Unit 5 Photosynthesis and Cellular Respiration (Chapters 8 and 9)
ENERGY
Remember the cell theory: “energy flows through living things during cellular metabolism”
Autotrophs: plants, some protists and some _____________________ are able to use the energy from the sun to
produce food.
Heterotrophs: animals, some prokaryotes, some _____________________ cannot use the sun’s energy directly,
and need to consume ________________________ as a food source.
Fungi are also __________________________ that _________________________ their food in order to obtain the nutrients.
Yeast are _____________________________ fungi.
ATP
ATP stands for ___________________________________________________________________________, because it contains 3
phosphates. ATP is a nucleic acid that plants and animals use for __________________. It carries energy in its
chemical bonds. Energy is released when the bonds are ______________________.
ADP (adenosine di-phosphate) has only ______________ phosphates and has ____________ energy than ATP.
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CELLS USE ENERGY (Review)
Active transport: moves ions across cell membrane through protein channels and pumps
Sodium-Potassium Pump – moves ions, 3 Na+ out and 2 K+ ions into the cell
Synthesis of Nucleic Acids: DNA, RNA, ATP
Reproduction: Mitosis and meiosis
Movement: work and transport across the cells using ATP
o ATP is good for _______________term use, it is poor at long-term energy storage. Glucose and
lipids are better for __________ term energy storage. Glucose stores 90X more energy than ATP.
Cells keep a small supply of ATP; they generate more from ADP when needed, by breaking
down carbohydrates like glucose.
SCIENTISTS WHO DISCOVERED PHOTOSYNTHESIS
Van Helmont (1643): Discovered that most of the __________________ of a plant comes from water.
Joseph Priestly (1771): Discovered plants produce a substance that kept a candle burning. Plants release __.
Jan Ingenhousz (1779): Discovered that plants only produce oxygen in the presence of __________________.
Melvin Calvin (1948): Determined the details of the Calvin Cycle.
Photosynthesis
using light (photons) to make glucose (C6H12O6) - (ie. Transforms light E into chemical E)
Photosynthesis takes place in ________________________ in plant cells and the ___________ ________________ in
prokaryotes. It uses a pigment that _________________ high energy red and blue light called ___________________.
This pigment appears green since it reflects green light. There are several pigments in plant cells.
Chloroplasts have and _________________ and ______________ membrane.
The stroma is the space and the granum are stacks of
thylakoids that contain the chlorophyll.
In photosynthesis, the LIGHT DEPENDANT REACTION takes place in
the ________________ and the LIGHT INDEPENDENT REACTION takes
place in the ____________________.
Unit 5 Photosynthesis and Cellular Respiration (Chapters 8 and 9)
The overall reaction of photosynthesis occurs in 2 reactions in the chloroplast:
LIGHT DEPENDENT REACTION and the LIGHT INDEPENDENT REACTION (CALVIN CYCLE)
Overall equation of photosynthesis:
Carbon dioxide + water produces -> glucose + oxygen =
6CO2 + 6H2O -> C6H12O6 + 6O2
LIGHT REACTION (photophosphorylation): takes place in the thylakoids and is composed of
PHOTOSYSTEM I and PHOTOSYSTEM II.
Uses light and water to make the energy storing molecules _________________ and __________________ (which are
used in the Calvin cycle), and releases oxygen as waste.
1. A photon of light is absorbed by chlorphyll in PHOTOSYSTEM II in the thylakoid membrane.
2. PHOTOSYSTEM II: the energy from the photons of light are transferred to electrons, which are
carried to the electron transport chain (ETC)
3. Electrons in PHOTOSYSTEM II split a molecule of H2O into H+ (makes ATP and NADPH) and O2
(waste).
4. Electrons from PHOTSYSTEM II are moved to ETC to provide energy for the synthesis of ATP. ATP
Synthase, a specialized ________________ channel in the thylakoid membrane at the end of the ETC
converts ADP to ATP as H+ ions pump through to the outside of the membrane. ATP synthase
turns/spins like a turbine as ions pass through. Chemiosmosis: occurs as H+ ions move across the
membrane to make ATP. (like osmosis but with chemical ions instead of water).
5. A photon of light is absorbed by chlorophyll in PHOTSYSTEM I and combines with electrons from
ETC.
Unit 5 Photosynthesis and Cellular Respiration (Chapters 8 and 9)
6. Electrons and H+ (from PSII) convert NADP+ + H+  __________ (nicotinamide adenine dinucleotide
phosphate) an energy electron carrier.
7. ATP and NADPH are the products of the LIGHT REACTION and are carried to the stroma to the
Calvin Cycle (LIGHT INDEPENDENT REACTION. Oxygen is also produced as a waste byproduct that is used in cellular respiration and released by the plant as a gas.
CALVIN CYCLE (LIGHT INDEPENDENT REACTION) – does not need sunlight. Uses ATP + NADPH to
convert CO2 into GLUCOSE, takes place in the stroma. Cycles 6 times to make glucose.
 6 molecules of CO2 enter the cycle from the air. They fixed by the enzyme ___________________, (which
is the most abundant protein in the world) to combine with RuBP (5C) and make 3Phosphoglycerate (3C).
 ATP and NADPH are used to convert the 3C molecules into higher-energy forms (endergonic)
 It takes 2 3-carbon molecules to form a 6-carbon sugar such as glucose.
