JMU Bio 140 Exam 3

Acetyl-CoA enters into what?

citric acid cycle

What do all cells require?

-a way to encode/transmit information

-a membrane separating inside from out

-energy

What does Adenosine Triphosphate (ATP) do?

provides energy in a form that all cells can readily use to perform the work of the cell

Where does the molecule ATP contain energy?

in its chemical bonds

What part of ATP has high energy potential?

phosphate group

All organisms are split into what two basic categories?

-phototrophs

-chemotrophs

Phototrophs get energy from where?

sunlight

Chemotrophs get energy from what?

chemical compounds

What are the two types of ways organisms receive carbon?

-autotrophs

-heterotrophs

Autotrophs receive carbon from where?

inorganic sources

Heterotrophs receive carbon from where?

organic compounds

Define metabolism

building up and breaking down of carbon sources

What are the two types of metabolism?

-catabolism

-anabolism

Does catabolism produce or require ATP?

produces

Does anabolism produce or require ATP?

requires

What are examples of work which metabolism helps with in the cell?

-synthesizing DNA, RNA, and proteins

-moving vesicles in a cell

-pumping substances across membranes

Define kinetic energy

energy in motion

What are forms of kinetic energy?

-movement

-light

-electricity

-thermal energy

Define potential energy

stored energy

Potential energy depends on what two things?

structure and position

Potential energy can be released when what happens?

structure or position is changed

Chemical energy is a form of what type of energy?

potential

Strong bonds have ________ potential energy than weak bonds.

less

Why are phosphate bonds so weak?

the negatively charged oxygens repel one another

What is the first law of thermodynamics?

energy is neither created nor destroyed, it simply changes from one form to another

How would you calculate the kinetic energy of a ball which rolled down the steps?

potential energy at the top minus the potential energy at the bottom of the stairs

How is energy released in electrons?

heat or lights

Define the second law of thermodynamic

the amount of disorder (entropy) increases when energy is transformed -> some energy is unable to do work

Define entropy

A measure of disorder or randomness (energy not available to do work)

In the universe, the degree of disorder can only _________?

increase

Define gibbs free energy

energy available to do work

∆G= what

G products-G reactants

If the products have more free energy than the reactants the ∆G is what?

positive

Endergonic reaction graph

If the products have lesfree energy than the reactants the ∆G is what?

negative

Exergonic reaction graph

Define ∆H

enthalpy - chemical energy in bonds

Define ∆S

entropy

What is the equation for ∆ change in a system?

∆H=∆G - T∆S

Is an endergonic reaction spontaneous or not?

non-spontaneous

Is an exergonic reaction spontaneous or not?

spontaneous

If your ∆G is positive what is your ∆S and ∆H?

-∆S and ∆H

If your ∆G is negative what is your ∆S and ∆H?

+∆S and -∆H

Is ∆G positive or negative in an anabolic reaction?

positive

Is ∆G positive or negative in an catabolic reaction?

negative

What type of reaction is hydrolysis?

exergonic

Define energetic coupling

spontaneous reaction drives a non-spontaneous reaction

Hydrolysis of what can drive the synthesis of ATP?

phosphoenolpyruvate

What are the two things enzymes do?

-speed up reactions

-selects which reaction will occur

What can enzymes not do?

make a non-spontaneous reaction spontaneous

What are the ways which enzymes lower activation energy?

-align substrates making a reaction possible

-alter ionic structure of substances

-put physical stress on substrates, forcing to transition state

An active site of an enzyme binds to what?

substrate

How are substrate interactions of an enzyme stabilized?

non-covenant interactions

Define activators

increase activity of enzyme

Define inhibitors

decrease activity of enzymes

What are the two types of enzyme inhibitors

-irreversible inhibitors

-reversible inhibitors

What are the two types of reversible inhibitors?

competitive and non-competitive

Where do competitive inhibitors bind

the active site

Where do non-competitive inhibitors bind

second (allosteric) site

How does an non-competitive inhibitory inhibit?

changes the shape of the enzyme

Define feedback inhibition

product from end of pathway turns off enzyme at start of pathway

Feedback inhibition will trigger what type of change?

confirmational change

What is the goal of cellular respiration?

-breakdown of organic molecules

-convert energy into ATP

What is the cell respiration formula?

C₆H₁₂O₆ -> 6CO₂ + 6H₂O +ATP

About how many ATP are make from a single molecule of glucose?

32 ATP

What percent of energy is harnessed in cellular respiration?

34%

What are the two ways which ATP is made in the cell?

-substrate-level phosphorylation

-oxidative phosphorylation

Define substrate-level phosphorylation

two coupled reactions carried out by a single enzyme -> phosphate group is added to ADP from an enzyme's substrate

Substrate-level phosphorylation produces what percent of ATP in cellular respiration?

12%

Define oxidative phosphorylation

a series of redox reactions store chemical energy in the form a proton gradient which is used to drive phosphorylation of ADP. Oxygen is the final election accept

Oxidative phosphorylation produces what percent of ATP in cellular respiration?

88%

The loss of electron is what?

oxidation

The gain of electron is what?

reduction

What are the important molecules for cellular respiration?

NAD+, NADP+, FAD

What is the reduced form of NAD+?

NADH

What is the reduced form of NADP+?

NADPH

What is the reduced form of FAD?

FADH₂

The more carbon or hydrogen atoms bonded to carbon the more ________ that carbon is.

reduced

The more oxygen atoms bonded to carbon, the more _______ that carbon is.

oxidized

What is oxidized in the cellular respiration reaction?

C₆H₁₂O₆

What is reduced in the cellular respiration reaction

O₂

What are the four stages of cellular respiration?

-glycolysis

-pyruvate oxidation

-citric acid cycle

-oxidative phosphorylation

What are other names for the citric acid cycle?

TCA or Krebs cycle

What occurs in the first two stages of cellular respiration?

fuel molecules are partially broken down, producing ATP and electron carriers

What occurs in stage 3 of cellular respiration?

fuel molecules are fully broken down to CO₂, producing ATP and electron carriers

What occurs in stage 4 of cellular respiration?

electron carriers donate electrons to the electron transport chain, leading to the synthesis of ATP

Where does glycolysis occur in the cell?

cytosol

Where does the pyruvate oxidation occur in the cell?

matrix of mitochondria

Where does the citric acid cycle occur in the cell?

matrix of mitochondria

Where does the oxidative phosphorulation occur in the cell?

inner mitochondrial membrane

How many reactions occur in the three stages of glycolysis?

10

What are the three stages of glycolysis?

-initial investment of ATP

-cleavage of 6-carbon sugar in half

-energy generation

How many ATPs are invested into glycolysis?

2

What occurs in stage 1 of glycolysis?

-consumes 2 ATP

-making molecules less stable, trapping in the cell

What occurs in stage 2 of glycolysis?

split molecules into two halves rearrange one

What occurs in stage 3 of glycolysis?

-NADH producing reaction

-First ATP producing reaction

-Second ATP producing reaction

What is the net yield of glycolysis?

2 ATP, 2 NADH, 2 puruvate

What are the two ways which pyruvate and NADH are metabolized?

fermentation & TCA cycle

Reactions in the mitochondria require what?

O₂

Pyruvate is oxidized to what?

Acetyl CoA