Transcript CH: 7 - PBworks

CH: 7
The Working Cell:
Energy from Food
7.1 Sunlight Powers Life
Compare and contrast how
autotrophs and heterotrophs obtain
food.
 Compare:
 Both get energy from
organic compounds
 Contrast:
More Info:
 Autotrophs convert
inorganic molecules
into organic molecules
 Autotrophs make their
 On land= mostly plants
own organic compounds
 In water= algae
 Heterotrophs get organic
 Autotroph=Producer
compounds by consuming
 Heterotroph=Consumer
autotrophs
Explain how cellular respiration
harvests the energy in food.
 Cellular Respiration:
 Chemical Process
 Changes organic compound into ATP
 Requires oxygen
 ATP is used by cells for:
 energy
 Which cells?
 ALL CELLS perform cellular respiration
Key Terms
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autotroph
photosynthesis
producer
heterotroph
consumer
cellular respiration
Concept Check 7.1
 1. Define autotroph and heterotroph, and
give an example of each.
2. Explain the role of food (glucose) in
both photosynthesis and cellular
respiration.
3. Explain how life on Earth depends on
the sun.
7.2
Food Stores Chemical Energy
Distinguish between kinetic and
potential energy.
 Kinetic Energy:
 Energy of anything that is in motion
 Thermal Energy= energy from
Moving particles (heat)
 Potential Energy:
 Stored energy due to position
Explain what chemical energy is and
how cells release it from food.
 Chemical energy=
 energy stored in the
bonds of organic
compounds
 Energy is released by:
 Cellular respiration
 Is a chemical reaction
 Requires oxygen
 Cells get 40% of energy
from compound, 60% is
lost as heat.
More Info:
 Remember…
 Lipids
 lots of energy
 Carbs =
 Sugars=
 shorterm, small
amounts of energy
 Starches=
 long term energy
Define calories and kilocalories as
units of energy.
 Calories
 amount of energy
required to raise the
temperature of 1
gram (g) of water by 1
degree Celsius (°C).
 Kilocalorie =
1000 calories
 More Info:
 “Calories” in
conversation is
usually a kilocalorie
7.2 Key Terms
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kinetic energy
potential energy
thermal energy
chemical energy
calorie
Concept Check 7.2
 1. Identify the types of energy you have
at the top of a staircase and as you go
down the stairs.
2. Explain how your body uses chemical
energy during exercise.
3. If a food has 10 kcal of energy, how
much could it increase the temperature of
100 g of water?
7.3
ATP Provides Energy for Cellular Work
How ATP Packs Energy:
 ATP = adenosine
triphosphate
 The tail end of 3 P
holds the energy
 When 1 P is removed,
energy is released =
ADP
 ATP is recycled by
adding a P back to
tail
ATP and Cellular Work
 3 Major types of work
 Chemical
 Mechanical
 Transport
ATP Cycle
 Cycle works super
fast
 Like a rechargeable
battery
7.3 Key Term
 ATP
Concept Check 7.3
 1. In what way is ATP like a compressed
spring?
2. List three main types of cellular work.
3. What is the source of energy for
regenerating ATP from ADP?
7.4
Electrons “fall” from food to oxygen
during cellular respiration
Cellular Respiration Equation
Cellular Respiration
 Aerobic process that releases chemical
energy (from organic compounds)
 Aerobic= requires oxygen
 Respiration & “Breathing”
 Breathing supplies cells with O2 and
removes CO2
 Respiration uses the O2 and gives off CO2
Falling Electrons
 As electrons fall from electron cloud
(energy levels) towards nucleuspotential energy is release
 Oxygen is a strong electron acceptor
(pulls electrons towards its nucleus)
 Hydrogen and Carbon and weak, lose
electrons to Oxygen’s pull
Electron Transport Chain
 Electron Transport Chain= series of
atoms that transfer electrons
 Each transfer releases a small amount of
energy
 Releases energy from large molecule in
small, slow steps
7.4 Key Term
 Aerobic
 Electron Transport Chain
Concept Check 7.4
1. Compare and contrast breathing and
cellular respiration.
2. List the reactants and products in cellular
respiration.
3. What is meant by the "falling" of electrons
to oxygen? How does this process release
energy?
4. How does an electron transport chain
result in the gradual release of energy
stored in glucose?
7.5
Cellular respiration converts energy
in food to energy in ATP
Structure of the Mitochondria
 Mitochondria
 Double membrane organelle
 Inner membrane has many folds
 Large surface area provides sites for C.R.
 Middle contains matrix
Cellular Metabolism
 Metabolism= all cellular processes
combined together
 C.R. , diffusion, photosynthesis, etc.
 Cellular Respiration consists of a series
of chemical reactions (3 Stages)
 Glycolysis
 Krebs Cycle
 Electron Transport
Step 1: Glycolysis
 Occurs outside mitochondria
 Splits sugar (glucose)
 Adds 2 ATPs to glucose
 Energy to start the process
 Results in:
 4 ATP
 2 Pyruvic Acid
Step 2: Kreb’s Cycle
 Occurs inside mitochondria
 Pyruvic acid is converted to Acetyl CoA
 1 cycle will produce 1 Acetyle CoA
 Cycles twice
 Produces 2 ATPs and 4 CO2
Step 3: Electron Transport Chain
 Final Stage
 2 Parts
 Electron Transport Chain
 ATP Synthase- produces the ATP
ATP Synthase
 Protein Structure
 Converts up to 34 ATPs from each
glucose molecule
Summary:
 Cellular Respiration makes ATP
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Glycolysis= 4 ATP – 2ATP = gain of 2 ATP
Krebs = 2 ATP
ATP synthase = 34 ATP
Total of 38 ATP per glucose molecule
7. 5 Key Terms
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metabolism
glycolysis
Krebs cycle
ATP synthase
7.5 Concept Check
1. How is the mitochondrion's structure
suited to its function?
2. Identify the three stages of cellular
respiration, where in the cell each takes
place, and how many ATP molecules it
produces.
3. Summarize the use and production of
ATP in one cycle of cellular respiration.
7.6 Fermentation
When does it occur?
 When O2 is unavailable or supply is
insufficient
 ATP demand is higher that supply
produced by Cellular Respiration
Fermentation in Muscle Cells
 Produces ATP through glycolysis
 Yields 2 ATPs
 Lactic Acid is a waste product
Fermentation by Microorganisms
 Occurs in anaerobic conditions
 Produces ATP
 Alcohol is waste product (instead of lactic acid)
 Utilized by humans to make:
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Bread
Wine/alcoholic drinks
Yogurt
Cheese
Soy sauce
sauerkraut
7.6 Key terms
 fermentation
 anaerobic
Concept Check 7.6
 1. How is fermentation different from
cellular respiration?
2. Describe one example of how
fermentation in microorganisms produces
human foods.
3. What is the waste product of
fermentation in your muscle cells?