bio 160 exam 2 utk

Energy

is the capacity to do work and cause change.

How is work accomplished?

work is accomplished when an object is moved against an opposing force, such as friction.

what are the two kinds of energy

kinetic and potential energy

kinetic energy

is the energy of motion

what is the molecular level of kinetic energy

thermal energy

potential energy

is energy that an object possess as a result of its location

- stored energy as a result of location or structure

what is the molecular level of potentional energy

chemical energy is stored in bonds

first law of thermodynamics

-energy is conserved

-energy cannot be created or destroyed

-energy can only be transferred and transformed

what do covalent bonds equal?

energy

chemical energy

is potential energy because of its energy available for release in a chemical reaction.

where is energy contained?

within the bonds of a molecule

what happens when bonds are broken?

energy is released

what happens when bonds are created?

energy input is required

amount of potential energy in an electron is based on

its position relative to positive and negative charges

electrons closer to negative charges and farther from positive charges

have higher potential energy

Molecular potential energy

Is a function of electron configuration and position

exothermic reactions

= catabolic

exothermic reaction...

-releases energy

-bonds are broken

- products have less potential energy than reactants

endothermic

=anabolic

endothermic reaction..

-heat energy is taken up

-bonds are created

-products have higher potential energy than recatants

When energy is released, it is spontaneous

an exergonic reaction

a reaction that requires energy input to occur is not spontaneous

- an endergonic reaction

Entropy

amount of disorder or "randomness"

-when the products of a chemical reaction becomes less ordered than the reactant molecules

-entropy increases

second law of thermodynamics

total entropy always increases in an isolated system

For most reactions to proceed

one or more chemical bonds have to break and others have to form

when the concentration of reactants is high

More collisions should occur and reactions should proceed more quickly

energetic coupling

-Between exergonic and endergonic reactions

-Allows chemical energy released from one reaction to drive another reaction

a living organism produces thousands of endergonic and exergonic chemical reactions

all of these combined is called metabolism

metabolic pathway

is a series of chemical reactions that either break down a complex molecule or build up a complex molecule

Reduction-oxidation reactions (redox)

are chemical reactions that involve electron transfer

When an atom or molecule gains an electron

it is reduced

reduction

gain of one or more e- and a hydergon ion (H^+)

when an atom or molecule looses an electron

it is oxidized

Oxidation

the loss of one or more electrons

oxidation and reduction events are always coupled

If one atom loses an electron, another has to gain it

Electron donors are always paired with electron acceptors

during a redox reaction, electrons can

Be transferred completely from one atom to another

Simply shift their position in covalent bonds

Each electron transferred from one molecule to another during a

redox reaction

- is usually accompanied by a proton H^+

- reduced molecule

reduced molecule

Gains a proton and has higher potential energy

oxidized molecule

loses a proton and has lower potential energy

reduction often

adds Hs

oxidation often

removes hs

nicotinamide adenine dinucleotide (NAD+)

is reduced to form NADH

NADH

reality donates electrons to other molecules

is called An electron carrier

has reducing power

ATP

(adenosine triphosphate) main energy source that cells use for most of their work

what is ATP composed of

it is composed of an adenine ring (nitrogenous base) , a ribose (5 carbon sugar), and three phosphate groups

atp is the cellular currency for what

energy

what provides the fuel for most cellular activities?

ATP

what has a high potential energy and allows cells to do work

ATP

what does ATP work by

phosphorylating target molecules

transferring a phosphate group

why do the electrons in ATP have high potential energy?

