Paper 1

• Plant cell- B1

  Cytoplasm, nucleus, ribosome, vacuole, mitochondria, cell membrane, cell wall , chloroplast
• Animal cell- B1

  Cytoplasm, nucleus, ribosome, mitochondria, cell membrane
• bacteria cell- B1

  cell wall, cell membrane, cytoplasm, single circular strand of DNA, flagellum
• sperm cell- B1

  long tail, streamlined head, mitochondria for energy, enzymes in its head
• nerve cells- B1


  carry electrical signals around the body

  long, branched connections
• muscle cell- B1

  long so that have space to contract, mitochondria for energy
• roots hair cells- B1

  large surface area
• phloem- B1

  transport food by translocation

  small pores in the end walls to allow cell sap to flow
• xylem- B1

  take water up, mineral ions from roots to stem and leaves by transpiration

  made of dead cells, no end walls
• Mitosis - B1

  growth and repair

  1. grow and increases sub cellular structures, e.g. mitochondria, ribosomes
  2. duplicates DNA. DNA is copied
  3. Chromosomes line at the centre and are pulled to each end
  4. membranes form around the chromosomes - the nucleus has divided
  5. cytoplasm and cell membrane divide
  6. producing two identical daughter cells
• active transport in the gut- B1

  glucose can be taken into the bloodstream from the gut even if the concentrations is already higher. it can be transported to cells for respiration
• structure of a leaf- B1


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• Mitosis- B1


  growth and repair

  1. grow and increases sub cellular structures, e.g. mitochondria, ribosomes
  2. duplicates DNA. DNA is copied
  3. Chromosomes line at the centre and are pulled to each end
  4. membranes form around the chromosomes - the nucleus has divided
  5. cytoplasm and cell membrane divide
  6. producing two identical daughter cells
• Digestive system- B2


  Glands- produce digestive enzymes, e.g. pancreas, salivary glands

  Stomach- protease starts to digest protein

  small intestine- break down food and absorb nutrients

  large intestine- absorbs water leaving faeces (rectum)

  pancreas- produces all digestive enzymes

  liver- produces bile to emulsify fats

  gall bladder- stores bile
• Protease, amylase, lipase, bile- B2 


  protease produced in the pancreas, stomach and small intestine

  amylase produced in the salivary glands and pancreas

  lipase produced in the mouth, pancreas, stomach and small intestine

  bile produced in the liver, stored in the gall bladder, released into small intestine

  
  

  protease breaks down protein into amino acids

  amylase breaks down starch into glucose

  lipase breaks down (emulsifies) fats into glycerol and fat acids
• Effect of pH on enzyme activity- REQUIRED PRACTICAL- B2


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• Food tests- B2

  Benedict's test- sugars. Colour change from green to brick red

  Iodine solution- starch. Colour change from orange to purple

  Biuret test- protein. Colour change from blue to pink/purple

  Sudan III test- lipids. Surface turns red
• Pathway of air- B2

  Nose, trachea, bronchi, lungs, bronchiole, alveoli
• Double circulatory system- B2

  Right ventricle pumps deoxygenated blood to the lungs to take in oxygen (gaseous exchange), the blood returns returns to the heart

  Left ventricle pumps oxygenated blood around the body, blood gives oxygen to cells and the deoxygenated returns to the heart to be pumped out to the lungs
• Blood vessels- B2

  Arteries- away from heart under high pressure so walls are strong and elastic. Thick walls of muscle.

  Capillaries- Arteries branch into capillaries. They carry blood near to cells and have permeable walls for gaseous exchange. One cell thick to shorten diffusion pathway

  Veins- Blood into the heart. Capillaries join to form veins. Thinner walls than arteries as blood is under lower pressure. Larger lumen than arteries to help blood flow. Valves prevent back flow
• Plants cells- B2

  epidermal tissue- covers the whole plant

  palisade mesophyll tissue- photosynthesis

  Spongy mesophyll tissue- air spaces to allow diffusion in and out of cell

  xylem and phloem- transport water, ions, food

  meristem tissue- stem cells

  epidermal tissue- waxy cuticle to prevent water loss by evaporation

  Palisade layer- chloroplasts for photosynthesis

  Guard cells open and close stomata to allow or prevent gas entering
• Guard cells- B2

