CELLULAR METABOLISM

Question 1

What is cellular metabolism?

Answer 1

• is the collection of all chemical reactions that occur in the body.

Question 2

What are anabolism and catabolism?

Answer 2

• Anabolism: small molecules are built up into larger ones (requires energy)
• Catabolism: larger molecules are broken down into smaller ones (releases energy)

Question 3

What does anabolism do?

Answer 3

• provides all the materials a cell requires for maintenance, growth and repair.

Question 4

What is hydrolysis responsible for?

Answer 4

Digestion

Question 5

What is intermediary metabolism?

Answer 5

• refers to the processes that obtain, release, and use energy.

Question 6

What is primary metabolites?

Answer 6

• are products of metabolism essential to survival

Question 7

What are secondary metabolites?

Answer 7

• are not essential for survival, but may provide an advantage or enhancement

Question 8

What type of energy is needed for metabolic reactions?

Answer 8

• Activation energy

Question 9

What do enzymes do in metabolism?

Answer 9

• Enzymes control rates of both catabolic and anabolic reactions by acting as catalysts to bring about specific biochemical changes

Question 10

What are the general functions of enzymes in metabolism?

Answer 10

• temporarily bind to and bring together reacting molecules so they are in the best position for chemical interactions resulting in the formation of a product.

Question 11

What is a substrate?

Answer 11

• a substrate is a molecule that only binds to a particular enzyme
• many substrates have “are” after.
  Example: lipase catalyzes a reaction that breaks down a lipids

Question 12

What is an enzyme’s active site?

Answer 12

• a part of the enzyme molecule where substrates temporarily attach - forming an enzyme-substrate complex
• this alters the shape of the enzyme slightly to form a precise fit to the substrate
• the product forms and the enzyme releases the substrate and can then be reused

Question 13

What is a metabolic pathway?

Answer 13

• a sequence of enzyme-controlled reactions that lead to the synthesis or breakdown of a particular biochemical

Question 14

What is a regulatory enzyme?

Answer 14

• an enzyme that catalyzes one step sets the rate for the entire sequence of reactions.

Question 15

What is a rate-limiting enzyme?

Answer 15

• enzymes that become saturated when the substrate concentration exceeds a certain level.
• The first in the series of reactions that comprises the metabolic pathway

Question 16

What are cofactors/coenzymes?

Answer 16

• some enzymes only become active when they combine with a nonprotein component called a “cofactor”
• the cofactor helps the active site fold into it’s appropriate conformation
• may be an ion, such as copper, iron or zinc. Or a small organic molecule called a COENZYME

Question 17

What is denaturation?

Answer 17

• Exposure to excessive heat, radiation, electricity, fluids with extreme pH values, or certain chemicals can denature, or alter, the conformation of an enzyme or inactivate it that makes the enzyme nonfunctional

Question 18

How do enzymes “recognize” their substrates?

Answer 18

• a substrate is a specific type of molecule that a certain enzyme can act on.
• It recognizes the substrate by the unique 3D shape, or conformation of the enzyme.

Question 19

What is a cofactor?

Answer 19

• a nonprotein molecule that must combine with an enzyme in order to activate it.
• Ion, or an organic molecule or vitamin

Question 20

What is a coenzyme?

Answer 20

• A small organic molecule such as a vitamin that acts as a cofactor.
• Both help the enzyme catalyze a chemical reaction

Question 21

What is energy in metabolic reactions?

Answer 21

• energy is the capacity to change something; it is the ability to do work

Question 22

What are common forms of energy?

Answer 22

• heat, light, sound, electrical, mechanical, and chemical energy
• chemical energy is the most abundant within the body

Question 23

Where is chemical energy held?

Answer 23

• Is held in the bonds between the atoms of molecules and is released when these bonds break

Question 24

What is oxidation?

Answer 24

• the loss of hydrogen atoms (with their electrons) from molecules such as glucose, resulting is loss or release of energy

Question 25

What percent of energy do cells capture from the breaking of chemical bonds in cellular Respiration?

Answer 25

• About 40%

Question 26

What is ATP?

Answer 26

• Is the primary energy carrying molecule within a cell
• Carries energy in a form that a cell can use
• Stores high amounts of energy in it’s phosphate bonds

Question 27

What does ATP consist of?

Answer 27

• an adenine, a ribose and a three phosphates chain

Question 28

What is an ADP?

Answer 28

• an ATP molecule that has lost it’s terminal end and is now left with two phosphate molecules