Download Cell Boundaries Chapter 7.3

I. Energy & Life
A. Autotroph
- Organism which uses the sun’s energy
to make its own food.
B. Heterotroph
- Organism which consumes organic
material for energy.
II. ATP
A. ATP (Adenosine Tri-Phosphate)
- “Energy currency of the cell.”
- When food is broken down, energy is
released in the form of ATP.
Example: There is too much energy stored in
glucose, so its broken down slowly in
order not to lose any energy. This
energy is stored in ATP.
B. What is Energy?
- The ability to do work.
C. ATP is a nucleotide.
1. Consists of 3 phosphate groups, the
sugar, ribose, and the nitrogen base
adenine.
2. The energy in ATP is stored
between the bonds of its
phosphate groups.
3. When a -P group is added to
another molecule, it will have
enough energy to react with other
molecules.
Chapter 8: Section 2; Pages 204-207
I. Photosynthesis
- Process where energy from the sun, CO2 and
water are used to make high-energy sugars.
AKA: GLUCOSE
II. History of Thought
How does a tiny seedling grow until it weighs several tons?
1. Jan van Helmont
- Believed plants grew by
absorbing water.
2. Joseph Priestly
- Discovered that plants release oxygen.
3. Jan Ingenhousz
- Discovered plants only release oxygen in
the presence of light.
III. The Photosynthesis Equation
A. 6CO2 + 6H2O + Light  C6H12O6 + 6O2
REACTANTS
PRODUCTS
IV.
LIGHT & PIGMENTS
A. Plants also need pigments to
undergo photosynthesis.
B. Pigments are what absorb energy
from the sun.
C. A pigment will be the color of the
spectrum of light that it CANNOT
absorb.
D. The main pigment in plant cells is
Chlorophyll.
1. There are two types of Chlorophyll:
a. Chlorophyll a
- absorbs blue-violet and red light.
b. Chlorophyll b
- absorbs blue and red light.
2. Green light is not absorbed!
E. Plants contain other “Accessory
Pigments.”
WHY DO LEAVES CHANGE COLOR?
• Chlorophyll:
Trees in the temperate zones store these
sugars for their winter dormant period.
Accessory Pigments:
• Carotenoids: which produce yellow, orange,
and brown colors in such things as corn,
carrots, and daffodils, as well as rutabagas,
buttercups, and bananas.
• Anthocyanins: which give color to such
familiar things as cranberries, red apples,
concord grapes, blueberries, cherries,
strawberries, and plums. They are water
soluble and appear in the watery liquid of
leaf cells.
Chapter 8: Section 3; Pages 208-214
I.
Inside a Chloroplast
A. Photosynthesis takes place within a
chloroplast.
B. Chloroplasts contain membranes
called “Thylakoids.”
1. A stack of thylakiods is called a
“Grana or Granum.”
c. The area outside the thylakoid is
called the “Stroma.”
1. Contains liquid which protects
and insulates the thylakoids.
Leaf Anatomy
• Stomata- pores found on bottom of a leaf
to allow CO2 to enter leaves and O2 exit.
– Open during the day and closed at night
– Why??
• Cuticle- Waxy coating on top of the leaf
• Mesophyll- Specialized plant cells
containing chloroplasts.
• Xylem- carries water absorbed by the
roots to the leaves
• Phloem- carries sugars made during
photo. to the rest of the plant.
II. Light Reactions & Dark Reactions
a. Light Reactions (Light Dependent)
- Take place within the grana.
• 3 raw materials needed are: Light,
Water and Chlorophyll.
• Uses light energy to convert ADP and
• NADP+ (Uncharged Batteries) into the
energy carriers ATP and NADPH
(Charged Batteries).
• 3 products made are: 1 ATP, 2 NADPH
and oxygen.
• Oxygen is produced as a byproduct and released
into the air.
b. The Calvin Cycle
(Light – Independent Reactions)
- Takes place in the stroma.
- Uses ATP and NADPH from the light
reactions to produce high-energy sugars
such as glucose.
- Uses 6 molecules of CO2 to produce one
6-Carbon sugar.
- The sugar is either then used for
immediate energy or to build larger
molecules such as cellulose or starch.
III. Factors Affecting Photosynthesis
a. Shortage of water
b. Temperature
* 32oF to 95oF is what enzymes
work best at.
c. Light Intensity
d. CO2 concentration