Ch. 3 Cell Metabolism

Front 1

Cell Metabolism

Back 1

study of energy of related concepts as they effect cells

The sum of all chemical reactions that occur in cells

Front 2

Energy metabolism

Back 2

set of reactions involved in energy storage and use

AKA energy exchange

Front 3

Reactants

Back 3

transformation of materials that enter the reaction

Front 4

Products

Back 4

A substance resulting from a chemical reaction.

Front 5

Bidirectional

Back 5

goes in both directions at the same time

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Catabolic

Back 6

A reaction that involves the breakdown of larger molecules into smaller ones.

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Anabolic

Back 7

A reaction that involves the production of larger molecules from smaller reactants.

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Metabolic reactions

Back 8

catabolic
anabolic

Front 9

Hydrolysis

Back 9

"splitting of water"
catabolic reaction

The breakage of a chemical bond through the addition of a water molecule

Front 10

Condensation

Back 10

The reverse of hydrolysis is called _________.

Front 11

Condensation

Back 11

involves joining together of 2 or more smaller molecules to form a larger one, as when amino acids are joined together to form proteins.

Front 12

Phosphoralation

Back 12

The addition of a high-energy phosphate group to a molecule

Front 13

Dephosphoralation

Back 13

The removal of a phosphate group from a molecule.

Front 14

Oxidation-reduction reaction

Back 14

Any reaction in which elelctrons are removed from one reactant molecule and transferred to another.

Front 15

Oxidation

Back 15

The loss of electrons or hydrogen atoms or the acceptance of an oxygen atom.

Front 16

Oxidized

Back 16

Once electrons have been removed from a molecule, molecule is said to be ______.

Front 17

Oxidative phosphoralation

Back 17

a process occuring in mitochondria that is crucial to energy metabolism

Front 18

Laws of mass action

Back 18

an INCREASE in the CONCENTRATION of REACTANTS tent to move the reaction towards the PRODUCTION of MORE PRODUCT.

An INCREASE in the conc. of products tends to push the reaction in reverse.

Front 19

Translation state

Back 19

Reacting molecules go into a high-energy intermediate form which then breaks down into the products.

Front 20

Activation energy barrier

Back 20

The "hump" in the middle of the curve, is known as _______ ______ ______, is due to the fact that potential energy of the transition state is greater than that of either the reactants or the products.

Front 21

Activation energy

Back 21

Energy that must be added to the REACTANTS to allow then to overcome the ACTIVATION ENERGY BARRIER and move through the TRANSITION STATE to produce the PRODUCTS.

Front 22

How does activation energy get the extra energy it needs?

Back 22

1. collisions from other molecules
a. adds energy to the molecules
b. increased molecular motion due to increases in temp. can act to add more energy to tmolecules via collision btwn molecules

Front 23

Rate

Back 23

a chemical reaction is a measure of how fast it comnumes reactants and generates products

expressed as moles/liter-second, or some equivalent

Front 24

Net rate

Back 24

difference btwn the rate of the forward reactants (reactants → products) and the rate of the reverse (products → reactants)

Front 25

increase;increase

Back 25

Any _______ in the conc. of reactants will bring about an _______ in the forward rate without affecting the reverse rate.

Front 26

increase; decrease

Back 26

An _______ in the concentration of products relative to reactants wil _______ the net forward rate, and can even make the reaction go in reverse if the change in conc. is large enough.

Front 27

decrease; increase

Back 27

As the height of the activation energy barrier _________, rates of both the reverse reaction and forward reaction ________ because the activation energy of both reaction becomes lower.

Front 28

Enzymes

Back 28

Natures answer to activation energy issues
Protein based molecules
act as catalysts (increase chemical reactions)

Front 29

Enzymes

Back 29

Act to lower the activation energy barrier for a given reaction
Act to orient the reactant to maximize the EFFECIENCY of the reaction.

Front 30

How do enzymes work?

Back 30

1. Enzymes have enzyme sites at which reactant(s) can bind.
2. Binding will allow the reaction to occur thus producing the products.
3. Product is released from the active site.
4. Enzyme can now interact with a new reactant.

Front 31

Enzymes

Back 31

______only react w/only a certain molecule type, and a related group of molecules.

Front 32

Substrate

Back 32

A participant (product or reactant) in an enzyme-catalyzed reaction.

