energy and metabolism

Question 1

What is energy?

Answer 1

The capacity to cause change

exists in various forms

Question 2

What is Kinetic energy associated with?

Answer 2

It is associated with motion

Question 3

What is potential energy?

Answer 3

It is energy that matter possesses because of its location or structure

Question 4

What are the three types of systems?

Answer 4

1. isolated system
2. closed system
3. open system

Question 5

what is an isolated system?

Answer 5

unable to exchange energy or matter with its surrounding - contains all of the energy it has or needs

Question 6

what is a closed system?

Answer 6

cannot exchange matter but can exchange energy - can gain or lose energy

Question 7

what is an open system?

Answer 7

energy and matter can be transferred between the system and its surroundings

Question 8

What is thermodynamics?

Answer 8

It is the study of energy transformations - specifically focused on maxim of power (ability to do work) and heat generated in the process

Question 9

How many laws govern thermodynamics and which two are we specifically focusing on?

Answer 9

There are 4 main laws and we are focusing on two:

1. First law of thermodynamics (principal of conservation of energy)
2. Second law of thermodynamics

Question 10

what is the First law of thermodynamics (principal of conservation of energy)

Answer 10

energy of the universe is constant - energy can be transferred/transformed but it cannot be created or destroyed

Question 11

what is the Second law of thermodynamics

Answer 11

every energy transfer / transformation increases entropy (disorder) of the universe- waste energy goes to increasing entropy
diffusion- entropy- disorder and chaos

Question 12

What are spontaneous processes?

Answer 12

they occur without energy input- they can happen quickly or slowly
for a process to occur without energy input, it must increase the entropy of the universe.

Question 13

what is a metabolic pathway?

Answer 13

a metabolic pathway begins with a specific molecule and ends with a product
Associated each step is a specific enzyme (protein—catalyst) it can change energy inputs

Question 14

What are two unique metabolic pathways?

Answer 14

1. Catabolic pathways

2. Anabolic pathways

Question 15

what is a Catabolic pathways?

Answer 15

release energy by breaking down complex molecules into simpler compounds (creates entropy)
cellular resperation- break down of glucose in the presence of oxygen is a pathway of catabolism

Question 16

what is a Anabolic pathways

Answer 16

consume energy to build complex molecules from simpler ones (increasing order)
synthesis of protein from amino acids is an example of anabolism

Question 17

What is free energy?

Answer 17

energy that can do work when temperature and pressure are uniform

Question 18

what is the outcome for a negative Delta-G

Answer 18

It is spontaneous (what else does this mean?) entropy increases

Question 19

what is the outcome for a positive Delta-G

Answer 19

is not spontaneous so entropy decreases

Question 20

What is free energy a measure of?

Answer 20

a measure of a systems instability, its tendency to change to a more stable state

Question 21

What happens during spontaneous change (2 things)?

Answer 21

Free energy decreases and the stability of a system increases

Question 22

What is equilibrium?

Answer 22

it is a state of maximum stability- it is done and there is no more free energy

Question 23

What is a defining feature of life?

Answer 23

is that metabolism is never at equilibrium- that would be death because blood cells could no longer function

Question 24

Two types of reactions in metabolism, what are they?

Answer 24

1. Exergonic reaction

2. Endergonic reaction

Question 25

what is a Exergonic reaction

Answer 25

proceeds with a net realize of free energy and is spontaneous

Question 26

what is a Endergonic reaction

Answer 26

absorbs free energy from its surroundings and is nonspontaneous

Question 27

What is an activation energy barrier?

Answer 27

It is the initial energy needed to start a chemical reaction which is called free energy/ activation, or activation energy (Ea)

Question 28

How is Activation energy usually supplied?

Answer 28

Often supplied in the form of thermal energy that the reactant molecules absorb from their surroundings

Question 29

What role do enzymes play in the Ea

Answer 29

enzymes catalyze reactions by lowering the activation energy barrier
Enzymes do not affect the change in the free energy instead they hasten reactions that would eventually occur

Question 30

What is a catalyst?

Answer 30

is a chemical agent that speeds up a reaction without being consumed by the reaction

Question 31

What is the substrate?

Answer 31

The reactant that an enzyme acts on is called the enzyme’s substrate

Question 32

How is an enzyme - substrate complex formed?

Answer 32

The enzyme binds to its substrate forming an substrate complex
the region catalyzed by each enzyme is a very specific - structure begins function (lock and key)

Question 33

What is the active sight?

Answer 33

is the region on the enzyme where the substrate binds

Question 34

What is the induced fit?

Answer 34

of a substrate brings chemical groups of the active sight into positions that enhance their ability to catalyze the reaction
snaps it and locks it in place- induced fit
challenges structure - once connected the name changes

Question 35

How does an enzyme reduce the Ea barrier? in an enzymatic reaction, the substance binds to the active site of the enzyme and the active site can lower and Ea barrier by: (4 ways)

Answer 35

1. orienting substances correctly
2. straining substate bonds
3. providing a favorable microenvironment - changing pH
4. covalently bonding to the substance