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TRANSCRIPT
Name ________________________________________________________ Period __________
BIO A.3 -‐ BIOENERGETICS (BIO.A.3) You should be able to:
1. Describe the role of ATP in biochemical reactions. 2. Describe the fundamental roles of chloroplasts and mitochondria in energy transformations. 3. Compare the basic transformation of energy during photosynthesis and cellular respiration.
Keystone Vocabulary:
adenosine triphosphate (ATP) heterotroph autotroph photosynthesis pigment chlorophyll thylakoid stroma NADP+ light-‐dependent reactions
light independent reactions aerobic anerobic cellular respiration glycolysis matrix Kreb’s cycle NAD+ fermentation calorie
ATP
Chemical Energy and ATP
• Energy = ability to do work • Energy comes in different forms (light, heat, electricity) • Cells need energy to do work • Cell energy comes from ATP (adenosine triphosphate)
• Consists of adenine, a 5-‐carbon sugar and THREE phosphates
• Phosphates are the key to ATP’s ability to store and release energy
Examples of ATP in Action
• Active transport
• Protein pumps in cell membrane need ATP • Movement
• Muscle contractions • Protein synthesis
How do cells release/use energy
from ATP?
• Cells release energy from ATP when the bond between the
second and third phosphate groups is broken • Phosphate released = energy released • ATP minus a phosphate group = ADP
How do cells regenerate/reuse
ATP?
• ADP (adenosine diphosphate) can be
recharged by adding another phosphate group to become ATP again
• Phosphate gained = energy stored • Cells regenerate ATP from ADP by
using energy in food like glucos
Connection between the food you eat and
ATP
• Cells do not keep a lot of ATP • Food is digested and converted into ATP • Different foods give different amounts of ATP
• Carbohydrate = 36 ATP • Lipid = 146 ATP • Proteins = broken down to make other proteins, not
energy!!!! • Plants use photosynthesis to produce the carbs so their cells can
get ATP
Photosynthesis
Light
• Energy • Mixture of different wavelengths (color) • Can be absorbed, transmitted or reflected
• Absorbed energy can be used for photosynthesis • Reflected light is not used for photosynthesis
• Absorbed by pigments (chlorophyll) in plant cell chloroplasts
Light Absorption by
Photosynthetis pigments
Chloroplasts
• Thylakoids = photosynthetic membranes (contain chlorophyll)
• Arranged in stacks called grana • Stroma = space around the thylakoids
PHOTOSYNTHESIS “BIG PICTURE”
• Multi-‐step process • Energy from the sun is used to convert water and carbon dioxide
(reactants) into high energy sugars and oxygen (products • Plants then use the sugars to make ATP (cell respiration…stay
tuned)
PHOTOSYNTHESIS
The role of High-‐Energy Electron
Carriers
1. Chlorophyll absorbs light 2. Absorption of light produces high-‐energy
electrons 3. Electrons picked up by NADP+ to become
NADPH 4. NADPH carries the high-‐energy electrons to
chemical reactions elsewhere in the cell
PHOTOSYNTHESIS
Details
I. Light dependent reactions • INPUT= sunlight, water, chlorophyll • OUTPUT = oxygen (waste), ATP, energy carriers (NADPH) • LOCATION = thylakoid
II. Light Independent reactions (a.k.a. Calvin Cycle)
• INPUT– carbon dioxide, energy carriers from light reactions • OUTPUTS – sugar (carbohydrate) • LOCATION -‐ stroma
Respiration
Chemical Energy and Food
• Autotrophs (plants) make their own food • Heterotrophs (animals) need to consume other organisms as food • Food represents chemical energy
• Fats and carbohydrates are primary sources of energy • Energy stored in food is measured by the calorie
• Amount of energy needed to raise the temperature of 1 gram of water 1 degree Celsius
• The Calorie on food labels is actually a kilocolarie or 1000 calories
•
Mitochondria
Site of Cellular Respiration Similar structure to chloroplast Double membrane Inside of mitochondria = matrix Folds of mitochondria = cristae Increase surface area
Cellular Respiration BIG PICTURE
• The process that converts food energy into cellular energy in the
presence of oxygen • Consists of many chemical reactions and many enzymes
1. Glycolysis 2. Kreb’s cycle 3. Electron transport chain
1. Glycolysis
• Anaerobic (doesn’t need oxygen) • Occurs in the cell cytoplasm • Glucose is “cut” in two • Small amount of ATP is made • Necessary for cellular respiration
• Products of glycolysis are broken down further in the mitochondria
2. Kreb’s Cycle
• Takes place in the mitochondrial matrix • Occurs twice for each glucose molecule that enters glycolysis • Cycle of chemical reactions, each catalzyed by a specific enzyme • Carbon dioxide released as waste • Electron carriers (NADH and FADH2) produced here are used in the
next step
3. Electron Transport Chain (ETC)
4. Occurs across the inner mitochondrial membrane 5. Proteins hand off high energy electrons to pump hydrogen ions
across the inner membrane against the concentration gradient 6. Hydrogen ions, at the end of the chain flow through ATP
synthase, a protein channel equipped with an enzyme to make ATP 7. Oxygen is the final electron acceptor in the ETC
Without oxygen, the ETC does not run, ATP will not be
ATP Production
Totals
• Glycolysis • 2 ATP
• Kreb’s Cycle • 2 ATP
• ETC • 32 ATP
1 glucose = 36 ATP
Fermentation
Fermentation – General
Information
• Recall that glycolysis, an anearobic process produced 2 ATP per molecule of glucose
• If oxygen is present, cellular respiration will come next to produce much more ATP
• If oxygen is not present, fermentation will begin to allow glycolysis to continue
• Fermentation DOES NOT produce ANY ATP • Fermentation is anaerobic (oxygen not needed) • Two types of fermentation
Lactic Acid Fermentation
• Occurs in your muscle cells and some bacteria • Produces lactic acid (which makes your muscles “burn” during
intense exercise) • Yogurt contains bacteria that undergo lactic acid fermentation –
lactic acid gives yogurt its flavor
Alcoholic Fermentation
• Occurs in yeast, some bacteria and certain types of plants • Produces alcohol and carbon dioxide as waste • Cheese, bread, beer and wine are examples of food made by
fermentation Bacteria which go through fermentation help anima
ATP and Exercise
• Stored ATP (only enough for short bursts) • ATP made by lactic acid fermentation (about 90 seconds worth) • ATP produced by cellular respiration (aerobic; requires oxygen)
Photosynthesis Overview
Label: light energy, light dependent reaction, chloroplast, thylakoid, water, oxygen, carbon dioxide, Calvin cycle, sugars, ATP, ADP, NADP, NADPH, stroma
Cell Respiration Overview
Label: pyruvate, NADH, carbon dioxide, Kreb’s cycle, glucose, FADH2, glycolysis, cytoplasm, ATP, mitochondria, matrix, inner membrane, Electron Transport Chain, oxygen