bio second exam

energy is the ability to do what?

the ability to do work or bring about change

_____ and ____ need a constant supply of energy.

cells and organisms

what are 3 things that energy allows?

1. growth
2. metabolism
3. reproduction

life on earth is dependent on ______ energy


what provides nutrients for the majority of other organisms?


Energy occurs in two forms:
___ energy is the energy of motion, while ____ energy is stored energy.


how is chemical energy stored?

in chemical bonds

______ ______ is energy of motion as in walking

mechanical energy

_____ energy comes from the sun


two laws of thermodynamics:

1. energy cannot be created or destroyed, but it can be changed from one form to another
2. energy cannot change from one form to another without a loss of usable energy

A leaf cell ___________.
it uses but does not create solar energy to form carbohydrates and some energy is lost as heat, but none is destroyed


What does a moose cell use for movement?

cellular respiration and the energy from carbs to power their muscles

______ released from cellular respiration or photosynthesis dissipates into the environment.
this type of energy is NOT useful- it is not available to do work


What does the second law of thermodynamics state?

No process requiring energy conversion is ever 100% efficient so every energy conversion makes makes the universe less organized

______ refers to the relative amount of disorganization


The processes used by cells are energy ________.


_______ processes require an input of energy from an outside source.
for example: living organisms depend on a constant supply of energy from the sun


what example of energy is more organized, with more potential energy and less stability (entropy)?


what example of energy is less organized, with less potential energy, and more stability?

carbon dioxide and water

An unequal distribution of ___ ions makes energy more organized, more potential energy, and less stable.


an equal distribution of ______ ions makes energy less organized, less potential energy, and more stable.


____ is the sum if all the chemical reactions that occur in a cell.
it includes the breaking down and building up of molecules.
_______= breaking down the molecules
_______=building up the molecules


In the reaction A + B --> C + D, the reactant(s) is/are ______________.
what are the products?

the reactants are participating in the reaction (A +B) and the products are substances that form as a result of a reaction (C+D)

_____ ______ is the amount of energy available.
how can you calculate the change in this?

free energy
you can calculate the change by subtracting the free energy of the reactants from that of the products

______ _____ are ones where energy is released .
the types of products have less free energy than reactants and are spontaneous

exergonic reactions

_____ ______ require an input of energy.
their products have more free energy than reactants and require a certain input of energy to run

endergonic reactions

What does ATP stand for and what is it?

it stands for adenosine triphosphate and its the energy that comes from ADP and is used as energy for cells

ATP is unstable and has a high amount of _____ ______

potential energy

_____ ______ are a series of linked reactions.
they may connect through common intermediates.
metabolic energy is captured and utilized more easily because it is released in _______

metabolic pathways

______ are typically proteins that function as catalysts to speed up chemical reactions but are not used up by the reaction.
They do not cause reactions to go forward, ____ ____ determines which reactions go forward

free energy

reactants are also called ______


energy of activation (Ea):
this is energy that must be added to cause reactants to react with one another.
give an example:

needing a match to start wood burning

enzymes lower the _____ of ______ but do not change the end result or increase the reaction rate

energy of activation

an enzyme binds with a _____ to form a ______.


the ____ ______ is a small part of the enzyme that complexes with the substrate.

active site

______ is when the substrate is broken down to smaller products. After this, the substrate binds to active site on the enzyme and ______ takes place, where the substrates are combined to produce to a larger product.


_____ _____ ______:
-substrate and active site shapes do not fit together like a lock and key
-the active site undergoes a slight change in shape to accomodate substrate binding and the products are released when the reaction is complete.

induced fit model

each reaction requires a specific _____.
these are often named for their substrate because they only complex with their substrate


______ reactions proceed much more rapidly.
for example, breakdown of hydrogen peroxide is 600,000 times faster when the enzyme catalase is present.


