Questions tagged [biochemistry]

The study of chemistry within the scope of biology: the compounds that occur and the reactions involving them in living organisms.

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28 views

In vivo, does it take energy to move double bonds from cis to trans in long chain unsaturated fatty acids

In vivo, I understood that because all polyunsaturated fatty acids bonds are -cis they are crowded, kinking the molecule, and because of that, the oxidative enzymes cannot initially access them. They ...
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205 views

Don't the radioactive labeled molecules of dNTPs or DNA harm themselves or their surroundings?

I'm reading some papers for the first generation sequencing methods and some earlier than them, like Ray's Wu first time DNA sequencing from a λ phage virus cohesive 5' ends. Ray Wu, like Maxam-...
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60 views

Regulation of the TCA cycle and glycolysis by adenine nucleotides

Why is the tricarboxylic acid cycle regulated by the ADP/ATP ratio as stated in the following quote : Isocitrate dehydrogenase is allosterically stimulated by ADP, which enhances the enzyme's ...
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About the mechanism of coupled reaction/metabolism with ATP

I am not in the field of biochemistry so this may be a rookie question or misconception. I heard occasionally about the energy "released" from ATP hydrolysis fueling (endergonic) biological reactions....
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118 views

What advantage does lactose have as the main sugar in milk?

Most organisms have lactose as their main sugar in their milk. What advantage does lactose give have over sucrose (Which is a common sugar in the plants, so it makes sense for it to be present in ...
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3answers
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How many molecules of ATP are actually produced in aerobic respiration?

I have been through the process of aerobic respiration a few times in different text books and almost every book quotes a different value for the number of ATP molecules produced. The consensus seems ...
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What's unique for vitamin B-12 group?

I've been trying to figure out what makes the vitamin B group really big with 8 vitamins. Chemically they have different structures. Solubility: not only vitamins from this group are water soluble ...
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2answers
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How to derive Hill equation (one specific part)

There is just one specific step in the derivation of the Hill equation for haemoglobin which I can't understand. Step from: $Y = \frac{(p\ce{O2})^n}{K_d + (p\ce{O2})^n}$ To: $Y = \frac{(p\ce{O2})^n}{(...
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What makes iodine an effective antiseptic?

I'm thinking about tincture of iodine, potassium iodide (Lugol's), and povidone-iodine (PVP-I) specifically, which, as is my understanding, work by solubilizing elemental iodine in an aqueous solution....
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22 views

Assembly of polypeptides expressed from different chromosomes to make a fully functional protein

In case of human beings, the whole genome is divided in 23 pairs of chromosomes in somatic cells. It has been observed that in case of many proteins (e.g. immunoglobulins, hemoglobin) different ...
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pH on skin penetration of salicylic acid

I have found that at lower pH, there is more free salicylic acid (due to pKa of roughly 3), which is neutral/uncharged and then can penetrate the skin's oils which are non-polar. At higher pH, more ...
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51 views

Can microbes become “overweight”?

Just out of some weird thoughts, can a microbe (any single-celled organisms, accepting answers for both prokaryotes and eukaryotes) ingest too much food (e.g. via absorbing too much involuntarily ...
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655 views

Which type of test tube should not be used for blood collection?

The following question is presented in my biology textbook: You are required to draw blood from patient and keep it in a test tube for analysis of blood corpuscles and plasma. You are provided with ...
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61 views

Can bacteria pick up lethal plasmids?

I am sorry if this question is too general, and does not have any concrete answer. I was explaining to my non-biology-background friend about plasmids and how they are picked up by bacteria from the ...
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How does salicylic acid (2-hydroxybenzoic acid) break down desmosomal proteins to exfoliate skin?

I've been searching for an explanation to salicylic acid's property of being able to break down desmosomal proteins, such as desmogleins in order to disrupt the outer layer of skin. Can someone ...
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What is the fastest speed you can centrifuge a blood sample without changes in analyte concentrations?

What is the fastest speed you can centrifuge a blood sample without changes in analyte concentrations?
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A question about L-Citrulline

I know that L-Citrulline enters in the second step of urea cycle in the liver mitochondria and I wonder if a person takes an overdose of L-Citrulline wouldn't that cause mild hyperammonemia or at ...
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49 views

How much heme is in cooked pork and beef; why is cooked pork (“the other white meat”) not red?

The new video See how Impossible Pork will make you forget about pig meat includes a very short discussion of the addition of heme to the product to make it taste like beef the deep red color of a ...
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What are the disadvantages of myelin

The myelination of axons has plenty of advantages. It increases signal speed in axons, and thereby reduces reaction times. This is, of course, very good for the survival of the animal in question. ...
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Why does absorption (at 260nm) of ssDNA increase with temperature?

In the graph below, I understand why A260 of double stranded DNA would increase with temperature increase, as more of the DNA becomes single stranded (and A260 of ssDNA is higher than that of dsDNA ...
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Appropriate regeneration of StrepTrap HP columns for FPLC

My question is related to protein purification using a ÄKTA FPLC. We used StrepTrap HP Columns (1 ml column Volume (CV)) from GE Healthcare Life Sciences to purify a strep-tagged protein. In the first ...
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1answer
62 views

Design rules for DNA linkers

I want to use double stranded DNA linkers to physically bind two "things" together, by grafting ssDNA on each one of them and using DNA hybridization as the locking mechanism. I do not expect the ...
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56 views

A question about cancer antigens and their mechanism [closed]

Can you name the most common antigen that cancer cells in general can't live without?
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Where do methyl groups in the human body come from?

