Download Chap 7 Energy from Food

Energy from
Food
Chap 7
 How are autotrophs and
heterotrophs different?
Give an example of each.
PRODUCERS - PHOTOAUTOTROPHS
PRODUCERS - CHEMOAUTOTROPHS
CONSUMERS - HETEROTROPHS
Concept 7.1 – Sunlight powers life.
Describe how organisms release energy from food.
Through cellular respiration, oxygen is used to
release energy from glucose and produce
ATP.
What are some types of
energy?
 Potential
 Kinetic
 Chemical
Concept 7.2 – Food stores chemical energy.
3.
What is the difference between kinetic energy and potential
energy?
Kinetic energy is the
energy of motion.
Potential energy is
energy that is stored.
Concept 7.2 – Food stores chemical energy.
4.
How do cells release chemical energy from food?
In cellular respiration, oxygen reacts with the
organic molecules of food (sugar), breaking the
molecules into smaller molecules and releasing
chemical energy (ATP).
What are some activities that
use energy?
Energy Consumed by Daily
Activities
What is ATP?
Adenosine triphosphate. Is a nitrogen
containing compound called adenine
and a five carbon sugar called ribose. Has
three phosphate groups.
7.3 ATP provides energy for
cellular work
 How
is energy released from ATP?
 Energy is released from ATP when a
phosphate bond is broken.
Concept 7.3 – ATP provides energy for cellular work.
6.
What are the three main types of cellular work?
Chemical work, mechanical work, transport
work (active transport)
7.4 Electrons fall
 How
is breathing related to cellular
respiration?
Breathing brings oxygen into the body that is
required by cells for cellular respiration
(mitochondria). Breathing also removes the
waste product of cellular respiration, carbon
dioxide.
Cellular Respiration Equation
8.
What are the products of cellular respiration?
Carbon dioxide, water, and energy (ATP)
7.5 Cellular Respiration

1.
2.
3.
Do you like to run, bike, or swim? These all are
good ways to exercise. When you exercise, your
body uses oxygen to get energy from glucose.
How does your body feel at the start of exercise,
such as a long, slow run? How do you feel 1
minute into the run; 10 minutes into the run?
What do you think is happening in your cells to
cause the changes in how you feel?
Think about running as fast as you can for 100
meters. Could you keep up this pace for a much
longer distance? Explain your answer.

Overview of Cellular Respiration
What is cellular respiration?
 Cellular respiration is the process that releases energy by breaking
down food (glucose) in the presence of oxygen.
Overview of Cellular Respiration

What is cellular respiration?
 Cellular respiration is the process that releases energy by
breaking down food (glucose) in the presence of oxygen.
C6H12O6
glucose

+
6 O2
oxygen

6 H2O + 6 CO2 + Energy
water carbon
ATP
dioxide
What would be the problem if cellular respiration occurred in just
one step?
 Burn up all energy instead of a gradual release of energy
Cellular Respiration:
An Overview
Section 9-1
Electrons carried in
NADH
Pyruvic
acid
Glucose
2
Krebs
Cycle
Glycolysis
2
Electrons
carried in
NADH and
FADH2
Electron Transport
Chain
32
36 Total ATP
Glycolysis
 First step in cellular respiration

Glyco / lysis – “to break glucose”
 Does not need oxygen to occur
 Where does

glycolysis take place in the cell?
Glycolysis occurs in the cytoplasm of the cell.
 Glycolysis

