Topic 2 - Organisation

• Cell


  Make up all living things, very very small
• Tissue


  A group of specialise cells with a similar structure and function
• Organ


  Formed from many different tissues working together to produce a specific function eg the stomach with muscular and epithelial tissue
• Organ system


  Group of organs which work together in order to perform a specific function eg digestive system with stomach,small intestine and etc.
• Organ in the digestive system


  Gland (salivary and pancreas), stomach, snalll intestine, liver, large intestine
• Glands function


  Produce digestive juices containing enzymes which break down food
• Stomach function


  Produces hydrochloric acid to kill bacteria and provide the optimum PH for protease enzyme to work, and churns food to break down
• Small intestine function 


  Where soluble molecules are absorbed into the blood,
• Liver function 


  Produces bile which is stored in gall bladder, helps with digestion lipids
• Large intestine function


  Absorbs water from undigested food to produces faces, passes out body through rectum and anus
• what are enzymes


  Biological catalysts made form protiens and are present in many reactions so they can be controlled, can break smal and large molecules down,
• Lock and key theory


  The shape of the substrate is complementary to the shape of the active site, so when they bond it forms a enzyme-substrate comple. Once bound, the reaction takes place and the products are released from the surface of the enzyme
• Induced fit


  In reality when a substrate bind to the active site of the enzyme, the active site and substrate change shape slightly to fit more perfectly together, this makes it easier for bonds within the substrate to break and new binds to form, producing products.
• Enzymes remain unchanged at the end of a reaction and work very quickly.
• As enzymes are enzymes , require optimum PH and temperature.
• Optimum temp for enzymes

  Around 37 degrees Celsius (body temp). Rate of reaction increases with increase in temperature up to optimum, but above it rapidly decreases and eventually stops, when temp is too high, bonds in the structure will break which changes shape of active site so substrate can no longer fit and is called denatured
• Optimum PH for enzymes


  For most is 7, but for some reduced in acidic conditions like stomach have lower optimum. If PH is too high or low, the forces that hold the amino acid chains that make up the protein will be affected and enzyme becomes denatured
• Digestive enzymes


  -carbohydrases

  -proteases

  -lipases
• Carbohydrases


  Covert carbohydrates into simple sugars, eg amylase breaks down into maltose. Produced in salivary glands, pancreas and small intestine
• Proteases


  Convert proteins into amino acids, e.g pepsin produced in stomach, other forms can be found in pancreas and small intestine.
• Lipases


  Convert lipids into fatty acids and glycerol. Soluble glucose, amino acids, fatty acids and glycerol pass into the bloodstream to be carried to all the cells in the body. Used to build new carbohydrates, lipids and proteins, with some glucose used in respiration,
• Food test for sugars


  Benedict’s solution

  Result: light blue to green-brick red (dependant on sugar amount)

  Need water bath and Bunsen burner and place food sample in water bath at 80 degrees
• Food test for Starch

  Iodine test

  Results: Orange brown to blue black
• Food test for proteins

  Beiruts solution

  Results: Blue to lilac purple
• Food tests for lipids


  Ethanol/Sudan III

  Results for ethanol: Colourless to cloudy emulsion

  Results for Sudan III: Colourless to red stained oil layer floating on water surface
• Bile function


  Produced in liver and stored in gallbladder, released into small intestine.

  -Is alkaline to neutralise the hydrochloric acid in the stomach (higher optimum PH than stomach enzymes).

  -Breaks down large drops of fat into smaller ones )

  (emulsifies). Larger surface area allows lipase to chemically break down lipid into glycerol and fatty acids faster
• Rate of enzymatic reaction required practical

  Do later
• Circulatory system


  Carries oxygen and nutrients to every cell in the body and removes waste products
• Hearts double circulatory system


  Pulmonary: Deoxygenated blood flows into the right atrium and then the right ventricle which pumps it to the lungs to undergo gaseous exchange and become oxygenated

  Systemic: Oxygenated blood flows into the left atrium and then into the left ventricle which pumps oxygenated blood around the body
• Structure of heart


  -Muscular walls to provide strong heartbeat

  -Left ventricle wall thicker as blood pumped all around body rather then just lungs into right ventricle

  -4 chambers seperate oxygenated blood from deoxygenated

  -Valves prevent back flow of blood

  -Coronary arteries cover heart to provide own oxygenated blood supply
• Heart Process 


  Blood from right atrium to vena cava, left atrium to pulmonary vein, atria contract force blood into ventricles, ventricles contract push blood left to aorta and right to pulmonary artery , valves close
• Heart rate 


  Natural is 70bpm controlled by cells in Right Atrium act as a pacemaker, artificial pacemaker can be used if person has irregular heart eat
• Arteries


  Carry blood AWAY from heart

  -layers of muscle make them strong

  -elastic fibres allow stretching to withstand high pressure

  -small lumen, thick walls
• Veins


  Carry blood TOWARDS heart

  -Wide lumen to allow low pressure blood through

  -valves to make sure correct direction of flow
• Capillaries


  Allow blood to flow very close to cells to enable substance to move between them

  -one cell thick walls for short diffusion distance

  -permeable walls so substances can move across them.
• Lungs


  Found in thorax and rotected by rib cage, supply oxygen to blood and remove carbon dioxide
• Gas exchange system


  Trachea

  intercoastal muscles

  bronchi

  bronchioles

  alveoli

  diphragm
• Ventilation


  Ribcage moves up and out, diaphragm moves down and contracts, coaxes volume of chest to increase, lower pressure so air is drawn in as air moves from high to low pressure, OPPOSITE with exhalation
• Gas exchange 


  Upon inhalation, alveoli fill with oxygen, blood in capillaries surrounding alveoli is deoxygenated and has lots of CO2 as product of respiration, oxygen diffuses down concentration gradient into capillary bloodstream (as low oxygen concentration), CO2 diffuses down concentration gradient from blood to alveoli
• Alveoli adaptations


  -small no arranged in clusters for large surface area for diffusion to take place on

  -good blood supply from capillary to maintain concentration gradient

  -very thin walls for shirt diffusion distance

  -well ventilated for diffusion concentration gradient