Biology paper 1

• Lipids food test


  Ethanol goes clear to cloudy white emulsions. shake
• Test for sugars


  Benedict’s quantitive scale. Blue to brick red. Heat in water bath and mix
• test for starch


  Iodine goes from orange to blue black and you mix it
• test for proteins


  Biuret test goes from blue to purple and you mix
• Amalyse 


  Breaks down starch into simple sugars

  produced in pancreas and small intestin and salivary glands
• Protease


  Breaks down proteins into amino acids

  produced in pancreas and small intestine and stomach
• Lipase


  Produced in pancreas and small intestine

  breaks down lipids into fatty acids and glycerol
• Monochlonal antibodies 


  Mouse injected with antigens

  Mouse lymphocytes produce antibodies for the pathogen

  take out mouse spleen cells

  Find them with myeloma cancer cells to make a hybridoma cell then harvested and used to treat diseases eg cancer
• Therapeutic cloning

  take stem cells from patient bone marrow

  remove faulty genes

  put nucleus of stem cell into an egg cell and allow it to develop into an embryo

  remove stem cells from embryo and allow them to differentiate into working body parts/ cells

  pros- less likely to be rejected since uses patients own stem cells

  cons- ethical issues and low success rate
• Types of stem cell

  Embryonic- any type of cell

  adult- only certain types of cell
• Bile

  • Produced in liver and stored in gall bladder
  • emulsifies fat
  • breaks down large insoluble molecules so that they can be absorbed by blood stream
• Immune system

  • defence- skin, tranchea and nose has mucus, stomach acid neutralises infection
• white blood cells

  • Phagocytosis- phagocytes engulf and ingest pathogens
  • antibodies produced to complement the antigen of pathogen
  • antitoxin produced to neutralise
• Viral disease

  • Measles- fever symptoms and red rash on ski, prevented by vaccines, spread by sneezing coughing and air droplets
  • tabaco mosaic virus- discolouration on leaves, stunted growth, spread plant to plant, prevented by removing plant, less photosynthesis
  • hiv- flu like symptom controlled with antiretroviral drugs, attacks immune system, spread by sexual contact or body fluids exchang, prevented by condoms
• Bacterial disease

  • Salmonella- shows fever symptom, vomiting, poultry in uk vaccinated, spreads through eating unhygenic meat, food poisoning
  • gonorrhea- thick yellow/green discharge from penis/vagina, pain urinating, spread by sex, use condoms treated with antibiotics
• Fungi virus

  Rose black spot- black spots on roses leaves so reduces photosynthesis so less growth leaves fall off, spread by wind/weather, prevented by fungicide and remove infected leaves
• Magnesium lack

  Stunted growth
• Nitrate lack

  Leaves discoloured
• Protist

  Malaria

  high fever can be fatal

  vector spread by mosquitoes prevented by mosquitoes nets and prevent mosquitoes breeding
• Amylase activity experiment


  1. Place one drop of iodine solution on each bit of a spotting tile

  2. Measure known volume of starch solution and amylase solution and known pH and concentration of buffer solution

  3. Combine solutions and mix and start timer

  4. After 30 seconds use stirring rod to transfer drop of solution to spotting tile

  5. Keep taking sample until iodine turns orange so starch no longer present and record results

  6. Repeat again with different pH of buffer solution
• Amylase rp

  • Breaks down starch into simple sugars
• Analyse required: Iodine turns blue black if starch is present
• Amalyse required: Iodine turns orange when starch is no longer present
• Amalyse required: Experiment is done in a water bath at 30 degrees for 10 minutes
• Photosynthesis required

  • Boiling tube away from led lamp at 10cm fill tube with sodium hydrogen carbonate. place pondweed in tube. Leave to adjust to temp. Time 1 min and count number of bubbles. Repeat to find mean. Move further back each time. Use gas syringe more accurate.
  • if double distance then number of bubbles gets 4x smaller
• Transpiration stream


  Xylem- transports water and mineral ions from roots to leaves

  • water evaporating from leaves and leaves through stomata
  • continuous chain
  • affected by- light intensity( up=more photo= rate up)
  • temperature( up=higher since have more energy)
  • air flow( up= up rate since more water molecules leave quicker so high concentration gradient)
  • humidity up= rate down
• Tanslocation


  Phloem-pores so allow movement of water and sugars both ways

  transport of sugars around a plant in phloem

  journey from where made to where used
• Sperm adapted


  Streamlined head so move fast

  lots of mitochondria for energy

  acrosomes in head to break down egg membrane
• Nerve cell adapted to transmit signals

  Long axon so impulses carried a long way

  lots of dendrites (extensions) so can form branched connections with other nerve cells

  nerve ends have mitochondria so supply energy for impulses to be passed
• Muscle cells adapted to contract

  Store glycogen used for respiration

  lots of mitochondria so lots of energy to contract

  special proteins that slide over each other for muscles to contract
• Root hair cells 


  Large surface area so more water can move by osmosis in

  large vacuole so speeds up water movement

  lots of mitochondria for energy from respiration for active transport
• Xylem transport water and mineral ions from roots to shoots


  Strengthened with lignin

  hollow dead cells so form continuous tube
• Phloem carry food to parts of plant

  sieve plates so can move food up and down cell

  alive cells
• Cell differentiation meaning


  Process by which cells become special to perform specific functions
• Animal and plant differentiation

  Animals- loose ability to differentiate in early stages

  plants- remain ability to differentiate through lifetime
• Stages of cell cycle

  Stage 1- cell dna duplicates

  stage 2- chromosomes like up in middle of the cell and are pulled apart by spindle fibres

  stage 3- cell divides since cytoplasm and cell membrane split to form 2 identical cells.
• Mitosis 


  Cell splits into 2 identical daughter cells

  halves once

  asexual
• Microscopes practical


  One cell thin sample put iodine on it so can see it. Put slide over. Lowest objective lens. Coarse focus knob to move state up. place slide in microscope. Line up specimin. adjust coarse focus knob. Change objective lens to be more resolution.
• Image =


  Actual x magnification
• Cultivating microorganisms


  Agar gel petri dish

  sterilise inoculating loop by put over ethanol then a flame

  swab bacteria with loop using clam method

  close and tape sides

  incubate for a few days

  or can also put types of antibiotics on there to see effectiveness