4 negative charges in its 3 phosphate groups repel each other

hydrolysis

of the bond between the two outermost phosphate groups results in...

what does it result in

in formation of ADP and pi (inorganic phosphate, H2PO4-)

in a highly exergonic reaction

in the transfer of the released phosphate group to a protein

ATP is a renewable source of energy

for the cell

energy released during ATP hydrolysis

Is transferred to a protein during phosphorylation

Usually causes a change in the protein's shape

clustered negative charges raise what

the potential energy of linked phosphate groups

How does ATP drive endergonic reactions?

energetic c

when a protein is phophorylated the exergonic phosphorylation reaction is

paired with an endergonic reaction

reactant molecules in an endergonic reaction are

phosphorylated

the free energy released during phosphorylation is

coupled to the endergonic reaction

all organisms have what

cellular respiration

all organisms use glucose to build what

fats, carbs, and other compounds

glucose is used to make ATP through

cellular respiration or fermentation

cellular respiration produces ATP from

A molecule with high potential energy—usually glucose

carbon atoms of glucose

are oxidized to form carbon dioxide

Oxygen atoms in oxygen are _______ (reduced/oxidized) to form what?

reduced to form water

Glucose is oxidized through?

A long series of carefully controlled redox reactions

The resulting change in free energy is used to

synthesize ATP from ADP and Pi

cellular respiration

any set of reactions that produces ATP in the presence of oxygen (Aerobic process)

what are the 4 phases of cellular respiration

glycolysis, pyruvate processing, citric acid cycle, electron transport chain

Glycolysis

6 carbon glucose is split into 2,

3 carbon pyruvate molecules

pyruvate processing

pyruvate is oxidized to form acetyl CoA

citric acid cycle

acetyl CoA is oxidized to CO2 (the remaining bonds are broken)

- the electrons are removed by redox reactions that pass the electrons to an electron acceptor (NAD^+ OR FAD^+ is reduced)

electron transport and chemisomosis

-NADH and FADH2 brings the electrons to the electron transport chain and are therefore oxidized when they donate the electrons to the electrons to the electrons transport chain

- the electrons flow down the chain, powering the production of ATP

For ATP production, cells

First use carbohydrates

Then fats

And finally proteins

proteins, carbohydrates, fats can all furnish

substrates for cellular respiration

Glycolysis is

a series of chemical reactions

the first phase of glucose oxidation

Where does glycolysis occur?

cytosol

in glycolysis

glucose is broken/split into two molecules of pyruvate

-the potential energy realeased is used to phosphorlyate ADP to ATP

substrate-level phosphorylation occurs when

atp is produced by the enzyme- catalyzed transfer of a phosphate group from a substrate to ADP

-atp is produced in glycolysis and the citric acid cycle

oxidative phosphorylation occurs in

-an electron transport chain

a proton gradient provides energy for ATP production

the membrane protein ATP synthase uses energy to

phosphorylate ADP TO ATP

feedback inhibition

when an enzyme in a pathway is inhibited by the end product of that pathway

cells stop glycolytic reactions

when Atp is abundant

Can conserve their stores of glucose for

times when ATP is scarce

Pyruvate produced during glycolysis is

transported from the cytosol into the mitochondria

what process occur in the mitochondria

pyruvate processing, citric acid cycle and etc

the citric acid cycle can be turned off at multiple points

via several different mechanianims of feedback inhabitation

what does citric acid start with and end with

starts with acetyl COA and ends with CO2

the potential energy that is relases is used

to produce NADH, FADH2, AND ATP

When energy supplies are high...

The cycle slows down

what levels are inhibited by high levels of potential energy

1, 2, and 3

during the fourth step in cellular respiration

the high potential energy of the electrons carried by NADH and FADH2 is gradually decreased as they move through a series of redox reactions

the proteins involved in these reactions make up

an electron transport chain

What is the final acceptor in the ETC?

O2-oxygen

what does the transfer of electrons along with proton to oxygen form?

water

most of the electron transport chain molecules are

proteins containing chemical groups that facilitate redox reactions

all but one of these proteins are

embedded in their inner mitochondria memberane

lipid soluble ubiquinone

can move throughout the membrane

electron transport chain pumps protons

from the mitochondrial matrix to the mitochondrial intermembrane space.

the proton motive force from this electrochemical gradient

-can be used to make ATP

-in a process known as chemiosmosis