Front 33

activation energy barrier

Back 33

The height of the _________ ______ ______ doesn't affect the overall energy change of a reaction, which depends only on the difference in energy btwn reactants and products.

Front 34

Catalytic Rate
Enzyme Concentration
Substrate Concentration
Affinity

Back 34

The rate at which an enzyme can catalyze a reaction is affected by several factors. (4)

Front 35

Catalytic Rate

Back 35

a maeasure of how many product molecules it can generate per unit time, assuming that the active site is always occupied by a substrate molecule.

influences how fast enzyme molecules can convert substrates into products

Front 36

Enzyme Concentration

Back 36

The rate of an enzymatic reaction also increases in direct proportion to the _______ _________ based on the law of mass action.

More enzymes molecules, the more product.

Front 37

Substrate Concentration

Back 37

increases when enzymatic reaction increases based on law of mass action

When __________ ___________ is low, more time will pass bofore the next substrate molecule binds to the enzyme, and as a result its active site wil remain unoccupied for a greater percentage of the time.

When high __________ _________, less time will pass before the next substrate molecule comes along.

Front 38

Affinity

Back 38

a measure of how tightly substrate molecules bind to its active site.

tightness of binding btwn any two molecules

Front 39

allosteric regulation
covalent regulation

Back 39

Two common mechanisms for altering the activity of existing enzymes are ________and_________.

Front 40

allosteric regulation

Back 40

regulatory mechanism in which a modulator bonds reversibly to the regulatory site on an enzyme, inducing a change in its conformation and activity.

Front 41

covalent regulation

Back 41

regulatory mechanism in which changes in an enzyme's activity are brought about by the covalent bonding of a specific chemical group to a site on the enzyme molecule

usually involves bonding of a phosphate group.

Front 42

modulator

Back 42

induces a change in an enzyme's conformation that alters the shape of the active site, causing a change in the enzyme's activity by altering its catalytic rate, it affinity for substrate, or both.

Front 43

Activator

Back 43

A modulator that increases the activity of an enzyme

Front 44

Inhibitor

Back 44

a modulatory that decreases the activity of an enzyme

Front 45

Regulatory site

Back 45

enzyme binding site

associated w/allosteric regulation

Front 46

Protein Kinase

Back 46

a type of enzyme that catalyzes phosphorylation of a target protein.

Front 47

Phosphatase

Back 47

enzyme that catalyzes the dephosphorylation of a target protein

Front 48

Feedback Inhibition

Back 48

Regulatory mechanism is which an enzyme in a metabolic pathway is inhibited by an intermediate appearing DOWNSTREAM

Front 49

Feedforward activation

Back 49

Regulatory mechanism which involves the activation of an enzyme by an intermediate appearing UPSTREAM in a metabolic pathway

Front 50

Substrate specificity

Back 50

Enzymes are generally able to catalyze one particular reaction because they have the ability to "recognize" and bind to only one particular type of substrate, a phenomenon known as ___________ ________.

Front 51

ATP

Back 51

serves as temporary energy storage
comes from ADP & Pi
synthesis occurs in two ways:
substrate-level phosphorylation
oxidative phosphorylation

Front 52

substrate-level phosphorylation

Back 52

a mechanism of ATP synthesis, in which an enzyme transfers a phosphate group from a substrate to ADP

Occurs in 7 & 10 steps of Glycolysis & 5 step of Krebs cycle

Front 53

oxidative phosphorylation

Back 53

a mechanism where ADP binds with a free inorganic phosphate (Pi) to form ATP

needs electron transport & oxygen

Front 54

ATP breakdown

Back 54

A process where an ADP and a free phosphate (Pi) releases stored energy that can be used to overcome the Activation Energy Barrier & allow a reaction to occur.

Front 55

ATP Hydrolysis

Back 55

Process that releases energy and involves the splitting of a single bond- the bond btwn ATP and one of the attached phosphate groups

Front 56

Glucose Oxidation

Back 56

Cells are able to synthesize ATP using energy derived from _______ _________ because it has a negative energy change and therefore occurs spontaneously

Has positive change too, but doesn't occur spontaneously.

