Bio SEM 2 Exam

• Prokaryotes


  no nucleus

  no membrane bound organelles

  unicellular

  DNA not enclosed in a nucleus
• Eukaryotes


  has nucleus

  has membrane bound organelles

  majority multicellular
• Organelles


  structures in cells with specific functions
• Cell membrane


  boundary of a cell

  controls what enters and exits

  semi-permeable (only allows some substances through)
• Cell wall


  around plants, fungi, & bacteria

  absent in animal cells

  provides support & protection for the cell

  it is the layer OUTSIDE the cell membrane
• Nucleus


  found only in eukaryotic cells

  surrounded by membrane

  contains DNA
• Mitochondria


  site of cellular respiration ~ energy in the form of ATP is produced

  found in both animal & plant cells

  surrounded by membrane = not in prokaryotic cells
• Ribosomes

  site of protein synthesis

  can be free floating in cytosol or attached to endoplasmic reticulum

  found in both prokaryotic and eukaryotic cells
• Endoplasmic Reticulum


  rough - has ribosomes attached ~ transports proteins to the golgi body & around the cell

  smooth - no ribosomes ~ site of lipid synthesis
• Golgi body


  packages and modifies protein into vesicles to be exported out of the cell

  found in eukaryotic cells
• Chloroplasts

  only in plant cells

  contains chlorophyll ~ green pigment

  captures the energy of sunlight to be involved in photosynthesis
• Vacuole


  large one only found in plant cells

  small one can be found in animal cells

  stores fluids and sugar
• Fluid mosaic model

  fluid because the phospholipids are free to move within the bilayer

  mosaic because there are things embedded throughout the phospholipid bilayer
• Endocytosis


  into the cell

  fold, trap, bud
• Exocytosis


  out of the cell

  vesicle transport, fusion, release
• Binary Fission

  asexual reproduction of prokaryotic cells
• The cell cycle

  interphase (G1, S, G2)

  mitosis: prophase, metaphase, anaphase, telophase

  cytokinesis
• G1

  increase of cytosol, duplication of organelles, synthesising of proteins
• S

  DNA is copied, single stranded chromosomes become double stranded
• G2

  increase of cytosol, synthesising of proteins in preparation for mitosis
• Prophase

  1

  chromosomes condense

  nuclear membrane breaks down

  spindle fibres form & attach to centromeres
• Metaphase

  2

  spindle fibres pull centromeres of chromosomes to line up along the equator
• Anaphase

  3

  spindle fibres contract

  centromere splits pulling each sister chromatid to opposite ends of the cell ~ opposite poles
• Telophase

  4

  new nuclear membranes form producing two genetically identical nuclei

  spindle fibres desintigrate
• Cytokinesis

  process of cell division where the parent cell divides into two daughter cells
• Apoptosis


  programmed cell death

  IMPORTANT FOR:

  • developmental changes
  • ridding of old, damaged, or infected cells
  • removing cells with DNA damage ~ become cancer
• Pathways of Apoptosis

  mitochondrial:

  • inside
  • cytochrome c is released into cytosol, binds with proteins which activities caspase enzymes initiating apoptosis.

  death receptor:

  • outside
  • death receptor proteins are released by immune cells which are recognised by death signalling molecules, caspase enzymes are activated and initiate apoptosis
• Stem cells


  undifferentiated cells with the capability of differentiating into specialised cells
• Totipotent


  stem cells that can differentiate into any cell type
• Pluripotent


  stem cells that can differentiate into multiple cell types but embryonic
• Negative feedback


  The response counteracts the stimulus, reducing it
• Positive feedback


  The response increases the stimulus
• Stimulus response model


  1. Stimulus

  2. Receptor

  3. Control Centre/Modulator

  4. Effector

  5. Response
• Type 1 diabetes


  Body attacks and destroys insulin-producing beta cells in the pancreas, therefore the signal relay in the response pathway would not occur. An individual with this type must manually take insulin
• Independent variable 


  the part of the experiment that is changed
• Dependent variable


  what is measured
• Controlled variables


  what remains the same
• Control group


  what will you compare against
• Experimental groups


  tests within the experiment that include independent variables
• Quantitive data


  measures a numerical value

  use a line graph to display this data