Chapter 3 - Metabolism and Energy

Question 1

What is Metabolism

Answer 1

the sum of all chemical reactions in a cell or organism

Question 2

Anabolic Reactions

Answer 2

• Condensation
• BUILDING of new chemicals
• Stored energy in bonds: making bonds creates stored energy used for other functions (potential energy)

Question 3

Catabolic Reactions

Answer 3

• Hydrolysis
• BREAKING substances down
• Releases energy

Question 4

Activation Energy

Answer 4

• Amount of energy needed to DESTABILIZE bonds of a molecule
• breaking bonds in initial reaction uses energy
  
  • TRANSITION STATE
• Reducing Activation Energy: enzymes reduce the amount of activation energy to start a reaction
  
  • MODS

Question 5

Energy

Answer 5

• contained within chemical bonds
  
  • for a reaction to occur/progress: chemical bonds must be broken
• ability to do work
• energy is used to move an object against an opposing force

Question 6

Kinetic Energy

Answer 6

→Energy that an object possesses due to its motion

Question 8

Potential Energy

Answer 8

Stored energy based on an object’s position or state

Question 9

1st Law of Thermodynamics

Answer 9

Energy cannot be created or destroyed, only transformed.

Question 10

Chemical Bonds

Answer 10

conversion of energy from one form to another depends on the breaking and formation of chemical bonds

Question 11

Bond Energy

Answer 11

• Stability of a covalent bond
• energy is absorbed when reactant bonds break
• energy is released when product bonds form

Question 12

Endergonic Reactions

Answer 12

• reaction ABSORB more energy than is released
• less reactants than products

Question 13

Exergonic

Answer 13

• reaction RELEASES more energy than is used
• Hydrolysis is exergonic
• more reactants than products

Question 14

Energy Coupling

Answer 14

use of energy released from one reaction to drive another reaction

Question 15

Enthalpy

Answer 15

change in energy (heat)

Question 16

2nd Law of Thermodynamics

Answer 16

Only some of the original energy ends up in the new form; the rest is lost as HEAT

Question 17

Disorder

Answer 17

• Entropy, which measures the level of disorder in a system
• Organelles getting old and stopping functioning creates disorder/Entropy in the cell
• Restoring order requires energy

Question 18

Spontaneous

Answer 18

continues on its own; DOES NOT require a continuous supply of energy

Question 19

Non-Spontaneous

Answer 19

cannot occur without a continual supply of energy

Question 20

Free Energy (G)

Answer 20

USEFUL energy available to do work in a system (not lost as heat)

Question 21

Phosphates

Answer 21

• negatively charged and repel from one
• AMP, ADP, ATP
• last phosphate has high energy bond
  
  • easy to break off because of repelling like charges
  • energy stored is released

Question 22

ATP Structure

Answer 22

• Ribose sugar
• Adenine base
• 3 phosphates

Question 23

Conversion of ATP to ADP

Answer 23

• Hydrolysis
• ADP and inorganic phosphate formed (charged)
• Makes bonds with water (H+): releases lots of energy
• Exothermic
• Increase of Entropy
• Produces free energy
• Reversable reaction - 30 KJ released every time 3rd phosphate is released/attatched
• Aerobic Respiration: glucose gets oxidized; redox reaction

Question 24

How ATP Works

Answer 24

• repulsion in the O- groups
• Breaking of O-P bond requires little energy ‒ HYDROLYSIS
• Phosphate bonds with water
  
  • releases energy, creates stable structure
• Entropy increases
• exergonic reaction

Question 25

ADP to ATP

Answer 25

- Phosphorylation: The addition of a phosphate group to a molecule - energy comes from oxidation of sugars (aerobic respiration) - 40% of energy released from exergonic reaction is used to do work

Question 26

Redox Reaction

Answer 26

- when electrons are lost, another must gain - they provide cellular energy, because the flow of electrons between molecules produces usable energy

Question 27

Reduction

Answer 27

- charge goes down, gains - charge - hydrogen is removed, OXYGEN is ADDED - energy release

Question 28

Oxidation

Answer 28

- change goes up, loses - charge - hydrogen is added, OXYGEN is REMOVED - energy absorption

Question 29

Coenymes

Answer 29

- Coenzymes are non-protein organic molecules that assist enzymes in catalyzing reactions - NADP, NADPH

Question 30

BONUS QUESTION

Answer 30

eg. NAD+ - the reduced form of NAD+ is NADH - the transfer of energy between NAD+ and food is efficient - The potential energy carried in NADH facilitates the synthesis of ATP

Question 31

Oxidizing agent

Answer 31

- The substance that gains electrons - It oxidizes the other substance - Eg. Oxygen

Question 32

Reducing Agent

Answer 32

- The substance that loses electrons - It reduces the other substance - Eg. Methane (carbon)

Question 33

Rapid Combustion

Answer 33

- Eg. burning of glucose - Oxygen gas does the oxidizing - Reaction produces CO2 and H2,O and releases energy - CO2 and H2O are fully oxidized and contain no more available chemical energy

Question 34

Controlled Oxidation

Answer 34

- Eg. Cellular respiration (controlled oxidation of glucose) in cells - Oxidation of glucose occurs through a series of enzyme-catalyzed reactions - Each step releases a small amount of energy following absorption of a small amount of activation energy. The energy released is given to energy-carrying molecules for the next step. - Cells capture more free energy and produce less thermal energy waste

Question 35

Energy Carriers

Answer 35

- The oxidation of food molecules often uses enzymes called dehydrogenases - A dehydrogenase is an enzyme that oxidizes a substrate and transfers hydrogen ion to an acceptor