Topic 1 - Cell biology

• what does the microscopy experiment include?

  -preparing a slide

  -using a microscope

  -drawing observations
• What is the independent variable for the osmosis/potato practical?

  concentration
• What is the dependent variable for the osmosis/potato practical?

  change in mass
• What is the control variable for the osmosis/potato practical?

  volume of solution, temp, time, surface area
• what happens to the potato in the sugar solution?

  loses water, lower mass at rnd
• what happens to the potato in the pure water solution?

  gains water/mass
• Name 3 similarities between plant and animal cells

  both have:

  -nucleus

  -cytoplasm

  -cell membrane

  -mitochondria

  -ribosomes
• Name 3 differences between plant and animal cells.

  -animal cells don't have chloroplast

  -animal cells don't have a permanent vacuole

  -animal cells don't have a cell wall
• what do bacteria cells have instead of a nucleus?

  A single circular strand of DNA that floats freely in the cytoplasm & a plasmid
• what is the function of a sperm cell?

  To get the male DNA to the female DNA
• what is the function of a nerve cell?

  Carry electrical impulses around the body
• what is the function of a muscle cell?

  contract quickly
• what is the function of a root hair cell?

  absorb water and minerals from the soil
• what is the function of a phloem cell?


  Transport substances around the plant
• what is the function of a xylem cell?

  transport water through a plant
• what are some adaptations of a sperm cell?

  -streamlined head

  -long tail

  -lots of mitochondria to provide energy
• what are some adaptations of a nerve cell?

  -long to cover distance

  branched connections to connect to a network
• what are some adaptations of a muscle cell?

  -long

  -lots of mitochondria for enegry
• what are some adaptations of a root hair cell?

  -large surface area to absorb water
• what are some adaptations of a phloem cell?

  -pores to allow cell sap to flow

  -cells are long and joined end to end
• what are some adaptations of a xylem cell?

  -hollow in the centre

  -tubes are joined end to end
• what is the equation for image size?

  Actual size x magnification
• how do you convert from micrometers to millimetres?

  divide by 1000
• How many pairs of chromosomes are in the nucleus of a human cell?

  23
• chromosomes contain what?


  genetic information: dna, large number of genes
• Where are adult stem cells found?

  bone marrow
• what can we use stem cells for?

  -replacing faulty blood cells

  -making insulin producing cells

  -making nerve cells
• why may people be against stem cell research?

  -embryos are human life

  -scientists should find other sources of stem cells
• why may people be for stem cell research?

  -they use unwanted embryos from fertility clinics, which would normally be destroyed
• where are stem cells found in plants?

  meristems
• meristems can produce what?


  clones of the plant
• what can meristems be used for?

  To produce identical clones of plants quickly and cheaply

  To grow more plant of rare species

  To grow crops with desired features, e.g. disease resistance
• why do multicellular organisms have a large surface area?

  so all the substances can be exchanged
• where does gas exchange in the lungs take place?

  alveoli
• why do millions of villi line the small intestine?

  to absorb more digested food
• why is the surface of a leaf flat?

  to increase the surface area for more gas exchange
• where does oxygen and water vapour diffuse out of? (in plants)

  out of the stomata

  guard cells open and close the stomata, controlling water loss
• define diffusion


  The movement of particles from an area of high concentration to an area of low concentration.
• define cell membrane


  the semipermeable membrane surrounding the cytoplasm of a cell. only small molecules can get through
• Define osmosis


  diffusion of water across a selectively permeable membrane