biology paper one

• whats the formula for image size?

  image size = actual size x magnification
• what are the specialisations of a sperm cell?

  tail - movement

  acrosome - contains enzyme to burrow into jelly layer of the egg

  nucleus - contains genetic material

  streamlined shape - quick movement

  mitochondria - respiration and energy
• what are the properties of an animal cell?

  nucleus, cell membrane, mitochondria, ribosomes, cytoplasm
• what are the additional properties of a plant cell?

  chloroplasts, vacuole, cell wall
• what are the two different types of microscopes?

  light microscope - cheaper, easier to use, lower resolution, can view living cells, sends beams of light through specimen

  electron microscope - more expensive, more complex, higher resolution, cant view living cells, sends beams of electrons through specimen
• what is the equation for rate of reaction?

  rate of reaction = change in measurable amount / change in time
• what does protein become?

  amino acids
• what does starch/carbohydrates become?

  glucose molecules
• what do lipids become?

  fatty acids + glycerol
• what are enzymes?


  biological catalysts
• what does optimum mean in regards to enzymes?

  the best conditions for the enzyme to work in - temperature or pH or concentration
• what happens after the optimum temperature/pH/concentration?

  active site changes, enzyme no longer fits and is denatured
• what is diffusion?


  movement of particles from a high to low concentration
• does diffusion require energy?

  no!
• what is active transport?

  movement of particles from a low to high concentration - opposite to diffusion
• does active transport require energy?

  yes!
• what is osmosis?


  movement of water molecules from a high to low concentration through a semi-permeable membrane
• what is mitosis?


  the process of cell division
• what is mitosis important for?

  growth and repair
• what are the three sections of the cell division cycle?

  interphase, mitosis, cytokinesis
• what happens when theres a mistake in mitosis?

  uncontrollable cell division - causes mutations
• how many daughter cells are created in mitosis?

  two genetically identical daughter cells
• what are stem cells?

  unspecialised cells that can differentiate into specialised cells
• what are the three different types of stem cells?

  embryonic - found in the embryo, can differentiate into ANY type of specialised cell

  animal (adult stem cells) - can only turn into certain specialised cells as they are already partially specialised

  meristem - found in plants, can turn into ANY specialised plant cells
• what is the nervous system?


  way that the body sends and receives information
• what body parts make up the central nervous system (CNS)?

  brain and spinal cords
• what are the three different types of neurone?

  sensory, motor, relay
• what do all three neurones have in common?

  axon terminal, dendrites, axon, myelin sheath
• what do sensory neurones do?

  detects and responds to external signals, connected to receptors
• what do motor neurones do?

  carry impulses to effectors (e.g - muscles and glands)
• what do relay neurones do?

  short neurones that connect sensory and motor neurones
• what do myelin sheaths do?

  insulates neuron and speeds up impluses
• what are the small gaps between neurones called?

  synapses
• what happens at the synapses?

  neurotransmissions released from axon terminals when the electrical impulse reaches the end - chemical impulses diffuse across the synapse
• what is a reflex arc?

  unconscious process that helps the body quickly react to potentially dangerous stimuli
• what is the happens during a reflex?

  1. stimulus
  2. receptor
  3. sensory neurone
  4. relay neurone
  5. motor neurone
  6. effector
  7. response
• what does a reflex arc bypass?

  the brain
• what are the differences between sexual and asexual reproduction?

  sexual - genetic variation, higher chances of mutations, takes longer, needs a mate

  asexual - very fast, does not need a mate, produces genetically identical offspring
• what is meiosis?

  type of cell division that produces gametes (sex cells)
• what are the steps of meiosis?

  1. DNA replication
  2. chromatids move away
  3. first division occurs
  4. chromatids move away again
  5. final division occurs