Paper 1

• Endocrine System

  System that produces hormones
• Adrenal glands

  Produce adrenaline which causes fight, flight or freeze response
• Pituitary gland


  The 'master gland' that produces hormones like FSH, LH, ADH
• Ovaries


  Release oestrogen in females
• Testes


  Produce testosterone in males
• Organs that produce hormones are called glands
• Glands release chemical messengers called hormones into the blood
• Hormones affect target regions of the body and bring about changes
• Eukaryotic Cells

  • Nucleus to store genetic material
  • Larger & more complex than Prokaryotes
  • E.g Animal & Plants cells
• Prokaryotic cells

  • Doesn't have a nucleus
  • Smaller and simpler than Eukaryotes
  • E.g Bacteria cells
• Differentiation

  Process in which a cell transforms into a specialized cell to carry out a specific function.

  • Involves development of different sub-cellular structures for various functions
• Differentiation in Animal cells

  • Most animal cells become specialized early in life by mitosis as the organism develops.
  • In mature animal cells, the ability to differentiate is used for repairing and replacing cells such as skin or blood cells.
• Differentiation in Plant cells

  • Plants never lose their ability to differentiate
• Sperm cells

  Specialized for reproduction:

  • Deliver male DNA to female DNA
  • Many mitochondria for energy
  • Head is streamlined to make movement efficient
  • Head contains enzymes to digest through the membrane of egg cells.
• Nerve Cells

  Specialized for sending electrical signals:

  • Long to cover more distance
  • Branched connections called dendrites create a large network around the body
• Muscle cells

  Specialised for contraction:

  • Long so they have space to contract
  • Filled with many mitochondria to transfer energy for contraction
• Root Hair cells

  Specialized for absorbing water and minerals:

  • Long hairs to increase surface area for absorption from soil
  • No chloroplasts as they are underground so they don't absorb light (more space or more sub-cellular structures)
• Xylem cells


  Specialized for transporting water and minerals:

  • Cells joined together to form tubes
  • Hallow for easy flow (no end walls)
  • Thick walls made from lignin (provides support)
  • Cells are dead (no sub-cellular structures)
• Phloem cells


  Specialized for transporting food substances:

  • Cells joined end to end to form tubes to transport food
  • Very few sub-cellular structure to help substances flow through easily (more space for food)
  • Have end walls (sieve-like plates with holes - more control in movement as energy is required)
  • Made from living cells
• nm --> μm --> mm --> m --> km

  Going left to right: the value you divide by to convert to the next unit
• nm --> μm --> mm --> m -->


  Going left to right: the value you divide by to convert to the next unit

  /100

  E.g 1nm = 0.001μm
• What is the difference between aerobic and anaerobic respiration in humans? (do not refer to oxygen)

  • Aerobic produces water and anaerobic doesn't.
  • Anaerobic releases less energy than aerobic.
• Explain 2 effects of anaerobic respiration on a person's body. (4m)

  • Muscle fatigue/muscle cramp
  • Anaerobic respiration produces lactic acid
  • Deeper breaths/faster breathing rates - after exercise
  • To get enough oxygen to break down the lactic acid.
• What are the 4 parts of the blood?

  white blood cells, Red blood cells. Plasma and Platelets
• Describe the structure of an Artery.

  Thick walls with a small lumen
• Explain the adaptations of a vein.

  Thick walls and thick lumen which prevents backflow of blood
• What are the 2 risk factors for coronary heart disease?

  Smoking and lack of exercise
• Blood:

  • Platelets = heal clots/scabs and are self-healing
  • Plasma = Liquid (minerals, amino acids, etc...) that are dissolved in
  • Red blood cell = carries oxygen around the body have no nucleus and are made up of haemoglobin
  • White blood cell = Defeats against viruses/bacteria/infections

  
• Infection and Response:

  • Communicable disease = diseases you can catch
  • Vaccination = Produces white blood cells to kills viruses
  • Antibiotics (only kill bacteria) and painkillers (lessen the illness)
  • Developing drugs = testing drugs to see if it cures illness or not
• Infection and Response

  Viruses: reduce inside your cells which makes you sick

  • Measles (transmitted in cough and sneezes)
  • HIV (a sexually transmitted disease, damages immune system and only treated with contraception.)
  • TMV (transmitted in plants and water e.g tobacco mosa plants)
• Infection and Response

  Bacterial: damages cells and tissues which makes you sick

  • Gonorrhea (sexually transmitted disease, treated with contraception)
  • Salmonella (food poisoning, releases toxins, symptoms are vomiting, and cramps, avoided by vaccinated chickens.)
• Plant cell:

  • Cell membrane: keeps unwanted substances out and allows transport of nutrients.
  • Cytoplasm: contains water, salts, and minerals.
  • Nucleus: the main job as it carries the genetic information and controls what happens inside the cells.
  • Cell wall: provides strength and protection against stress.
  • Vacuole: filled with liquid and molecules, acts like a storage.
  • Chloroplast: converts light energy into stable chemical energy by the process of photosynthesis.

  
• Animal cell:

  • Cell membrane: separates gel-like fluids of the cell from the outside environment.
  • Mitochondria: where most of the reaction happens
  • Nucleus: the main job as it carries the genetic information and controls what happens inside the cells.
  • Cytoplasm: gel-like fluid that fills the whole cell.

  
• Difference between Plant and Animal cells

  Plant cells:

  • no central vacuole
  • limited movement
  • cells are square or geometrically shaped
  • contains chloroplast for photosynthesis
  • has a cell wall to maintain it's structure

  Animal cells:

  • no cell wall
  • no chloroplast
  • has a small vacuole
  • cells can move around
  • cells are fluid and flexible and can come in many shapes
• What does "Osmosis" mean?


  movement of water particles from a dilute to a concentrated region
• What does "Active transport" mean?


  movement of particles from a low to high concentration
• What does "Diffusion" mean?


  movement of particles from a high to low concentration
• What type of movement would be used to move water?


  Osmosis
• What type of movement would be used to move minerals in soil?


  Active transport
• What type of movement would be used to move oxygen into the blood from the alveoli?


  Diffusion