Process in which one molecule of glucose is broken
in half, producing two molecules of pyruvic acid.
Glycolysis
• How does the cell get glycolysis going?
 The cell uses energy. 2 molecules of ATP are
used up.
• What are the products of glycolysis?
 Pyruvate and 4 ATP molecules
C. Glycolysis
• Why is there only a NET of 2 ATP molecules
produced during glycolysis?
 2 ATP molecules were used to start reaction
What happens after glycolysis???
Glycolysis is ALWAYS the first step in the break down
of glucose.
 Glycolysis does not need oxygen to occur
If oxygen is NOT present, glycolysis is followed by
anaerobic respiration.
 Alcoholic Fermentation
 Lactic Acid Fermentation
What happens after glycolysis???
Glycolysis is ALWAYS the first step in the break down
of glucose.
If oxygen is NOT present, glycolysis is followed by
anaerobic respiration (Fermentation)
 Alcoholic Fermentation
 Lactic Acid Fermentation
If oxygen is present, glycolysis is followed by aerobic
respiration – a process that requires oxygen
Anaerobic Respiration:
Fermentation

What is fermentation?


Where does fermentation occur in the cell?


Fermentation is a process by which cells release energy in the absence
of oxygen.
Cytoplasm of the cell.
Why is fermentation considered an anaerobic process?


Anaerobic is process that does not require oxygen
Fermentation does NOT require oxygen
Anaerobic Respiration:
Fermentation
 Two main types of fermentation
1.
2.
Alcohol fermentation
Lactic acid fermentation
Glycolysis
 What
o
o
Alcoholic Fermentation
organisms use alcoholic fermentation
Yeasts and other microorganisms use alcoholic fermentation
Waste products are alcohol and carbon dioxide
 What
happens to the small amount of alcohol produced
during the baking of bread?
 Evaporates when bread is baked.
Glycolysis
Alcoholic Fermentation
 How does fermentation allow the production of ATP to continue?

NAD+ is looped to start the process over again.
Glycolysis
Lactic Acid Fermentation
Section 9-1
Glucose
2 Pyruvic acid
2 Lactic acid
2. Lactic Acid Fermentation –
• Lactic acid is produced by your muscles
during rapid exercise when not enough
oxygen is present.
• Prokaryotes produce lactic acid as a waste
product which is used in production of foods:
yogurt, cheese, sour cream, sauerkraut, etc.
SUMMARY
Glycolysis
Glycolysis is ALWAYS the first step in the break down
of glucose.
If oxygen is NOT present, glycolysis is followed by
anaerobic respiration.
 Alcoholic Fermentation
 Lactic Acid Fermentation
If oxygen is present, glycolysis is followed by aerobic
respiration.
The Krebs Cycle and Electron Transport
1.
At the end of glycolysis, how much of the
chemical energy in glucose is still unused?
Approx. 90%
2.
Because the final stages of cellular respiration
require oxygen, they are said to be aerobic.
The Krebs Cycle and Electron Transport
Where do the reactions of
the Krebs cycle take place
in the cell???
Mitochondrial matrix
The Krebs Cycle and Electron Transport
 The
Krebs Cycle
 Second stage of cellular
respiration, in which pyruvic
acid is broken down into
carbon dioxide in a series of
energy-extracting reactions
Electron Transport Chain
Where do the reactions of
the electron transport
chain take place in the
cell???
Inner membrane of
mitochondria
The Electron Transport
 The

Electron Transport Chain
series of proteins in which the high-energy electrons from the
Krebs cycle are used to convert ADP into ATP
Cellular Respiration and Energy
In the presence of
oxygen, the cell can
produce 36 ATP
molecules per one
glucose molecule
Transfer of Energy to ATP
Where


does the energy in food go?
When broken down, the energy gets stored in a
molecule known as ATP
ATP delivers energy wherever it is needed in the cell.
For example:



ATP drives muscle movement
Transport of molecules across the cell membrane
ATP drives cellular respiration
How
does ATP deliver energy to the
cell?
It is in it’s structure
ATP
Is
a nucleotide
Adenosine TriPhosphate
It is made of:
 a nitrogen base (adenine)
 a sugar (ribose)
three phosphate groups
When
the third phosphate
group of ATP is removed by
hydrolysis, energy is
released.
Hydrolysis
= when a
molecule is broken down by
adding water.
•ATP is constantly recycled!