UNIT 3:
Cell Membrane,
Photosynthesis and Respiration
Test Date: __________________
Essential Concepts and Skills
1. Describe the structure and function of the cell membrane, and explain
how substances get into and out of cells.
a) The cell membrane separates the inside of the cell from the environment.
b) The cell membrane controls what enters and leaves the cell in order to
maintain HOMEOSTASIS.
c) Homeostasis is the biological balance, which cells must maintain for survival.
d) Be able to explain why the cell membrane is made of a phospholipid bilayer.
e) Very small molecules, like water, can pass directly through the cell membrane,
this, is called passive transport. While large molecules, like sugar, must pass
through “protein gates”.
f) When energy is required to move particles through protein gates, this is
called active transport.
2. Explain interactions between cells and their environment in terms of
Passive Transport.
a) Diffusion is the movement of very small particles from an area of
higher concentration to an area of lower concentration, with the
concentration gradient.
b) Osmosis is the movement of water through a semi-permeable membrane
from an area of high water concentration to an area of lower water
concentration, with the concentration gradient.
c) In our respiratory and circulatory systems, oxygen diffuses into our
blood and carbon dioxide diffuses out of our blood.
Reading
p. 68
p. 85-86
Notes
p.84-87
Notes
Active Transport
a) Requires the cell to use energy to move particles in or out.
Move particles against the gradient.
Particles to large to enter membrane – Endocytosis
Particles to small to leave cell membrane – Exocytosis
Hint Vesicle is the same as a vacuole…..
3.
Cellular Energy : Photosynthesis (Plants only).
a) Describe the process of photosynthesis in terms of raw materials and products generated.
b) During photosynthesis, in chloroplasts, plant cells use sunlight, carbon dioxide
and water to produce energy-rich organic molecules and oxygen.
c) Describe that chlorophyll is a chemical in chloroplasts that can absorb or trap light energy.
d) Explain how organisms utilize the energy stored from the products of photosynthesis.
e) Relate the importance of photosynthesis to the role of producers as the foundation of food
webs.
f) Know this equation……
Mercer Middle
Loudoun County Public Schools
Aldie, VA
p.88
Notes
4. Cellular Energy: Respiration (Plants & Animal Cells)
a)
b)
c)
Respiration occurs in the mitochondria and involves the breakdown of organic molecules
(C6H12O6) to release energy.
The energy released during respiration is transported within the cell in the form of
ATP.
During cell respiration, in mitochondria, both animal and plant cells burn organic
molecules with oxygen to produce energy, carbon dioxide and water.
1.
2.
3.
4.
Aerobic Respiration
Requires Oxygen
A.K.A. Cellular Respiration
Produces 36 ATP’s
Waste Products CO2 + H2O
1.
2.
3.
4.
Anaerobic Respiration
Does Not Require Oxygen
A.K.A Fermentation
Produces 2 ATP’s
Waste product examples:
-Lactic Acid
-Alcohol
p. 89
p. 91
Notes
d) Know this equation…….
5. Explain how photosynthesis and respiration are complementary processes
for cycling carbon dioxide and oxygen in an ecosystem.
a)
b)
c)
d)
State that respiration occurs in the mitochondria and involves the
breakdown of organic molecules to release energy stored by
photosynthesis.
Understand that PLANT use both Photosynthesis (obtain food) &
Respiration (obtain energy).
The product of Photosynthesis becomes the reactants in Respiration and
the products of Respiration become the reactants in Photosynthesis. It is a
cycle between the two organelles.
Do you Notice anything about
these two equations?
Labs:
1. Egg Lab: In a FORMAL LAB FORMAT!!
a. Identify: variables, constants & controls,
write a hypothesis and a step procedure.
b. Do the experiment, recording observations.
c. Write that includes: a description of your
findings, a conclusion related to your
hypothesis and a discussion of possible
sources of error.
d. Typed or in Black Ink (neat)
Mercer Middle
Loudoun County Public Schools
Aldie, VA
p. 90
Assessments:
1. QUIZ on Cell Membrane & Exchange /
2. QUIZ on Photosynthesis & Respiration
3. Test: Covering the 4 Essential Concepts
4. Honors Essay Question: Can a snail and a piece
of Elodea support each other in a closed
container?
 Be sure to discuss energy flow and matter
cycling in your answer