organisation

• cell organisation

  • make up living organisms
  • specialised cells from tissues , which forms organs , which form organ systems
  • large multicellular organisms have different systems for exchanging and transporting materials
• tissue

  • tissue is a group of similar cells that work together to carry out particular function
  • muscular tissue = contracts to move what its attached to
  • glandular tissue = makes and secretes chemicals
  • epithelial tissue = cover some parts of the body
• organs

  • group of different tissues that work together
  • organ system is a group or organs working together
  • digestive system = breaks down and absorbs food
  • pancreas and salivary glands = produce digestive juices
  • stomach and small intestine = digest food
  • liver = produces bile
  • small intestine = absorbs soluble food molecules
  • large intestine = absorbs water from undigested food
• enzymes

  • biological catalysts = reduce need for high temperatures and speed up useful chemical reactions
  • large proteins , made of chains of amino acids
  • has active site unique to substrate that fits - lock and key method
  • higher temperature increases rate at first too hot enzyme denatures , too cold not enough energy
  • ph too high or low enzyme denatures
• enzymatic reactions

  • amylase breakdown starch to maltose - detect starch using iodine solution(brown to black)
  • drop of iodine on spotting tile
  • place bunsen burner on heat proof mat and heat
  • add 1cm of amylase solution and 1cm of buffer solution , tube in beaker and wait 5 mins
  • add starch solution
  • mix contents , starts stop watch
  • record how long takes amylase to break down starch
  • repeat using different values
  • rate = 1000/time
• enzymes and digestion

  starch , proteins and fats need to be broken down by digestive enzymes into smaller molecules like sugars , amino acids and fatty acids , smaller soluble molecules easily absorbed into bloodstream
• carbohydrases

  • amylase - made in salivary gland , pancreas and small intestine
  • converts carbohydrates into simple sugars
• proteases

  • made in stomach , pancreas and small intestine
  • converts proteins into amino acids
• lipases

  converts lipids into glycerol and fatty acids

  made in pancreas , small intestine
• bile

  • produced in liver
  • stored in gall bladder before it is released into small intestine
• hydrochloric acid

  • stomach makes ph too acidic for enzymes
  • bile is alkaline - neutralises the stomach acid
  • emulsifies fats , given it a bigger surface area
  • breakdown of food is catalysed by enzymes
• salivary glands

  produce amylase enzyme in saliva
• stomach

  • pummels food with muscular walls
  • produces protease enzyme pepsin
  • produces hydrochloric acid to kill bacteria , give right ph for enzymes
• liver

  • where bile is produced
  • bile neutralises stomach acid and emulsifies fats
• pancreas

  • produce protease , amylase and lipase enzymes
  • releases these into small intestine
• gall bladder

  while bile is stored before its released into the small intestine
• large intestine

  • excess water is absorbed from the food
• rectum

  faeces is stored before they leave the anus
• small intestine

  • produces protease amylase and lipase to complete digestion
  • digested food is absorbed into blood
• food tests

  Benedict's test for sugars

  iodine solution test for starch

  biuret solution test for proteins

  sudan 111 test for lipids
• lungs

  • thorax is the top part of your body
  • separated from lower part of the body by diaphragm
  • lungs protected by ribcage and surrounded by pleural membranes
  • air that you breathe comes through trachea - splits into bronchi
  • bronchi split into progressively smaller tubes called bronchioles
  • bronchioles end at alveoli
• heart

  • right ventricle pump flows into ps deoxygenated blood to lungs , then return to heart
  • left ventricles pumps oxygenated blood all around the organs and returns to heart deoxygenated
  • blood flows into atria from vena cava and pulmonary vein
  • atria contract , pushing blood into ventricles
  • ventricles contract , forcing blood into pulmonary artery and aorta and out off the heart
  • blood flows to organs
• arteries

  • carry blood away from the heart
  • heart pumps blood at high pressure , artery walls strong
  • walls thick compared to lumen
  • contain layers of muscle to make them strong , elastic fibres to allow them to stretch and spring back
• capillaries

  • involved in exchange os materials
  • really tiny
  • carry blood really close to every cell to exchange substances with them
  • permeable walls , substances can diffuse in and out
  • supply food and oxygen , take away waste like co2
  • wall one cell thick , increases rate of diffusion by decreasing distance
• viens

  carry blood to the heart

  blood is lower pressure so walls are not as thick

  bigger lumen to help blood flow

  have valves to keep blood flowing in right direction
• red blood cells

  • carry oxygen
  • biconcave discs = large surface area for absorbing oxygen
  • no nucleus = more room to carry oxygen
  • contain haemoglobin
  • which binds to oxygen in lungs - opposite in tissues
• white blood cells

  • defend against infection
  • change shape in process called phagocytosis
  • produce antibodies to fight microorganisms and antitoxins
  • have a nucleus
• platelets

  • helps blood clot
  • small fragment of cells - no nucleus
• plasma

  • liquid carries everything in blood
  • nutrients like glucose and amino acids
  • carbon dioxide from organs to lungs
  • urea from liver to the kidneys
  • hormones , proteins
  • antibodies , antitoxins produced by white blood cells
• coronary heart disease

  • when coronary arteries get blocked by layers of fatty material - causing them to narrow
• stents

  • inserted inside arteries - blood can pass through
  • complications during operations , risk of infection , could develop blood clot
• statins

  • reduce cholesterol i the blood
  • advantages = reduce chance of disease , reduce bad cholesterol, and increase good
  • disadvantages = forget to take them , side effects
• artificial heart

  • pump blood and acts as temporary fix until donor heart can be found
  • less likely to be rejected
  • lead to bleeding , infection , wear out , thinning of blood
  • faulty heart valves can be replaced with biological or mechanical valves
• cancer

  • caused by uncontrolled cell growth and division
  • benign = tumour stays in one place
  • malignant = tumour spreads
  • smoking , obesity , uv exposure , viral infection , genes
• phloem

  • transports food
  • columns of living cells with small pores to allow cell sap
  • transport food substances , in both directions - translocation
• xylem

  • take water up
  • made of dead cells - strengthen with lignin
  • transport water and mineral ions - transpirations
  • caused by evaporation and diffusion on the leaves
  • creates a shortage of water so more is drawn up
  • constant transpiration stream of water
• transpiration and stomata

  light intensity = bright greater transpiration , stomata begin to close as it get darker , so dont need let co2 in , little water can escape

  temperature = warmer , faster transpiration rate , more energy to evaporate and diffuse out of stomata

  airflow = better airflow , greater transpiration rate

  humidity = drier air around leaf = greater transpiration rate