cell biology

• what are both plant and animal cells


  eukaryotes
• what are eukaryotic cells?


  contain their genetic material in a closed nucleus
• what are prokaryotic cells


  the genetic material is not enclosed in a nucleus
• which cell is bigger prokaryotic or eukaryotic 


  eukaryotic
• what does prokaryotic cells genetic material consist of


  single loop of DNA
• what is plasmids and where are they found


  small rings of DNA found in bacteria
• 1cm=


  (m)1x10$^{-2}$
• 1mm=


  (m)1x10$^{-3}$
• what does μm stand for


  micrometer
• 1μm=


  1x10$^{-6}$m
• what is the size of a typical human cell


  10-20μm
• 1nm(nanometer)=


  1x10$^{-9}$m
• size of haemoglobin molecule


  5nm
• what does one order of magnitude mean?


  10x
• how do you work out the order of magnitude


  count the number of 0s
• what is the function of the nucleus


  enclose genetic material
• what does the cytoplasm do


  where chemical reactions take place
• what does the cell membrane do

  control molecules that can leave/enter the cell
• what is the mitochondria 


  where aerobic respiration takes place
• what are ribosomes


  the sites of protein synthesis
• what type of shape do plant cells have?


  regular
• what are chloroplasts


  contain chlorophyll and are the sites of photosynthesis
• what is the cell wall


  strengthens the cell wall and is made of cellulose
• what is the vacuole


  its filled with fluid called cell sap. it helps give the plant cell its shape
• what are most animal cells


  specialised
• what does it mean if an animal cell is specialised


  they have adaptations which help them carry out their particular function
• what do scientist call cells that have become specialised


  differentiation
• what is the job of a sperm cell


  join with an ovum(egg cell)
• what is the process where an egg cell joins with sperm cell


  fertillisation
• adaptations of a sperm cell


  they have a long tail which helps them swim to egg cell

  they are streamlined to help them swim

  they have lots of mitochondria for energy when swimming

  they contain enzymes which allow them to digest outer layer of egg cell
• job of nerve cell


  send electrical impulses around the body
• what does the axon do in the nerve cell


  carries electrical impulses from one part of the body to another
• what does myelin do in the nerve cell

  insulates the axon and speeds up the transmissions of nerve impulses
• what is at the end of the axon


  synapses
• what are synapses

  junctions which allow the impulse to pass from one cell to another
• what do dendrites do in nerve cells


  increase surface area so that other nerve cells can connect more easily
• muscle cell adaptations


  they can contract
• what do protein fibres do in muscle cells


  change their length
• what happens when a muscle cell contracts


  protein fibres shorten decreasing length
• what are muscle cells packed with


  mitrochondria for energy for muscle contraction