Biology paper 1

• what is a prokaryote?

  a cell, smaller than a eukaryote, that contains a cytoplasm, cell wall, cell membrane, a single DNA loop (not in a nucleus), and plasmids, bacteria
• what is a eukaryote ?

  a cell, larger than a prokaryote, that has a cell membrane, cytoplasm, and genetic material within a nucleus
• what is the function of a nucleus?

  stores genetic information and controls the function of the cell
• what is the function of a cytoplasm?

  a gel like substance where most chemical reactions occur
• what is the function of the cell membrane ?

  controls what enters and exits the cell
• what is the function of the mitochondria?

  where aerobic respiration occurs to release energy
• what are the function of ribosomes?

  where protein synthesis occurs (where proteins are made)
• what is the function of the cell wall


  a structure surrounding the cell that gives it strength and support
• what is the function of the permanent vacuole?

  contains cell sap
• what is the function of chloroplasts?


  contains chlorophyll for photosynthesis to occur
• what are the function of plasmids?


  a small ring of DNA found in bacterial cells
• order these from smallest to largest : nucleus, gene, chromosome, cell


  gene, chromosome, nucleus, cell
• characteristics of electron microscopes


  - they use electrons to form an image

  - very expensive

  -very high resolution

  - very high magnification
• characteristics of a light microscope

  -they use light to form an image

  - relatively cheap

  - low resolution

  - low magnification
• how do you calculate magnification

  magnification = image size / actual size
• what does magnification mean

  how much bigger an image is compared to the actual size of the object
• what does resolution mean


  the ability to distinguish between two points that are close together
• what is differentiation


  the process by which a cell becomes specialised to carry out its function
• what are the 8 life processes


  movement

  respiration

  sensitivity

  growth

  reproduction

  excretion

  homeostasis

  nutrition
• how do you convert centimetres to millimetres

  multiply by 10
• how do you convert millimetres into micrometers

  multiply by 1000
• how do you convert micrometers into nanometers

  multiply by 1000
• how do you convert nanometers into micrometers

  divide by 1000
• how do you convert micrometers into millimeters

  divide by 1000
• how do you convert millimeters into centimetres

  divide by 10
• what does highly specialised mean

  when a cell has a specific shape and size
• what is a stem cell

  completely undifferentiated cell
• what does undifferentiated mean

  when a cell is unspecialised
• what cells can differentiate in humans

  skin and blood
• what are the 5 kingdoms of life

  animals, plants, fungi, bacteria, protoctists
• how are sperm cells specialised


  - have a flagellum to swim

  - contain acrosome (enzymes to digest egg)

  - lots of mitochondria
• how are nerve cells specialised?

  - long axon to transmit over distances

  - synapses to connect to over nerves

  - fatty sheath to speed up impulses
• how are muscle cells specialised


  -contract and relax for movement

  -contains filaments of protein that slide over each other

  - lots of mitochondria

  - lots of ribosomes

  -elongated
• How are xylem cells specialised?


  - the ends are broken to allow water to move through

  - narrow

  - hollow

  - elongated
• how are phloem cells specialised?

  - contain small hands le's to allow food products to move up and down

  - they have sieve tubes for transport

  - no nuclei
• how are root hair cells specialised


  - a large surface area for absorbing mineral ions from the soil

  - a lot of mitochondria that release energy in order to provide the energy needed for active transport
• what is a cell


  the smallest structural and functional unit of an organism
• what is a tissue

  a group of similar cells that work together to carry out a function
• what is an organ


  a group of different tissues that work together to perform a specific function
• what is an organ system?


  a group of organs that work together to perform a specific function