Chapter 8 Cellular Energy

8.1 Cells and the Flow of Energy

8.2 Metabolic Reactions and Energy Transformations

8.3 Metabolic Pathways and Enzymes

8.1 How Organisms obtain energy

Objectives Summarize two _________ of thermodynamics. Compare and contrast __________________ and

heterotrophs. Describe how ATP works in a _______________.

Transformation of Energy

Energy: The ability to do _______________ Thermodynamics: study of the flow &

transformation of ____________________ in the universe.

Laws of Thermodynamics Energy cannot be __________________ or

destroyed, but it can be changed from one form to another. Potential Kinetic Law of conservation of ____________________

Energy cannot be changed from one form to another without a _____________ of usable energy. Often times, it is lost in the form of _____________.

(thermal)

Autotrophs & Heterotrophs

All organisms need energy Nearly all energy for life comes from the __________ Autotrophs make their own _______________. Chemoautotrophs use inorganic substances for an energy

source ________________autotrophs use the sun Heterotrophs need to ingest food (other organisms) to

obtain __________________

Metabolism Metabolism: all the ___________ reactions in a cell Metabolic pathway: product from one becomes the

__________________ for the next (all enzymatic!) Catabolic: release energy, break down big molecules

into ________________ ones Anabolic: use ________________ energy by

catabolic to build bigger molecules from smaller ones

Photosynthesis

Anabolic Light energy + carbon dioxide + water glucose

+ oxygen Glucose can be __________________ to other

organisms when consumed as food

Cellular Respiration

Catabolic Organic molecules are _________________ down to

release energy for use by the cell Oxygen is used to break them down producing

________________________ and water

ATP: The Unit of Cellular Energy Types of energy: mechanical,

thermal, chemical, ____________ Adenosine triphosphate:

__________: is the most important biological molecule that provides chemical energy.

Adenine base, a ribose _______________, and three phosphate groups

Energy is stored in that phosphate bond and is released. ATPADP

8.2 Photosynthesis

Objectives: Summarize the two ___________________ of

photosynthesis. Explain the function of a ___________________

during the light reactions. Describe and diagram __________________

transport.

Photosynthesis Light energy converted to __________________ energy 6CO2 + 6H2O C6H12O6 + 6O2

Two phases: Light-_______________________: light e is absorbed

and converted into chemical e in the form of ATP and NADPH

Light-__________________________ : ATP and NADPH are used to make glucose

Glucose can be joined to other simple carbs, such as starch.

Can also be made into proteins, lipids, and nucleic acids

Phase One: Light Reactions Absorb light and make NADPH and ATP Chloroplasts: capture __________________ in

photosynthetic organisms Mainly found in the cells of ________________ Thylakoids: flattened saclike membranes that are

arranged in ________________________. Grana: the stacks Light dependent _________________ take place

in thylakoids Stroma: fluid-filled space outside the grana Light independent reactions take place in stroma

Pigments Pigments: light-absorbing colored molecules found in

the thylakoid _____________________ of chloroplasts

Chlorophylls are the major light-absorbing _______________________ in plants.

Chlorophyll a, chlorophyll b are the most common Absorb most strongly in the violet-blue region and reflect

green Carotenoids: absorb in the ____________ and green

regions and reflect in the yellow, orange, and red regions.

Fall colors are the result of chlorophyll molecules breaking down and allowing the other pigments to show through.

Electron Transport Light energy absorbed by photosystem II is used to split

water. Oxygen is released, protons (H+ ions) stay in the thylakoid space and an activated electron enters the electron transport ______________________.

As electrons move through the membrane, _____________ are pumped into the thylakoid space.

At photosystem I, electrons are re-energized and NADPH is formed.

Chemiosmosis: protons accumulate in the thylakoid space, creating a ____________________________ gradient.

When protons move across the thylakoid membrane through ATP synthase, ADP is converted to ATP.

Phase Two: The Calvin Cycle NADPH and ATP are not stable enough to store

energy for a ___________________________. Carbon fixation: carbon ________________

combines with 5-carbon compounds to make 3-carbon molecules called 3-phosphoglycerate.

ATP and NADPH give their stored energy to form glyceraldehyde 3-phosphates.

Two glyceraldehydes leave to make _____________. Rubisco (enzyme) converts the remaining G3P

molecules back to 5-carbon molecules so that the cycle can continue.

Alternative Pathways C4 plants

Minimizes water __________________ Use four-carbon rather than three-carbon molecules Stoma do not open on ___________________. Special

cells take the carbon compounds so carbon dioxide can enter and photosynthesis can occur.

CAM plants Occurs in plants that live in the _________________

(minimize water loss), salt marshes, and where water is minimal

Only open stoma at ______________. During the day, carbon dioxide is released from these

compounds and enters the Calvin cycle.

8.3 Cellular Respiration

Objectives: Summarize the stages of ___________________

respiration. Identify the role of ____________________

carriers in each stage of cellular respiration. Compare alcoholic fermentation and lactic

_______________ fermentation.

Cellular Respiration

Two main parts: Glycolysis and aerobic respiration

Anaerobic processes: no ______________ required

Aerobic respiration: includes Krebs __________ and electron transport.

Aerobic processes require oxygen Equation is the _____________ of photosynthesis

Glycolysis

Glucose is broken down in ________________ via glycolysis

First, two ATP are used to break _____________ into two G3P.

Then, each of these 3-carbon compounds give phosphates and H+ ions to produce 2 ATP and one NADH.

Result: 2 NADH and 4 ATP – 2 ATP = 2 ATP and two pyruvates for Krebs cycle

Krebs Cycle Pyruvate converted to acetyl-CoA before cycle

begins, ______________________released. Pyruvates are transported to mitochondrial matrix

in the presence of ___________________. Acetyl-CoA combines with 4-carbon compound

to make citric ___________________. Citric acid broken down, releasing _________

carbon dioxides, one ATP, three NADH, and one FADH2.

Results in a four-carbon sugar that can combine with acetyl-CoA to turn it again.

Electron Transport This is when NADH and FADH2 from the Krebs cycle

convert ADP to ___________________. Electrons move along the mitochondrial membrane through

________________________. The NADH and FADH2 are converted to NAD+ and FAD,

the H+ ___________________ released into m. matrix. As H+ ions come back through ATP synthase, ADP is

converted to ATP. One molecule of glucose yields 36 ATP via cellular

respiration.

Anaerobic Respiration Aka fermentation. Fermentation: occurs in the __________________

and regenerates the cell’s supply of NAD+ while making some _________________.

Lactic acid fermentation and alcohol fermentation are the two types

Lactic acid: skeletal _________________ produces lactic acid during strenuous exercise when not getting oxygen; results in cramping…eat bananas!

Alcohol: Yeast and some bacteria. Results in ethyl alcohol and carbon dioxide.

Sister Processes The products from one reaction are the

____________________ for the other…photosynthesis and cellular respiration.