  Kidney shape which open and close stomata

  When the plant has lots of water, the guard cells fill and go plump and turgid. This opens the stomata for gas exchange and photosynthesis

  When the plant is short of water, the guard cells becomes flaccid making the stomata close. This stops too much water vapour escaping

  Thin outer walls and thickened inner walls

  Close at night to save water

  Usually found on the underside of a leaf as it is cooler and shaded so less water loss
• Measles- B3

  Virus

  spread by droplets from on infected person

  develop a red skin rash and a fever
• HIV- B3

  Virus

  spread by sexual contact/bodily fluids

  cause flu-like symptoms and attack immune cells
• TMV- B3

  Virus

  causes a mosaic pattern on leaves and discolours it

  can't carry out photosynthesis so causes stunted growth
• Rose black spot-B3

  Fungus

  causes purple/black spots on rose plants, turn yellow and drop off

  Spread by water or wind

  Can be treated using fungicides and removing affected leaves
• Malaria- B3

  Disease caused by a protist

  Mosquitoes are vectors, they pick up the malarial protist from an infected animal when they feed, when feeding on another animal it inserts the protist into the animals blood vessels

  causes fever, can be fatal

  can be stopped by stopping mosquitoes breeding, insecticides and nets
• salmonella- B3

  Bacteria

  causes food poisoning, fever, cramp, vomiting, diarrhoea

  caused by contaminated food

  treated with vaccination
• Bacteria- B3

  very small cells that reproduce rapidly

  produce toxins that damage cells and tissue
• Viruses-B3

  reproduce rapidly

  replicate themselves, cell will burst and release viruses

  cell damage makes you ill
• Protist- B3

  single celled eukaryote

  often transferred by vector
• fungi- B3

  grow and penetrate skin and plants surface, causing disease

  spores can be spread to other animals and plants
• Body's defence system- B3

  Skin- acts as a barrier and secretes antimicrobial substances which kill pathogens

  hairs and mucus in nose- trap particles that contain pathogens

  trachea and bronchi- lined with cilia, waft the mucus to the back of the throat where it can be swallowed

  stomach- produces hydrochloric acid that kill pathogens
• Immune system- B3

  Phagocytosis- white blood cells engulf foreign cells and digest them

  Lymphocytes- antigen causes antibodies to lock onto unknown antigens on invading cells and are destroyed by other white blood cells

  Lymphocytes- produce anti toxins to counteract toxins produced by invading bacteria
• Photosynthesis- B4

  Endothermic reaction

  carbon dioxide + water -> glucose + oxygen

  6H2O + 6H20 -> C6H12O6 + 6o2
• uses for glucose in plants- B4

  Respiration- transfers energy from glucose which enables the plants to convert the rest of the glucose into other useful substances

  Cellulose- strong cell walls

  amino acids- made into proteins

  oils or fats- turned into lipids for storing in seeds

  starch- stored in stems, leaves, roots ready for when photosynthesis isn't happening, like in winter
• rate of photosynthesis- REQUIRED PRACTICAL- B4

  Fill conical flask with sodium hydrogen carbonate

  place pondweed in solution

  cover with bung and gas syringe then measure gas produced

  Repeat with different light intensities, concentration and temperature

  CV- pondweed, temp

  IV- limiting factors

  DV- gas produced
• inverse square law- B4

  light intensity = 1/distance squared

  half distance = 4 times greater the light intensity

  double the distance = 4 times smaller
• Respiration- B4

  exothermic

  transferring energy from the breakdown of glucose

  used to build up larger molecules from smaller molecules

  Allow muscles to contract allowing movement

  Control body temperature
• metabolism- B4

  the sum of all the reactions that happen in a cell or the body

  glucose-> starch, a storage molecule in plants

  -> glycogen, a storage molecule in animal cells

  -> cellulose, a component of plant cells

  lipids-> glycerol and fatty acids

  glucose combined nitrate ions to make amino acids into proteins