Chapter 7 - Energy And Metabolism

Question 1

Matter

Answer 1

Anything that has mass and takes up space

Question 2

Energy

Answer 2

The capacity to do work, which is any change in the state or motion of matter.

Can be measured as heat energy, thermal energy that glows from an object with a higher temperature to an object with a lower temperature.

The unit of heat energy is kilocalorie (kcal), which is equal to 4.184 kJ.

Question 3

Heat energy-kilocalories (kcal)

Answer 3

Thermal energy that flows from an object with a higher temperature to an object with a lower temperature.

Question 4

Kinetic energy

Answer 4

The energy of motion. Eg. an archer draws a bow.

Question 5

Potential energy

Answer 5

Stored energy. (Tension in the bow and string represent stored(potential) energy.

Question 6

Closed system

Answer 6

Doesn’t exchange energy with its surroundings

Question 7

Open system

Answer 7

Can exchange energy with its surroundings

Question 8

ATP (Adenosine Triphosphate)

Answer 8

A nucleotide that consist of adenine(a nitrogen containing base), ribose(a 5 carbon sugar), and 3 phosphate groups.

ADP + Pi + energy = ATP

Question 9

ADP (Adenosine diphosphate)

Answer 9

The hydrolysis of ATP yields ADP and inorganic phosphate(Pi). ADP consists of adenine, ribose and phosphate groups, one of which is inorganic phosphate.

AMP + Pi + energy = ADP

Question 10

Phosphorylation

Answer 10

A reaction in which a phosphate group is transferred to some other compound.

Question 11

Oxidation

Answer 11

Substance that becomes oxidized gives up energy

A loss of electron
A gain of oxygen
A loss of H
An increase in oxidation number

Question 12

Reduction

Answer 12

Gain an electron(gain energy)
Loss of oxygen
Gaining of H
A reduction in oxidation number

Question 13

Redox

Answer 13

Oxidation and reduction occur simultaneously.
The oxidized substance gives up energy as it releases electrons.
The reduced substance receives energy as it gains electrons. Redox reactions usually involve a transfer of hydrogen atom rather than just an electron.
XH2 + NAD+ ➡️ X + NADH + H+
Oxidized. Reduced

Question 14

Enzymes

Answer 14

Biological catalyst that increase the speed of a chemical reaction without being consumed by the reaction.

Lower activation energy

Very sensitive to temperature, pH, Concentration, Inhibitors.

Increase temp above optimum-denature enzyme

Decrease- it will slow down the reaction but will not denature the enzyme

Question 15

Catalase

Answer 15

Enzyme that decompose molecules of hydrogen

Question 16

Activation Energy(Energy of activation Ea)

Answer 16

The energy required to break the existing bonds and begin the reaction.

Question 17

Substrate

Answer 17

The substance on which an enzyme acts.

They attach to active site.

Question 18

Enzyme-Substrate complex(ES complex)

Answer 18

When ES complex breaks up, the product is released; the original enzyme molecule is regenerated and is great to form a new ES complex:

Enzyme + substrate ➡️ ES complex
ES complex ➡️ enzyme + products

Enzymes can be reused

Question 19

Coenzyme

Answer 19

Non polypeptide organic molecule that binds to the apoenzyme( a protein) and serves as a cofactor( additional chemical component).

Question 20

Buffers

Answer 20

Minimize pH changes in cells so that pH is maintained within a narrow limit.

Question 21

First law of thermodynamics

Answer 21

Energy cannot be created or destroyed but can be transferred and changed in form.

Question 22

Second law of thermodynamics

Answer 22

Disorder (Entropy) in the universe, a closed system, is continuously increasing.
No energy transfer is 100% efficient; some energy is dissipated as heat, random motion that contributes to entropy (S), or disorder.

Question 23

Exergonic

Answer 23

Spontaneous reaction
releases free energy that can perform work.

Has a negative value of 🔼G

Question 24

Endergonic

Answer 24

Non spontaneous

Requires additional energy

Has a positive value of🔼G

Question 25

Coupled reaction

Answer 25

The input of free energy required to drive an endergonic reaction is supplied by an exergonic reaction.

Question 26

Enzyme inhibitors

Answer 26

Molecules that interact in some way with the enzyme to prevent it from working in a normal manner.

Many drugs are enzyme inhibitors.

Question 27

Competitive inhibitors

Answer 27

Compete with the substrate for access to active site of the enzyme.

Question 28

Non competitive inhibitors

Answer 28

Binds outside the active site of the enzyme.

Allosteric site - binding causes conformational change in enzyme active site inhibiting enzyme function.

Feedback inhibition - product of pathway inhibits early steps to prevent over accumulation of product.

Question 29

Anabolism

Answer 29

Complex molecules synthesized from simpler substances

Question 30

Catabolism

Answer 30

Larger molecules broken down into smaller ones