Biology paper 1

• A balanced and varied diet is essential for staying healthy
• Components of a balanced diet

  • Carbohydrates
  • Fats
  • Proteins
  • Vitamins
  • Minerals
• Carbohydrates


  Provide energy
• Fats


  Provide energy
• Proteins


  Useful for growth and repair of cells
• Exercise is important for staying healthy
• An unbalanced diet can lead to problems like malnutrition, anaemia, obesity, type 2 diabetes
• Pathogens


  Bacteria and viruses that can cause disease
• Bacteria


  • Very small cells that reproduce rapidly
  • Produce toxins to make you sick
  • Damage cells
• Viruses


  • Even smaller than cells
  • Invade cells, reproduce, and burst out without destroying the cell
• Body's defences against pathogens

  • Skin barrier
  • Mucus trapping pathogens
  • Immune system with white blood cells
• How white blood cells defend against pathogens

  1. Engulf and consume pathogens

  2. Produce antitoxins

  3. Produce antibodies
• Vaccination


  Injecting a small amount of dead or inactive virus to allow the body to produce antibodies and build immunity
• Vaccination is an effective and cheap way to prevent diseases like measles, mumps, rubella, and polio
• Antibiotic resistance is a growing problem that needs to be addressed
• Growing bacteria on an agar plate

  1. Sterilize loop

  2. Pick up bacteria

  3. Spread on agar plate

  4. Seal and incubate at 25°C
• Testing for antibiotic resistance involves placing antibiotic disks on the agar plate and seeing if bacteria grow around them
• Nervous system


  • Allows responding to environmental changes
  • Coordinates actions
• Types of receptors


  • Light receptors (eyes)
  • Sound receptors (ears)
  • Taste receptors
  • Touch receptors (skin)
• Nervous system signalling


  1. Receptors detect stimulus

  2. Sensory neurons carry signal to central nervous system

  3. Relay neurons carry signal within central nervous system

  4. Motor neurons carry signal from central nervous system to effectors
• Reflexes are fast, automatic responses that don't go through the central nervous system
• Homeostasis


  Maintenance of a constant internal environment
• Factors controlled by homeostasis

  • Body temperature
  • Water balance
  • Ion balance
  • Blood glucose levels
• Hormones


  Chemical messengers that travel in the bloodstream and have widespread, long-lasting effects
• Nerves


  Provide fast, targeted responses
• Menstrual cycle


  1. Uterus lining builds up

  2. Egg released (ovulation)

  3. Uterus lining breaks down (menstruation)
• Hormones involved in menstrual cycle

  • Follicle stimulating hormone (FSH)
  • Estrogen
  • Luteinizing hormone (LH)
• Contraceptives


  Hormonal methods that reduce risk of pregnancy
• IVF


  Assisted reproductive technology that involves stimulating egg production, extracting eggs, fertilizing them, and implanting the embryo
• IVF has side effects, is expensive, and doesn't always work
• Plant growth responses


  • Phototropism (towards light)
  • Gravitropism (towards gravity)
  • Hydrotropism (towards water)
• Auxin is the hormone that causes plant growth towards light, gravity, or water
• u baby when you can't have a baby otherwise the problems with IVF is that the drugs have a large large number of side effects which are truly horrific again either lots and lots more detail you can see the very large number of drugs that I had to take em to go with my ivf video you can get multiple pregnancies so twins triplets and it doesn't always work base for endlessly expensive equals roughly about seven to ten thousand pounds per cycle and there's any about 40% chance of it working
• Plants will grow towards three things light which is phototropism gravity which is geotropism or gravitropism and though great awards water
• The way Eunice happens

  You get your chute and at the top there with this little hormone called books in produced and oxen will cause things to blend towards the lights by causing this part this part where their their birth their hormones grow to grow towards it
• Types of drugs


  • Medicinal drugs (e.g. painkillers, antibiotics)
  • Recreational drugs (legal and illegal)
  • Performance-enhancing drugs
• If we're against performance-enhancing drugs


  There could be serious health risks of taking and things like steroids for a long time and it's unfair if only certain athletes can afford to buy the drugs whereas athletes from poorer countries can't afford to buy these drugs
• If we're arguing for performance-enhancing drugs

  People at least have the right to make their own decisions about what they do with their life and that's drug-free sports isn't really only isn't really fair because there's no level playing field in sports any way that athletes have different access different facilities
• Illegal recreational drugs


  You'll generally buying them from somebody that you don't know don't necessarily trust if absolutely no idea what is in them
• Legal recreational drugs


  Nicotine and alcohol, which while legal does not mean they are safe, loads and loads people die each year from nicotine use and alcohol use