Unit 3

Question 1

*Metabolism

Answer 1

-All of the chemical reactions within each cell of an organism.

Question 2

*Chemical reactions

Answer 2

-The breaking and forming of bonds between different substances during chemical changes.

Question 3

*Catabolic

Answer 3

-Reactions that break down larger molecules into simpler compounds.

Question 4

*Anabolic

Answer 4

-Reactions that build larger molecules from smaller ones.

Question 5

*Activation energy

Answer 5

-The amount of energy needed to make a chemical reaction start.

Question 6

*Reactant (substrate)

Answer 6

-Substance that is changed during a chemical reaction.

Question 7

*Product

Answer 7

Substance that is made during a chemical reaction.

Question 8

*Endothermic

Answer 8

-A reaction that overall absorbs more energy (in the form of heat or light) than it releases.

Question 9

*Exothermic

Answer 9

-A reaction that overall releases more energy (in the form of heat or light) than it absorbs.

Question 10

*Enzyme

Answer 10

-(Usually a protein) that speeds up a biochemical reaction by lowering its activation energy.

Question 11

*Catalyst

Answer 11

-Substances that speed up reactions without being permanently altered.

Question 12

*Active site

Answer 12

-Location on an enzyme where the substrate binds.

Question 13

*Denaturation

Answer 13

When an enzyme’s active site loses its specific shape, causing a loss in biological activity

Question 14

Summarize how energy changes during a chemical reaction as bonds are broken and formed.

Answer 14

*Energy is released when bonds are formed.
*Energy is absorbed when bonds are broken.
*No energy in the system gets lost, but can seem lost due to a change in form.

Question 15

Explain the overall function of enzymes in biochemical reactions like photosynthesis and cellular respiration.

Answer 15

*Enzymes control all metabolic reactions. They speed up reactions (that can occur on their own, just slowly) by lowering the activation energy needed to get the reaction started.

Question 16

Draw and label energy diagrams of biochemical reactions (endothermic AND exothermic), including products, reactants, and activation energy.

Answer 16

check doc

Question 17

Describe five factors that affect the rate of chemical reactions.

Answer 17

As temperature increases, the rate increases (to a degree) due to molecules moving faster and colliding more.

Enzymes work in specific pH ranges. They can lose function outside of that range and not be able to speed up the reaction.

As substrate concentration increases, the rate increases, due to more particle collisions.

Catalysts (like enzymes) speed up reactions by lowering the activation energy needed.

Competitive inhibitors lower the rate by competing with substrate for the enzyme’s active site.

Question 18

*ATP

Answer 18

-An energy-carrying molecule that carries/stores energy for cell functions; the main energy currency for the cell

Question 19

*Chemiosmosis

Answer 19

-Movement of ions down a concentration gradient

Question 20

Explain the purpose of ATP.

Answer 20

*ATP carries energy in a usable form for the cell wherever it is needed.

Question 21

2.Draw the structure and label the parts of a molecule of ATP.

Answer 21

check doc

Question 22

Describe the ATP-ADP cycle. Include what is and is not recycled, and the role of ATP synthase.

Answer 22

*ATP is really unstable, so it doesn’t take a lot of energy to break the bond between the 2nd and 3rd phosphates.

*When this happens and the P goes off to bond elsewhere, energy is released for the cell to use.

*When consumed food gets broken down during cellular respiration, the energy gets stored in ATP by adding a 3rd phosphate back on to ADP.

*ADP is recycled, nothing else necessarily is.

*ATP Synthase is the enzyme that catalyzes the addition of the 3rd phosphate to make ADP à ATP.

Question 23

Explain what the energy is used for when a phosphate is removed, and where that energy initially comes from.

Answer 23

*Energy can be used for active transport, cell division, or other cellular processes.
*That energy initially comes from glucose (a carb) and other macromolecules.

Question 24

Summarize why the overall process of breaking down ATP is considered an exothermic process, while the overall process of forming ATP is considered an endothermic process.

Answer 24

*It doesn’t take a big input of energy to break the 3rd phosphate off (since ATP is so unstable).
Overall, more energy is released than absorbed by this process, and thus it is considered exothermic.

*It takes a lot of energy to attach the 3rd phosphate, so very little is released when ATP is formed.
Overall, because more energy is absorbed than released, it is considered an endothermic process.