4.1 Chemical Energy and ATP
KEY CONCEPT
All cells need chemical energy.
Cell Energy = ATP
ATP = Adenosine Triphosphate
4.1 Chemical Energy and ATP
4.1 Chemical Energy and ATP
• ATP transfers energy from the breakdown of food
molecules to cell functions.
– Energy is released when a phosphate group is removed.
– ADP – adenosine diphosphate
– ADP is changed into ATP when a phosphate group is
added.
adenosine
triphosphate
tri=3
adenosine
di=2
diphosphate
4.1 Chemical Energy and ATP
Molecules in food store chemical energy in their bonds.
Starch molecule
Glucose molecule
4.1 Chemical Energy and ATP
• Fats store the most energy.
– 80 percent of the energy in your body
– about 146 ATP from a triglyceride
• Proteins are least likely to be broken down to make ATP.
4.1 Chemical Energy and ATP
Autotroph - manufacture own food
• most use photosynthesis
– converts sunlight into chemical E
– chemical E is stored in the form of sugars
Heterotrophs – rely on other sources for E
4.1 Chemical Energy and ATP
A few autotrophs do not need sunlight and photosynthesis
as a source of energy.
• live in places that never get
sunlight.
• Chemosynthesis
– uses chemical E (S)
instead of light E to make
food
– Chemosynthetic bacteria –
hydrothermal vents
4.1 Chemical Energy and ATP
4.1
Energy
and ATP
4.2 Chemical
Overview of
Photosynthesis
Photosynthetic organisms are autotrophs =
producers
•
•
•
•
Photosynthesis captures E from
sunlight to make food – sugar
Glucose
All sugars end in -ose
2 phases of photosynthesis
1. light-dependent reactions
2. light-independent reactions
4.1 Chemical Energy and ATP
4.1
Energy
and ATP
4.2 Chemical
Overview of
Photosynthesis
Light and Pigments
1. visible spectrum – wavelengths the human eye can see
2. different colors have different wavelengths
3. Pigment - absorb specific wavelengths of light
crest
I------------------I
wavelength
Trough
4.1 Chemical Energy and ATP
4.1
Energy
and ATP
4.2 Chemical
Overview of
Photosynthesis
Photosynthesis takes place in chloroplast
Chloroplast contains pigments to capture light
• Chlorophyll reflects green light & absorb all others
• Carotenoids – reflect orange light & …
• Anthocyanine – reflect purples and red light & …
4.1 Chemical Energy and ATP
4.1
Energy
and ATP
4.2 Chemical
Overview of
Photosynthesis
The light-dependent reactions
– Takes place in the grana (thylakoids)
– water and sunlight are needed
– chlorophyll absorbs E from sunlight
– water molecules are split – Photolysis – H2O  H + O
– E and hydrogen ions are passed on to the lightindependent reactions
– oxygen is released as waste
4.1
Energy
and ATP
4.2 Chemical
Overview of
Photosynthesis
The light-independent reactions
– Takes place in the Stroma – space between
– needs carbon dioxide from atmosphere
– Calvin cycle - Carbon fixation
– use E from light dependent reaction to build a 6 carbon
chain of sugar (glucose)
– C6H12O6
4.1
Energy
and ATP
4.2 Chemical
Overview of
Photosynthesis
• Sugar is then transported to the roots, stems, and fruits of
the plants
• sugar can be used, or stored as starch, and some is built
into cellulose
• We obtain E from plants by eating the stored sugar
4.1
Energy
and ATP
4.2 Chemical
Overview of
Photosynthesis
• The equation for the overall process is:
6CO2 + 6H2O  C6H12O6 + 6O2
granum (stack of thylakoids)
1
chloroplast
6H2O
thylakoid
6CO2
3
6O2
2
energy
stroma (fluid outside the thylakoids)
1 six-carbon sugar
4
C6H12O6
4.1 Chemical Energy and ATP
4.1 Chemical Energy and ATP
Light Dependent
Light Independent
4.1 Chemical Energy and ATP
4.5
Respiration
in Detail
4.1 Cellular
Chemical
Energy and
ATP
Glycolysis - splits glucose into two molecules of pyruvate
(pyruvic acid)
– C-C-C-C-C-C  C-C-C + C-C-C
– Produces some ATP molecules
– Takes place in cytoplasm
4.1 Chemical Energy and ATP
Aerobic
Anaerobic Respiration
4.1 Chemical Energy and ATP
Aerobic Respiration
Two steps
1. Krebs Cycle
4.4
Cell Respiration
4.1 Overview
Chemicalof
Energy
and ATP
Aerobic Respiration
1. The Krebs cycle
– takes place in
mitochondrial matrix
– breaks down pyruvic acid
– makes a small amount of
ATP
– releases carbon dioxide
1
mitochondrion
matrix (area enclosed
by inner membrane)
ATP
and
6CO2
Krebs Cycle
energy
2
3
energy from
glycolysis
inner membrane
ATP
and
and
6H2 O
6O2
4
4.5
Respiration
in Detail
4.1 Cellular
Chemical
Energy and
ATP
Aerobic Respiration
2. The Electron Transport Chain
takes place on the cristae
Makes a large amount of ATP
Water is released as a waste product
4.4
Cell Respiration
4.1 Overview
Chemicalof
Energy
and ATP
• The equation for the overall process is:
C6H12O6 + 6O2  6CO2 + 6H2O
• The reactants in photosynthesis are the same as the
products of cellular respiration.
4.6 Fermentation
4.1 Chemical Energy and ATP
KEY CONCEPT
Fermentation allows the production of a small
amount of ATP without oxygen - Anaerobic
4.6 Fermentation
4.1 Chemical Energy and ATP
•
Lactic acid fermentation occurs in muscle cells.
1. glycolysis  two pyruvate molecules
2. converts pyruvate into lactic acid
– Muscle pain and weakness
4.6 Fermentation
4.1 Chemical Energy and ATP
Fermentation and its products are important in several
ways.
• Fermentation is used in food production.
– Alcoholic fermentation
- energy is used to split pyruvate into ethyl alcohol and carbon
dioxide
- Yogurt, cheese, bread
4.6 Fermentation
4.1 Chemical Energy and ATP
• Fermentation is used in food production.
– yogurt
– cheese
– bread
4.1 Chemical Energy and ATP
CO2
4.1 Chemical Energy and ATP
4.1 Chemical Energy and ATP
Extra Credit
• Create an alphabet picture book for middle school kids
with ideas relating to cell biology
• Due: Monday Oct 22nd