Chapter 12: metabolism bioenergetics

Question 1

Definition of metabolism

Answer 1

The set of all catabolic and anabolic activities constitutes an organism’s metabolism.
There is a 50/50 of catabolism and anabolism

Question 2

Definition and characteristics of catabolism

Answer 2

• Set of reactions involved in :
• breaking down large molecules into smaller ones. They are degrading the nutrients. Fats, carbs and proteins
• oxidizing molecules
• release energy and it will be captured in the form of ATP*

Question 3

Definition and characteristics of anabolism

Answer 3

• Build large molecules
• Also known as synthetic reactions.
• reductive
• use’s ATP energy. ATP cannot be stored.

Question 4

Digestion

Answer 4

a. Hydrolysis of the macromolecular nutrients: proteins, polysaccharides, and triacylglycerol’s, to their components: amino acids, monosaccharides and fatty acids.
b. They are known as metabolic fuels.

Question 5

Digestion of proteins

Chemical reaction and enzymes involved

Answer 5

a. Chemical reaction: proteins are hydrolyzed by proteases.
b. There are dozens of proteases
- Addition of water to break the peptide bond

Question 6

Digestion of carbohydrates

Chemical recations and enzymes involved

Answer 6

a. Polysaccharides are hydrolyzed by amylases

Question 7

Digestion of triglycerides

Chemical reaciton and enzymes invovled

Answer 7

a. Triacyclglycerols are hydrolyzed by lipases
b. Two fatty acids and one mono_____

Question 8

Fats of digesiton products

Answer 8

a. They can be degraded in catabolism or
b. They can be stored as large molecules which can be later mobilized as needed.
c. When in excess the body can start storing it
d. The body stores glycogen. Eating a lot of starch will become the glucose that will be reconnected and it will from glycogen *

Question 9

Storage form of glycose and reaciton needed to remove it from storage

Answer 9

a. Glycogen is broken down through phosphorolysis. Combo of hydrolysis and phosphorolysis
b. Called phosphorolysis because the glycosidic bond at the ends is hydrolyzed while simultaneously it will be phosphorylated.

Question 10

Storage of triglycerides and how the products of triglyceridies are transported

Answer 10

a. Triglycerides are stored in the adipocytes (fat cells)
b. Not all the fat cells will be hydrolyzed
c. When needed, stored fat can be hydrolyzed releasing fatty acids which are transported by the protein albumin or linked to cholesterol
d. The cholesteryl esters and some intact fats combine with proteins to form the lipoproteins
e. Lipoproteins are the transport proteins of lipids

Question 11

Metabolic pathways

what are they?

Answer 11

A series of conecutive reactions

Question 12

metabolic pathway

what is a metabolite

Answer 12

inolvve mostly intermediates called metabolites

Question 13

Metabolic pathway

What is a precursor. And what is an example

Answer 13

Few metabolites may be used as precursors. Pyuravte is a precurosor

Question 14

Relationship between the reduction state of a compound and the amount of energy released

Answer 14

a. Many metabolic pathways involve oxidation-reduction reactions.
i. In Ch4, C is the most reduced form and in CO2, C is in the most oxidized form.
b. Carbons in fatty acids and carbohydrates are oxidized to CO2
i. These are reduced or partially reduced carbons represent a form of stored free energy

Question 15

Coenzymes (cofactors) used as acceptors and electrons

Answer 15

a. Some cofactors undergo oxidation-reductions.
b. The coenzymes NAD+ and NADP+ accept electrons in the form of a hydride ion (a hydrogen with 2 electrons).
i. NAD+ is the most common
c. NAD+ contains adenosine
d. When a compound is oxidized it releases energy
e. NAD+ when it accepts electrons it can be reduced to NADH. It participates in catabolism (degrading the foods we are eating) as an acceptor of electrons
f. NADP+ when it accepts electrons it becomes NADPH. It participates in anabolism as a reducing agent.
g. Ubiquinone, another electron acceptor, is reduced to ubiquinol.
h. Ubiquinone or Q or CoQ or coenzyme Q accepts 2 electrons ( one at a time).
i. The Q is the oxidized form ready to accept electron
ii. QH2 is the reduced form; it has already accepted the electrons

Question 16

How cofactors are recycled

Answer 16

a. Reduced cofactors release electrons in the electron transport chain (ETC) through process called oxidative phosphorylation.
b. The components are known as the ETC ____
c. The process is known as the oxidative phosphorylation

Question 17

The steps of metabolism figure

Answer 17

Question 18

Characteristics of metabolic pathways

Answer 18

a. They are all connected
b. They are all regulated
c. Not all of them are found in all cells. The only cells that have everything are the liver cells.
d. Cells have a unique metabolic repertoire
e. Organisms may be metabolically interdependent

Question 19

Types of substances humans cannot make and why thee substances are called essential

Answer 19

a. To be essential it means that it is needed in our diet.
b. Other organisms can make them ( like plants)

Question 20

Role of vitamins in metabolism and characteristics

thiamine

Answer 20

a. They are classified as water solute and fat soluble
i. Some are very important because they are precursors for coenzymes.
b. Thiamine (vitamin B1)
i. First B vitamin discovered
ii. It is a prosthetic group of some essential enzymes

Question 21

Role of vitamins in metabolism and characteristics

Niacin

Answer 21

c. Niacin
i. Vitamin B3
ii. A component of the coenzymes NAD+ and NADP+

Question 22

Characteristics of free energy changes in metabolic reactions

Answer 22

a. Metabolic reactions are linked and not isolated.
b. Thus, free energy of metabolism (entire system) is constantly changing
c. It changes when in the system a chemical reaction takes place

Question 23

Relationship between equilibrium constant and standard free energy

Answer 23

a. The free energy change depends on reactant concentrations
i. It is the driving force that reactants experience to reach their equilibrium

Question 24

Meaning of standard free energy change

Answer 24

a. The conditions are going to be different

Question 25

Biochemical standard state conditions

Answer 25

Question 26

How the actual free energy change is calculated

Answer 26

Question 27

Components of ATP

Answer 27

a. ATP is often involved in coupled processes

Question 28

Meaning of “a coupled process”

Answer 28

a. Coupling a favorable with an unfavorable

Question 29

Features of the ATP cycle

Answer 29

a. ATP hydrolysis provides the energy for glucose phosphorylation

Question 30

Factors that explain the favorable hydrolysis of ATP

Answer 30

Question 31

Meaning of “high” and “low” energy phosphorylated compounds

Answer 31

Question 32

Position of ATP in the table of “high” and “low” energy phosphorylated compounds

Question 33

Why does ATP have an intermediate position in the table?

Question 34

The phosphocreatine hydrolysis reaction

Answer 34

Phosphocreatine has a standard free energy of hydrolysis of -43.1 kJ/mol

Question 35

The thioesters hydrolysis reaction

Question 36

Which steps are regulated in a metabolic pathway