Ch 8 - 10 Flashcards Preview

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Flashcards in Ch 8 - 10 Deck (66):

Define metabolic pathways

Begins with a specific molecule, which is then altered in a series of defined steps, resulting in a certain product.
ex. Molecule (A) undergoes a reaction w/ an enzyme to create molecule (B) which under goes a rxn w/ an enzyme to create molecule (c) etc. until it transforms into the desired molecule.


What two types of pathways are their and define them?

Catabolic (breakdown) - Exergonic, spontaneous, down hill
Anabolic (Build up) - consumes energy to build up complex molecules
endergonic, uphill rxn, not spontaneous


What is the name of the process of which organisms transform energy?

Thermodynamics - the study of the energy transformations tht occur in a collection of matter.


What is the first law of thermodynamics

Energy can be transferred and transformed, but it cannot be created or destroyed .
1st law AKA the principle of conservation of energy


what is the second law of thermodynamics

• 2nd law: Every energy transfer and transformed increases the entropy(A measure of Disorganization) of the system
Heat:random movement of particles; Disorganization energy
Every time energy has been used it is less organized


how is energy transformations of life are subject to the laws of thermodynamics

living things are an opens system, tht react with the environment.
energy and matter can be transferred between the system and its surroundings.


an example of an open system

living things absorb energy - for instance, light energy or chemical energy in the form of organic molecules - and release heat and metabolic waste such as CO2, to the surroundings


ATP powers cellular work: it couples exergonic to endergonic rxn
another way of asking is
How does energy released from catabolism of ATP become coupled to cellular work?

> ATP + H2O V
E from catabolism(exergonic)/\ Energy for cellular work endergonic
/\ ADP + P- <


Organisms live at the expense of free energy

it is usable energy. energy ready to do work.
free energy is used to do all of the cellular work.[VERY IMPORTANT]
ex. atp is used to change the shape of transport proteins.
also used to move motor proteins.


What is energy and define it

Energy is the capacity for work
the ability to do work or produce change


What types of energy are there?

Kinetic energy- objects in motion
Potential- not moving
Thermal Energy- is kinetic energy associated with the random movement of particles.


how can energy be transferred or transformed

a bear can transfer or transform chemical energy of the organic molecules in its food to kinetic energy and other forms as it carries out biological processess


what happens to energy after each transformation?

every energy transfer or transformation increases the entropy of the system


define entropy

a measure of of disorder or randopmness


define free energy

is the portion of a systems energy tht can perform work when temperature and pressure are uniform throughout the system .


define endergonic rxn

anabolic , building up
requires an input of free energy
uphill rxn
not spontaneous


define exergonic

catabolic - breaking down
release of free energy


define enzyme

a protein catalyst


define catalyst

a chemical agent tht speeds up a rxn without being consumed by the rxn


define activation energy

The amount of energy needed to push the reactants to the top of the energy barrier


define active site

is a pocket or groove on the surface of the enzyme where catalysis occurs


define inhibitors

certain chemicals inhibit the action of specific enzymes


define competitive inhibitor

reduces the productivity of the enzyme by blocking substrates from entering active sites


define noncompetitive inhibitor

do not directly compete w/ the substrate to bind to the active site. they bind else where and change the shape of the enzyme


define ATP

the bodies currency
Adenosine Triphosphate


define induced fit

brings chemical grps of the active site into positions tht enhance thesi ability to catalyze the chemical rxn


define open system?

an interaction with its environment


Define reduction and oxidation

Reduction (Oxidizing agent) - Reduces overal charge , gains e-
Oxidation (reducing agent) - increases overal charge by lossing e-


define aerobic respiration

is a catabolic pathway / oxygen is consumed as a reactant along w/ organic fuel


define NAD+

A coenzyme tht accepts a H+ and can cycle easily between oxidation


define substrate lvl phosphorylation

A smaller amount of ATP is formed directly in a few reactions of glycolysis and the citric acid cycle(Krebs cycle).


Aerobic Respiration Review ATP NADH FADH2
Transition / Bridge rxn
Krebs cycle
Total ATP produce

Glycolysis 2 2 0
Transition / bridge rxn 0 2. 0
Krebs cycle 2 6 2
Total ATP produce in aerobic respiration is 30 -32


Aerobic respiation
Each NADH passed down the ETC yields a maximum of ______ ATP
Each FADH2 passed down from ETC yields approximately ______ ATP
In fermentation, NADH produced in glycolysis yield approx. ______ ATP
Most ATP porduced in aerobic respiration is generated by?

Oxidative Phosphorylation


define gylcolysis where and what does it break down into

occurs in the cytosol.
breaks down glucose into 2 pyruvates
produces 2ATP and 2NADH but no (0) FADH2


Transition / bridge rxn (oxidation of pyruvate)

requires O2
Occurs in the matrix of the mitochondria
Turns 2 pyruvate -----> 2 Aceytl CoA + CO2
Produced NO ATP , NADH or FADH2


Define krebs cycle

Requires O2
Occurs in the matrix of the mitochondria
8 Enz-catalyzed steps
2 Acetyl Coa ----> 4CO2 (completes oxidation of glycose)
Produces 2ATP 6NADH 2FADH2


define Electron transport chain

it accepts e- (most often from NADH) from the breakdown products of the first 2 stages and passes e- from one molecule to another
9 members, - 8proteins and 1 ubiquinone
Occurs in inner membrane of mitochondria
O2 is final Electron Acceptor
6H2O are formed


