3
votes
3answers
1k views

How to increase the shelf life of yogurt without refrigeration?

When we make yogurt at home and do not refrigerate it, it will become sour because of conversion of lactose into lactic acid by Lactobacillus bacteria, but this does not happen in case of Nestle's ...
5
votes
0answers
107 views

How does an organism know when to stop growing, whether it is already on the outermost layer? [closed]

When a multicellular organism is under its development how does the current outermost layer of cells "know" that they should not divide furthermore, as their bodyplan coded into DNA is already ...
4
votes
1answer
238 views

How pain can stimulate the vagus nerve

I'm trying to find out why a prompt, severe, short pain is causing a stimulation of the vagus nerve. What could the physiological explanation be? Is that because the pain is triggering the ...
3
votes
0answers
173 views

How to get only perfect matches with blastn? [closed]

I have installed Blast locally and I've configured the nucleotide database to use. I want to search some sequences (from a .fastafile) in this genome. So I used blastn: ...
18
votes
2answers
3k views

Is it known how the first viruses formed?

The oldest known virus is known to have infected prehistoric insects 300 million years ago. A virus is basically a parasitic strand if DNA or RNA encapsulated in a protein coat. It enters cells by "...
5
votes
1answer
76 views

Genes-of-interest analysis between organisms

I am interested in identifying the differential expression between several genes-of-interest of different organisms. I am trying to assess the benefits of RNA sequencing over microarrays. Both ...
8
votes
4answers
1k views

Is there any way a human could whistle and be unable to speak?

Is there any situation anatomically, where a human could understand the speech of others perfectly, without any capabilities of speech themselves, but would retain the ability to whistle with a tune? ...
0
votes
2answers
28 views

Risk of autosomal dominant disorder [closed]

What can you conclude about the risk (with each pregnancy) that a couple could have a child affected with an autosomal dominant disorder if... One parent is affected (heterozygous) and the other ...
-2
votes
1answer
172 views

Blood Type/Punnett Square [closed]

Male: Blood type O (Genotype written as: i^o i^o since O allele is recessive to the A and B alleles). Female: Blood type AB Draw a punnett square to show all of the possible offspring. I got Ai^o, ...
3
votes
1answer
194 views

Why are skin tactile receptors considered to be phasic receptors?

A phasic receptor by definition is one that quickly adapts to change. In terms of neuron firing, this means that it does not trigger another firing because the receptors are used to the stimulus. But ...
3
votes
1answer
94 views

How to determine genotype?

In humans, the ability or inability to roll the tongue is a single gene trait. The allele for tongue rolling (R) is dominant to the allele for not being able to roll the tongue (r). Whether or ...
2
votes
1answer
62 views

Serious question about a piece of meat

Does anyone know some scientific rigorous way to look at a slice of meat. I am not asking what kind of meat it is or which part of the animal it came from. I wonder what is the different lining on the ...
10
votes
1answer
831 views

Where is the aneurysm in this picture?

I'm a curious person, I've never had any medical training, but I wish to know some more about aneurysms. Aneurysms are basically weakened spots in the elastic artery wall. This can eventually result ...
1
vote
1answer
29 views

What factors, other than its homochirality, make our “brand” of biology unique? [closed]

If humans were to discover organisms on another planet, it is supposed that (unless both we and they were seeded by the same source) we would have nothing to fear from alien pathogens, as they would ...
2
votes
0answers
34 views

How to gauge the clinical significance of specific cell type presence?

How does one decide whether the presence of certain cell types is clinically important or negligible? Would the presence of certain cells in conjunction with other symptoms be enough, or should it be ...
2
votes
0answers
58 views

Is the “concept of time” coded into the genome? [closed]

What I'm interested about is whether environmental changes' effects are coded into the genome, like metamorphosis, deciduous plants. Can it be explained by morphogens, or it's something completely ...
8
votes
2answers
77 views

Is there a genomic code for nucleosome positioning?