Front 57

Glucose Oxidation

Back 57

Glycolysis
Krebs cycle
Oxidative phosphorylation

Front 58

Glycolysis

Back 58

"spitting of sugar"
occurs in cytosol
O2 not necessary (anerobic)
Requires initial input of energy
Produces a net of 2 ATPs for each glucose entering glycolysis
Produces 2 reduced NADs for each glucose
Final products are 2 pyruvates

Front 59

Krebs cycle

Back 59

has no starting or ending points because its circular

Occurs in mitochondria when O2 is present
Uses acetyl-CoA or breakdown products from proteins or fats
Produces many reduced molecules (NAD2, FADH2, CO2, & a little ATP)

Front 60

Oxidative phosphorylation

Back 60

Most ATP is during this process

the transport in the inner mitochondrial membrane of H ions through electron transport chain (releases energy)
Uses this energy source to make ATP in a process called Chemiomotic coupling

Front 61

Chemiomotic coupling

Back 61

The use of energy released during electron transport to pump ions across a membrane against a conc. gradient

The energy "stored" by this gradient & a special type of enzyme are used to make ATP.

Front 62

Lactid Acid

Back 62

For pyruvate production by Glycolysis to enter the linking reaction & Kreb's chemistry there must be sufficient O2 available to the mitochondria to accept all the electron and H+ produced

If not enough O2 is delivered to cell then some of the pyruvate must be converted to another compound, ______ ____.

Front 63

Purpose of Lactaid Acid

Back 63

1. ↑ the NADox available in the cytosol, it must be available for glycolysis to occur
2. Stops an ever increasing conc. of pyruvate in the cytosol (law of mass action)
3. Allows Glycolysis to cont. as to PRODUCE ATP even when cell has limited O2 available
4. Lactate can exit a cell, go to liver, and be converted to glucose, pyruvate cannot.

Front 64

Cell membrane transport

Back 64

Molecules must be able to pass into or out of cells through the cell membrane.

(Ch.4)

Front 65

Lactate acid

Back 65

______ acid like muscle cells the best.

(Ch.4)

Front 66

harmful

Back 66

Lactate can be ______, so needs to be converted back to pyruvate.

(Ch.4)

Front 67

Passive Transport

Back 67

Molecular motion across a cell membrane not requiring cell energy
motion is due to the kinetic (thermal) energy of the molecules.

(Ch.4)

Front 68

Active transport

Back 68

Molecular motion across a cell membrane that requires the use of cell energy (ATP) and transport proteins often called carriers or pumps.

(Ch.4)

Front 69

Chemical

(factor to produce molecular motion)

Back 69

The existance of a conc. gradient for a given type of a molecule across a cell membrane.

Molecules always moves from areas of high concentration to areas of lower conc. The greater the conc., the more molecules will move.

(Ch.4)

Front 70

Electrical


(factor to produce molecular motion)

Back 70

1. Ions are affected by differences in charge found inside & outside of cell membranes.
2. Is in fact, an unequal distribution of charged particles across a cells membrane
A. more - ions inside a cell
B. more + ions outside a cell
3. Creates an electrical charge differences across a cell membrane, measured in millivolts
A. called the Membrane Potential, often about 70 millivolts inside composed to outside
4. Charge difference can affect ion movement across membranes.
a. like charges repel
b. unlike charges attract

(Ch.4)

Front 71

glucose

Back 71

When ______ is scarce, the body can breakdown proteins and fats for energy.

Front 72

Glycogen

Back 72

A polysaccharide that is an important energy reserve; a polymer consisting of a long chain of glucose molecules.

Front 73

glycogenesis

Back 73

The synthesis of glycogen from glucose molecules.

Front 74

glycogenolysis

Back 74

Glycogen breakdown and the liberation of glucose molecules

Front 75

gluconeogenesis

Back 75

The synthesis of new glucose from protein or lipid precursors which usually takes place in liver.

Front 76

lipolysis

Back 76

The first stage of fat breakdown which sep. of fatty acids from glycerol molecule.

The catabolism of lipids as a source of energy

Front 77

lipogenesis

Back 77

The synthesis of lipids from nonlipid precursors.

Front 78

proteolysis

Back 78

metabolic breakdown of proteins to A.A.s

Front 79

Essential nutrient

Back 79

any biomolecule necessary for proper body function that cannot by synthesized in cells and therefore must be obtained from dietary sources.

Front 80

Goes to liver and turns into UREA and then goes to kidneys

Back 80

What happens to ammonia that is produced when A.A.s are broken down for energy?