Define Oxidative phosphorylation

Occurs in the inner membrane of the mitochondria
High energy e-


define Chemiosmosis

Free energy released by electron transfer in the electron transport chain causes proteins to pump H+ from mitochondrial matrix to the inter-membrane space
and is used to drive cellular work such as synthesis of ATP


define proton-motive force

Proton gradients created by ETC is a force
Protons come back through


define Cytochromes

most of the remaining carriers between ubiquinone and oxygen are called cytochromes


Define Fermentaion

used wen O2 is not available
Glucose --> 2pyruvate
The purpose of Fermentation is to oxdize NADH ---> NAD+ (NAD+ needed for glycolosis)
Net transfer is 2.1%


define anaerobic respiration

anaerobic respiration and cannot survive in the presence of O2


define alcohol fermentation

pyruvate is converted to ethanol in 2 steps


define lactic acid fermemtation

pyruvate is reduced directly by NADH to form lactate as an end product w/ no release of CO2


Glycolysis in detail
where does it occur
whats the products
how many steps
what are the costs

•Glycolysis , occurs in the cytoplasm
6CH12O2 ----> 2 pyruvate
Energy investment phase Costs 2 ATP (5 enz-catalyzed steps)[Phosphofructosekinase]
§ Glucose---> 2 Glyceraldehyde 3-phosphate (G3P)
Energy Yielding / payoff phase [ gain 4 ATP + 2NADH Net: 2ATP and 2NADH[Substrate lvl phosphorylation
§ (5 Enz-catalyzed steps)
§ 2G3P ----> 2 Pyruvate


why do cells constantly recycle ATP instead of storing enough for a days need?

The avg. adult uses about or over 100 lbs of ATP a day. so instead of storing 100 lbs per day we constantly make it


If glucose provides the ultimate source of energy for cells, why do they transfer tht energy to other molecules like ADP --> ATP or NAD+ --> NADH?

Because ATP is the right amount of energy to do work in our body
aka energy currency of the cell


Compare Substrate lvl phosphorylation to oxidative phosphorylation?
which requires enzymes?
What are the oxidizing agents?
Where do these processes occur

Glycolysis (substrate lvl phosphorylation) requires enzymes occurs: cytoplasm
Krebs cycle (substrate lvl phosphorylation) occurs: matrix of Mitochondria
Oxidative Phosphorylation occurs: inner membrane mitochondria


Explain the phrase: In respiration, electrons fall "downhill" from organic molecules to oxygen.

in cellular respiration the rxn occurs in stages: an ETC breaks the "fall" of e- in this rxn into a series of smaller steps and stores some of the released energy in a form tht can b used to make ATP.


how does Chemiosmosis relate to osmosis?
What diffuses?Where?
How is chemiosmosis relateed to proton motive force?

Free energy released (by electron transfer in the electron transport chain) causes proteins to pump H+ from mitochondrial matrix to the inter-membrane space (Proton motor force is used to pump the H+)
○ Proton gradients created by ETC is a force
○ Protons come back through
H+ then moves back across the membrane , passing through the protein complex


describe how ATP and ADP act as allosteric regulators of respiration?

When to an excess of ATP exist at a point and time the enzyme phosphofrutokinase slows done the process of creating more ATP(by citrate attaching to the enzyme). but wen the output of ATP decreases from the amount being produced the enzyme again turns back on to produce a sufficient amount of ATP.


Which process is older Fermentation or respiration? what evidence do we have?

Fermentation is older bcuz O2 wasnt available until 2.5 billion yrs ago


what is the Pasteur affect? explain

He observed tht yeast consumed sugar at a much faster rate under anaerobic conditions than when O2 was available
They hav to ingest sugar at a much faster rate so they can consitently make ATP bcuz fermentation is a much less effeicent way of cresating ATP 2.1% compared to cellular respiration which is 34%


What is the Molecular formula of Photosynthesis?

Solar energy (Light) + 6CO2 + 6H2O ----->C6H12O6(glucose) + 6O2


What is the molecular formula of cellular respiration?

C6H12O6 + 6O2 ----> 6CO2 + 6H2O + ATP


what are the differences between photosynthesis and respiration?>?

Photosynthesis is a reactant in the process to create glucose where as ATP is a product in respiration


Statement (no Question): photosynthesis traps solar energy and uses tht energy in the synthesis of sugar. In eukaryotic plants this 2 step process occurs in the chloroplast. The first step, known as the light rxn, occurs in thylakoid membranes within the chloroplast. Here, chlorophyll a and accessory pigments absorb photons of light which excite an electon into a higher energy orbital. this initial capture of light energy fuels the synthesis of ATP (through chemiosmosis) and powers the reduction of NADP+ --> NADPH + ATP NADPH power the synthesis of a sugar in the stroma of the chloroplast. this process Calvin cycle



What are the three steps to the calvin cycle?

1)the fixation of carbon (from CO2, powered by ATP)
2) reduction of the 3 carbon intermediate into a 3 carbon sugar (powered by NADPH)
3) regeneration (powered by ATP)


Define Autotrophs

Self feeders


Define heterotrophs

Other feeding


Define chloropyll

the green pigment tht gives leaves their color


Define light rxn

The photo part of photosynthesis
step of photosynthesis tht convert solar energy to chemical energy.
Water is split providing a source of e- and H+ and giving O2 as a by product


Define Photons

light behaves as though it consists of discrete particles


define absorption spectrum

a graph plotting a pigments light absorption vs wavelength


define photosystem

there are 2 types of photosystems PSII and PSI (thts the order in which they were found)