What does a genomic code for nucleosome positioning in eukaryotes actually mean? By the code is it right to think that specific DNA sequences favour nucleosomes and others don't? I see that there for ...
7
votes
2answers
162 views

Naming convention of miRNAs

I'm trying to understand naming convention of miRNAs. I've found the wikipedia article about it nomenclature Based on it, I try to figure out what is hsa-let-7a. As far as I understood, hsa refers to ...
2
votes
1answer
686 views

When contracting a muscle will the muscle spindle stretch or contract?

When you contract your muscle, will your muscle spindle stretch or contract? And why? I was always under the impression that it was contracting your muscle spindle, but now I am not sure.
5
votes
2answers
231 views

Do changes in an organism's cell modify the genetic information it uses for reproduction?

What I'm actually interested about is whether a modification in one cell during the life of an asexually reproducing organism affects its genetic information? Which cell's genetic information is used ...
3
votes
0answers
438 views

Can't resolve protein with native PAGE

This is a native gel. Let's call the left 2 lanes protein A and the right 2 lanes protein B. B is the same as A except it has a FLAG tag. They are both homotetramers of about 65 kDa. After ...
0
votes
1answer
33 views

How are Stem Cells Produced for Stem Cell Based Therapies?

I was doing an initial search on google but couldn't come up with anything I'm looking for. I know were stem cells come from and a bit about their levels of differentiation. For example, embryonic ...
4
votes
1answer
43 views

Oligonucleotide purification with desalting

I have ordered 36bp oligonucleotides that anneal to each other and create sticky ends to be cloned in a vector afterwards. I have tried cloning many times with different methods and I failed. Now I ...
4
votes
3answers
321 views

Amino acid compatibility

The (human) genetic code encodes 20 amino acids. They form a protein using peptide bonds. Each amino acid has a carboxyl group (COOH) and an amino group (NH2) that can potentially form a peptide bond. ...
10
votes
3answers
739 views

Why are fruits so large compared to their seeds?

Why do many plants produce such large fruits(apples and strawberries,for example) if those contain only relatively small seeds?
3
votes
1answer
46 views

Finding confidence level of miRNA disease associations

I'm an undergraduate computer engineering student, and I have a project about bioinformatics. In this manner, I need to find prediction( or association I'm not sure the correct terminology) confidence ...
3
votes
0answers
42 views

Should gene therapy safety protocol include isolation?

In the case of a gene therapy trial where viral vectors are used to deliver genes into mammalian cells, including humans, should biosafety and ethical protocols include isolation of the patient as a ...
7
votes
1answer
197 views

DNA-DNA cross-linking with formaldehyde?

The 3C (chromosome conformation capture) technology for studying chromatin 3D organization starts by a cross-linking step using formaldehyde to find segments of DNA interacting. In my understanding ...
1
vote
0answers
30 views

Why can't some organisms match miRNA perfectly to the target mRNA like in plants? [closed]

What causes other organisms to be impaired in making perfect matches like plants do and is there a way to increase matching?
1
vote
1answer
3k views

What is an apomorphy? What is a plesiomorphy? Can someone confirm these definitions?

I want to know the correct definitions for the terms apomorphy and plesiomorphy. Unfortunately, there seems to be a variety of ways to define these terms depending on the language one uses. Thus, it ...
2
votes
0answers
29 views

Founders of Cnidarian colony

I know that colonial Cnidaria enlarge their colony by the means of asexual reproduction and sexual and asexual reproduction can originate individuals that will be part of other colonies. Nevertheless,...
7
votes
2answers
186 views

Is there a biological neuron that spikes in response to hyperpolarizing currents?

As some background I've been building Electrophysiological models of neurons, and in the process stumbled upon a model, that in all respects is biologically plausible, but has a bizarre property I ...
0
votes
1answer
160 views

Similarity between a heart attack and a spasm

When someone is having a heart attack, could it be considered , in some situations, a spasm? Below, I have written how I believe the process may work. The heart is basically a muscle working ...
2
votes
1answer
81 views

Does mung bean nuclease cleave a phosphate group when it's chewing off 5' or 3' ssDNA ends?

