celluar respiration(units 3&4)

Question 1

What do enzymes do?

Answer 1

Enzymes speed up biochemical reactions by lowering the activation energy required for the reaction.

Question 2

What does activation energy mean in the context of enzymes?

Answer 2

Enzymes help reactions overcome activation energy by stabilizing the transition state, reducing the energy needed to initiate the reaction.

Question 3

Are enzymes consumed in a reaction?

Answer 3

No, enzymes are not consumed and can catalyze many reactions repeatedly.

Question 4

What fits into the active site of an enzyme?

Answer 4

A specific substrate fits into the active site; specificity is high due to precise molecular complementarity.

Question 5

What can affect the rate of an enzyme?

Answer 5

Temperature, pH, substrate concentration, and the presence of inhibitors or activators.

Question 6

What metal is found in the active site of catalase?

Answer 6

Iron (Fe).

Question 7

What do coenzymes do?

Answer 7

Coenzymes assist enzymes by transferring chemical groups or electrons during reactions.

Question 8

What vitamins are coenzymes?

Answer 8

B vitamins, such as B1 (thiamine), B2 (riboflavin), and B3 (niacin).

Question 9

What is NAD used for?

Answer 9

NAD is used in redox reactions to carry electrons to the electron transport chain.

Question 10

What is an enzyme inhibitor?

Answer 10

An inhibitor binds to the enzyme, reducing or blocking its activity.

Question 11

What is the name of the site that can regulate the active site of an enzyme?

Answer 11

Allosteric site.

Question 12

What are enzymes made of?

Answer 12

Enzymes are complex folded molecules made of proteins (amino acid chains).

Question 13

What does denaturation mean?

Answer 13

Denaturation disrupts the enzyme’s structure, rendering it inactive.

Question 14

Where does pepsin reside and what is the independent variable in its activity graph?

Answer 14

Pepsin resides in the stomach; the independent variable is pH.

Question 15

What is Taq polymerase used for?

Answer 15

Taq polymerase is used in PCR for DNA replication; it is heat-tolerant due to its origin in Thermus aquaticus, a thermophilic bacterium.

Question 16

What organism uses hydrogen peroxide and catalase to defend itself?

Answer 16

Bacteria like Staphylococcus aureus and some immune cells.

Question 17

What fits into the active site of lactase and what are the products?

Answer 17

Lactose fits; products are glucose and galactose; ~35% of adults retain lactase.

Question 18

What suffix is used for almost all enzyme names?

Answer 18

‘-ase.’

Question 19

How is the head of a phospholipid different from the tail?

Answer 19

The head is polar (hydrophilic), and the tail is non-polar (hydrophobic); they form a bilayer with heads outward and tails inward.

Question 20

Is a phospholipid amphiphilic?

Answer 20

Yes, because it has both hydrophilic and hydrophobic regions.

Question 21

Why are cell and organelle membranes bilayers?

Answer 21

Bilayers provide structural stability and form selective barriers.

Question 22

What do we call the diffusion of water across a selectively permeable membrane?

Answer 22

Osmosis.

Question 23

What is a saltwater solution made of?

Answer 23

Water (solvent) and salt (solute); water is the solvent.

Question 24

If you bathe a cell in a high salt solution, will the water enter or leave the cell?

Answer 24

Water will leave due to osmosis, as the solution is hypertonic.

Question 25

Distinguish between hypotonic, isotonic, and hypertonic solutions.

Answer 25

Hypotonic: low solute, water enters; Isotonic: equal solute, no net movement; Hypertonic: high solute, water exits.

Question 26

Is there water movement in an isotonic solution?

Answer 26

Yes, but it is balanced (no net movement).

Question 27

Distinguish turgid vs plasmolyzed cell.

Answer 27

Turgid: swollen with water; Plasmolyzed: shrunken due to water loss.

Question 28

How do marsh plants like pickleweed adapt to a high salt environment?

Answer 28

They sequester salt in vacuoles or excrete it.

Question 29

What organ in your body uses osmosis to concentrate urine?

Answer 29

Kidneys.

Question 30

Why does a diet high in salt increase your blood pressure?

Answer 30

Excess salt retains water, increasing blood volume and pressure.

Question 31

What do cells use vesicle transport for?

Answer 31

To transport large molecules and particles.

Question 32

What is it called when the vesicle is going INTO the cell?

Answer 32

Endocytosis.

Question 33

What do we call the bulk transport OUT of a cell?

Answer 33

Exocytosis.

Question 34

Why are vesicles spherical?

Answer 34

Spherical shapes minimize surface tension and are energetically favorable.

Question 35

Why can’t ions freely move across a membrane?

Answer 35

Membranes are hydrophobic, and ions are charged.

Question 36

What type of protein-mediated transport does not require energy?

Answer 36

Facilitated diffusion.

Question 37

What are the two gradients that molecules will diffuse down?

Answer 37

Concentration gradient and electrochemical gradient.

Question 38

Which type of transport uses energy?

Answer 38

Active transport; energy is ATP.

Question 39

Distinguish uniport, symport, antiport.

Answer 39

Uniport: one substance, one way; Symport: two substances, same way; Antiport: two substances, opposite ways.

Question 40

What is the name of the protein channel that moves water across a membrane?

Answer 40

Aquaporin.