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Questions tagged [molecular-biology]

The study of the molecular processes underlying life.

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Gene terminology - is one gene a concrete, single physical sequence?

Suppose you have two identical copies of the same, coding nucleotide sequence (e.g. two copies of BCL2 - a random gene I found on Wikipedia). Could you say that these are two genes (i.e. the name "...
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1answer
27 views

What does ensemble-based model of enzyme mean?

I am reading Pan et al. (2000), a paper about dihydrofolate reductase (DHFR). They claim using a ensemble-based model of DHFR. What is a ensemble-based model?
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0answers
113 views

Question about Racemic Mixtures in Miller-Urey Experiment

I'm studying the Miller-Urey Experiment for my Biology class, and a significant point made by my professor was that Miller made a 50/50 racemic mixture of chiral monomers. However, life is homochiral....
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0answers
57 views

What's the ratio of saturated to unsaturated fatty acids in human cell membrane?

It's well established that the fluidity of a cell is largely dependent upon the ratio of saturated to unsaturated fatty acids that exist within the membrane, but, what exactly are the values for this ...
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0answers
35 views

Do influenza viruses obey a Hayflick limit similar to human cells .. or do they spread and divide forever like HeLa?

I would think the latter since they are so simple and are parasitic but even proteins break down over time .. only found a few answers on the net and it was over a decade ago but nothing in any papers ...
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2answers
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Why aren't 'exons' named 'introns'?

Why are introns called 'introns' when they are the actual ones who are getting spliced out from the pre-mRNA. Shouldn't exons be named introns as they are the ones that are 'in' and are not 'exiting'? ...
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0answers
39 views

Should I use glycogen in isopropanol to precipitate RNA or does glycogen have harmful consequences on downstream protocols such as RNA seq?

I have heard that one can use glycogen in isopropanol to better visualise the RNA pellet after centrifugation. What are the advantages and disadvantages of adding glycogen in isopropanol for RNA ...
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0answers
18 views

Incomprehensible Bioanalyzer profile

I have extracted RNA from about 4000 C. elegans worms today, using my Trisure and phase-lock gel protocol. The ratios at the Nanodrop are excellent, indicating that there is not protein or salt ...
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0answers
97 views

Coding potential map, what are the number of possible different starts

Looking at coding potential map, what are the number of possible different starts for the gene identified by the computer algorithm?
2
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1answer
151 views

Power consumption of a ATP synthase in Watts

Considering the ATP synthase to be a rotating machine, does anybody know its power consumption and/or power production in Watts? At least roughly, e.g. based on the average chemical energy produced ...
3
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1answer
278 views

Terminology of the sequences of promoters in relation to DNA strands

I'm studying molecular biology and I'm trying to understand an experiment which shows the importance of promoters in the relative transcription level (RT). The image below comes from Rolf Knippers' ...
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0answers
17 views

Repeat-Induced Point Mutation in RNA?

this is my first post so please bare with me. For the life of me I cannot find out the specifics on the RIPing mechanism (pertaining to N. crassa) in terms of RNA. I know that this mechanism prefers ...
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1answer
296 views

Do dead cells always contain no nucleus?

If I examine a dead cell, can I be sure that it has not a nucleus? And what about the other organelles?
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1answer
105 views

cloning and blue white screening in pet21a

I am using pet21a as a carrier vector for my gene, with R.E BamHI and XhoI,in reverse primer I haven't added any extra nucleotide sequence so that it should code for the histag towards C-terminal. Am ...
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0answers
15 views

Collagen Type V

Lodish - Molecular Biology of the Cell: "Two quantitatively minor fibrillar collagens, type V and type XI, co-assemble into fibers with type I collagen, thereby regulating the structures and ...
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1answer
320 views

Is there a double helix RNA?

I wonder what is its function and if it can be the genetic material for a living organism. If not, why?
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0answers
254 views

DNA linking number, twist and writhe

The image below is taken from a molecular biology textbook. It is not clear to me that what is happening at the two writhe crossings matches up with the numbers provided. Is there a problem with ...
3
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1answer
52 views

Is Ellman's reagent specific for low molecular weight proteins and thiols?

Is it still possible to quantify cystein rich low molecular weight proteins such as Metallothionein in a given sample using Ellman's reagent if the sample is contaminated with some high molecular ...
2
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1answer
68 views

Can a gene be inactivated using CRISPR if it is not in the interspace of short palindromic repeats?

I have recently studied how CRISPR works but there is something that I do not understand at all. I have heard a lot of people claiming that with this method it is possible to modify any genome by ...
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2answers
36 views

Organism and plants reduce radioactivity?

I would like to ask if there are organisms or plants that could help in reducing any one of types radioactive contamination?
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0answers
33 views

How do cell signaling ensures time synchronization?

Let us suppose two cells A and B communicating with one another, I want to know how do cells ensure time synchronization while communicating. For instance, let us assume cell A sends a sequence '110'. ...
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0answers
56 views

Western blotting quantification

I need to quantify my western blotting results. I used the software Imagej and it gave me the area and percent but I am not sure how to compare my various groups with beta actin or if there are any ...
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2answers
363 views

Why EtBr migrate toward the opposite direction?

We known that DNA would run toward the positive electrode, because of they have negative electricity. then why EtBr migrate toward the opposite direction to DNA? is because they have positive ...
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1answer
71 views

Backcrossing in Hybrid

Can anyone help me in understanding how backcrossing helps hybrid to achieve pureline? I have been looking into the references i possess but couldn't seem to find anything
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1answer
54 views

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 is ...
4
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1answer
114 views

DNA quantification in a high school bio lab

I'm working on a project in a high school bio lab (so limited resources), and I need a way to quantify the concentration of DNA in a PCR product. I can't use spectrophotometry (cheap ...
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1answer
65 views

Do cells communicate only in binary levels?

