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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Why isn't the human zygote considered a human life how is a living anatomically modern human defined biologically? [closed]

It has 46 chromosomes by default when healthy(Differences almost always are pathological) and has almost every biological functions, processes a Newborn or and Adult person has. It even invades ...
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Difference between fertilin and fertilizin

I am confused between fertilin and fertilizin.Are these two same or different? Here are a few sources i referred Julian Lombardi (auth.) - Comparative Vertebrate Reproduction-Springer US (1998) Page ...
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Cerebral/Cerebellar Cortex versus Deep Nuclei

I have troubles using the terms Cortex & Deep Nuclei, and 'Nuclei' in general. From what I understand, a brain has '3 matter types in accordance to anatomical locations' Superficial Grey matter - ...
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2k views

Meaning of units in ELISA based tests?

For some ELISA based antibody tests (e.g. h-tTg antibody test), labs report units as RU/mL or U/mL. Also different labs have different cut off (normal range) values. I understand that different kit ...
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What enzyme or bacteria could dissolve plastic?

What enzyme or bacteria could dissolve plastic aside from acetone? Preferably, low-cost and environmentally friendly. Any suggestions would be helpful. I'm targeting for thin plastic (low-density ...
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What is the subcellular location of synthesis of non-essential amino-acids?

What is location of non-essential amino acids synthesis in a cell? Is it some specific organelle? And what is the gene driver behind this? I thought the whole point of DNA is coding for how to ...
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How can I get the yield of my purified immunoglobulins?

In order to get the yield of IgY through a set of purification steps, what method can I use? Thanks in advice!
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How can I change my buffer system for protein purification?

I have a protein that I purified in PBS buffer, pH 7. I will do dialysis to remove salt and will then further purify the protein with ion exchange chromatography. I will need to use another buffer (...
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Rice left in water for several months - what biological reactions or growths would occur?

In an attempt to make a hair care product, uncooked white basmati rice was left in an air-tight container half filled with tap water for several months. When opening the container, the smell was ...
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How to troubleshoot in vitro formaldehyde fixation for nucleosomes?

For an experiment, I am trying to fix the mononucleosomes (100ng) using formaldehyde as crosslinking agent in HEPES buffer. I have been using 2% formaldehyde in a reaction buffer containing 1mM EDTA, ...
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1answer
527 views

Cellular respiration in carnivorous animals

What is the equation for cellular respiration in carnivores as they don’t consume carbohydrates to break down into glucose in the following manner: Glucose + oxygen -> water + CO2 +energy. Do they (...
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Why is double stranded DNA considered to be one molecule? [duplicate]

Wikipedia, for example, refers to DNA as "a" molecule, not two separate molecules forming a double-helix structure. Isn't this technically incorrect? There are two separate polynucleotide strands (...
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Edible and non-edible leaves [closed]

For humans, what's the difference between an edible leaf like lettuce, and a non-edible (in the sense of null nutritional value) leaf like grass?
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Blood acidity and bones

By consuming acidic foods, could one cause their blood to become acidic and therefore cause an acid+base reaction between their blood and bone? I ask this because i recently discovered bone is a ...
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54 views

Cooperative Enzyme Question

I'm currently studying for the MCATs. After doing some biochemistry practice questions, I came upon a question that I believe may be incorrectly posed. I was wondering if I'm correct in saying this or ...
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253 views

Difference between cerebroside and globoside

I have a general idea about their difference that cerebrosides have a single sugar while globosides have more than one sugars. This is the structure of a ceramide (syphingosine and a fatty acid ...
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351 views

Why is beta- D fructofuranose two different structures when in free form and as part of sucrose?

This is the structure of fructose in free form: The right moiety is the fructose as part of sucrose. The left one being glucose: Both of the fructose are beta-D fructofuranose. But as it can be ...
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Does cat urine really fluoresce? If so, why?

I temporarily got caught in the Sad and Useless website, and found Science is Fun. Most of the claims seem plausible, but I can't guess why cat urine would fluoresce. Comments have directed me to ...
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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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SDS-PAGE compared to western blotting

SDS-PAGE and western blotting are both used to separate and isolate proteins. My question is, which technique should be used when? Does one of them has advantages over the other one?
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Cracking sounds made by glowing plankton

Recently I had opportunity to swim in place with glowing plankton, it was amazing experience and it as well gave birth to few questions in my head. I manged to google that they can glow thanks to ...
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How do organophosphates actually work?

The common explanation as to what the primary mechanism of action for organophosphates (and carbamates) is is the inhibition of the enzyme acetylcholinesterase and resulting buildup of acetylcholine ...
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1answer
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Why magnesium ion is needed for activity of G-proteins?

I was studying about G-protein coupled signaling sysytem, somewhere they have mentioned about need of Mg$^{2+}$ for acticty of G-protein and related it to increase of cyclic AMP production. On further ...
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What is the difference among biochemistry, molecular biology, molecular genetics and structural biology?

I have never heard of straigthforward definitions of these fields in my college lectures, and the Internet searches were not very helpful. However, from what I have learned at different subjects, this ...
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Immunoprecipitation compared to western blotting

Immunoprecipitation and western blotting are both used to locate a specific protein within a sample and to isolate it. In immunoprecipitation, a specific antibody and agarose beads ( or other ...
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What structural features make a molecule a potent opioid receptor agonist?

For instance, take morphine. It is used as a baseline for measuring the potency of opioid agonists. Its structure looks like this: But then, take heroin, around three times as potent, its structure ...
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What substances can selectively destroy certain cells?