I'm looking to create blunt ends from sticky ends with mung bean nuclease for subsequent ligation. Does anyone know full mechanism by which mung bean nuclease will do this? In particular after the ...
10
votes
2answers
247 views

Why do mitochondria fuse together?

Contrary to all of the textbook images of mitochondria that I have seen over the years, I had just learned that the mitochondria within a cell form a dynamic branching network along microtubule ...
3
votes
1answer
452 views

What does these $\Delta \Delta G$ numbers signify?

I was reading a paper and came across this table showing $ \Delta \Delta G$ numbers of different nucleotide sequences in DNA/RNA. I know that $\Delta G$ is free energy and $ \Delta \Delta G$ is ...
3
votes
2answers
466 views

Why can we use mouse-produced antibodies on mice tissues?

I have seen biologists use mouse grown primary antibodies in mouse tissue, and they've told me that if the blood is perfused well then there is no problem with this method. How does the secondary ...
4
votes
2answers
4k views

Why can't the human eye focus blue light?

I recently noticed that it is hard to focus on blue light sources, especially at night. When observing a blue light source, e.g. a neon sign, it looks somewhat blurry. A sign with a different colour ...
5
votes
2answers
278 views

Can someone who cannot talk still whistle?

Can someone who has a damaged larynx, which does not allow them to talk, still create a tune when they whistle? I know that the larynx is what allows a person to manipulate their pitch and volume, ...
1
vote
1answer
282 views

Blast output - program to count the number of hits [duplicate]

I have to use the old version of Blast (not Blast+) to compare DNA sequences and I have to know the number of all hits. They are not given in the header and I have to know them for many many of blast ...
2
votes
0answers
140 views

Are there sterilisation methods that do not denature proteins as heat does?

Context: Most countries require milk to be sterilised through radiation or heat to remove possible harmful bacteria. Both of these processes denature the proteins in the milk (ref). Are there methods ...
6
votes
2answers
67 views

Can molecular genetics make a boolean variable from a continuous variable?

In the same kind of idea than this question. Gene expression are regulated through complex interactions. The concentration of enhancers and repressors is an important aspect that dictate the level of ...
3
votes
2answers
60 views

Are restriction enzymes active at −20 °C?

I have digested my DNA with NotI enzyme and put it in the −20 °C freezer without heat inactivating it. Can restriction enzymes work at −20 °C? Should I expect STAR activity?
15
votes
2answers
2k views

How do birds deal with their eyes drying out at high speeds?

My eyes tear up when cycling at 15 mph, which is nothing compared to bird airspeeds. Do birds continuously produce lots of tears and blink a lot, or do the eyes self-moisturize from the inside ...
1
vote
1answer
59 views

Explaining natural selection in moth [closed]

Industrial melanism is an example of natural selection. Can it be considered as a evolution due to anthropogenic action?
8
votes
2answers
263 views

Are unilaterally deaf people able to determine where sound comes from?

My question is on people deafened in one ear, but normal hearing in the other. Time and level differences between the two ears are only part of how the human body can localize the source of the sound....
2
votes
1answer
114 views

Edman method to identify peptides with Phenylisothiocyanate (PTH)

We all know that in this method the PTH reacts with the first amino acid (aa) from the N-terminal to the peptide and separates from it giving PTH-aa so that we can know the amino acids sequence in the ...
3
votes
1answer
49 views

Obvious phenotypic inheritance markers in humans

In humans, are there phenotypic markers that prove parenthood? For example, if mother and father have <trait characteristic> (let's say, specific ear lobe ...
17
votes
2answers
2k views

What's the difference between male and female?

As long as we only look at humans the differences are clear: males have chromosomes XY, produce sperm and don't get pregnant. Females have chromosomes XX, produce egg cells and bear babies. But when ...
2
votes
1answer
795 views

Why does gaining a hydrogen in biology considered reducing a molecule? [closed]

I've learnt in chemistry that gaining electrons means reduction, while losing electrons means oxidation. But why is it in Biology textbooks I sometimes come across the term gaining hydrogen??

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