Metabolism - 2

Question 1

Defintion:

Energy intake = internal heat produced + external work + internal work + energy storage

Answer 1

Energy balance

Question 2

Definition:

Energy Input

Answer 2

Energy in ingested food, cells capture portion in high-energy bonds of ATP

Question 3

Definition:

Energy expended when skeletal muscles are contracted to move objects or to move body in relation to the environment

Answer 3

External work

Question 4

Defintion:

Energy Output

Answer 4

energy from nutrients that is not used to perform work, transformed into thermal energy or heat

Question 5

What percent of chemical energy in food is harnessed to do biological work?

Answer 5

25% - remainder is converted to heat (a lot is used to maintain body temperatures

Question 6

Definition:

Internal work

Answer 6

all other forms of biological energy expenditure that do not accomplish mechanical work outside the body (skeletal muscle used for postural maintenance, shivering, heartbeat - things that are necessary to sustain life)

Question 7

What is the most effective way to change metabolic pool in the body?

Answer 7

Food energy

Question 8

What are the 3 possible states of energy balance?

Answer 8

• neutral
• positve
• negative

Question 9

Defintion:

Energy Input = Energy output. (body weight remains constant)

Answer 9

Neutral energy balance

Question 10

Definition:

Energy input is greater than energy output. Energy not used is stored primarily as adipose (body weight increases)

Answer 10

Positive Energy Balance

Question 11

Definition:

Negative energy balance.

Answer 11

Energy input is less than energy output. Body must use stored energy to supply energy needs (body weight decreases)

Question 12

Definition:

Total amount of energy we need to expend (both internal and external work) in order to perform a given task.

Answer 12

Metabolic rate

Question 13

What is the equation for metabolic rate?

Answer 13

Energy expenditure/unit of time

Question 14

Definition:

Basal metabolic rate (BMR)

Answer 14

Minimal internal energy expenditure we need to maintain in order to meet the basic physiological functions of our body

Question 15

What conditions does a person need to be under in order to perform a calorimetry assessment to determine BMR?

Answer 15

• person should be at physical rest
• person should be at mental rest
• done at comfortable room temperature
• no food consumed within 12 hours

Question 16

What factors influence metabolic rate?

Answer 16

• thyroid hormones levels (primary determinant of BMR)
• sympathetic stimulation (epinepherine/norepinepherine)
• exercise (post exercise BMR stays high)
• daily activities
• sex/gender (male have higher BMR)
• age (babies use more energy/weight than adults)

Question 17

Definition:

Set of life sustaining chemical processes that enables organisms transform the chemical energy stored in molecules into energy that can be used for cellular processes

Answer 17

Metabolism

Question 18

Is your brain or you bones more metabolically active?

Answer 18

Brain

Question 19

Definition:

Cellular process that build complex molecules.

Answer 19

Anabolic reaction

Question 20

Definition:

Catabolic reaction

Answer 20

Cellular process that breaks down complex molecules

Question 21

Definition:

Exothermic reaction

Answer 21

Reaction that releases energy

Question 22

Definition:

Reactions that require energy to proceed

Answer 22

Endothermic

Question 23

T/F: all chemical reactions that take place inside cells are a part of our cellular metabolism

Answer 23

True

Question 24

What energy stored in chemical bonds can be harnessed to perform work for biological processes?

Answer 24

The potential energy stored within chemical bonds

Question 25

Fill in the blank:

All reactions in our body require a certain amount of _______ energy?

Answer 25

activation

Question 26

What do enzymes do when they act as catalysts?

Answer 26

Lower the activation energy required for a certain chemical reaction to occur which increases the reaction rate

Question 27

T/F: Enzymes are able to control multiple different types of chemical reactions.

Answer 27

False! One enzyme can only control a single type of chemical reaction. if an enzyme is not active the entire pathway will stop working

Question 28

Why are enzymes fundamental for cell functionality?

Answer 28

Enzymes determine which chemical reactions a cell can carry out and the rate at which they can proceed

Question 29

T/F: Specific molecules can regulate enzymes in order to promote or inhibit certain chemical reactions.

Answer 29

True

Question 30

Definition:

Competitve Inhibition

Answer 30

An inhibitor molecule is similar enough to a substrate that it can bind to the enzymes active site to stop it from binding to the substrate, therefore competing with the substrate to bind to the enzyme

Question 31

Definition:

An inhibitor molecule binds to the enzyme at a location other than the active site (allosteric site). Substrate can still bind to the enzyme but the inhibitor changes the shape of the enzyme so it is no longer in optimal position to catalyze the reaction.

Answer 31

Non-competitive inhibition

Question 32

T/F: Noncompetitive inhibitor is sensitive to substrate concentration

Answer 32

False! It is not sensitive to substrate concentration

Question 33

Are allosteric inhibitors the only molecules that bind to allosteric sites?

Answer 33

No

Question 34

Definitions:

Allosteric activators.

Answer 34

Bind to allosteric sites and increases reaction rates by inducing conformational change that increases the affinity of the enzymes active site for its substrate.

Question 35

Many enzymes only work if bound to non-protein helper molecules called _______

Answer 35

cofactors and coenzymes

Question 36

What are the most common coenzymes?

Answer 36

Dietary vitamins

Question 37

What does binding to cofactors and coenzymes promote?

Answer 37

optimal conformation and function

Question 38

Definition:

Feedback inhibition

Answer 38

When a reaction product is used to regulate its own further production

Question 39

How is feedback inhibition used to regulate enzyme activity in metabolism?

Answer 39

By using the products of the enzymatic reactions further enzyme activity is inhibitied

Question 40

T/F: Metabolic reactions proceed according to cellular demands.

Answer 40

True

Question 41

How does metabolism maintain chemical equilibriuma nd meet cellular needs?

Answer 41

Some metabolic products inhibit the enzymes in the chemical pathway while some reactants activate them.