Biology paper 1

• root hair cell adaptations

  long projection, lots of mitochondria
• what does a root hair cell do?

  absorbs water and minerals from soil
• palisade cell adaptations

  lots of chloroplasts and top of leaf
• What does a palisade cell do


  carries out photosynthesis
• sperm cell adaptations

  tail, lots of mitochondria
• what does a sperm cell do

  fertilises egg
• nerve cell adaptations

  branched endings, myelin sheath insulation
• what does a nerve cell do?

  carries electrical impulses
• red blood cell adaptations

  no nucleus, haemoglobin, bi-concave
• what does a red blood cell do

  carries oxygen 
• electron microscopes

  can’t view live samples, expensive, higher magnification / resolution
• genetic material in prokaryotic 


  single DNA loop (plasmid)
• what does a cell wall do

  strengthens and supports cell
• ribosomes


  protein synthesis
• chloroplasts


  contain chlorophyll to absorb light energy for photosynthesis
• mitochondria


  respiration
• cell membrane


  controls movement of substances
• where is DNA found

  in the nucleus
• what are bacteria cells

  prokaryotic
• two types of eukaryotic cells

  animal and plant
• active transport


  dilute to concentrated
• osmosis


  dilute solution to concentrated solution
• lung adaptations

  alveoli - large s.a

  moist membranes

  one-cell-thick membranes

  good blood supply
• villi adaptations


  long and thin, one-cell-thick membrane, good blood supply
• factors affecting diffusion

  concentration gradient, temperature, membrane surface area
• diffusion


  high concentration to low concentration, down the concentration gradient
• mitosis event

  chromosomes are pulled apart and nucleus divides
• stage 1 of cell cycle

  chromosomes duplicate, sub-cellular structures increase
• mitosis purpose

  growth and repair, asexual reproduction
• mitosis


  divide to form two daughter cells
• meristem disadvantage 


  no variation
• meristem advantages


  protects extinction, disease resistance can be reproduced
• plant meristems


  roots and shoots
• embryonic stem cells disadvantages


  ethical issues, viral infections
• embryonic stem cell advantages

  many different specialised cells, easy to obtain
• adult stem cell disadvantages

  takes a long time to find donor, can only differentiate into certain cells
• adult stem cell advantage


  fewer ethical issues
• therapeutic cloning advantage


  not rejected because same genes
• therapeutic cloning


  stem cells from patient embryo treatment
• adult stem cell location

  bone marrow