Biology paper 1

• eukaryotik cells


  animal and plant cells

  cell membrane

  cytoplasm

  nucleus
• prokayrotik 


  cell wall

  cell membrane

  strand of DNA
• what is smaller- prokaryotic or eukaryotic

  prokaryotic
• nucleus


  contains DNA in an enclosed membrane
• cytoplasm


  where chemical reactions occur due to it containing enzymes
• cell membrane


  controls the substances that go in and out of the cell
• mitochondria 


  where aerobic respiration reactions happens
• ribosomes


  site of protein synthesis
• chloroplasts


  where photosynthesis happens
• chlorophyll


  green pigment in chloroplasts
• vacuole


  cell sap that improves the rigidity of the cell
• cell wall


  contains cellulose- strengthens the cell
• plasmid


  a small ring of DNA
• cell specialisation


  gaining new sub cellular structures in order to help them be suited for a role
• how are sperm cells specialised

  streamlined aids swimming

  mitochondria provides energy to move

  acrosome contains enzyme to get through the egg
• how are nerve cells specialised

  long axon so impulses can be transferred long distance

  nerve endings have mitochondria so they have energy
• how are root hair cells specialised

  large surface area so more water can be absorbed

  vacuole effects the speed of absorption

  mitochondria for respiration
• how are xylem cells specialised

  lignin to strengthen the cell
• what is cell differentiation

  when genes are switched on or off for different proteins
• how do specialised cells reproduce

  mitosis
• what is a stem cell


  an undifferentiated cell
• embryonic stem cells 


  cells from embryos that can turn into any cell

  ethical issues
• adult stem cells


  found in bone marrow
• merristem cells


  found in plant roots and shoot tips

  they can also be used to clone plants
• factors which affect diffusion

  temperature

  surface area of the membrane
• what is diffusion


  the movement from a high concentration to a low concentration
• how are the small intestines adapted for diffusion

  they have villi
• how are they lungs adapted for diffusion

  they have capillaries
• what is osmosis


  movement across partially permeable membranes

  dilute concentration to high concentration
• Mitosis stage 1= interphase


  dna is replicated

  energy imcreases
• mitosis stage 2 = mitosis


  chromosomes line up at each each side of the cell
• mitosis stage 3= cytokinesis


  2 identical daughter cells are produced when the membranes divide
• what does an objective lens do

  produces a magnified image
• mitochondria

  the site of respiration in cells
• what does active transport require

  energy
• resolution 


  the ability to see clearly when using a microscope
• where is bile produced

  liver
• what is the enzyme that breaks down lipids

  lipase
• benign 


  a tumour that is non cancerous
• xylem


  non living cell that transports substances from the roots