Questions tagged [molecular-biology]

The study of the molecular processes underlying life.

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6
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1answer
209 views

How did genome duplication in jawed vertebrates allow gene specialization?

I am currently reading from Chapter 15 in Principles of Life, 2nd Edition: Many gene duplications affect only one or a few genes at a time, but in some cases entire genomes may be duplicated. When ...
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0answers
26 views

How does Ran GDP get from the cytoplasm back to the nucleus following nuclear import and export?

I understand that in Ran-dependent nuclear import Ran GTP binds importin in the nucleus, and after diffusing through the nuclear pore complex Ran GTP is hydrolyzed to Ran GDP and releases importin. ...
4
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1answer
502 views

Enzyme Inhibition in relation to Aspirin

I see that aspirin (in part) works by inhibiting cycloxygenase isoenzymes and that this inhibiting is irreversible. I've had a few classes mentioning this topic in passing, but never with depth. I ...
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2answers
3k views

Is tyrosine hydrophobic or hydrophilic?

I’ve seen tyrosine classified as a hydrophobic amino acid due to its aromatic ring in some textbooks and as hydrophilic due to its hydroxyl group in other textbooks. How does tyrosine actually ...
0
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1answer
102 views

Hydrophobic interactions in the helix-turn-helix

This slide states that the second helix works to stablize the configuration of the two helixes via hydrophobic interactions. What exactly is this hydrophobic interaction? In other words, what ...
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3answers
95 views

You need DNA to make RNA, and RNA to make DNA, so they had to come into existence at the same time?

A statement I recently read: 'Evolution is debunked and gives no basis for morality. Natural Selection throws away info, it does not add. You need DNA to make RNA, and RNA to make DNA, so they had to ...
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1answer
72 views

Protein electrophoresis

Three proteins A, B and C of equal molecular weight are being investigated in a study. They contain six, four and four cysteine residues respectively. Only Proteins A and B were treated with β-...
12
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3answers
20k views

Why does replication require primers while transcription does not?

In transcription, there is no need for any primer. I guess the basic mechanism of DNA polymerase & RNA polymerase is the same. So why does replication have the need for a primer?
6
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1answer
237 views

What is the advantage of using plant-derived antibacterials rather than bacteria-derived antibacterials?

So obviously we have a big problem with antibiotic resistance. Most of our antibiotics originate from bacteria themselves (or are synthetic variations on scaffolds which originate from bacteria). I ...
4
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1answer
9k views

Manual Primer Design for a gene on the reverse strand

My question might sound very naive and stupid but I am hopeless now. I read so many websites and pages but could not figure out this PCR primer design thing completely. Some genes are on the reverse ...
2
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2answers
611 views

What makes/breaks the hydrogen bonds between DNA and RNA during transcription?

So I know that RNA polymerase catalyzes the phosphodiester bonds that hold the sugar backbones of a growing mRNA molecule together during transcription. However, I'm less sure about the hydrogen bonds ...
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0answers
36 views

Does every protein encoding gene necessarily have a transcription factor?

For instance, transcription factor gene A is responsible for activating gene B that encodes protein 1. However, it is possible for genes like gene B to encode proteins without having transcription ...
15
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2answers
6k views

How does translational coupling work in prokaryotes?

Today I heard about a phenomenon called "translational coupling", where the translation of one protein influences the translation of another protein. The messenger RNA levels don't seem influenced. ...
0
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1answer
82 views

Does the deletion of Chromosome 20 cause immunity against prion disease?

I was reading recently about prion disease and it caught my attention that a normal prion protein is coded n chromosome 20, therefore, in order for an infectious prion protein to attack, there must be ...
2
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1answer
42 views

How to find idea for essay [closed]

I'm studying microbiology in Iran The university that I'm studying in doesn't provide that much help in research areas and we don't get to research or write essays that much ,while I'm trying to write ...
2
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1answer
54 views

What does it mean to use DMSO as a dissolvant in biology experiemnts?

In many biology publications, I saw that dimethyl sulfoxide (DMSO) is used to dissolve drugs. However, the cell-based assays are still performed in water-based medium such as RPMI or PBS. My ...
9
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1answer
2k views

What is the role of glucose in plasmid isolation?

