Introduction to Metabolism

Question 1

Metabolism

Answer 1

Totality of an organisms chemical reactions.

Metabolism is an emergent property of life arising from interactions between molecules within cell.

Question 2

Metabolic Pathways

Answer 2

Begin with a specific molecule (substrate/reactant) and end with a product.

Each step is catalyzed by a specific enzyme.

Question 3

Types of metabolic pathways.

Answer 3

Catabolic Pathway

Anabolic Pathway

Question 4

Catabolic Pathway

Answer 4

Release energy by breaking down complex molecules into simpler compounds.

Question 5

Example of Catabolic Pathway

Answer 5

Cellular Respiration

Glucose

Question 6

Anabolic Pathways

Answer 6

Consume energy to build complex molecules from simpler ones.

Question 7

Example of Anabolic Pathways

Answer 7

Synthesis of protein

Question 8

Bioenergetics

Answer 8

Study of how organisms manage their energy resources.

Question 9

What is Energy?

Answer 9

The capacity to do/cause change.

Question 10

What are the 4 forms of Energy?

Answer 10

Kinetic Energy
Thermal Energy
Potential Energy
Chemical Energy

Question 11

Kinetic Energy

Answer 11

Energy associated with motion

Question 12

Thermal Energy

Answer 12

Kinetic energy associated with random movement of atoms or molecules

thermal (aka heat)

Question 13

Potential Energy

Answer 13

Energy that matter possesses because of its location/structure.

Question 14

Chemical Energy

Answer 14

Potential energy avaliable for release in a chemical reaction.

Question 15

First Law of Thermodynamics

Answer 15

The amount of energy in the universe is constant.

meaning

energy can not be created or destroyed; only transferred

Question 16

Second Law of Thermodynamics

Answer 16

Every energy transfer or transformation increases entropy (disorder of universe).

Question 17

Free Energy Change

Answer 17

A living systems free energy is energy that can do work when temperature and pressure are uniform, as in a living cell.

Change in free energy (delta G) is related to change in total energy (also called enthalpy delta H), change in entropy (delta s), and temperature in Kelvin (T)

Question 18

Free-Energy Change Formula

Answer 18

delta G = delta H - (T*deltaS)

G = free energy
H= total energy of a system
T = temperature in Kelvin
S = entropy

Question 19

A cell reaction that decreases entropy of a system is ________

Answer 19

Anabolic

Question 20

Free Energy

Answer 20

Measure of a system’s instability, its tendancy to change to a more stable state.

Question 21

Equilibrium

Answer 21

State of maximum stability.

A process is only spontaneous and can perfom work when it is moving toward equilibrium.

Question 22

Systems with high G (free energy)

Answer 22

complex/organized/non-random

Question 23

Systems with low G (fre energy)

Answer 23

disordered/random

Question 24

Exergonic Reaction

Answer 24

Proceeds with a net release fo free energy and is spontaneous.

In a graph reactants are higher and products are lower in energy.

Exo - release

Question 25

Endergonic Reactions

Answer 25

Absorbs free energy from its surroundings and is non-spontaneous. Products have higher energy than reactants.

Question 26

Exergonic and Endergonic reactions

Answer 26

- take place together

Question 27

Reactions in a closed system & equilibrium

Answer 27

Reactions in a closed system eventually reach equilibrium and then do no work

Question 28

Open systems

Answer 28

cells not in equilibrium

Question 29

Is metabolism at equilibrium

Answer 29

NEVERRRR

Question 30

Equilibrium and Metabolism

Answer 30

Energy from exergonic reactions are coupled with endergonic reactions

Question 31

Biological Systems - Equilibrium and Metabolism

Answer 31

- open - not at equilibrium - metabolism never at equilibrium

Question 32

Three kinds of cellular work

Answer 32

Chemical Transport Mechanical

Question 33

To do work, cells manage energy resources by energy | coupling.

Answer 33

Enery Coupling powered by ATP. | Ecergonic reaction -deltaG coupled to endergonic reaction deltaG

Question 34

Energy Currency of Cell is

Answer 34

ATP

Question 35

The Structure and Hydrolysis of ATP

Answer 35

Bonds between the phosphate groups of ATP can be broken by hydrolysis 3rd bond is average high energy bond Free energy for work

Question 36

The Regeneration of ATP

Answer 36

ATP is a renewable resource | This molecule is recycled over and over

Question 37

Catalyst

Answer 37

A catalyst is a chemical agent that speeds up a | reaction without being consumed

Question 38

An enzyme is a ______

Answer 38

catalytic protein

Question 39

example of an | enzyme-catalyzed reaction

Answer 39

Hydrolysis of sucrose by sucrase

Question 40

Energy Profile of an Exergonic Reaction

Answer 40

Every chemical reaction between molecules involves bond breaking and bond forming. Initial energy needed to start a chemical reaction is called free energy of activation.

Question 41

How Enzymes Lower the EA Barrier

Answer 41

Enzymes catalyze reactions by lowering EA barrier. Enzymes do not affect change in free energy (∆G)

Question 42

substrate

Answer 42

The reactant that an enzyme acts on. Enzymes bind with substrates to form a complex. The substrate than an enzyme binds to, and therefore the reaction catalyzed by each enzyme, is very specific Enzymes have an affinity for a specific substrate.

Question 43

active site

Answer 43

region on an enzyme where the substrate binds

Question 44

Induced fit

Answer 44

Induced fit of a substrate brings chemical groups of active site into positions that enhance their ability to catalyze reaction

Question 45

Catalysis in the Enzyme’s Active Site

Answer 45

In an enzymatic reaction, the substrate binds to the active | site of the enzyme

Question 46

Active site can lower an EA barrier by

Answer 46

Orienting substrates correctly Strain bonds of substrates Provide favorable microenvironment Covelently bond w/substrates

Question 47

The Active Site and Catalytic Cycle of an Enzyme

Answer 47

1. Substrates enter active site; enzyme changes shape such that its active site enfolds the substrates (induced fit) 2. substrates are held in active sites by weak interactions, such as hydrogen bonds and ionic bonds 3. The active site lowers EA and speeds up teh rxn 4. Substrates are converted to products 5. products are released 6. Active site is avaliablefor 2 new substrate molecules