BSC2010C Exam 3

Kinetic Energy

Energy associated with motion (example: riding a bike uphill)

Potential Energy

Energy stored due to location or position (example: when you get to the top of a hill)

What happens to Potential Energy when you being moving again?

Gets converted back to Kinetic Energy

Chemical Energy

Potential Energy that is stored in chemical bonds

What happens when you break down bonds with chemical energy?

Energy is released

1st Law of Thermodynamics

Energy can be transferred or transformed, but cannot be created or destroyed

The total amount of energy in the universe is _____

Constant

2nd Law of Thermodynamics

Every energy transfer or transformation increases the entropy (disorder) of the universe. The transfer/transformation is not 100% efficient

Photoautotrophs

Helps convert sunlight into G3P, including plants, algae, and some bacteria

Heterotrophs

Feeds off of photoautotrophs, including animals (eukaryotes) and most bacteria

What is the conversion of G3P into Glucose?

2 G3P = 1 Glucose

Metabolic Pathways

Begins with a specific molecule (reactant) which is then altered in a series of steps to get a product

Gibbs Free Energy (G)

The amount of free energy available to the cell to do work

Formula of △G

G of Products - G of Reactants

What does △G mean?

The change in free energy

-△G

Gives off energy and is spontaneous

+△G

Requires energy and is non-spontaneous

Endergonic

Reaction that requires energy (△G > 0 (a positive number)). Its products have more potential energy than the reactants

Exergonic

Reaction that releases energy (△G < 0 (a negative number)). Its products have less potential energy than the reactants

Activation Energy

The small input of energy, also known as the Energy of Activation E_A

What does Energy of Activation E_A help regulate?

Exergonic reactions so energy is not wasted

Anabolic

Synthesizes things (builds) and requires energy

Catabolic

Breaks things down (degradative) and releases energy

Anabolic, Needs Energy, +△G, Endergonic, Nonspontaneous

Builds things

Catabolic, Releases Energy, -△G, Exergonic, Spontaneous

Synthesizes (breaks) things down

Enzymes

Binds to specific substrates (reactants) at an active site

What model do enzymes use?

Lock and Key Model

Specificities of Enzymes

Enzymes (unchanged and not consumed) convert substrates into different products

Function of Enzymes

They’re proteins, affected by temperature, pH, salt concentrations, and inhibitors

Competitive Inhibitor

Binds and blocks active site, mimics shape of substrate

Non-Competitive Substrate

Binds to enzyme at a site remote from the active site, alters the shape of the active site, and prevents substrate from binding

Examples of Competitive Inhibitors

Cancer Treatments and Antibiotics

Energy/Reaction Coupling

Exergonic reactions power endergonic reactions

Which of the following correctly describes ATP's energy role in the cell?

Hydrolysis of the third phosphate group releases energy for the cell

Which of the following correctly states the relationship between anabolic and catabolic pathways?

 Anabolic pathways synthesize large, complex organic molecules using the energy derived from catabolic pathways

Which of the following is changed by the presence of an enzyme in a reaction?

The activation energy

First stage of Cellular Respiration

Glycolysis

Who is the main reactant in Glycolysis?

Glucose

What are the reactants in Glycolysis?

• 2 ATP

• 2 NAD+

• Glucose

What are the products of Glycolysis?

• 2 ATP (net) - used right away

• 2 Pyruvate - goes to pyruvate oxidation

• 2 NADH - goes to ETC

Where does Glycolysis take place?

Cytosol

Why does Glycolysis happen?

• To oxidize Glucose into pyruvate (1 glucose makes 2 pyruvates)

• Creates NADH electron carriers

What is the main reactant of Pyruvate Oxidation?

Pyruvate

What are the reactants of Pyruvate Oxidation?

• 2 Pyruvate

• 2 NAD+

• 2 Coenzyme A

What are the products of Pyruvate Oxidation?

• 2 CO2 - exhaled

• 2 Acetyl-CoA - goes to the Citric Acid Cycle

• 2 NADH - goes to the ETC

What stage does Pyruvate Oxidation happen?

Post Glycolysis

Where does Pyruvate Oxidation take place?

Matrix

Why does Pyruvate Oxidation happen?

• To oxidize Pyruvate into Acetyl-CoA

• More NADH electron carriers are created

Who is the main reactant in the Citric Acid/Krebs Cycle?

Acetyl-Coa

What are the reactants for ONE CYCLE of the Citric Acid Cycle?