 The rest of the carbons are resued to make RuBP so the cycle continues.
 Overall, the Calvin Cycle uses ______ molecules of CO2 to make _____molecules of glucose and cycles
____ times.
Unit 5 Photosynthesis and Cellular Respiration (Chapters 8 and 9)
Reaction Formulas:
Light Dependent Reactions in the _____________________ and use _______________ to capture photons of light.
NADP + H  excited e-  _________________ + _____________
ADP + P  ATP synthase  _______________
Light Independent Reaction (Calvin Cycle)
ATP + NADPH + CO2  ______________________
Oxidation-Reduction Reactions always take place together:
Oxidation: lose e- and H+, gain O2, release energy.
Reduction: lose O2, gain e- and H+, takes in energy.
What factors can effect photosynthesis?
Light intensity: more will ______________________photosynthesis
Carbon Dioxide amount: more will _________________photosynthesis
Temperature: too high or too low will ___________________ photsynthesis
Plants have adapted to close stomata during the day (CAM or desert plants); deciduous plants lose their
leaves in the fall and do not perform photosynthesis in the winter; etc.
Unit 5 Photosynthesis and Cellular Respiration (Chapters 8 and 9)
Cellular Respiration converts chemical energy into usable energy for the cell.
All organisms use cellular respiration in one form or another to use energy.
Chemical Energy:
We need to consume food so we can break it down into _______________energy, like glucose
The amount of food we can get from food is calculated by the amount of ________________ it contains.
Calorie = amount of energy needed to raise the temperature of 1 g of H2O by 1 degree Celsius.
You do not use all the glucose in food at once: your cells _______________ release the energy it contains over
time. This is measured by your ________________________.
Mitochondria:
The site of cellular respiration in eukaryotes. Structure is made of
______membranes (inner and outer); the folds called the ______________
and the space called the _________________.
Cellular Respiration:
 To release energy by breaking down food molecules in the presence of ___________________.
 Formula: C6H12O6 = 6H2O + energy (heat and ATP) + 6CO2
 It is an exergonic reaction
 There are 3 steps to cellular respiration:
Unit 5 Photosynthesis and Cellular Respiration (Chapters 8 and 9)
Step 1: Glycolysis
 Occurs in the ________________________ outside of the mitochondria.
 The process of breaking 1 molecule of glucose into 2 molecules of __________________________.
 Glycolysis is fast and this step of respiration does ______________ require oxygen (______________________).
 Because glycolysis is so fast, the cell uses up its available NAD+ quickly, and then ATP production
will stop unless more is made (NAD+ is regenerated in the Electron Transport Chain in the
mitochondria)
 Produces ____ ATP molecules and ______ NADH molecules which are transported to the ETC.
Step 2: Krebs Cycle or Citric Acid Cycle.
The ____________________made during glycolysis is converted into _________________ which enters the Citric Acid
Cycle and used to make CO2, NADH, ATP and FADH2 inside the matrix of the mitochondria. The Krebs cycle
turns 2 times for each molecule of glucose and makes ___molecules of CO2, ___molecules of NADH,
__molecules of ATP and ___ of FADH2.
Unit 5 Photosynthesis and Cellular Respiration (Chapters 8 and 9)
Step 3: Electron Transport Chain and Chemiosmosis
 The ETC uses high energy electrons from Glycolysis (NADH) and the Krebs Cycle (NADH and
FADH2) to convert ADP to __________.
 The ETC is located in the inner membrane of the mitochondria and requires ________________. (for
prokaryotes the ETC is in __________________)
 The ETC oxidizes NADH to _______________ and FADH2 to ____________. As a result high energy e- are
pumped through the inner membrane and H+ are released into the intermembrane space.
 The high energy e- combine H+ + O2 to produce ________________ (the final electron acceptor).
 The H+ ions are pumped back through the membrane by ATP ___________________ to make ________ ATP.
Unit 5 Photosynthesis and Cellular Respiration (Chapters 8 and 9)
Fermentation:
When oxygen is __________ present, glycolysis is followed by fermentation, an _______________ process. The
purpose is to replenish NAD+ for glycolysis (since it can not be made in the ETC). There are 2 types:
Lactic Acid Fermentation: occurs in muscle cells when not enough oxygen is supplied
Pyruvic acid + NADH  lactic acid + NAD+
Alcoholic Fermentation: occurs in yeast and some bacteria (make bread, alcohol, etc)
Pyruvic acid +NADH  ethyl alcohol + CO2 + NAD +
*** Cellular Respiration results in the production of 36 ATP molecules
Process
ATP
release
Where in the cell?
Need O2
Type of
Respiration
Glycolysis
Krebs or Citric Acid
Cycle
Electron Transport
Chain
Fermentation
Total
36
Overview of Photosynthesis and Cellular Respiration
PHOTOSYNTHESIS
CELLULAR RESPIRATION
FUNCTION
Energy storage
Energy release
LOCATION
Chloroplasts
mitochondria
REACTANTS
CO2 and H20
C6H12O6 and O2
PRODUCTS
C6H12O6 and O2
CO2 and H20
EQUATION
6CO2 + 6H2O

C6H12O6 + 6O2
C6H12O6 + 6O2
-->
6CO2 + 6H2O
Unit 5 Photosynthesis and Cellular Respiration (Chapters 8 and 9)