Where do methyl groups in the human body or other mammals come from? Do we synthesize them (where?) Do we get them from our diets (in what? anything beside methionine?) Do our gut microbes produce ...
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what is the princlple of using DMS (Dimethylsulphate) for structural analysis of rRNA?

I want to check the secondary structure of rRNA (PTC) in a particular position by using DMS footprinting. I have deleted the modified nucleotide (m5c) which is present in the PTC and it helps in the ...
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Does drinking coffee have negative effects?

From what I collected, coffee is a magical potion that lets you feel energetic, and essentially not-sleepy. But are there any tradeoffs? I mean, if it was so beneficial, wouldn't the human body ...
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535 views

Does a generator potential pass along a nerve the same way an action potential does?

I have read that a generator potential is a localized depolarization of a membrane. Does that mean that it does not pass along a neuron the same way an action potential does ? If not, then how do ...
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Glucose 6-phosphate dehydrogenase: reaction mechanism

I have searched the internet for the reaction mechanism of G6PD but couldn't find it, so I am asking whether anyone here knows its mechanism and whether they could recommend some sources that give ...
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1answer
67 views

How does SDS-PAGE separate based on mass?

If $F=qE =ma$ then $\frac{m}{q}a=E$, and in SDS-PAGE electric field and mass-to-charge ratio is all approximated to be constant for all proteins. Thus, all proteins must migrate with a constant ...
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Why is ATP the preferred choice for energy carriers?

Why is ATP the most prevalent form of chemical energy storage and utilization in most cells?
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What is the role of the pyrrolidine/piperidine moieties in fagopyrins?

Fagopyrins are phototoxic compounds that cause fagopyrism. They are chemical compounds related to hypericin and pseudohypericin. Some variations lack one or both methyl groups, which I think is to ...
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How does lipoid pneumonia lead to acute respiratory distress syndrome (ARDS)?

How does lipoid pneumonia lead to acute respiratory distress syndrome (ARDS)? The vaping illnesses that have been happening on the news in the United States are being caused by the federal ...
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Do pyrocalciferol and isopyrocalciferol form in vertebrate skin?

I heard that pyrocalciferol and isopyrocalciferol can only be formed above 100°C/212°F, yet some images in the web depict them as forming in vertebrate skin. So, I wonder if pyrocalciferol and ...
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It there any experimental approach to determine the electronic structure of a given aminoacid inside a protein?

It there any experimental method to determine the electronic structure of a given amino acid inside a protein?
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Difference between prions and amyloid proteins?

Amyloid and prions are misfolded proteins, but what, if any, is the difference between them? Is amyloid a type of prion with a fibrillar structure?
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How can I liquefy egg shell membrane

I want to extract egg shell membrane from the eggs. And I want to put them together and turn them into fluid so that I can make whatever shape I want. Is there any method that can make them into fluid?...
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1answer
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Why does the structure for cellular retinol binding protein show interactions with cadmium ions?

A structure of cellular retinol binding protein (1CRB) contains two cadmium ions as ligands. Is Cd2+ a ligand of CRBP and, if so, is that interaction necessary for protein function or is the protein a ...
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How many water molecules will be produced starting from acetyl-CoA in citric acid cycle

I am puzzeled by the answer. Acetyl-CoA when enter citric acid cycle, it produces 3NADH, 1FADH2, total 4 reducing equivalents. If each one makes 1H2O, then 1acetyl-CoA should make 4H2O. Why some ...
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68 views

Can something cause both breaks and cross-links in DNA?

A double strand break in DNA is exactly that: the strands of DNA are severed. A cross-linkage occurs when something forms a covalent bond between two nucleotides in DNA. However, is it possible for ...
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110 views

What does the presence of 6 molecules of water in this equation indicates to?

so I was studying biology today and I went over this weird question that says: The presence of 6 molecules of water in this equation: C6 H12 O6 + 6O2 --> 6CO2 + 6H20, Indicates that the: a) Complete ...
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What do the the different arrowheads mean in a cell signalling diagram?

What do the different arrowheads mean in the figure below? Are there arrows upstream or downstream signalling?
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What's the difference between mannanase and mannosidase?

Specifically, in Aspergillus spp mannandegrading enzymes. I saw this table at the BRENDA's page for 3.2.1.25 and 3.2.1.78 enzymes and the synonims are reciprocal to me. So, why a mannanase is also (...
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Does food grade diatomaceous earth contain mercury

Not sure if this is the right site to ask this question, but since diatomes are or once were biological creatures it seemed to fit this one more than any of the others. I have been supplementing my ...
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What does it mean to be a fully human monoclonal antibody?

I somewhat understand that some monoclonal antibodies are developed from the cells of mice, or a fusion of human and mice genes. When something is a fully human monoclonal antibody does that mean it ...
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How can we digest lactose even though it has Beta glycosidic linkages?

I have Read that we cannot digest cellulose because we do not have enzymes to digest Beta glycosidic linkages in Cellulose Then how is it that we have an enzyme called Lactase to digest the Beta ...
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Does more ATP present mean that a microbe can ferment more and decrease the pH? [closed]

I noticed that EMP produces 2 ATP and EDP produces 1 ATP. Does that mean that if more ATP is present that would give more energy for fermentation and lowering the pH of a system?
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In a sugar such as a disaccharide are both ends of the sugar known as reducing ends?

For example, in maltose (a disaccharide of glucose monomers) are both of the ends either side able to be opened to form an aldehyde group?
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What are the chemicals in the gap at a synapse? [duplicate]

I am learning about (introductory level) biological psychology and the synapse structure came into mind. I do understand that neurotransmitters are transmitted between two neurons via the synapse ...