Enzyme activity increases as ____ _____ increases.
There are then more collisions between enzymes and these and they fill active sites causing more product to form.
When is the maximum rate achieved?

substrate concentration
when all the active sites of an enzyme are filled with substrate

enzyme activity also increases as the ______ rises, and the decrease of it decreases enzyme activity.
Causing more effective collisions between substrates and enzymes, but after a certain point, the enzyme activity levels out.
What does it mean when enzym

enzymes become denatured when they lose structure and function once the temperature gets high

the body temperature of an ectothermic animal (lizard) often ______ rates of reactions while the body temperature of endothermic animals (polar bears) _______ rates of reactions.


Each enzyme has an optimal ____ at which its activity is the highest.
the structure of enzymes depend on this and extremes of it can denature an enzyme.
the preferred _____ of enzyme varies based on its location. (typsin and pepsin)


Not all enzymes are needed all the time in a cell.
Cells regulate ______ by regulating which enzymes are active.
_____ producing enzymes can be turned on and off to regulate the concentration of enzymes.
An enzyme can be modified by adding or removing ___


_____ ______ occurs when substrate cannot bind to the active site of an enzyme.
the activity of almost every enzyme in a cell is regulated by feedback inhibition.

enzyme inhibition

an example of the simplest type of ____ ______:
when a product is abundant it binds to enzymes active site and blocks further production. when a product is all used up, it is then removed from the active site and the enzyme begins to function again.

enzyme inhibition

a more complex example of _____ ______:
Product binds to a site other than the active site, which changes the shape of the active site.
poisons, cyanide, and penicillin are examples of these.

enzyme inhibition

What is the difference between an enzyme having an active pathway and an inactive pathway?

active pathways allow enzymes to bind on active site while inactive pathways cannot bind due to the altered site of enzyme.
so, inactive pathways do not produce results

Enzymes require an inorganic ion or non-protein organic molecule to assist in reaction.
_______= inorganic ions such as copper, zinc, and iron
_______= organic non-protein ions


_____ _____ reactions:
_____= loss of electrons.
______= gain of electrons
____ reactions are the pair of reactions that are usually coupled.

redox reactions

In Oxidation-Reduction reactions, the term oxidation is used even when oxygen is not involved. The term also applies to _____ reactions involving hydrogen atoms.


_______: Chloroplasts convert solar energy to ATP and use it to reduce carbon dioxide to carbohydrate.
Oxygen is a by-product that is released.
*remember to study the overall equation for this


________ oxidize carbohydrates and use released energy to build ATP.
Oxygen is consumed and produces carbon dioxide and water.
*remember to study the overall equation for this


Complete oxidation of a mole of _____ releases 686 kcal of energy.
Some of the energy is harvested to form ATP.
The oxidation of this step-by-step allows energy to be gradually stored and then converted to make ATP


Human beings are involved in the cycling of molecules between _____ and ______.
Our food is derived from plants, or we eat animals that have eaten plants.
Food nutrients and oxygen enter mitochondria in our cells to produce ATP.
Without the supply of thes

chloroplasts and mitochondria

Food consists of ____, ____, and _____ that are broken down into simpler molecules in digestion and can enter cellular respiration at various steps in the pathway to make ATP.

carbs, fats, and proteins

Excess glucose can be used to form ____ _____.
These and glycerol form lipids or fats.

fatty acids

Certain substrates recur in __________. This allows the cell to switch to building molecules instead of breaking them down.


____ _____ is the release of energy from molecules such as glucose accompanied by the use of this energy to synthesize ATP molecules.
aerobic-requires O2
gives off O2

cellular respiration

_____ is a high energy molecule and as it is broken down energy is released to produce ATP.
The breakdown of one glucose molecule results in 36 or 38 ATP molecules


The pathways of cellular respiration allow the energy within a glucose molecule to be released slowly for ____ _____.