My understanding is that glucose is used in the resuspension solution to prevent cells from bursting by maintaining the appropriate osmotic pressure. Why do we even bother doing this? The cells are ...
1
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0answers
47 views

Fruiting of trees — environmental stimuli and biochemical cascades

My question concerns fruiting of trees in general. However, I live in a tropical country (Philippines) where mango trees are ubiquitous, so I'll use it in stating my question. The question is about >...
2
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0answers
65 views

Why does M1 RNA together with C5 protein in 100mM Mg(II) fail to cleave tRNA?

Sidney Altman discovered that RNA moeity of RNAse P (M1 RNA) alone is able to perform enzymatic cleavage of ptRNA, which won him the Nobel Prize of Chemistry in 1989. However, when I read the Nobel ...
0
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1answer
31 views

Biology and dna samples to determine parental lineage [closed]

How could you use nuclear and mitochondrial DNA samples run through electrophoresis to determine parental lineage.
0
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1answer
40 views

How is the timing of gene expression controlled in developing embryo? [closed]

I understand how cell differentiation works in general (gradients of homeobox proteins etc), but how is timing controlled? Why do some genes switch on at a very specific moment of development and then ...
8
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1answer
455 views

How do centrioles auto-locate to opposite sides of cell during mitosis?

I realize that centrioles are made of 9 triplets of microtubulin wound together with a hollow core, and that they are responsible for the configuration of the spindle during mitosis. The spindle ...
2
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3answers
2k views

How does low cysteine conditions affect pheomelanin production?

So we were studying this amino acid called cysteine. Specifically we were studying it's effect on melanin genesis. Our teacher told us how excess of cysteine affects the melanin synthesis by ...
0
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1answer
65 views

How can two biological sequences be anything but homologous?

If we consider homology between two nucleotide sequences as a yes/no answer to whether they have shared a common ancestral sequence, then given that all life share common ancestry and sequences are ...
1
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1answer
33 views

What does “novel, predicted deleterious, within autozygome” mean in genetics?

I am a medical student and just got involved with a genetic lab and research. I read a lot phrases like: "Although no mutations have been reported in this gene, we think this variant is interesting ...
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2answers
60 views

There are small parts between Genes in an Operon that does not encode for any amino acids. What is the purpose of these parts?

What is the purpose of these parts in the translation process ? Picture to demonstrate below :
2
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2answers
68 views

How different can the Tm be between 2 primers?

I have a forward primer with Tm 85 degree Celcius. I cannot change this primer. But I have two options for the reverse primer. One with Tm 65 degree Celcius (Annealing at 65 degree Celcius) and ...
2
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0answers
75 views

How do molecular biologists determine biochemical pathways?

I'm new to this community, so hopefully this is the right place to ask this question. I know my question is really general, but in all of my biology courses we are merely taught the chemical pathways ...
1
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1answer
115 views

What is (roughly) the net charge of the DNA in an average human cell?

I was wondering about what general range for the net charge of DNA in human cells is in Coulombs. I imagine that kind of thing would be hard to measure but could be approximately calculated/estimated....
1
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1answer
18 views

What is the reason behind studying seroprevalence of a disease?

Scientific literature on viral disease, specifically ones like Zika and Dengue, contains seroprevalence data. What is the reason behind understanding seroprevalence?
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2answers
33k views

Agarose vs agar? Why do DNA gels use agarose only and how do you obtain agarose from agar?

Agar is a relatively cheap substance from red algae. And it contains a saccharide agarose as well as a small amount of pectin. Agar is used for culture plates as is, but for DNA gels a grade of ...
5
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1answer
292 views

What does the “Psi” in “Psi broth” stand for?

When making competent cells I've been using a medium called "Psi broth", which per liter consists of 20 g tryptone, 5 g yeast extract and 5 g MgSO4. Today I got curious about why it's called "psi". Is ...
2
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1answer
191 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 ...
1
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1answer
434 views

Genotypes of gametes produced by an F1 individual?

