Lecture 25

Question 1

Are channels and pores saturable with a substrate?

Answer 1

No

Question 2

What is the movement of channels and pores relative to the concentration gradient?

Answer 2

Down

Question 3

Is energy input required for channels and pores?

Answer 3

No

Question 4

Is passive transport saturable with substrate?

Answer 4

Yes

Question 5

What is the movement of passive transport relative to the concentration gradient?

Answer 5

Down

Question 6

Is energy input required in passive transport?

Answer 6

No

Question 7

Is primary and secondary active transport saturable with substrate?

Answer 7

Yes

Question 8

What is the movement of primary and secondary transport relative to the concentration gradient?

Answer 8

Up the concentration gradient

Question 9

Which types of transport are saturated with substrate?

Answer 9

Passive transport, Primary and Secondary active transport

Question 10

What kind of transporter os the Na+/K+ ATPase?

Answer 10

A primary active transporter

Question 11

How does the Na+/K+ ATPase affect ions in each cycle?

Answer 11

3 Na+ ions exported, 2 K+ ions imported in each cycle

Question 12

What happens to ATP in each cycle of the Na+/K+ ATPase?

Answer 12

ATP + H2O ➡️ ADP + Pi + H+

Question 13

What provides the energy for the Na+/K+ ATPase?

Answer 13

The hydrolysis of ATP

Question 14

Because the sodium and potassium are moving in opposite directions in the Na+/K+ ATPase what kind of transporter is it?

Answer 14

An antiport

Question 15

Why is the Na+/K+ ATPase electrogenic?

Answer 15

Because it is making a charge gradient, it is exporting more positive charge than importing

Question 16

What is the free energy of transport of both sodium and potassium in terms of the Na+/K+ ATPase and what does this mean?

Answer 16

> 0, so the reaction won’t proceed spontaneously

Question 17

What must be done in order for the movement of sodium and potassium to occur in terms of the Na+/K+ ATPase?

Answer 17

The free energy of the reaction must be combined with ATP hydrolysis with has a G <0

Question 18

What is the sum of the free energy of the whole reaction in terms of the Na+/K+ ATPase?

Answer 18

The whole free energy is <0 because the hydrolysis of ATP is sufficiently low enough to cancel out the free energy of sodium and potassium being greater than 0

Question 19

What is the activity of the Na+/K+ ATPase determined by?

Answer 19

The size of the concentration gradient

Question 20

What makes it more difficult to move the ions into a region of high concentration in terms of Na+/K+ ATPase?

Answer 20

Having a larger gradient

Question 21

What are the steps in the Na+/K+ ATPase starting from the binding of ATP?

Answer 21

1. 3 Na+ bind into the ion binding site
2. ATP binds and phosphorylates the protein
3. Change in conformation change allowing ions to exit on other side
4. Potassium binds
5. Hydrolysis removes phosphate
6. Conformation returns back and potassium exits

Question 22

What is the side chain in the Na+/K+ ATPase?

Answer 22

Aspartate

Question 23

What happens to Aspartate in the Na+/K+ ATPase?

Answer 23

It is phosphorylated

Question 24

What is the free energy of the transport of sodium with the sodium glucose transporter?

Answer 24

It has a negative free energy

Question 25

What is the sum of the free energy of the sodium glucose symporter?

Answer 25

The free energy of sodium is less than zero and the free energy of glucose is greater than zero but the sum of them both is also less than zero so that movement can occur

Question 26

What are Metabolic Pathways?

Answer 26

A series of enzyme-catalyzed reactions

Question 27

What are the chemical intermediates of Metabolism?

Answer 27

Metabolites or metabolic intermediates

Question 28

What are the two major purposes of metabolism?

Answer 28

1. To obtain usable chemical energy from the environment | 2. To make the specific molecules that cells need to live and grow

Question 29

What is breaking things down?

Answer 29

Catabolism

Question 30

What is building things up?

Answer 30

Anabolism

Question 31

What do Anabolic pathways do?

Answer 31

Use energy to build larger molecules and are generally reductive

Question 32

What do Catabolic pathways do?

Answer 32

Release energy and are generally oxidative

Question 33

Which pathways are generally oxidative and which pathways are generally reductive?

Answer 33

Anabolic - Reductive | Catabolic - Oxidative

Question 34

What are Amphibolic pathways?

Answer 34

Pathways that operate in both catabolic and anabolic processes depending on the conditions

Question 35

Why are Anabolic pathways considered reductive?

Answer 35

Because they use reducing agents that are used to make generally more reduced molecules from oxidized molecules

Question 36

What is used to make new bonds in Anabolic pathways?

Answer 36

Electrons

Question 37

What is released as a product from oxidative processes?

Answer 37

Carbon dioxide

Question 38

Which pathways are reduced cofactors produced from?

Answer 38

Catabolic pathways

Question 39

What are examples that act as transient stores of electrons?

Answer 39

NAFH, FADH2, ATP

Question 40

What are the 4 dietary Mecromolecules?

Answer 40

* Nucleic acids * Proteins * Polysaccharides (complex carbohydrates) * Triacylglycerol (fat)

Question 41

Which dietary macromolecule is not a significant fuel source?

Answer 41

Nucleic Acids

Question 42

Which dietary macromolecules are the most significant fuel source?

Answer 42

* Polysaccharides (complex carbohydrates) | * Triacylglycerol (Fat)

Question 43

What do we need a constant supply of?

Answer 43

ATP

Question 44

How is energy in the body stored?

Answer 44

As fat or as carbohydrates

Question 45

How does the liver store carbohydrates?

Answer 45

As glycogen

Question 46

What is glycogen?

Answer 46

A polymer of glucose molecules in the liver and in skeletal muscles

Question 47

What are fatty acids stored as?

Answer 47

Fat (triacylglycerols) in adipocytes

Question 48

Why is the fat the primary way of storing energy?

Answer 48

Because it stores energy at a significantly higher density than carbohydrates