Cells and Energy
Chapter 4
4.1 Chemical Energy and ATP
4.2 Overview of Photosynthesis
4.4 Overview of Cellular Respiration
4.6 Fermentation
Chemical Energy and ATP
 ATP is needed for ALL processes in the cell
 Molecules in food like starch, sugars, and fats store
energy in the bonds
Starch molecule
Glucose molecule
ATP, ADP, AMP (forms of energy)
A = Adenosine (nitrogenous base)
P = Phosphate
ATP- fully charged
ADP- half charged
AMP- uncharged
T = Tri= Three
D = Di- Two
M = Mono= One
ADP
ATP
Energy
Energy
Adenosine diphosphate (ADP) + Phosphate
Partially
charged
battery
Adenosine triphosphate (ATP)
Fully
charged
battery
 ATP transfers the energy from food to the
cell function
 Break bonds – Release energy
 ATP  ADP + P
 Form bonds – store energy
 ADP + P  ATP
Where does ATP come from?
 Living things have to break down carbon
compounds to make ATP
 We digest food: break down to
carbohydrates, lipids, and proteins
Carbohydrates = 36 ATP
Lipids 146 ATP
Proteins- usually broken down into
amino acids
- about the same amt of ATP as carbs
Plants don’t eat…
 How do plants get their
food?
 PHOTOSYNTHESIS!
Process by which plants
convert LIGHT ENERGY
into CHEMICAL ENERGY
(sugars)
LIGHT  FOOD
How does one get energy?
 Autotroph: Make their own food
 Heterotroph: need to CONSUME food
 Chemoautotroph: Do not Eat. Do not go
through Photosynthesis.
CHEMOSYNTHESIS - use CHEMICAL
ENERGY to make ATP.




Live near cracks of ocean floor
Energy comes from chemicals
Nitrogen-fixing bacteria
Video
Section 4.1 Review
 What is the difference between an autotroph and a
heterotroph?
Autotroph—makes own food
Heterotroph—needs to eat food
 How are ADP and ATP related?
ADP is missing a phosphate (and energy)
ATP has all 3 phosphate and lots of energy
They go back and forth
 What is the use of chemicals for a source of energy
known as?
Chemosynthesis
4.2 Overview of Photosynthesis
 Producers make their own
food
 Plants are producers.
 Photosynthesis captures
energy from sunlight to
make sugars.
Light + carbon dioxide + water
glucose + oxygen
Where does photosynthesis happen?
Chloroplast!
• Go inside a chloroplast.
• Find a Thylakoid – disc-like structure
• Inside the thylakoid - Chlorophyll is a
molecule that absorbs light energy.
Two Processes of Photosynthesis
 Light Dependent Reaction
 Calvin Cycle or light independent
reaction or dark reactions
Overview of
Photosynthesis
Light Dependent Reaction
1. Chlorophyll absorbs energy
from sunlight.
 Water is broken down
 Oxygen is released
Calvin Cycle
Light Independent
Dark reactions
1. CO2 is added to a cycle of
2. Oxygen leaves the plant and
reactions to build larger
goes into the air
molecules (ATP and NADPH
are used)
3. ATP and NADPH are made to
FUEL the Calvin cycle (Light 2. A molecule of simple sugar is
independent reactions or also
formed
known as the dark reactions)
Glucose (C6H12O6)
Sunlight + 6CO2 + 6H2O  C6H12O6 + 6O2
Overview
H2O
(Water)
Light
Dependent
Reaction
O2
(Oxygen)
ATP
NADPH
CO2
Carbon dioxide
Calvin Cycle
Glucose
C6H12O6
Section 4.2 Review
 What is the role of chlorophyll in photosynthesis?
Absorbs energy from sunlight
 What goes into the light reactions? What comes out as a
waste product? What is given off that is needed to
power the Calvin Cycle. IN: light and water
Waste OUT: Oxygen
OUT: ATP and NAPDH
 What goes into the dark reactions? What comes out as a
useful product? What else comes out that is needed for
the light reactions?
IN: CO2, ATP and NADPH
OUT Product: Glucose (C6H12O6)
OUT: ADP and NADP+
4.4 Overview of Cellular Respiration
 There is LOTS of energy available in GLUCOSE-FOOD.
 If all the energy in food was released at once, you
would blow up!
 Energy has to be released and CAPTURED- a little
bit at a time
 Requirements: OXYGEN!
mitochondrion
 Where? In the mitochondria
animal cell
Big Picture
GLUCOSE
Glycolysis
Not a lot of ATP
made
Then
With oxygen
Aerobic
Respiration
Without oxygen
Fermentation
Alcoholic
Lactic Acid
Glycolysis- splitting sugar
 First Step
 anaerobic process (does not require oxygen)
 takes place in cytoplasm
 splits glucose into two three-carbon molecules
 produces some ATP molecules in the process
If there IS Oxygen:
Two Stages of Cellular Respiration
Occur
1. Krebs cycle
 O2 is required
 Breaks up the compounds
from Glycolysis
 Makes some ATP
 Makes more molecules
that carry energy to send
to the ETC
 Produces CO2
2. Electron Transport
Chain (ETC)
 O2 Required
 Makes LOTS of ATP
 H2O made as waste
product
Cellular Respiration: Mirror Image of
Photosynthesis
Overview
Cellular Respiration
Glycolysis
1. Kreb’s Cycle
2. Electron Transport Chain
Fermentation
•Alcoholic or Lactic Acid
If there is NO Oxygen??
 Fermentation occurs
 No ATP is made.
Fermentation

Two types

_______________
Alcoholic fermentation (Products: CO2 and Alcohol)

Lactic ________
acid fermentation (Product: Lactic acid)
__________
Section 4.4 Review—Part A
 Where does glycolysis take place?
Cytoplasm
 What goes into glycolysis? What comes out of glycolysis?
IN: Glucose
OUT: 2 ATP & 2 - 3 carbon molecules
 Why does fermentation occur?
No oxygen present; to allow for glycolysis to continue
 What are the two different types of fermentation?
Lactic acid
Alcoholic
Section 4.4 Review—Part B
 Where does Cellular respiration take place?
Mitochondria
 What goes into the Kreb’s cycle? What comes out?
IN: 3 carbon molecules
OUT: ATP, CO2
 What goes into electron transport? What comes out?
IN: Energy Storing compounds and Oxygen
OUT: Water and ATP!!!
 How are photosynthesis and cellular respiration
related?
Reactants of one are basically the products of the other