Studied by 0 people
Looks like no one added any tags here yet for you.
How is ethanol broken down? Is it an oxidation reaction?
Ethanol —> Acetaldehyde —> Acetic acid
Yes it is
What is the enzyme that is responsible for oxidizing ethanol to acetaldehyde?
Alcohol dehydrogenase
What is the enzyme that is responsible for oxidizing acetaldehyde to acetic acid?
Aldehyde dehydrogenase
In a biological system would we have acetic acid?
No we would have acetate in a biological system
What is a general rule when it comes to determining oxidation?
Carbon atoms are assigned +1 for each bond to oxygen and -1 for each bond to hydrogen
Where does ethanol metabolism take place in the body? Is there metabolic use of acetic acid?
In the liver and yes
What is the chemical reaction that explains why there is calories in alcoholic beverages?
Acetate —> acetyl CoA —> TCA cycle —> ATP production
Energy is being produced from drinking alcohol as the body metabolizes it
Is ethanol metabolism purely an oxidation reaction?
No it is also paired with reduction as it is a redox reaction
What is NAD+? What is it derived from?
Nicotinamide adenine dinucleotide and is derived from niacin (vitamin B3). NAD+ is reduced in ethanol metabolism to NADH
What are NAD+ and NADH?
They are co-enzymes (not technically enzymes but co-substrates)
Is ethanol metabolism reversible?
Yes
Is NAD+ reduced or oxidized form? NADH?
NAD+ is oxidized form and NADH is reduced
Why can we not use a strong oxidizing or reducing agent like in organic chemistry?
This is because it will kill our cells
What is a coenzyme?
It is an oxidizing and reducing agent that is the same molecule. It is an oxidizing agent in its oxidized form and a reducing agent in its reduced form
What is an oxidized state? Reduced state?
Oxidized: No hydrogen
Reduced: Hydrogen
What are the three main causes of the hang over effect?
Acetaldehyde
Acetate
[NADH] increases
Describe how acetaldehyde contributes to the hang over effect
It is very reactive and will covalently modify proteins/ enzymes. The consequence is denaturation.
Describe how acetate contributes to the hang over effect
It is the conjugate base of acetic acid so [H+] will increase in the blood. The consequence is metabolic acidosis.
Describe how [NADH] contributes to the hang over effect
Increased levels of NADH means decrease in NAD+ leading to a redox imbalance
Why was hydroxyzine used as an anti-histamine?
This is due to our body converting this poor anti-histamine into cetirizine through alcohol dehydrogenase which is a very good anti-histamine
How do we explain the alcohol flush reaction?
There is a mutation in aldehyde dehydrogenase which makes the enzyme less efficient. This causes acetaldehyde to accumulate.
What is disulfiram? What is it used for?
It is a covalent (irreversible) inhibitor of aldehyde dehydrogenase. It is used to treat alcoholism because if you drink alcohol it leads to acetaldehyde accumulation.
What is the chemical reaction that occurs when methanol enters our body? What are the two enzymes? Is it a redox reaction? Where does this reaction occur?
Methanol —> Formaldehyde —> Formic acid. Alcohol dehydrogenase and aldehyde dehydrogenase. Yes it is (NAD+ to NADH). Occurs in the liver.
Is formic acid a weak or strong acid? What about in comparison to acetic acid?
It is a weak acid but stronger than acetic acid. Therefore it will change the body’s pH balance.
Does ethanol or methanol have a smaller KM?
Ethanol has a smaller KM indicating that it has a higher binding affinity.
Why is it worse if a person drank methanol rather than a mix of methanol and ethanol?
Their cells would be saturated with ethanol first as it has a smaller KM and therefore the enzyme is occupied and can’t bind to methanol. This prevents the formation of toxic metabolites from methanol. Ethanol will outcompete methanol.
What can D-glucitol (sabitol) interconvert to? What enzyme? Is it an oxidation or reduction reaction? Is it reversible?
Can interconvert to D-glucose via the enzyme aldose reductase. It is a reduction reaction and there is also an oxidation reaction happening (NADPH to NADP+). Yes
What can D-glucose turn into? What pathway is this part of?
D-gluconic acid and this is part of the pentose phosphate pathway (PPP)
Is glucose a reducing sugar?
Yes
What is the chemical reaction to determine if a patient has diabetes or not? Explain below
Glucose + Cu2+ ———> -RCOOH + Cu+
Conditions are heat and alkaline conditions
Cu+ is a red precipitate. Cu2+ is blue. Therefore if urine is red after reaction then glucose is present and the patient has diabetes
