5
votes
1answer
127 views

What is an operon?

What is an operon in a eukaryotic cell, and how does it regulate the expression of genes? I've already read Wikipedia, but it is not enough clear to me. Unfortunately my knowledge in genetics are very ...
4
votes
2answers
253 views

Phylogenetics and the Tree of Life

As far as I understand, evolution is nowadays pretty much analyzed through phylogenetic trees, that is cladograms. These are constructed using the available records and taking some key structures and ...
6
votes
1answer
92 views

Blood cells penetration

Is there a type of blood cell that can reach all other body cells? By "reach", I mean to "touch" the surface of the target cell. If we look at the red blood cell for example, that moves in blood ...
17
votes
9answers
6k views

Why didn't the polar bear change its color from white to black during evolution to absorb heat?

Polar bears are white in color and white color is not a good absorbant of heat. Why then didn't they evolve a black color to absorb more heat?
1
vote
1answer
56 views

how to reconcile PDB structures' sequences via Uniprot references?

I’m trying to reconcile structures in PDB entries with their sequences as reported in their chemList.polymer.dbref entries. E.g.: considering structures for HIV ...
3
votes
1answer
80 views

Why are canines not nauseated by similar foodstuffs/state of decay as human beings?

I am continually surprised at the items my pet dog is willing to ingest. I understand part of the consumption is driven by nutritional instincts (licking salty liquids such as sweat) or nurturing ...
1
vote
0answers
61 views

What genetic distance model should be used when calculating genetic differences in Arelquin?

I'm using Arelquin to look at the genetic structure between a number of different populations. I want to compare the populations by producing pairwise FST values, however I don't know what model for ...
1
vote
0answers
33 views

what's the vascular cambium?

is the vascular cambium equivalent to interfascular cambium or intrafascular cambium? isn't the vascular cambium similar to the intrafascular cambium because both occur inside the vascular bundle
10
votes
1answer
670 views

Cloning and Telomeres

I read that the length of telomeres in Dolly was shorter, because the DNA was taken from an old sheep. Shorter telomeres may lead to early aging. What is happening now with cloning? Do we use a ...
5
votes
1answer
45 views

Is there any conclusive study relating the food consumed and the occurrence of acne?

The internet says a million things about what to eat and what not to in case of acne. For instance: Refrain from dairy products. Refrain from food heavy in unsaturated fat. Refrain from too much ...
4
votes
3answers
86 views

Identifying a tree with an image

I have trouble identifying a tree that I saw on a vacation. This is the image: I would like to know the name of the tree, I only know that its not European.
6
votes
1answer
64 views

Can plants grow under extreme (>1%) carbon dioxide concentrations?

Related to but distinct from this question due to the concentrations involved. While small carbon dioxide concentration increases can positively impact plant growth under some circumstances and at ...
1
vote
0answers
65 views

How organized is the inside of a cell? [closed]

I know cells have many ways of organizing and controlling what goes on inside their membranes. But just how ordered or chaotic is it inside a cell? Here's a few thoughts I had. Consider the ...
1
vote
0answers
42 views

Superpatients for Cancer resistance

I was reading an article on MIT Technology review about superpatients for low cholesterol that got me thinking whether such patients exist for cancer. The article is http://www.technologyreview.com/...
3
votes
1answer
189 views

How do CO₂ and carbonic acid (H₂CO₃) work in buffering the blood?

Been struggling with this for the past few days even after reading half of the acid base tutorial here, if someone could help me that'd be great. What I don't understand is how HCO3- is supposed to ...
1
vote
0answers
185 views

The skin color of bonobos

Why is that bonobos skin color on the areas not covered by hair are dark throughout life unlike the chimpanzee?
6
votes
2answers
298 views

Advantage of opponent color?

Opponent process is a color theory that states that the human visual system interprets information about color by processing signals from cones and rods in an antagonistic manner (source). What is ...
1
vote
1answer
65 views

About the apoptosis mechanisms in a cell

The apoptosis mechanisms in a cell are like a type of 'self-destruction mechanism': is this correct? As with any type of complex system with various necessary functions, if it has a set of self-...
6
votes
1answer
178 views

The origin of molecular machines

DNA holds genetic information and holds the key to the evolution of living organisms. Transcription and translation mechanisms enable living cells to process information encoded in DNA. To that end, ...
8
votes
2answers
292 views

Why don't we see turbulence in the aorta even in normal situations?

I read about the Windkessel effect. Then I read about pulse pressure waves getting reflected from the periphery. If the pulse pressure wave is reflected during diastole and at the same time blood is ...
3
votes
3answers
875 views

If ants have an antibiotic gland, how can they spread hospital infections?

Wikipedia describes how antibiotics are produced in ants: "Metapleural glands ... are responsible for the production of an antibiotic fluid that then collects in a reservoir ... also referred ...
1
vote
1answer
164 views

What's the meaning of 'plasma' in 'plasma membrane'?

I wonder why is it called plasma membrane - what's the biological meaning of the word 'plasma'?
1
vote
0answers
86 views

I brought a hibernating yellow jacket queen into my house accidentally. What will happen?

There was apparently a hibernating yellow jacket queen in my stack of firewood outside. An hour or so after bringing in the firewood, we saw the queen fly off into the house, where we can't find her. ...
1
vote
1answer
644 views

How does salinity affect the bonds of an enzyme?

According to my textbook, "Too much or too little salt can interfere with the hydrogen bonds that hold an enzyme in its three-dimensional shape". I know that NaCl is held together by an ionic bond, ...
3
votes
1answer
135 views

How do catalase and other antioxidants neutralize free radicals?

In learning about how cofactors are essential to proper enzyme function, my textbook mentioned catalase and its relation to the human body. According to my textbook, catalase is similar to hemoglobin ...
10
votes
1answer
7k views

What's the smallest size a human eye can see?

