Chapter 5 – Cell Processes


 

5.1 Movement of Substances
 

-maintaining a relatively constant internal
   cell environment is essential for life

-several processes need to occur in the
   cell in order to maintain this homeostasis
 

cell membrane

-controls movement of materials into
    and out of the cell
-maintains homeostasis
 
  cell membrane structure
-two layers-lipids
-made of lipids, proteins, and
    carbohydrates
-different proteins for different
    functions
 
 

permeability of the cell membrane

selectively permeable
- some substances can pass
    through freely (permeable)
- some only at certain times
    (semi-permeable)
- others not at all (impermeable)
- fluid-mosaic model-double lipid

layer in which proteins float


[OH#6 Fluid Mosaic/Fig. 5.2, p95]

TRANSPORT

passive
-no cellular energy is used
-e.g. diffusion, osmosis

active
-requires energy
-"pumps" material from low concentration
    to a higher concentration
-large protein particles in the cell
    membrane are involved and are called
    "carriers"
 
 

DIFFUSION
-form of passive transport
-material goes from higher concentration
    to a lower concentration
 

OSMOSIS

-the diffusion of water into or

out of the cell -from a region of high water
    concentration to a lower water
    concentration

5.2 Energy Processes

-all animals depend on other organisms to
    obtain energy

-plants do not depend on other organisms
 

PHOTOSYNTHESIS
-plants get their energy through the
    process of photosynthesis
- means "putting together with light"

6CO2 + 6H2O +light energy -> C6H12O6+6O2
Carbon dioxide       Water                    SUN                                     Glucose               Oxygen

                        Reactants                                    Products
 

RESPIRATION C6H12O6 + 6O2 -> 6CO2 + 6H2O  +  energy
   Glucose                      Oxygen          Carbon dioxide        Water          ATP FERMENTATION

5.3 Cell Growth and Division

CELL DIVISION

cell division   - process during which your
                        body makes new cells
                     - two identical cells are
                        produced
                     - in single-celled organisms,
                       two new organisms are
                       formed

CYCLE OF CELL GROWTH

[see Fig. 5.7 p 103 in textbook]

- most of a cell's life is spent in the phase
    of growth and development called
    interphase
-cell doubles in size during interphase

mitosis - when cell nucleus divides into two
                identical nuclei

chromosomes - threadlike strands in the nucleus that controls cell activity and carry the genetic material (DNA)

FOUR STEPS OF MITOSIS: (in order)

PROPHASE -first step in mitosis

METAPHASE - second step

ANAPHASE -third step

TELOPHASE -final step of mitosis
   -phase of mitosis when cell divides
            into two new cells
   -two identical nuclei exist

Make up a mnemonic to remember order, e.g.
"propose meeting and television"
      or just "pmat"
your mnemonic:
 
 

    [OH#12 Phases of Cell Cycle, part a]
  [OH#13 Phases of Cell Cycle, part b]

See Fig. 5.8 Animal Cell Cycle pg104 & 105 in Text book

For the test



END of Chapter 5 Notes