• 1 Acetyl-CoA

• 1 FAD

• 3 NAD+

What are the products for ONE CYCLE of the Citric Acid Cycle?

• 1 ATP - used immediately

• 1 FADH2 - goes to ETC

• 2 CO2 - exhaled

• 3 NADH - goes to ETC

How many times does the Citric Acid Cycle happen?

Twice

Where does the Citric Acid Cycle take place?

Matrix

When does the Citric Acid Cycle take place?

After Pyruvate Oxidation

Why does the Citric Acid Cycle take place?

• To oxidize Acetyl-CoA into CO2

• To create more electron carriers for NADH and FADH2

What are the main reactants of Oxidation Phosphorylation?

NADH and FADH2

What are the reactants of Oxidative Phosphorylation?

• 10 NADH

• 2 FADH2

• Oxygen

What are the products of Oxidative Phosphorylation?

• 26-28 ATP

• Water

What two make up Oxidative Phosphorylation?

Electron Transport Chain (ETC) and Chemiosmosis

What phase does Oxidative Phosphorylation take place?

The last

Where does Oxidative Phosphorylation take place?

Prokaryotes → Plasma Membrane

Eukaryotes → Inner Membrane

NADH+ deposits electrons into which complex?

Complex 1

FADH2 deposits electrons into which complex?

Complex 2

Electrons go out of the matrix into the inner membrane through which form of transport?

Active Transport

Electrons come back into the matrix from the inner membrane through the ATP Synthase using which form of transport?

Passive

What is the final electron acceptor?

O2 (oxygen)

Why does Oxidative Phosphorylation happen?

To make ATP

What are the two types of Fermentation?

Alcohol and Lactic Acid

What reactant plays the largest role in Fermentation?

Pyruvate

What are the products of Alcohol Fermentation?

Ethanol and 2 ATP

What are the products of Lactic Acid Fermentation?

Lactate and 2 ATp

When does fermentation occur?

After Glycolysis

Where does Fermentation take place?

In the Cytoplasm

Since Fermentation repeats itself, do the products continue through Cellular Respiration?

No, it does not

Which phases of cell respiration produces ATP via substrate level phosphorylation?

Glycolysis and the Citric Acid Cycle

What is substrate level phosphorylation?

enzyme catalyzed; a substrate with a phosphate and an ADP bind to the active site of an enzyme, the enzyme catalyzes the removal of the phosphate from the substrate and adds it to the ADP to make ATP

What is oxidative phosphorylation?

ATP is generated by the addition of a free (i.e., unbound) inorganic phosphate to ADP

Although glucose is the primary fuel source for cellular respiration, what other molecules can also be used?

Proteins and Lipids

Oxidation

Loses an Electron

Reduction

Gains an Electron

Who is the main reactant in the Light Reaction?

Sunlight

What are the reactants of Light Reaction?

• Light Energy

• Water

• ADP

• NADP+

What are the products of Light Reaction?

• ATP - goes to the Calvin Cycle

• NADPH - goes to Calvin Cycle

• Oxygen - releases from the plant into the environment

What stage does the Light Reaction take place in Photosynthesis?

1st Phase; only during the day

Where does the Light Reaction take place?

Thylakoid Membrane

Why does Light Reaction happen?

To convert light energy into chemical energy (ATP) and to make electron carriers for NADPH

What is the main reactant in the Calvin Cycle?

Oxygen

What are the reactants of the Calvin Cycle?

• 9 ATP - from the light reactions

• 6 NADPH - from the light reactions

• 3 CO2 - absorbed from atmosphere

What are the products of the Calvin Cycle?

• 9 ADP

• 6 NADP+

• 6 G3P (a 3 carbon sugar)

Where does 1 of the 6 G3P go towards?

Building sugar, starch, and cellulose

Where do 5 of the 6 G3P go towards?

Recycled back to RuBP in the regeneration phase

When does the Calvin Cycle take place?

After the light reaction at day or night

Where does the Calvin Cycle take place?

In the stroma

Why does the Calvin Cycle happen?

To make G3P

What is the equation for Photosynthesis?

Light Energy + 6CO2 + H2O → C6H12O6 + 6O2

How do plants get their color?

When light shines on a plant, the color that is not being absorbed/reflected, causing the plant to be that color

What happens when a molecule of chlorophyll absorbs a photon of light?

It becomes excited, releasing heat and photons, giving off energy

Photosystem II

Chlorophyll a (P680), the first photosystem

Photosystem I

Chlorophyll a (P700), the second photosystem

What does Photosystem II charge?

Photosystem I via the electron transport chain