Unit 8 Flashcards

1
Q

Integration level- flow of key metabolites between different pathways

A

Cellular level

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2
Q

Integration level- interdependence of different organs and tissues

A

Tissue and organ level

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3
Q

Major metabolic fuel

A

Glucose

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4
Q

What is the storage form of glucose?

A

Glycogen

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5
Q

Cells that contain _________ can generate glucose and send to the blood stream.

Name some examples

A

Glucose 6-phosphate.

Liver, kidney, and small intestine

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6
Q

Other sources of glucose

A

TAGs and glucogenic amino acids- used for gluconeogenesis

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7
Q

What carries nutrients to the liver?

A

Portal vein

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8
Q

______ turn nutrients into fuel

A

Hepatocytes

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9
Q

What causes enzymes to increase or decrease?

A

Changes in diet

Needs of other tissues

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10
Q

What allows for passive diffusion of glucose in and of the blood? Found in hepatocytes

A

GLUT2

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11
Q

What is the glucose phosphorylating enzyme?

A

Glucokinase (Hexokinase IV)

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12
Q

What makes glucokinase soo special?

A

It has a higher Km (10mM) than other kinases (4mM)

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13
Q

When is glucose-6-phosphate not made? Why?

A

When glucose is low

other tissues need the glucose?

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14
Q

Where is GLUT2 found?

A

In the liver and pancreas

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15
Q

What are the monosaccarides in the liver that can convert into glucose-6-phosphate?

A

Fructose, galactose, and mannose

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16
Q

What are the potential fates of glucose-6-phosphate in the liver?

A

1- It is dephosphorylated by glycogen phosphorylase (yields free glucose to send to other tissues)

2- Makes glycogen with phosphoglucomutase

3- Enter glycolysis to make Acetyl-CoA for FA biosynthesis

4- Enter glycolysis pathway to make acetyl-CoA for ATP generation

5- Enter Pentose phosphate pathway to yield NADPH

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17
Q

Glucose-6-phosphate metabolism generates nucleotides and reductive biosynthesis power in the form of ______ via what pathway?

A

NADPH

Pentose phosphate pathway

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18
Q

Potential fates of amino acids in the liver:

A

1- Biosynthesis of proteins for the liver and other tissues

2- Biosynthesis of hormones and nucleotides

3- Biosynthesis of CAC intermediates or pyruvate for gluconeogenesis

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19
Q

What is pyruvate converted to acetyl CoA?

A

For liver cell energy and conversion to lipids

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20
Q

Potential fates of fatty acids in the liver:

A

1- Synthesize liver lipids

2- Oxidize to acetyl-CoA and NADH

3- Convert to phospholipids

4- Convert to TAGs for storage

5- Carried to heart and muscle for oxidation

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21
Q

Fate of Acetyl-CoA in the liver:

A

1-Sent thorugh CAC and oxidative phosphorylation to make ATP

2- Some is converted into cholesterol, which in turn becomes either bile salts or steroid hormones in the blood

3- Excess Acetyl-CoA is converted to ketone bodies for the brain and heart in carbohydrate restriction and fasting

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22
Q

Free fatty acids in the blood bind to what?

A

Albumin

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23
Q

Ketone bodies include: (3)

A

Beta-hydroxybuterate

Acetoacetate

Acetone

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24
Q

When are ketone bodies made?

A

when oxaloacetate pools are insufficient to condense with acetyl-CoA

25
Q

Why are ketone bodies able to enter the brain?

A

they do not bind to albumin

26
Q

Ketone bodies are _____ for energy in place of, or to supplement ____.