I have an urgent question as I have an exam tomorrow. I was skimming some past exam papers and one question came up which has me completely confused. A cross was made between a pure breeding ...
0
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1answer
28 views

Thousands of Reporters Integrated in Parallel (TRIP) barcodes

Has anyone worked with constructing barcodes for TRIP? How does constructing of barcodes work in general? I don't seem to be able to grasp the basics of constructing these barcodes.
5
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1answer
297 views

Compare affinity to potency h1 receptor

This quote from Miller (2004) makes it clear that the affinity of drugs for the H1 receptor does not correlate to sedation: Although both dosage and affinity for histamine H1 receptors play a part ...
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1answer
66 views

Is there any liquid that can replace water?

I understand this is a little futuristic but water freezes and damages cell causing cryostasis yet a reality. Is there any liquid that can be added to the blood synthetic or not that either plants and ...
2
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0answers
55 views

Molecular Docking Enzyme Inhibitor Biosensor?

I had some task to study Molecular Docking relations with Biosensor and I am really new with this discipline (beginner). I am docking C60 with Glucose Oxidase and my question is: what would happen if ...
2
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1answer
41 views

qPCR : Cross-contamination while sealing plate

I'm trying to do realtime PCR on a plasmid and I have my positive and negative controls close to each other along with a no-template control. I add 1ul of my template last into the 96 well plates (on ...
10
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1answer
7k views

Difference in length of Okazaki fragments

The length of Okazaki fragments in the lagging strand is about 100-200 nucleotides in eukaryotes and about 1000-2000 nucleotides in prokaryotes. What (molecular mechanism, enzyme type ) determines ...
0
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1answer
40 views

Oxygen in the earth’s atmosphere

If CO2 only makes up about 0.04% of the earth’s atmosphere how do trees and organisms in the ocean produce oxygen to 10% of the earth’s atmosphere?
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0answers
27 views

Why is CLL B-Cell leukemia t(12;21) more responsive to chemotherapy?

Chronic Lympoid Leukemia targeting B-Cell (with the particular translocation mutation on chromosome 12 and 21) is known to be more responsive to chemotherapy. Is there a known molecular mechanism for ...
1
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1answer
65 views

What is the source of the fat in adipose tissue?

I have heard the opinion that all of it comes from de novo lipogenesis of carbohydrates, but I'm skeptical. Is there evidence either way - either that dietary fat definitely gets stored in the adipose ...
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1answer
81 views

Apolipoprotein B48 and fat storage

Can chylomicrons formed in the intestine, with apolipoprotein B48, transport lipids to adipose cells for storage?
4
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2answers
322 views

How does transcription end?

In rho-dependent termination in prokaryotes, how does RNA polymerase “know” that it has reached the end of a gene and that it has to stop so that the rho-factor can bind mRNA’s rut site? Is there a ...
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0answers
37 views

What Does Transcription Factor E25 Activate When a Cell is Transitioning from G1 to S

Cyclin D/ CDK4 phosphorylates Rb allowing for the activation of transcription factor E25 during the G1 phase of the cell cycle. Supposedly, this transcription factor then activates as set of genes ...
1
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1answer
56 views

Consensus symbols in multiple sequence alignment [closed]

I was using multAlin for multiple aligning a set of sequences. The output I and came across included the following documentation (English corrected): Consensus symbols: ! is any of IV $ is any ...
2
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2answers
1k views

On which DNA strand is TATA box present?

My book (Snustard and Simmons) mentions that TATA box is present on the non-coding DNA strand but that was for the promoter of mouse thymidine kinase gene. I have tried to find out more information ...
2
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1answer
75 views

When in Ampicillin degraded (gone) in liquid TB-media? Concerns about selectivity

Question: Specifically regarding Ampicillin; When growing cells in TB (terrific broth) for protein expression - when should I expect the ampicillin to be gone due to degradation by b-lactamases? (and ...
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1answer
306 views

How to find the amino acid that is bound to a tRNA with the anticodon? [closed]

What amino acid is bound to a tRNA with the following anticodon: $5^{\prime}$ A U G $3^{\prime}$ The answer is Histidine. What amino acid is attached to the tRNA with the ...