Transcript Cells and Their Environment

Cells and Their
Environment
Chp 4
I. Cell Membrane
a. Cell membrane also known as plasma
membrane, selectively permeable membrane,
and semi-permeable membrane.
b. The cell membrane maintains homeostasis by
controlling substances entering and leaving
cell.
c. The cell membrane is a fluid phospholipid
bilayer (double layer) with proteins.
d. The phospholipid heads attract to water
(hydrophillic).
e. The phospholipid tails repel water
(hydrophobic).
f. Proteins are the workers of the cell membrane.
g. Carrier/Transport proteins help move
substances across cell membrane.
II. Passive Transport
A. Passive transport is the movement of a
substance across a cell membrane without the
use of energy (ATP) from the cell.
B. During passive transport substances move
down the concentration gradient from an area
of high concentration to an area low
concentration
1. Concentration Gradient- Difference in the
concentration of substance across a space
2. Equilibrium- concentration of a substance is
equal throughout a space
D. Types of Passive Transport
1) Simple Diffusion- the movement of a substance
(very small or neutral molecules) from an area of
high concentration to an area of low
concentration across the lipid bilayer.
Ex. Blue dye demo, smells
(Discuss solvent, solute and solution)
2. Osmosis: the diffusion of water only.
Prefixes refer to the concentration of the solute
(substance being dissolved)
Hypotonic- less solutes
Hypertonic- more solutes
Isotonic- equal solutes
Hypotonic solution (water moves into the cell)
Hypertonic solution (water moves out of the
cell)
Isotonic Solution (water moves in and out at
the same rate)
CONTRACTILE VACUOLES-pump out excess
water (only found in unicellular organisms that live
in water)
TURGOR PRESSURE= the amount of
water pressure in the plant cell
Which hose has more turgor
pressure?
3) Diffusion through ion channels- ion channels
are proteins that have a pore through which charged
ions can cross the cell membrane (ex. Na+1, K+1, Cl-1,
Ca+2)
4) Facilitated Diffusion- uses a carrier protein to move
substances through cell membrane
(ex. Large molecules such as glucose & amino acids)**faster
Animations of Passive Transport
http://www.northland.cc.mn.us/biology/Biology1111/animations/passive1.html
http://biomedicum.ut.ee/armpgb/1kursus/Ani_5.swf
III. Active Transport
A.
B.
C.
Movement of substances from areas of LOW
concentration to HIGH concentration
REQUIRES ENERGY FROM THE CELL!
Types:
1. Sodium-Potassium Pump- a protein pumps 3 Na+1 out
and 2 K+1 in the cell
**important b/c too much Na+1 is toxic and cells need K+1
hemistry_d/templates/student_resources/shared_resources/animations/ion_pump/ionpump.html
2. Vesicles- moves very large molecules either in or
out of the cell (ex. proteins & polysaccharides)
a) the cell membrane forms a pouch around the
substance and pinches off from the membrane &
forms a vesicle
2 processes
i. Endocytosis- moves substances in the cell by
either phagocytosis (cell eating) or pinocytosis
(cell drinking)
ii. Exocytosis- move substances out of the cell
http://www.stolaf.edu/people/giannini/flashanimat/cellstructures/phagocitosis.swf
http://highered.mcgraw-hill.com/olc/dl/120068/bio02.swf
Animations of Active Transport
http://www.northland.cc.mn.us/biology/Biology1111/animations/passive1.html
Ch. 5- Energy
I. Photosynthesis- the
process of using light
energy to produce
glucose & oxygen
*Drawing of Photosynthesis
Chlorophyllcapture light
O2 given off
LIGHT
DEPENDENT
REACTION
(we breathe it!)
H2O splits
LIGHT
INDEPENDENT
REACTION
6(CO2 + H2)
C6H12O6
H2O
Given off
evaporated
CO2 in
MITOCHONDRIA AND O2 release energy by cellular respiration
Light Dependent Reaction:
H2O + light energy
air
O2 + H2
roots
Dark (Light Independent)Reaction:
H2 + CO2
C6H12O6
air
glucose
evaporation
H2O
END RESULT: Produces O2 and Glucose
(C6H12O6) which drive cellular respiration
II. Cellular Respiration- breaks down glucose to
make energy (ATP) for the cell, occurs in the
mitochondria
A. 2 types
1. Aerobic Respiration- occurs in the
presence of oxygen, produces 38 ATP each cycle
2. Anaerobic Respiration- occurs when
oxygen is not available, produces only 2 ATP
each cycle
END RESULT- Produces Energy, CO2 & H2O
which drive photosynthesis
Comparison of Equations
Photosynthesis
H2O + CO2 + light (energy) -> C6H12O6 + O2
 Cellular Respiration
C6H12O6 + O2 -> H2O + CO2 + ATP (energy)

Photosynthesis and
Cellular Respiration
Photosynthesis
Glucose? o
CO2? o
O2? o
Day /night? o
Organelle? o
Plant/Animal? o
H2O? o
Cellular Respiration
makes
uses
makes
Occurs in light
o
Occurs in Chloroplast
Plants only
uses
o
o
o
o
o
o
uses
makes
uses
Occurs day & night
Occurs in Mitochondria
Plants & Animals
makes