A

oxidized

glucose

27
Q

% of ketone bodies that supply energy for the brain:

For the heart:

A

70

30

28
Q

Liver functions: (4)

A

Provide glucose and ketones for other organs

Process amino acids into urea, etc

Store nutrients (iron, fat soluble vitamins)

Detoxify and solubilize organic compounds via cytochrome P45 system

29
Q

Adipocyte function: (4)

A

Carry out glycolysis though oxidative phosphorylation

Convert acetyl-coa into fatty acids

Use FA to make TAGS

Release FA when other tissues need them

30
Q

FA make TAGS from ______ found in intestinal lipids

and ____ found in the liver

A

chylomicrons

VLDL

31
Q

What does skeletal muscle use for energy?

A

glucose

FA

Ketone bodies

32
Q

What does resting skeletal muscle rely on for energy?

A

fatty acids

33
Q

what do active skel muscle rely on for energy?

A

glucose and ketone bodies

34
Q

What muscle type is rich in mitochondria and is fed by many blood vessels?

How does it provide energy?

A

Slow-twitch muscles

via slow and steady oxphos

35
Q

What muscle type has fewer mitochondria and has lower O2 delivery?

A

Fast-twitch muscle (aka white muscle)

36
Q

why do fast twitch muscles use ATP faster and fatigue faster?

A

Due to greater demands (more tension), combined with reduced O2 delivery

37
Q

What can increase mitochondria in skel muscle?

A

endurance training

38
Q

Sources of glucose and ATP for skel muscle

A

Muscle glycogen -> glucose 6-phosphate

phosphocreatine

39
Q

muscle glycogen -> glucose-6-phosphate yields # ATP

why?

A

3 (opposed to glycolysis making 4)

glycogen breakdown skips ATP dependant hexokinase reaction

40
Q

Pyruvate->lactate creates _____ to enable _____ to continue

A

NAD+

glycolysis

41
Q

Phosphocreatine acts on _____ ____ to release _____. Another biproduct released is:

A

creatine kinase
ATP

Creatine

42
Q

During muscle contraction, lactate is produced ______.

CO2 is from ____ ___.

A

anaerobically

aerobic oxidation

43
Q

Epinephrine cascade stimulates ____ ____. It breaks down:

A

glycogen phosphorylase

glycogen in muscle and liver

44
Q

What is O2 debt?

A

continued rapid breathing after vigorous exercise. This is bc O2 is still needed for oxphos to make ATP.
(ATP is then used for gluconeogenesis to use up lactate and replenish muscle glycogen)

45
Q

Heart or skeletal muscle- which has more mitochondria?

A

heart

46
Q

What does the heart muscle primarily use for fuel?

A

fatty acids (although it does use some ketones, glucose and phosphocreatines

47
Q

The heart is an (AEROBIC/ANAEROBIC) organ.

What does this mean?

A

aerobic

if O2 suppy is cut off, the muscle dies (myocardial infarction)

48
Q

Metabolic cooperation between the skel muscle and liver

A

Cori cyle

49
Q

Overall cori cycle pathway:

A

Glucose -> lactate -> glucose

50
Q

What ketone body is used for the brain during starvation?

A

beta-hydroxybuterate

51
Q

What maintains the transmembrane potential essential to information transfer among neurons?

A

elecrogenic transport by the Na+K+ATPase

52
Q

____ of the nervous system can use fatty acids for energy

A

astrocytes

53
Q

ATP is used to maintain ___ ____ across membranes of neurons. Especially:

A

electrical potential

NA+K+-ATPase

54
Q

What stimulates glucose intake in muscle and fat? Pathway?

A

Insulin

glucose->glucose-6-phosphate

55
Q

In the liver, insulin stimulates ___ ____ and ____, and inactivates ____ ____.

A

glycogen synthase and glycolysis

glycogen phosphorylase

56
Q

What stimulates TAG synthesis in the fat and liver/

A

insulin

57
Q

Insulin is an ____ hormone, except for:

A

anabolic

glycolysis

58
Q

How is NADH necessary for lipid synthesis obtained?

A

by oxidation of glucose in the pentose phosphate pathway

59
Q

Dietary fats move via the ___ system as ____ from the ____ to the liver, muscle and adipose tissue

A

lymphatic

chylomicrons

intestine