Lect 10 Integration of Metabolism Flashcards Preview

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Flashcards in Lect 10 Integration of Metabolism Deck (14):
1

Preferred Energy Sources of Different Cell Types:

RBC

Brain

Adipose

Liver

Muscle

RBC: Glucose

Brain: Glucose and Ketones

Adipose: Glucose and FA

Liver: FA (B-oxidation)

Muscles: Glucose, FA, AA

2

What is Adipose Tissue's function?

How do FAs travel in the blood?

Synthesizes/Store TAGs (insulin)

Release FA and glycerol (glucagon/epi)

FA attached to Albumin in Blood

3

How much oxygen does the brain utilize?

20% total O2 consumed by resting human (2% of body mass)

4

How does the Heart generate energy?

What does it use?

What will lack of O2 cause?

  • Exclusively aerobic 
  • Uses: Glucose, Lactate, FA, Ketones Bodies
    • No glycogen stores
  • Lack of O2 leads to tissue death (MI)

5

How does Skeletal Muscle produce energy?

Can it export glucose?

What else will it use if lack of glucose?

  • Glycogen (75% of body's stores) broken down to G6P for glycolysis
  • Lacks G6 Phosphatase, so muscle cannot export
  • FA and Ketone bodies

6

What is the ATP/PCr Energy System

What enzyme catalyzes ATP production?

  • Quick exhaustion of ATP stores (1-2 sec)
  • Metabolism of phosphocreatine --> creatine via phosphocreatine kinase produces ATP
    • PCr stored in muscle to quickly regenerate ATP from ADP

 

7

What is the Anaerobic Glycolysis Energy System

What forms in the absence of O2?

How is it recycled?

  • Oxidation of glucose or glycogen (glycogenolysis)
  • Lactate formation
    • Glycogen --> G6P --> Pyruvate --> Lactate
  • Cori Cycle: Lactate sent to liver to regenerate glucose

8

What is Oxidative Phosphorylation?

Why does proton pumping occur?

What produces ATP?

  • Production of energy from oxidation of coenzymes NADH/FADH2 (2.5/1.5) in the ETC
  • To establish PMF
  • ATP Synthase

9

Energy charge of a cell defined as the ratio of _

ATP to ADP

10

Reducing power of a cell is defined as the ratio of _

NADH to NAD+

11

What is secreted by SI in response to meal to signal satiation?

Short term or long term?

  • Cholecystokinin (CCK) --> Blood --> GPCR peripheral neurons in Brain
    • Postprandial Signal: Decrease Food Intake / BW
  • Glucagon-Like Peptide 1 (GLP-1) --> Brain and Pancreas
    • Increase insulin secretion and biosynthesis
  • Short Term Signals

 

12

What is Ghrelin and where is it secreted from?

Where does it act on?

Peptide secreted from stomach

Acts on Hypothalamus to stimulate appetite

13

What two signal molecules regulate Energy Homeostasis?

Where are they secreted from?

  • Leptin: secreted by adipocytes (reports on status of TAG stores)
  • Insulin: secreted by B-cells (reports on status of blood glucose)

14

What is the Overall Energy Sensor in the Cell?

When is it active/inactive?

Competition between what 2 substrates determines activity?

AMP-Activated Protein Kinase (AMPK)

ATP is High: AMPK inactive

ATP is Low: AMPK allosterically activated and phosphorylates targets controlling cellular energy production/consumption

Competition between ATP and AMP for AMPK allosteric sites determines activity of AMPK