Recently, I've watched a documentary about how, in the 1980s, people were buying and using drugs from the streets and then becoming paralyzed a few days afterwards. The drugs that they were using were ...
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Preparing sample for SDS PAGE

I have more than 10 cell lysate samples (70 µL each) whose concentration varies from 1.9 mg/mL to 4.8 mg/mL. I have 5X and 2X SDS sample buffers. I would like to prepare SDS PAGE samples in such a way ...
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Do histones constitute the largest proportion of the protein in chromosomes at mitosis?

Do histones contribute more (by mass) than non-histone proteins in the chromosomes formed during mitosis?
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Is NMDA produced in the body?

On the wiki page for NMDA it says that NMDA is a synthetic substance that mimics glutamate. So why does the body not use glutamate instead of NMDA? Also how is it possible that our body can produce ...
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If fish gills do not split H2O into H2 and O, and just take the dissolved oxygen what is left leaving the gills? [duplicate]

Could you please explain to me the exact left overs after a fish takes oxygen out of H2O?
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What phosphorylates tau protein & and what causes tau to be phosphorylated?

I want to know what phosphorylates tau protein and its 6 isoforms. I know kinases cause phosphorylation events, and in tau it can be phosphorylated in a healthy neuron in the trans conformation, but ...
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1answer
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Backbone hydrogen bonds between adjacent amino acids in a protein?

Is it possible for two adjacent amino acids in a peptide to form hydrogen bonds between the backbone NH and CO? Are there any examples of such situations in proteins and how common are they? If ...
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which enzyme phosphorylates sodium potassium pump?

I know that Na+/k+ pump possess atp-ase function; so the pump will hydrolyze ATP into ADP + Pi. And I see in a figure that the pump is phosphorylated but couldn't really find which protein catalyzes ...
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Does digestion require hydrochloric acid?

Would our digestion function any differently if we secreted something else, like sulfuric or nitric acid, instead? I'd assume an acidic environment may be required, but not sure if chloride is also ...
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If overcooked hard boiled eggs show these green sulfide rings, why do scrambled/fried eggs not show this?

In the image above, the dark green rings are ferrous sulfide rings, caused when the sulfur from the egg white reacts with the iron in the egg yolk when the egg is overcooked. I was wondering, given ...
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Is it possible to stop more/extra fat from being stored in the body?

I don't mean simply by restricting eating or upping the activities, but a way to basically stop the body from adding more fat on itself down on the bio level. For example, I'm not too knowledgeable on ...
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Do cats produce DMT?

Edit: If somebody (anybody) wants to add an answer so the bounty won't go to waste, please do so! The comments have already introduced me to the Kegg metabolism database, some interesting papers, and ...
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Living potato clock? [duplicate]

Could a potato stay alive and power a clock while growing in the ground? I know how a potato clock works as a electrochemical cell and involves chemistry, but I am only interested in a growing ...
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1answer
266 views

Does every protein starts with Methionine amino acid [duplicate]

During process of protein synthesis we need AUG Codon to start translation .As we know this codon codes for Methionine amino acid so can we say that every protein starts with Methionine amino acid ?
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What are the (evolutionary) advantages of secondary transport?

Secondary active transport uses electrochemical gradients as a source of energy for the uphill transport of substrates (coupled to downhill transport of the ion). However except for in a few cases (e....
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Exocytosis of synaptic vesicles

I'm reading the following paper: http://jcs.biologists.org/content/123/6/819 The part I am really confused about is when they say: Exocytosis appears to use two alternative pathways: clathrin-...
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What is the difference between Warburg effect and Crabtree effect in metabolism? [closed]

In addition to answering my question, please suggest a good review article that provides comparison of the above effects. Which pathways affect central carbon metabolism to produce these effects? Also,...
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Base pair and amino acid weights? [closed]

How does a base pair weigh approx. 650 Da (which is two paired nucleotides) but an amino acid (3 nucleotides) weighs only approx. 110 Da ?
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Can sperm cells penetrate the cell membrane of non-ovum cells?

Sperm cells have tiny bags of enzymes on their tip (the acrosome) which allow them to penetrate the ovum. My question is whether or not the process that allows sperm cells to penetrate the cell ...
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Lysosomal Storage Disease

In my biochemistry class today we did a problem detailing two lysosomal storage diseases. In the first scenario, a cell line for I-cell disease can synthesize lysosomal hydrolases that are perfectly ...
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The truth behind human urine and marking territory?

So some years ago, I remember watching a survival show in which the host said that human males produce a type of chemical in the urine that animals such as wolves can acknowledge as a territory marker....
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The effect of salt, pH and temperature to the salivary amylase

If I prepare the following set of tests, incubate for 15 mins, then add 2-3 drops of iodine solution to each test tube: Salt test (1ml starch solution + 0.5 ml enzyme + 1ml 1M NaCl, incubate at 37 oC ...
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How is it possible for phosphate to form two ester bonds in DNA replication?

I understand that in phosphodiester bond formation, two hydroxl groups on the phosphate molecule bind to the 3' and 5' OH groups on two independent pentose sugars. This is a condensation reaction, so ...
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Is there a relationship between HDL-C and LDL-C?

For a gentle introduction to cholesterol and its functions, see a great answer on SE Biology Whenever I read about how to deal with cholesterol level, the rule is to keep a low LDL fraction, ad a ...

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