Brainscape's Knowledge GenomeTM

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


See full index

LS1 Metabolism > General Energy Metabolism in Cells > Flashcards

General Energy Metabolism in Cells Flashcards

1
Q

Which tissues breakdown nutrients to release energy?

A

All tissues

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

Which tissues synthesise cell components?

A

All tissues except mature erythocytes

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

Which tissues store nutrients?

A

Liver, adipose tissues and skeletal muscle

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

Which tissues can interconvert nutrients to other nutrients?

A

Liver, adipose tissue, kidney cortex

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

Which tissues can excrete nutrients?

A

Liver, kidneys, lungs

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

What four things does cell metabolism of nutrients provide?

A
  1. ATP - for cell function and synthesis of components
  2. Building block molecules
  3. Organic precursors - that allow interconversion of building block molecules (e.g. acetyl-CoA)
  4. Bio-synthetic reducing power - used in the synthesis of cell components (NADPH)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Define catabolism

A

The breakdown of larger molecules into smaller ones - generally oxidative releasing large amounts of free energy (some of which is converted to ATP) and producing intermediary metabolites

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

Define anabolism

A

The synthesis of larger molecules from smaller intermediary metabolites - usually reductive, requiring ATP from catabolism to drive the synthesis of cell components

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

What does an oxidation reaction involve?

A

Addition of oxygen or removal of H+&e- or e-

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

What does a reduction reduction involve?

A

Removal of oxygen or addition of H+&e- or e-

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

Name the three major carrier molecules, in their oxidised (left) and reduced forms (right)

A

NAD+ –> NADH + H+
NADP+ –> NADPH + H+
FAD –> FADH2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

NAD+,NADP+and FAD+ are complex molecules which contain components which cannot be synthesised in the body and therefore must be obtained from our diet. Name the vitamins which supply these components

A

NAD+ and NADP+ come from the vitamin niacin

FAD+ comes from the vitamin riboflavin

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

Why must carrier molecules cycle between oxidative and reductive forms if cell function is to be maintained?

A

The total concentration of carrier molecules (oxidised and reduced) is constant, therefore if e.g. FAD+ is all in its oxidised state, reductive reactions that require FADH2 cannot occur

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

Name the two types of reactions that serve to reoxidise reduced carrier molecules

A
  1. Cell respiration - ETC (NADH&FADH2) which ultimately reduced O2 to H2O and the free E released –> ATP synthesis
  2. Substrate reducing reactions - use NADH or FADH2
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

NADPH is not used in the electron transport chain. What reactions require it?

A

Biosynthetic reactions involving reduction steps e.g. fatty acid and cholesterol synthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

In the cell what reactions can occur spontaneously?

A

Exergonic reactions

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

What reactions do exergonic reactions facilitate?

A

They can provide energy to drive endergonic (energy requiring) reactions

18
Q

The energy change in a reaction represents the difference in energy between the products and reactants of a reaction. What is this energy change known as?

A

Enthalpy change (delta-H)

19
Q

What is the entropy of a reaction (delta-S)?

A

Entropy is a measure of the disorder of the products relative to the reactants.

20
Q

What does positive delta-S mean?

A

There is an increase in disorder in the products of a reaction compared to the reactants

21
Q

The energy released by an exergonic reaction (delta-H negative) is not all available for work, why?

A

Some of the energy may appear in the form of a decrease in entropy.

22
Q

What is the name of the energy that is available for work?

A 
Free energy (Gibbs free energy):
d.G = d.H - T x dS
23
Q

What is noticeable about the free energy (delta-G) of a reaction which is spontaneous?

A

It’s negative

24
Q

What does a positive delta-G value for a reaction indicate?

A

The reaction requires an input of free energy to drive the reaction

25
Q

What is the standard free energy change (delta-G^o’) of a reaction?

A

The free energy change (delta-G) of a reaction WHEN measured under standardised conditions:
25oC
reactant and product concentrations: 1M
pH 7.0

26
Q

Why is the actual free energy change that is seen in a cell different from that of the values of the standard free energy change?

A

In the conditions of a cell temperature is 37oC not 25oC and the concentration or reactants and products is never 1M

27
Q

Which molecule plays a major role in coupling the free energy release during catabolism of fuel molecules to the energy requiring activities of the cell?

A

ATP

28
Q

What is Pi?

A

Inorganic phosphate (mixture of HPO4^(2-) and H2PO4-)

29
Q

What is the chemical equation for the hydrolysis of ATP?

A

ATP + H2O –> ADP + Pi

30
Q

What is the phosphate bond in ATP known as and why?

A

“high energy of hydrolysis bond” because relatively large amount of energy are available during the hydrolysis of it

31
Q

Why is ATP a carrier of free energy and NOT a store?

A

There is limited amount of ATP and ADP in the cell and the concentration of ATP is only sufficient for a few seconds of energy requiring cellular activity. Therefore it must be rapidly resynthesised from ADP using free energy released from the catabolism of fuel molecules

32
Q

What is a high-energy signal?

A

Molecules that signal that the cell has adequate energy for its immediate needs and tends to activate anabolic pathways. This is an example of negative feedback

33
Q

What is a low-energy signal?

A

Molecules that signal that the cell has not got adequate energy for its immediate needs and activates catabolic pathways to produce more ATP

34
Q

List some high energy signals

A

ATP
NADH
NADPH
FADH2

35
Q

List some low energy signals

A 
ADP
AMP
NAD+
FAD
NADP+
36
Q

List the two reactions in glycolysis, in which the reactants are phosphorylated compounds with high energy of hydrolysis bonds and therefore are coupled to substrate level phosphorylation

A
  1. Step 10:
    phosphoenolpyruvates + ADP –> pyruvate + ATP
  2. Step 7:
    1,3-bisphosphoglycerate + ADP –> 3-phosphoglycerate + ATP
37
Q

Write the chemical equation for the synthesis of the high energy bond in creatine phosphate

A

creatine + ATP –> creatine phosphate + ADP

38
Q

Write the chemical equation for the synthesis of ATP from creatine phosphate

A

creatine phoshpate + ADP –> creatine + ATP

39
Q

Which cardiac and skeletal muscle energy store is important in the first few seconds of vigorous muscle activity such as sprinting?

A

Creatine phosphate

40
Q

Why is the daily excretion of creatinine a useful indicator of skeletal muscle mass?

A

Creatinine is the product of non-enzymatic chemical changes of creatine and creatine phosphate (which happens at a constant rate). It has no function and is readily excreted via the kidneys in the urine. The rate of production of creatine is proportional to the concentration of creatine in the muscle and is related to skeletal msucle mass. Therefore increased excretion can be indicative of active muscle wasting

41
Q

Other than muscle wasting what can the excretion of creatinine in urine and the concentration in blood be an indicator of?

A

Kidney function - kidneys are normally very efficient at excreting creatinine, therefore a high creatinine concentration in blood and a low concentration in urine can indicate reduced kidney function

LS1 Metabolism (18 decks)

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