22 Answered Questions for the topic Metabolism

Metabolism Biochemistry

07/29/19

#### Cellular demand for antioxidants?

Antioxidants such as ascorbate and glutathione serve to inactivate radicals and counteract spontaneous oxidation reactions, such as unwanted disulfide bonds in proteins. These systems are cycles,... more

07/29/19

#### About acetyl-coA in the Krebs Cycle of respiration?

In respiration, Krebs cycle starts with acetyl coenzyme A which is made from pyruvate. However, it is said that the cycle keeps repeat it self with oxaloacetate turning back to citrate and cycle... more
Metabolism Biochemistry

07/17/19

#### Energy released during the production of ATP?

When glucose is used during aerobic and anaerobic exercise, how much energy is expended or required?During aerobic exercise:$C_6H_{12}O_6 + 6 O_2 \ o ATP + H_2O + 6 CO_2$ + energyDuring anaerobic... more

07/11/19

#### Can bacteria metabolize fatty acids for fuel?

I'm not a microbiologist, but rather a physiologist curious about microbial metabolism. Much like humans bacteria can utilize glucose, but when it comes to long chain, medium chain, or short chain... more

07/10/19

#### What is an irreversible reaction?

There are reactions with large Delta G negative values. Why these reactions are irreversible? As in: out of 10 steps of Glycolysis, 3 are irreversible steps. I need an explanation for why they are... more
Metabolism Biochemistry Glucose

07/03/19

#### Why is GTP, not ATP, produced in Gluconeogenesis & TCA Cycle?

In both gluconeogenesis and the TCA cycle, there is a point in each that GTP is produced instead of the usual ATP. My question is why GTP and not ATP for these 2 specific steps?

06/04/19

#### What is the molecular basis of hangovers?

Well, most of us have experienced the wonderful feeling of the dreaded hangover. How does it work exactly? I imagine it has something to do with dehydration but what are the underlying... more
Metabolism Biochemistry Insulin

06/03/19

#### Why doesn't glucagon promote glycogenolysis in muscle?

Insulin stimulates glycogenesis in both liver and in muscles. Epinephrine stimulates glycogenolysis in both liver and muscles. But glucagon stimulates glycogenolysis in liver only. Why is this so?
Metabolism Biochemistry Glucose

06/01/19

#### Why would lactate be high in diabetics?

Why are lactate level high in diabetes? For example, type II diabetes are resistant to insulin. If those patients are insulin resistant their gluconeogenesis should be working at a high rate and,... more
Metabolism Biology Cell Biology

05/29/19

#### Do strictly anaerobic organisms use metabolic reactions requiring oxygen?

When looking through genome annotations of strictly anaerobic organisms I see reactions featuring oxygen. I suspect these are likely an artifact of the annotation process. But I am wondering if it... more

05/24/19

#### Why do mice have a higher metabolic rate than humans?

Mice and other small animals have higher metabolic rate than humans. How does that happen on cellular level, if we look on one cell in the mouse body?What is it in this cell that will be different?... more
Metabolism Biology Cell Biology

05/24/19

#### Excercise and fitness in old age?

I have seen so many news and study online, saying exercise keeps body healthy in old age and keeps us fit? how is this possible normal tear and wear will become more with activity hence more... more

05/10/19

#### What is the purpose of gluconeogenesis?

The gluconeogenesis pathway seems quite pointless to me. I don't understand why an organism would want to spend energy to create a molecule that can then be metabolized again for less energy? The... more

05/10/19

#### During starvation, does the human body do anything to prioritize which organs receive nutrients?

When food is scarce, the body slows its metabolic rate to conserve energy. Are there any other systems or processes that prioritize which organs receive nutrients?
Metabolism Biology Physiology

05/07/19

#### Is there any use of CO₂ in human body?

We all know CO₂ as a waste product of metabolism . Does CO₂ have any helpful role , apart from having a role in pH of blood ?

05/07/19

#### How do antioxidants affect human metabolism?

I'd like to know how antioxidants affect human metabolism and which ones are essential for metabolic processes.

05/04/19

#### Why is the brain dependent on glucose?

The strict dependence of the (human) brain on glucose has always been puzzling to me. While ketones can substitute for a portion of the brain's energy needs, it cannot substitute completely: blood... more

04/30/19

#### What are the effects of caffeine on the mammalian circulatory system?

A friend of mine told me an anecdote about his mother, who drank too much caffeine, to the point she became hypotensive and would pass out. Because caffeine acts as a stimulant, I'm assuming the... more
Metabolism Biology Cancer

03/17/19

#### Energy metabolism in Cancer cells?

The TCA cycle intermediate Isocitrate dehydrogenase commonly undergoes point mutations in cancers. This allows IDH to reduce a-Ketogluterate to 2Hydoxygluterate, causing a reduction in pVHLs... more

03/15/19

#### What is/are the molecular differences between HDL and LDL cholesterol?

Why exactly is HDL-cholesterol good for us and LDL-cholesterol bad for us. It has been well-established that LDL-cholesterol is associated with atherosclerosis and that HDL-cholesterol helps remove... more
Metabolism Genetics Pharmacology

03/14/19

#### What is the biological mechanism underlying caffeine intolerance? (CYP1A2 or other?)?

As far as I can tell, caffeine metabolism occurs primarily via the CYP1A2 enzyme. I am curious as to whether mutations in the CYP1A2 gene are associated with caffeine intolerance. Some site that... more
Metabolism Combustion Enthalpy

10/20/15

#### What is the standard enthalpy of combustion of maltodextrin?

Writing a lab about yeast metabolism and one metabolite we used was maltodextrin. I cannot find the standard enthalpy of combustion anywhere for this sugar but I can find it for the other sugars we... more

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