Name _____________________________________ Number ______
Chloroplasts and Mitochondria
Period _____
Plant cells and some Algae contain an organelle called the chloroplast. The chloroplast allows
plants to harvest energy from sunlight to carry on a process known as Photosynthesis. Specialized
pigments in the chloroplast (including the common green pigment chlorophyll) absorb sunlight and use
this energy to combine carbon dioxide and water and make GLUCOSE and OXYGEN. The complete
chemical reaction for Photosynthesis is:
6 CO2 + 6 H2O + energy (from sunlight)
REACTANTS
ENERGY
C6H12O6 + 6 O2
PRODUCTS
In this way, plant cells produce glucose and other carbohydrates that they can store for later use.
Photosynthetic cells found mainly in the leaves may have thousands of chloroplasts.
1. What type of cells contains chloroplasts?
2. What is the energy autotrophs use to make their own food?
3. The food making process is called ___________________.
4. What are the raw materials for photosynthesis?
5. What simple sugar is produced?
6. What gas is USED? ________________ RELEASED? ________
7. Where are most photosynthetic cells in plants found?
Chloroplasts are double membrane organelles with a smooth outer membrane and an inner membrane
folded into disc-shaped sacs called thylakoids. Color and label the outer membrane light green.
Thylakoids, containing chlorophyll and other accessory pigments (red, orange, yellow, brown), are in
stacks called granum (grana, plural). Color and label the grana (STACK) dark green.. Grana are
connected to each other by structures called lamellae, and they are surrounded by a gel-like material
called stroma. Color and label the lamellae brown. Color and label the stroma light blue in figure 1.
8. How many membranes surround a chloroplast?
9. The outer membrane is S____________.
10. The INDIVIDUAL SACS formed by the inner membrane are called _________________ and
are arranged in ___________ like pancakes.
11. What pigment is found inside a thylakoid? What color will it be?
12. Other pigments that trap sunlight are called A_____________ pigments. What colors are these
pigments?
13. STACKS of thylakoids are called G___________ (plural) or GRANUM (singular).
14. Stacks or grana are connected to each other by _____________.
1
FIGURE 1-CHLOROPLAST
Light-capturing pigments in the grana are organized into photosystems. On figure 2, color and label
a single thylakoid (SINGLE DISK) dark green. Color and label a granum (STACK) red.
FIGURE 2-THYLAKOID
Scientists describe the reactions of photosystems in 2 parts: the light-dependent reactions and
the light-independent reactions (Calvin Cycle). The light-dependent reactions take place within the
thylakoid membranes. Color and label the light-dependent reactions dark green on figure 3. The lightindependent reactions take place in the stroma, the region outside the thylakoid membranes. Color and
label the light-independent reactions (the Calvin Cycle) purple in figure 3.
FIGURE 3 – PHOTOSYNTHESIS: AN OVERVIEW
sugars
2
15. What is another name for the light-independent reactions?
16. Where do the light-dependent reactions take place?
17. Where do the light-independent reactions take place?
Photosynthesis Step 1: Light Reaction – occurs in the __________ inside the __________
e1b
1a
1c
Electron
transport
chain
Chlorophyll in
the thylakoids
-
e
e
eNADPH
-
1d
-
Oxygen
Water
e-
1a. Light energy is
absorbed by the
chlorophyll
1b. Electrons
jump out of the
chlorophyll atoms
1c. Electrons move down
the electron transport
chain (series of proteins
that pass the electrons
along). Electrons are
caught by the NADPH
compound. ATP is made.
ATP
1d. Photolysis: Water is
broken down into oxygen
(given off by plant) and
electrons (replace lost
electrons in chlorophyll).
These electrons recharge the
system so the light reaction
can happen again.
Photosynthesis Step 2: Dark Reaction (___________ _________) – Occurs in the
__________
NADPH -
e
ATP
e-
-e
-- e
e-
-
Carbon
dioxide
from the air
Calvin Cycle
PGAL
3
2 PGAL = 1 glucose
2a. Electrons and
ATP from light
reaction get dumped
into the Calvin Cycle
to run it
2b. Calvin Cycle: Series of
steps that build up
compounds using carbon
dioxide from the air
2c. PGAL compound
sometimes leaves the cycle.
