses into the body cells were there is a low concentration. At the same time carbon dioxide diffuses out of the body cells (high concentration) into the blood (low concentration) and then carried back to the lungs
• breathing rate

  breaths per minute (bpm)= no. of breaths / no. of minutes
• what type of blood does the right side of the body pump ?

  Deoxygenated blood to the lungs
• what type of blood does the left side of the body pump ?

  oxygenated blood to the body
• PROCESS OF BLOOD PUMPING

  Blood flows into the two atria from the vena cava (R) and pulmonary vein(L). The atria contracts pushing the blood into the ventricles. The ventricles contract forcing the blood into the pulmonary artery and the aorta, and out of the heart. The blood then flows to organs through arteries and returns through veins. The atria fills again and the whole cycle starts over.
• coronary artery

  supplies the heart with all the oxygenated blood and nutrients it needs
• what is a pacemaker ?

  resting rates is controlled by a group of cells in the right atrium wall that act as a pacemaker. These cells produce a small electrical impulse which spreads to surrounding muscle cells causing them to contract
• artificial pacemaker

  patient with an irregular heartbeat is given a little device implanted under the skin and has a wire going to the heart, producing an electric current to keep beating regularly
• characteristics of arteries

  arteries carry blood away from the heart. They carry blood at high pressures, artery walls are strong and elastic. The walls are thick compared to the size of the hold down the middle. Thick layers of muscle to make them strong and elastic fibres to allow them to stretch and spring back
• characteristics of veins

  capillaries join up to form veins. Blood is at lower pressure in veins so the walls don't need to be as thick. Bigger lumen than arteries to help blood flow. Valves to keep blood flowing in the right direction
• characteristics of capillaries

  arteries branch off into capillaries. They are really tiny. Carries blood really close to every cell in the body to exchange nutrients (glucose and amino acids) and waste products (urea and carbon dioxide). They have permeable walls so substances can diffuse in and out. Walls are one cell thick which increases the rate of diffusion decreasing the distance it occurs.
• what is the epidermal tissue covered with ?

  waxy cuticle
• waxy cuticle


  helps reduce water loss by evaporation
• upper epidermis 


  is transparent to allow light to pass through its palisade layer
• palisade layer


  lots of chloroplasts and are near the top of the leaf where they can get the most light
• xylem and phloem


  network of vascular bundles which deliver water and other nutrients to the entire leaf and take way glucose produced by photosynthesis which helps support the structure of the cell