In modern communication we generally have various schemes to communicate the given signal, one of them is to convey information with different levels. does cell signaling too have levels apart from ...
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3answers
138 views

Biology Intuition and Origin of the “facts” [closed]

I am a graduate physics student but also taking biology classes. I am new to the field of bio. Most of what we do in class seem like memorizations and stating-facts. I am wondering: How can I develop ...
4
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1answer
92 views

Overexpression by integration of an additional copy vs promoter exchange

In Becker et al (2011), the authors increase the expression of several genes through different methods. For some genes (e.g., lysA, ddh), they achieve overexpression by integrating an additional copy ...
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1answer
100 views

Difference between 'fitness' and 'fitness effects'

Term 'fitness' is pretty obvious, but, often 'fitness effects' is commonly used in many research articles in the field of evolutionary biology. I suspect that 'fitness effects' has a different ...
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2answers
60 views

How can ionized amino acid form be important for the catalytic activity?

I can imagine that protonated amino acid form, particularly at the active site, is important for the catalytic activity so hydrogen bonds can be created between the substrate and the enzyme. However, ...
6
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2answers
138 views

How do membrane proteins find their target locations?

The question might be asked for any kind of "bound" proteins, but I'd like to restrict it to membrane proteins. Assuming membrane proteins (or their main parts) don't (or aren't) build in situ but at ...
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2answers
60 views

Reaction centre in Photosystems of higher plants

In photosystems of higher plants, there are about 250-400 pigments (number wise) in a particular photosystem. Out of which,approx 170-180 pigments are of chlorophyll a molecules. And any one of them ...
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1answer
83 views

Limit on the Number of Facial Phenotype [closed]

Individuals of each species all have unique facial structure variations (shape of nose, position of chin etc) from humans to birds and fish etc. We humans don't seem to be reaching mathematical limit ...
5
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1answer
660 views

Why is liquefactive necrosis only seen in brain?

Liquefactive necrosis is a type of necrosis uniquely observed in brain. This occurs due to breakdown of cellular proteins by the action of hydrolytic enzymes. In other parts of the body, usually a ...
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2answers
82 views

Meaning of term ‘rapidly labeled RNA’

I encountered the term, “rapidly labeled RNA”, in the article: Rapidly labeled HeLa cell nuclear RNA. I. Identification by zone sedimentation of a heterogeneous fraction separate from ribosomal ...
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0answers
26 views

What is a control in an enzyme question.

If Im conducting an investigation to test how pH (2,5,7,9,11) affects the effect of catalase on hydrogen peroxide, what would the control(s) be in the investigation
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1answer
190 views

How to Calculate how many times an enzyme would cut a plasmid

I'm a little confused as to how to figure out the formula needed to figure this out. I have a plasmid that is 7.3Kb and am told that it is cut with an enzyme of 4bp. For some reason I thought that ...
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1answer
1k views

What's the relation between Kinase, Phosphatase and ATPase, GTPase (GTP/ATP)? [closed]

I'm wondering what's the relationship between Kinase, Phosphatase, ATPase (ATP) and GTPase (GTP). For example, when reading online the impression is created that ATPase is a type of Kinase (?). But I ...
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0answers
30 views

Facial uniqueness of some animals of the same species [duplicate]

Do birds of the same species ,such as each pigeon that we see in cities, have unique facial geometries (facial phenotypes) regardless of their feather ,colors, spots etc? Sometimes it is almost ...
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0answers
74 views

MOPS Media Recipe Protocol - Well Defined

I am trying to find a clear protocol for making MOPS media. However, when looking online, I am finding that this media is loosely defined and I can not find a good protocol. (I have been looking for a ...
1
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1answer
57 views

How could this molecule affect the body? (Lysergic acid derivative)

First of all, could you please help me name this molecule? I think the name of it is something like this: N,N-pentamethylene lysergic acid. Secondly, my main question is what could be the pharmacology ...
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0answers
15 views

microsatellite amplification for new species

The primer was designed among one of the species in the genus Aloe L. But in my PCR amplifications none of them show any result at all, even the species which the primer designed from.
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0answers
56 views

Downstream Promoter Element’s Role

The promoters‘ role is to bind polymerase to get started transcription. And in fact: by Wikipedia “Like all core promoters, the DPE plays an important role in the initiation of gene transcription by ...
0
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1answer
186 views

Why isn't photosynthesis catabolic reaction? [closed]

Here is the chemical equation of photosynthesis $$CO_2 + H_{2}O \longrightarrow C_{6}H_{12}O_{6} + O_2 $$ We see that the water is in reactant side of the equation. By the way, It ought to be ...
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1answer
112 views

DNA or enzymes — which came first?

Considering that the DNA needs enzymes, to be formed, however enzymes need DNA to be formed too. What biomolecule was created first?
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1answer
15k views

Catabolic and Anabolic Reactions

How do we differenciate between catabolic and anabolic reactions? According to my researches; Catabolic Reactions Catabolic reactions (also called “catabolism”) break down larger, more complex ...
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0answers
235 views

Shell-less Chick development - Incorporation of Calcium carbonate instead of Calcium lactate pentahydrate powder?

I'm a college undergrad biology student and currently studying developmental biology as part of my curriculum. I've read a research journal titled, A Novel Shell-less culture system for chick embryo ...
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1answer
383 views

What causes us to see white light?

Humans have three cones of color light, red, green and blue. If the region of the green cone is hit by his photons we will see green light. Now we don't really receive green light but our eyes and ...
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1answer
163 views

Why is the outer circle of human mitochondrial DNA ‘heavy’, whereas the inner circle is ‘light’?

Why is the outer circle of human mitochondrial DNA "heavy" whereas the inner circle is "light"?