2 PGAL compounds added
together make 1 glucose.
Mitochondria are the powerhouses of the cell because they “burn” or break the chemical bonds of
glucose to release energy to do work in a cell. Remember that this energy originally came from the
sun and was stored in chemical bonds by plants during photosynthesis. Glucose and other
carbohydrates made by plants during photosynthesis are broken down by the process of aerobic
Cellular Respiration (requires oxygen) in the mitochondria of the cell. This releases energy (ATP)
for the cell. The more active a cell (such as a muscle cell), the more mitochondria it will have. The
complete chemical reaction for Cellular Respiration is:
6 O2 + C6H12O6 +
REACTANTS
6 CO2 + 6 H2O + energy
PRODUCTS
The mitochondria are about the size of a bacterial cell and are often peanut-shaped. Mitochondria
have their own DNA and a double membrane like the nucleus and chloroplast. The outer membrane is
smooth, while the inner membrane is convoluted into folds called cristae in order to increase the
surface area.
18. Why are mitochondria called the powerhouse of the cell?
19. What cell process occurs in the mitochondria?
20. Why do some cells have MORE mitochondria? Give an example.
21. What simple sugar is broken down in the mitochondria?
22. Where does the energy in glucose come from ORIGINALLY?
23. Where is this energy stored in glucose?
24. Why is cellular respiration an aerobic process?
25. What energy is released when the chemical bonds of glucose are broken?
26. Name two other organelles besides the mitochondria that contain DNA and have a double
membrane.
27. Describe the outer membrane of the mitochondria.
28. Why is the inner mitochondrial membrane folded?
29. What are the folds called?
Color and label the outer membrane pink and the cristae red on figure 4. This greatly increases
the surface area of the membrane so that carbohydrates (simple sugars) can combine with oxygen to
produce ATP, adenosine triphosphate (the energy molecule of the cell). The electron transport
chain takes place across the membranes of the cristae (crista, singular). Inside the folds or cristae
is a space called the matrix that contains enzymes needed for the Kreb's Cycle? Color and label
the matrix yellow on figure 4.
4
FIGURE 4 - MITOCHONDRIA
Adenosine triphosphate (ATP) is the energy molecule used by all cells to do work. It is a
nucleotide consisting of a nitrogen-containing base (adenine, thymine, cytosine, or guanine), a 5-carbon
sugar, and 3 phosphate groups. ATP is able to store and transport chemical energy within cells. The
LAST TWO phosphate groups (PO4), are joined by HIGH-ENERGY bonds. When these bonds are broken,
energy is released for cells to use and ADP forms. Enzymes help to break and reform these high-energy
bonds.
Adenosine
Phosphate
Phosphate
High-energy bond: Stores much energy
*This energy is released when the bond is
broken*
ATP
Adenosine
Phosphate
Phosphate
Phosphate
Energy
ADP
30. What does ATP stand for?
31. What three main things make up an ATP molecule?
32. How many high-energy bonds does ATP contain?
33. Where are these high-energy bonds found in ATP?
34. What helps weaken these bonds so energy can be released and then later help reform them?
35. When ATP loses a phosphate group __________ is released for cells and a molecule of
_________ forms.
5
In Figure 5, Color the 5-carbon sugar red and Label it RIBOSE. Color and Label the nitrogen-base
dark blue, the 3 phosphate groups yellow, the 2 high-energy bonds green.
FIGURE 5 – ATP MOLECULE
36. What is the energy molecule of the cell called?
37. What macromolecule made by plants is "burned" in the mitochondria?
38. Where is chlorophyll found in the chloroplast?
39. In which part of a plant would you expect to find the most chloroplasts and why?
40. How would the number of mitochondria in an insect's wing compare to the amount found in other
cells in an insect's body? Explain your answer.
