paper 2 bio

• Photosynthesis is going to take water, carbon dioxide, and turn it into oxygen and glucose
• Light


  Not a reactant in photosynthesis, just a condition that's needed
• Photosynthesis formula


  Water (H2O) + Carbon dioxide (CO2) → Oxygen (O2) + Glucose (C6H12O6)
• The photosynthesis formula needs to be balanced, with the numbers in the right places
• Photosynthesis


  An endothermic reaction that takes in energy
• Requirements for photosynthesis


  • Chlorophyll
  • Water
  • Carbon dioxide
  • Sunlight
• Percentage level of carbon dioxide

  Affects the rate of photosynthesis
• As the percentage level of carbon dioxide increases

  The rate of photosynthesis increases, up to a point
• After the point where carbon dioxide is no longer the limiting factor


  Other factors like water, light, or temperature need to be increased to increase photosynthesis
• As temperature increases


  The rate of photosynthesis increases
• At very low temperatures


  Photosynthesis happens very slowly
• At the optimal temperature


  Photosynthesis is maximised
• At very high temperatures


  Enzymes become denatured and the rate of photosynthesis falls off rapidly
• As light intensity increases

  The rate of photosynthesis increases
• Even when the graph is flat, there is still a steady rate of photosynthesis
• The actual rate of photosynthesis depends on many different factors at once
• Glucose from photosynthesis


  Stored as starch, with potatoes being a common example
• Leaf structure

  • Palisade mesophyll (photosynthesis)
  • Cuticle (waxy layer)
  • Upper and lower epidermis
  • Spongy mesophyll (gas exchange)
  • Guard cells and stomata (transpiration)
• Xylem


  Carries water upwards from roots to leaves
• Phloem


  Carries ions and food downwards from leaves to roots
• Factors affecting transpiration rate

  • Bright light
  • High temperature
  • High wind
  • Low humidity
• Parts of the endocrine system

  • Pituitary gland
  • Thyroid
  • Adrenal glands
  • Pancreas
  • Ovaries
  • Testes
• Testosterone


  Produced by testes, has effects like muscle growth, hair growth, and sexual development
• Estrogen


  Produced by ovaries, responsible for egg maturation and menstrual cycle
• Insulin


  Produced by pancreas, regulates blood glucose levels
• Adrenaline


  Produced by adrenal glands, part of the fight-or-flight response
• Thyroxine


  Produced by thyroid, regulates metabolism
• Follicle Stimulating Hormone (FSH)


  Produced by pituitary gland, stimulates egg growth
• Luteinizing Hormone (LH)


  Produced by pituitary gland, triggers egg release
• Contraception methods


  • Condoms (barrier)
  • Pill (hormonal)
  • IUD (hormonal)
  • Diaphragm (barrier)
  • Sterilization (permanent)
• Around one in six people experience infertility, with half due to male factors and half due to female factors
• IVF


  • Advantages: Can result in a baby, helps with mental health issues from infertility

  Disadvantages: Requires many drugs with side effects, very expensive, low success rate
• Homeostasis is the maintenance of a constant internal environment
• Things homeostasis controls


  • Blood glucose levels
  • Water levels
  • Body temperature
• Brain


  The control center for homeostasis, sending signals to other parts of the body
• Blood glucose regulation


  1. Pancreas detects high blood glucose

  2. Pancreas produces insulin

  3. Insulin causes cells to remove glucose from blood

  4. Pancreas detects low blood glucose

  5. Pancreas produces glucagon

  6. Glucagon causes stored glucose to be released back into blood
• Type 1 diabetes


  Pancreas doesn't produce enough insulin
• Type 2 diabetes


  Cells become insensitive to insulin
• Symptoms of both types of diabetes include weight loss, increased urination, thirst, blurred vision, fatigue, and hunger
• Treatment for type 1 diabetes is insulin injections, while type 2 is diet and exercise control