Lecture 25 Flashcards

1
Q

Are channels and pores saturable with a substrate?

A

No

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2
Q

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

A

Down

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3
Q

Is energy input required for channels and pores?

A

No

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4
Q

Is passive transport saturable with substrate?

A

Yes

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5
Q

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

A

Down

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6
Q

Is energy input required in passive transport?

A

No

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7
Q

Is primary and secondary active transport saturable with substrate?

A

Yes

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8
Q

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

A

Up the concentration gradient

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9
Q

Which types of transport are saturated with substrate?

A

Passive transport, Primary and Secondary active transport

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10
Q

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

A

A primary active transporter

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11
Q

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

A

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

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12
Q

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

A

ATP + H2O ➡️ ADP + Pi + H+

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13
Q

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

A

The hydrolysis of ATP

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14
Q

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

A

An antiport

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15
Q

Why is the Na+/K+ ATPase electrogenic?

A

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

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16
Q

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

A

> 0, so the reaction won’t proceed spontaneously

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17
Q

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

A

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

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18
Q

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

A

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

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19
Q

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

A

The size of the concentration gradient

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20
Q

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

A

Having a larger gradient

21
Q

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

A
  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
22
Q

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

A

Aspartate

23
Q

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

A

It is phosphorylated

24
Q

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

A

It has a negative free energy

25
Q

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

A

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

26
Q

What are Metabolic Pathways?

A

A series of enzyme-catalyzed reactions

27
Q

What are the chemical intermediates of Metabolism?

A

Metabolites or metabolic intermediates

28
Q

What are the two major purposes of metabolism?

A
  1. To obtain usable chemical energy from the environment

2. To make the specific molecules that cells need to live and grow

29
Q

What is breaking things down?

A

Catabolism

30
Q

What is building things up?

A

Anabolism

31
Q

What do Anabolic pathways do?

A

Use energy to build larger molecules and are generally reductive

32
Q

What do Catabolic pathways do?

A

Release energy and are generally oxidative

33
Q

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

A

Anabolic - Reductive

Catabolic - Oxidative

34
Q

What are Amphibolic pathways?

A

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

35
Q

Why are Anabolic pathways considered reductive?

A

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

36
Q

What is used to make new bonds in Anabolic pathways?

A

Electrons

37
Q

What is released as a product from oxidative processes?

A

Carbon dioxide

38
Q

Which pathways are reduced cofactors produced from?

A

Catabolic pathways

39
Q

What are examples that act as transient stores of electrons?

A

NAFH, FADH2, ATP

40
Q

What are the 4 dietary Mecromolecules?

A
  • Nucleic acids
  • Proteins
  • Polysaccharides (complex carbohydrates)
  • Triacylglycerol (fat)
41
Q

Which dietary macromolecule is not a significant fuel source?

A

Nucleic Acids

42
Q

Which dietary macromolecules are the most significant fuel source?

A
  • Polysaccharides (complex carbohydrates)

* Triacylglycerol (Fat)

43
Q

What do we need a constant supply of?

A

ATP

44
Q

How is energy in the body stored?

A

As fat or as carbohydrates

45
Q

How does the liver store carbohydrates?

A

As glycogen

46
Q

What is glycogen?

A

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

47
Q

What are fatty acids stored as?

A

Fat (triacylglycerols) in adipocytes

48
Q

Why is the fat the primary way of storing energy?

A

Because it stores energy at a significantly higher density than carbohydrates