MEH 1 - Energy Reactions In Cells Flashcards Preview

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Flashcards in MEH 1 - Energy Reactions In Cells Deck (18)
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What is metabolism?

The set of processes which derive energy and raw materials from food and use them to support repair, growth and activity of the tissues of the body to sustain life


What are the two main types of metabolic pathways?

Catabolic pathways and anabolic pathways


What is the function of catabolic pathways?

- break down larger molecules into smaller ones
- release large amounts of free energy
- oxidative (release H atoms) and have 'reducing power'


What is the function of anabolic pathways?

- Synthesise larger cellular components from intermediary metabolites
- use energy released from catabolism (ATP)
- reductive (use H released in catabolism)


What do metabolised fuel molecules supply?

- building block materials (eg sugars, amino acids, fatty acids)
- organic precursors (acetyl CoA)
- biosynthetic reducing power (eg NADH, NADPH)
- energy for cell function (ATP)


Energy is the capacity to do work. What sort of work must be carried out in the body?

- biosynthetic work (anabolism)
- transport work (eg maintenance of ion gradients, nutrient uptake)
- specialised functions (includes mechanical, electrical and osmotic work)


How do the standard international unit of energy and the units of energy used for food differ?

The standard international units of energy are Joules or kJ, while food is measured in kcal.

1 kcal = 4.20 KJ


Which has the most energy in it - fat, carbohydrate, protein or alcohol?

Fat, then alcohol, then carbohydrate, then protein


What is the basal metabolic rate?

Energy required by an awake individual during physical, digestive and emotional rest. Approx. 1400-1700 kcal


What is the difference between an exergonic and an endergonic reaction?

Exergonic - releases energy, reaction is spontaneous (catabolism)

Endergonic - requires energy, reaction not spontaneous (anabolism)


What are the standard conditions that delta G is usually measured under?

25 degrees C, 1 atm, 1 molar concentration of reactants and products, pH=7


What is oxidation?

Removal of electrons or removal of H atoms


Give some examples of H-carrier molecules



How does ATP concentration affect catabolic/anabolic pathways?

[ATP] high = anabolic pathways are activated

[ATP] low and [ADP/AMP] low = catabolic pathways activated


What is phosphocreatine?

A molecule that can phosphorylate ATP in the muscles, in cases where ATP supplies have run out


What is creatine kinase used as a marker of?

Used to indicate myocardial infarction. Specific isoform combinations are specific to certain locations, including heart muscle. This means that we can be sure there is heart damage.


What is creatinine?

Breakdown product of creatine and creatine phosphate, excreted via kidneys


Give some clinical uses of creatinine

- creatinine excretion per 24h is proportional to muscle mass of individual, so provides a measure of muscle mass
- concentration in urine is marker of urine dilation
- can be used to test urinary loss of many substances

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