During a biology experiment at school, where we would look at waterweeds under a microscope, my teacher said something about that it's impossible for the human eye to see the cells without a ...
6
votes
1answer
264 views

When did our ancestors switch to a menstrual cycle instead of the estrous cycle?

The Wikipedia page on the Estrous cycle says: Humans have menstrual cycles instead of estrous cycles. They shed their endometrium instead of reabsorbing it. Unlike animals with estrous cycles, ...
2
votes
0answers
40 views

How much difference in genome is enough to prevent interbreeding? [closed]

I am not a biologist. I am a software developer interested in genetic algorithms therefore i am probably talking to biologists who also have a knowledge of genetic algorithms. I need to "breed" ...
2
votes
2answers
61 views

Are we more/less resistant to infectious diseases during an allergic reaction?

To my understanding, an allergic response is a non-adaptive response of the immune system to some molecule. The molecule in question is therefore "thought by the immune system" to be infectious ...
3
votes
2answers
113 views

Need help in codon optimization

I want to chemically synthesize a GFP gene for expressing in rice.I am using the IDT Codon Optimization program and found that not all the codons are 100% optimized. Some of them are the 2nd or 3rd in ...
5
votes
1answer
113 views

How does the body “know” how to metabolize foreign substances

As a freshman biochemistry major, I find myself befuddled by our body's ability to perform complex chemical reactions to break down foreign substances. I can see how we would evolve explicit pathways ...
3
votes
0answers
37 views

Color perception vs shade perception demo

I can't seem to find one of the best demos I've seen of color vs brightness perception. It consisted of a rotating animation of earth made of red of bright red points on a dark green background. As ...
4
votes
1answer
42 views

Medium for Pseudomonas?

What is a good minimal medium for Pseudomonas bacteria? Do I need different media for different Pseudomonas species?
1
vote
0answers
36 views

Download FunCat Database for Programmatic Access

I am enriching RNA-seq data for the fungus Neurospora crassa and would like to be able to search the genome by functional category, determine similarity of genes by category membership, and any other ...
1
vote
0answers
19 views

What are the main principles of the Bacteriological Code?

Although the Bacteriological Code is an important guideline for taxonomists and microbiologists, describing the criteria for delineating species and higher taxa of the prokaryotes, I, and plenty of ...
6
votes
1answer
165 views

Why doesn't Sanger (fluorescent) DNA sequencing double count nucleotides?

My understanding is that PCR is carried out until a fluorescent nucleotide halts replication. The segments of DNA are fed through the capillary tube based on size, sifting through the segments from ...
2
votes
1answer
56 views

Repair of cloning vector nicks digested with antarctic phosphatase and ligated with T4 enzyme

The vector product obtained by ligation between a vector previously digested with antarctic phosphatase lacks 5' phosphate groups. T4 ligase can ligate it to an insert with complementary sticky ends ...
1
vote
0answers
87 views

How does anxiety cause chest pain?

An acute instance of anxiety can cause a sudden sharp chest pain for a very brief period of time. What is the mechanism behind anxiety leading to chest pain? Is the pain coming from the heart itself,...
2
votes
2answers
105 views

Downloading specific yeast genes in an automated manner?

I have 6 genes of Candida albicans yeast namely orf19.723, orf19.5908, orf19.610, ...
5
votes
1answer
61 views

About radiation therapy

With radiation therapy, could some of the radiation used cause new mutations in non-cancerous cells that are near the tumour that is being irradiated? If so could these new mutations lead to new ...
5
votes
1answer
105 views

Is funnel web spider venom poisonous?

Does the venom of the Sydney funnel web spider have to be injected into the bloodstream to have an effect? If the venom was swallowed (e.g. if a spider was eaten), would it still have an effect? Or ...
5
votes
2answers
115 views

Cytochalasin B in cell movement

In an experiment by Pollard, T.D. and R.R. Weihing, amoeba cells injected with Cytochalasin B were inhibited of movement, while the control group amoeba cells did move. A hypothesis was made that ...
3
votes
2answers
9k views

What causes muscles to generate heat on contraction?

I'm curious what the exact cause is of dramatic heat generation that comes along with muscle activity. Can anybody explain this in understandable language?
6
votes
1answer
117 views

When are a female's eggs created?

Since a human woman is born with a set number of eggs, and meiosis is the process by which sex cells are produced, would meiosis in a woman happen before she is born or soon after she was born? If ...
3
votes
1answer
460 views

What does the empty space in the bamboo stem do?

Is the empty space inside a bamboo stem a xylem? And why is the space so large?
5
votes
4answers
2k views

What is SDS PAGE gel polymerization time?

I am working on 20% SDS PAGE. I want to know optimum polymerization time for 20% resolving gel and 6% stacking gel. If I increase the time then would it affect the band pattern?
5
votes
3answers
422 views

In what sense is the “histone code” a code?

Since I started learning about molecular cell biology, I have witnessed an increasing amount of attention to this thing called a "histone code." However, unlike the central dogma of molecular cell ...
2
votes
1answer
47 views

How are lesions in the RNA corrected?

I quite understand why thymine is present in DNA. So we can mark it out where cytosine undergoes a reaction and is converted to uracil. Then we can repair the DNA. But how can we make that out in RNA ...
3
votes
1answer
1k views

Why does our voice change when we get affected by cold or cough?

Why does our voice change when we get affected by cold or cough? I observed the voice change thing in so many people including me.
1
vote
1answer
698 views

Why are some vegetables/fruits seasonal?

How does the mango tree perceive the summer season, so tree starts producing the fruits? Every tree requires sunlight to grow but what limits the production of fruits to a certain season? For ...

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