Paper 2

Cards (69)

  • Nervous system
    One of the ways that different parts of our body communicate with each other
  • Parts of the nervous system
    • Central nervous system (brain and spinal cord)
    • Peripheral nervous system (cranial nerves and other nerves throughout the body)
  • How nerves work
    1. Receptor (sensory organ) detects stimulus
    2. Sensory neuron transmits signal
    3. Relay neuron transmits signal to brain
    4. Motor neuron transmits signal to effector (muscle or gland)
  • Neuron
    Main body, axon (long tail), dendrites (hair-like connections to other neurons)
  • Myelin sheath
    Fatty sheath around the axon that speeds up signal transmission
  • Synapse
    Gap between neurons where neurotransmitters transmit signals
  • Stimulants and depressants
    Drugs that speed up or slow down neurotransmitter transmission
  • Reflex
    Reaction that bypasses the brain, going straight from receptor to effector
  • Measuring reaction time
    1. Grab ruler when dropped
    2. Repeat with different stimuli (audible, distractions)
    3. Repeat after drinking sugary drink
  • Parts of the brain
    • Cerebral cortex (controls motor functions)
    • Cerebrum (controls some motor functions)
    • Medulla oblongata (controls reflex functions like breathing)
  • Contralateral
    Nerves cross as they enter the brain, so right side of brain controls left side of body and vice versa
  • Eye
    • Light hits cornea, then pupil (controlled by iris), then lens, then focuses on retina (rods and cones)
  • Accommodation
    Lens changing thickness to focus on distant or close objects
  • Long-sightedness
    Lens not powerful enough to focus on close objects, needs glasses
  • Endocrine system glands
    • Pituitary
    • Thyroid
    • Pancreas
    • Ovaries
    • Testes
    • Adrenal
  • Insulin regulation
    1. Pancreas makes insulin
    2. Insulin tells liver to store excess glucose
    3. Liver releases glucose when blood sugar is low
  • Diabetes
    Pancreas can't make enough insulin, leading to high blood sugar
  • Menstrual cycle
    1. FSH from pituitary stimulates ovary to make estrogen
    2. LH from pituitary triggers egg release
    3. Empty follicle makes progesterone to inhibit FSH and LH
  • Thermoregulation
    Controlling internal body temperature of 37°C
  • Cooling mechanisms
    1. Sweating and evaporation
    2. Hairs standing up to trap air (goosebumps)
    3. Blood vessels dilating to release heat
  • Warming mechanisms
    Blood vessels constricting to retain heat
  • Hypothalamus
    Part of brain that detects and regulates body temperature
  • Water control
    1. Kidneys remove urea and water to make urine
    2. Urine stored in bladder
  • Contraception methods
    • Physical (e.g. condoms)
    • Hormonal (e.g. pill, patch)
  • Fertility treatments
    1. Artificial insemination
    2. In-vitro fertilization
    3. FSH and LH therapy
    4. Surrogacy
    5. Egg donation
  • Ethical questions around fertility treatments like IVF
  • Plant hormones
    • Auxins (promote/inhibit growth)
    • Ethene (ripens fruit)
    • Gibberellins (promote flowering, increase fruit size)
  • How auxins work
    1. In shoots, auxin collects on bottom due to light, causing upward growth (positive phototropism)
    2. In roots, auxin collects on bottom due to gravity, inhibiting growth and causing downward growth (positive geotropism)
  • Reproduction methods
    • Asexual (cell cloning)
    • Sexual
  • Auxin
    A chemical that can make cells elongate or stop them from elongating, used as a weedkiller and rooting powder
  • Ethene
    A chemical that can be used to ripen fruits
  • Gibberellins
    Chemicals that promote flowering and make fruit size bigger
  • How auxin works

    1. If in the shoot, light destroys it so it collects on the bottom side, making the stem grow upwards (positive phototropism)
    2. If in the root, it collects on the bottom side, inhibiting growth and making the root bend downwards
  • Methods of reproduction
    • Asexual
    • Sexual
  • Asexual reproduction
    A cell is cloned, no genetic variation between parents and offspring (mitosis)
  • Sexual reproduction
    Gametes (haploid cells) join to form a diploid cell (meiosis)
  • DNA
    A polymer with 4 bases (A, T, C, G) that code for amino acids and proteins
  • Protein synthesis
    DNA is unzipped, RNA copies the code and takes it to the ribosome, ribosome puts amino acids in the correct order to make a protein
  • Genome
    All the DNA in an organism
  • Gene
    Part of DNA that codes for a certain protein