Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

FLC > Metabolism Integration > Flashcards

Metabolism Integration Flashcards

1
Q

Why is our metabolism specialised?

A

Different organs and tissues have different needs
Their needs and the way particular metabolites used may vary with changing circumstances
e.g. disease
these changes can alter the way organs interact

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How does the liver integrate the bodies metabolism?

A

Provides energy for muscle, brain and other peripheral organs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Which molecule provides energy for myosin?

A

ATP directly powers myosin by converting chemical energy into movement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How does cardiac muscle recieve their energy?

A

Exclusively via aerobic respiration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the function of the liver?

A

Central role in regulating metabolism as most compounds absorbed by the gut pass through the liver

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

When do glucose levels become too dangerous?

A

Danger point when plasma glucose drops to below 2.2mM

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How does phosphocreatine provide muscles with energy?

A

Phosphocreatine + ADP ATP + Creatine using creatine kinase enzyme

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How do the kidneys aid the body under low glucose conditions?

A

During starvation, the kidneys provides the body with 1/2 of its blood glucose via the process
of gluconeogenesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How is the use of glycogen, fats and ATP regulated?

A

Regulated by Acetyl CoA synthesis from fat

Regulates glucose going into citric acid cycle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How do we get fatty acids in the body?

A

Fatty acids obtained mainly through the diet

some gained from FA synthesis in liver

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How is glucose used in muscles metabolism?

A
  1. Glucose uptake vie GLUT4 (insulin sensitive)
  2. Glucose converted to G6P via hexokinase
  3. free [glucose] low inside cells
  4. Glucose mobilised from glycogen during exercise
  5. G6P glycolysis occurs for a rapid ATP source
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How much glucose does the brain use daily?

A

Approximately 100-120g daily

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How much energy is consumed via the kidneys?

A

Kidneys use 10% of the body’s energy despite only being 0.5% of the body’s mass

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

During long term exertion, why is it most efficient to use both glycogen & fats as an energy source compared to ATP?

A
  • ATP required exceeds the amount stored in muscles
  • Complete oxidation is slow
  • Fats are a large source of ATP but metabolism is even
    slower than glycogen & phosphocreatine
  • so is efficient to use both
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What happens after intermediate starvation?

A
  • Glycogen stores depleted
  • increased lipolysis and ketogenesis
  • increased gluconeogenesis (to miantain bgl)
  • 60 hours fatty acids account for 3/4 energy provision
  • after 8 days β hydroxybutyrate is raised x 50
  • further starvation causes kidney to take over
    gluconeoegenesis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How are fatty acids delivered to target adipose tissues?

A

Via chylomicrons (dietary lipids)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Outline how actin and myosin filaments cause muscle contraction

A
  1. Myosin head binds to actin filament
  2. ATP hydrolysed into ADP + Pi (reversible reaction)
  3. Causes actin filament to be pulled along
  4. Pi molecule released
  5. Actin filament bound tightly
  6. ADP converted to ATP in myosin head to prep for new
    cycle
  7. ADP released and myosin head detaches and
    reattaches further along actin filament
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Which metabolic cycle does the body use during exercise?

A

During exercise glycolysis exceeds capacity of citric acid cycle so pyruvate is converted to
lactate and transported to the liver cori cycle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How are fatty acids used in the brain?

A

Not normally used for energy

Fatty acids used for membrane biosynthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Explain the difference in hexokinase and glucokinase

A

Both catalyse same reaction but hexokinase is present in all cells
Glucokinase is only present in hepatocytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What do adipose tissues store?

A

Reservoir metabolic energy in triglycerides and fatty acids

22
Q

What are the consequences of prolonged starvation (< 3 weeks)?

A
  • β hydroxybutyrate plateaus at 20 days
  • brain adjusts to using ketone bodies
  • other gluconeogenic precursors used (lactate and
    glycerol)
  • cori (lactic acid) cycle recycles lactate
  • glycerol & amino acids oxidised
  • Proteins broken down
23
Q

How do the kidneys ensure minimal water is lost?

A

Water soluble material is largely reabsorbed to prevent loss, producing a small concentrated volume of urine

24
Q

After 12 hours of starvation how is energy obtained?

A

45% resting energy gained from fatty acids

40% from glucose

25
Q

What is muscle creatine phosphate?

A

A small store of ATP (5-6s of energy reserves)

26
Q

Where is energy stored in cardiac muscle?