41. What are the raw materials for photosynthesis?
42. What product of photosynthesis is used in cellular respiration?
43. What is the advantage of having a folded inner membrane in the mitochondria?
44. What is the energy for photosynthesis?
45. Besides chlorophyll, what other pigments are found in the chloroplasts?
Aerobic Cellular Respiration has 3 main stages: glycolysis, the Kreb’s Cycle, and the Electron
Transport Chain. Glycolysis takes place in the cyctoplasm of the cell and it is the process in which 1
molecule of glucose is broken on half to produce 2 molecules of pyruvic acid. In figure 6, color and label
where Glycolysis occurs light blue. The Kreb’s Cycle and Electron Transport Chain (ETC) takes place
within the mitochondria. The Kreb’s cycle takes the pyruvic acid formed during glycolysis and breaks it
down into CO2 and energy (ATP). The ETC uses the high-energy electrons from the Kreb’s cycle to form
ATP. Color and label the Kreb’s Cycle blue, the ETC green, and the mitochondria yellow.
6
FIGURE 6 - CELLULAR RESPIRATION: AN OVERVIEW
46. Where does Glycolysis take place?
47. What is produced by Glycolysis?
48. How is the ETC fueled?
Step 1:
__________ – Occurs in the cytoplasm
ATP
Enzymes
Glucose
Pyruvate
Pyruvate
Glucose breaks down into 2 pyruvate (2 ATP are also made)
Intermediate step: Pyruvate becomes acetyl CoA (Occurs in the __________)
Pyruvate
Acetyl CoA
7
ATP
Step 2: Citric Acid Cycle (Krebs Cycle) – Occurs in the __________
ATP
Citric Acid
Cycle
Acetyl CoA
ATP
Citric
acid
e- - eeNADH
eStep 3: Electron Transport Chain – Occurs in the __________
NADH
ee
-
-
- e-
e
Electron
transport
chain
Made in Step 2
e-
Electrons move down the
electron transport chain
(series of proteins that pass
the electrons along).
Electrons are caught by
oxygen to make water.
32 ATP are made.
34
ATP
Oxygen we breathe
We use
for
energy
Water
8
If there is no oxygen present, then fermentation occurs after glycolysis. There are 2 main types of
fermentation: alcoholic and lactic acid. Alcoholic fermentation occurs in yeasts and a few other
microorganisms. It is the type of fermentation that allows bread dough to rise and gives us the ability
to make beer from grains. Lactic acid fermentation occurs in our muscles during times of rapid exercise
when the body cannot supply enough oxygen to the tissues. A buildup of lactic acid causes a painful,
burning sensation. Lactic acid is also a waste product of some unicellular organisms and is used in the
production of cheese, yogurt, sour cream, pickles, and sauerkraut.
49. What is fermentation?
50. What are the 2 types of fermentation?
51. Which type is used in the beer-making process?
52. Why do our muscles feel sore after a quick burst of intense activity/exercise?
Only 2 ATP are made
in anaerobic
respiration so it is not
as good as aerobic
respiration (36 ATP)
Glycolysis
Glucose  pyruvate + 2 ATP
Lactic acid fermentation
Pyruvate  lactic acid
Alcoholic fermentation
Pyruvate  ethyl alcohol +
carbon dioxide



Carried out by yeast and some
bacteria
Used in brewing beer, making wine,
and baking bread and cakes

9
Carried out by your muscles when
you’re exercising hard (need ATP)
and can’t get oxygen into you fast
enough (can’t do aerobic
respiration)
Causes muscle cramps and
soreness
Relationship between Photosynthesis & Cellular Respiration – The Circle of Life
Photosynthesis
Respiration
Plants
* use ___________ to make ___________
* take in ___________ ___________
* give off ___________
*___________+ ___________+ sunlight 
___________+ ___________
Animals and plants
* eat ___________to get ___________
* take in ___________
* give off ___________ ___________
*___________+ ___________
__________+ ___________+ ATP
10