ATP synthesis

Cellular respiration involves many individual reactions each requiring its own enzyme.
certain enzymes utilize two coenzymes:
each carry two _____ and two _____ _____.
they pick up electrons at specific reactions and carry them to the electron

electrons and hydrogen atoms

Phases of cellular respiration:

-preparatory reaction
-citric acid cycle
-electron transport chain

_____ is the breakdown of glucose into two molecules of pyruvate.
Oxidation by removal of electrons (e-) and hydrogen ions (H+) provides the energy for the immediate building up of ATP.


Prepatory (Prep) Reaction:
_____ is oxidized to acetyl CoA and carbon dioxide is removed.
one three-carbon molecule becomes one two-carbon molecule
prep reaction occurs ____ because glycolysis produces ____ pyruvates


Citric Acid Cycle:
cyclical series of oxidation reactions that produce one ____ and ___ ____ per turn.
Acetyl CoA is converted to citric acid and enters the cycle.
Citric acid cycle turns twice because two acetyl CoA's are produced per glucose

ATP and carbon dioxide

______ are folds of the inner membrane that stick out into the matrix and 3C pyruvate is converted to 2C acetyl group.


Electron Transport Chain:
series of ________ carrier molecules that pass from one carrier to another and as they move from a higher energy state to a lower one, they release energy to make ATP.
under aerobic conditions 32-34 ATP per glucose molecule can b


______= a very important metabolite in cellular respiration that is used to reduce lactate (in animals) or alcohol and carbon dioxide (in plants) in a process called fermentation


Glycolysis takes place in the _____, does not require oxygen, and transforms one 6-carbon molecule into two 3-carbon molecules


energy _____ steps: two molecules of ATP used to activate glucose as glycolysis begins
energy _____ steps: oxidation of G3P results in NADH synthesis
-additional chemical changes lead to direct substrate level phosphorylation, which is the formation of 4

energy investment steps
energy harvesting steps

______= if O2 is limited, cells may utilize anaerobic pathways by this process
_____ generates ethyl alcohol and CO2 by this


In animal cells, _____ from glycolysis accepts two hydrogen ions and two electrons and is reduced to lactate.
Two ______ pass electrons to pyruvate to reduce it to lactate.


fermentation is essential to humans since it can provide a rapid burst of ______.
in muscles working vigorously over a short period, fermentation, is used when oxygen is in low supply.
_____ is toxic to cells and as is accumulates it changes the pH of the


fermentation yields only ___ ATP by substrate-level ATP synthesis.
these ATP represent a small fraction of _____ energy shared in glucose. In cellular respiration, 36-38 ATP molecules are produced. Therefore, most of this energy stored in glucose has not


electron transfer chain is located in ____ of mitochondria.
some carriers of electrons are cytochromes, iron-containing proteins.
high energy electrons enter system and low-energy electrons leave
Two electrons per NADH + H+ and FADH2 enter the electron tr

located in the cristae or mitochondria

NAD+ and FAD are recycled to pick up more ______ from glycolysis, prep reaction, and citric acid cycle


Electron carriers are located in the ____ of the ____.
NADH pass electrons to first acceptor of the electron transport chain and as they pass along, the energy is released to pump H+ into the intermembraneous space (proton gradient)

cristae of the mitochondria

where do protons accumulate?

the inter membranous space

the cristae also have ATP ___ _____ that allow H+ ions to flow through them and back into the matrix.
As the H+ pass through, energy is released and captured to form ATP from ADP.
this process is called __________.

synthase complexes

What is the energy yield for the complete breakdown of glucose to CO2 and H2O?

total of 4 ATP by substrate level synthesis and 32-34 ATP produced by electron transport chain and chemiosmosis

The difference in energy content of reactants and products is ____ kcal.
ATP phosphate bond has 7.3 kcal of energy.
36 ATP are produced in respiration.
36 x 7.3 = 263 kcal
263/686 = 39% efficiency of energy capture
the rest of the energy is lost as ______