A

Has no glycogen store
Fatty acids are the main energy store
Ketone bodies and lactate also used
(lactate -> pyruvate -> acetyl CoA)

27
Q

What happens to BGL in the post absorptive phase?

A

BGL falls
insulin levels fall
Glucagon levels rise

28
Q

Where does the liver get its energy from?

A

Liver takes energy from α-ketoacids

29
Q

What factors affect metabolism ?

A 
Metabolism differs depending on:
- level of activity 
- food input 
- lifestyle 
etc.
30
Q

What is the energy obtained from glucose, used for in the brain?

A

Over half the energy obtained is used in maintaining the membrane potential via the Na+/K+
pump
The rest is used in the synthesis of neurotransmitters
(AcH and NA)

31
Q

How does the skeletal muscle aid during starvation?

A

Transamination of pyruvate -> alanine

which is released into blood and taken up by liver and converted to glucose

32
Q

What is short term muscle exertion powered by?

A
  • ATP stores
  • Glycolysis
  • Glycogen
  • Creatine Phosphate
33
Q

What are the 2 major priorities of the body when the body is deprived of food?

A

1st priority: maintain glucose levels

2nd priority: preserve protein

34
Q

How is glucose transported to the brain?

A

Via GLUT3 receptor which is saturated under most conditions due to its low km

35
Q

How does the body obtain energy during early hours of starvation?

A

Glucose released from liver due to gluconeogenesis and glycogenolysis
Mobilisation of fatty acids from adipose tissues
Insulin drops causing GLUT4 expression in muscle to fall
- reduces glucose uptake

36
Q

How many times daily is our blood plasma filtered?

A

Plasma is filtered up to 60 times daily

37
Q

How does our metabolism maintain bgl and proteins under starvation?

A

Metabolism shifts from glucose to fatty acids and ketone bodies

38
Q

How much energy is stored as triglycerides in an average human?

A

70kg man will have approximately 15kg of triglycerides stored in adipose tissue

39
Q

Why does the brain require a constant energy supply?

A

The brain lacks energy stores

40
Q

How does muscle use amino acids?

A

Muscle uses amino acids for carbon skeletons

can’t produce urine (doesn’t contain urea forming enzymes)

41
Q

What is an efficient way for muscles to gain energy?

A

Aerobic respiration is the most efficient

However requires cooperation between muscle, liver and adipose tissue

42
Q

How are blood glucose levels regulated by liver metabolism?

A
  1. Glucose transported into hepatocytes via GLUT2 (not
    insulin sensitive)
  2. Glucose immediately phosphorylated by glucokinase
  3. G6P formed
  4. G6P also gained from glycogen breakdown or
    gluconeogenesis
  5. G6P converted to glucose via G6Phosphatase
  6. GLUT2 transport glucose out of cells and into blood
43
Q

Why does anaerobic respiration cause a decrease in pH?

A

Anaerobic breakdown of glycogen stores produces lactic => fall in pH due to acid

44
Q

Outline how the transport of alanine and lactate between the liver and muscle enables anaerobic respiration to provide energy during long term exertion

A
  1. Glucose in muscle -> pyruvate
  2. Pyruvate -> alanine or lactate
    protein degradation also forms alanine
  3. Lactate and alanine transported to liver –> pyruvate
  4. Pyruvate undergoes gluconeogenesis -> G6P
  5. Glycogen in liver -> G6P
  6. G6P converted to glucose
45
Q

What is the power and speed of muscle contraction dependent on?

A

As the muscle’s energy stores are small, power and speed depends on the rate of ATP production

46
Q

How much energy does the body’s glycogen store provide?

A

Approximately 103 moles

47
Q

Why are both hexokinase and glucokinase used for the same reaction?

A

Normal cells use hexokinase due to its lower km - more efficient
Hepatocytes use glucokianse due to its higher km - takes longer due to low affinity , slowing down glycolysis, so more glucose can be stored as glycogen

48
Q

What is the consequence of rising glucagon levels?

A

Glucagon signals phosphorylase a activity
Glycogen breakdown increases
Drop in insulin reduces glucose uptake via muscle & adipose tissue

49
Q

How much energy is required for long term muscle exertion?

A

e.g. for a marathon = 150 moles of ATP required

50
Q

What is the major function of kidneys?

A

Urine production

51
Q

How is glucose transported to adipose tissues?

A

Glucose transported to adipose tissue via GLUT4 which is insulin sensitive

FLC (34 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions