6
votes
3answers
165 views

Why are diabetic people often overweight?

I was looking at diabetes the other day, and I noticed something strange. Lower amounts of lipase are a symptom of diabetes, as is overweightness. However, since lipase is the enzyme that breaks down ...
2
votes
2answers
328 views

Why doesn't human consumption of plants cause infectious diseases the way consumption of animals can?

At first I want to clarify that I do know that there are naturally poisonous plants and plants that can hold radioactive stuff or toxic material from the environment. What I mean by "diseases" (I ...
10
votes
2answers
2k views

What is the evolutionary reason behind the fragility of teeth?

Almost all organs in the human body have a rather large threshold within which the organ or tissue is capable of repairing itself using materials supplied by the body, whether it's made from organic ...
7
votes
2answers
451 views

Do teeth have the capacity to heal?

Could a cavity in a human tooth "heal over" or possibly fill back in?
4
votes
2answers
11k views

What happens to the holes in the skull where teeth were developing?

In Skeptics.SE, a question regarding the skulls of children arose. Depicting a scary skull where the permenent teeth are "hidden" inside the jaws and the milk teeth are in the their place. After all ...
2
votes
1answer
737 views

Difference between 'Orbit' and 'Globe' in eye anatomy?

What's the difference between 'Orbit' and 'Globe' in eye's anatomy. Do they refer to the same ? I encountered this in this text: ... ciliary ganglion, which is approximately 3 mm in size, and ...
5
votes
1answer
593 views

Using ion-exchange chromatography to purify DNA from a cell extract - Is DNA more negatively charged then RNA?

When applying this method we have a glass or plastic column of resin which is positively charged. Then we pour cell extract into the column in order to capture the negatively charged particles which ...
1
vote
1answer
50 views

Genetics - Is this hybridization possible?

Suppose you hybridize two plants - One has a red flower and a long stalk, the other has a pink flower and a short stalk. This resulted in these 4 type of plants, with ratio 1:1:1:1 Long stalk red ...
4
votes
2answers
526 views

How do insects such as crickets circulate blood through their antennae?

Some insects, like the crickets pictured below, have such slender antennae it seems no blood could fit. How do they get blood through their antennae?
1
vote
1answer
27 views

Confusion regarding the ventricle system in the brain

I have a hard time finding out a small detail about the ventricle system. As the CSF flows into the 4th ventricle, there's a small foramen in the lateral aspect, as well as an open space bounded by ...
1
vote
1answer
189 views

Characteristics of life

If all of the characteristics of life are required for something to be defined as living, how can we account people or other life that can not reproduce?
5
votes
2answers
197 views

If a dead snake reflexively attacks itself, why does it not always attack itself?

Recently there has been this video going around of a snake that had been decapitated. Its body swung around to the decapitated head and the head attacked the body on "reflex". Now we know that most ...
1
vote
0answers
40 views

Does sleep duration vary for animals based on time of the year?

I'm interested in the sleep patterns of wild animals, that still use sun for controlling their biological clock. Animals entrain their biological clock to the day/night cycle using light as the ...
9
votes
2answers
237 views

Why do animal teeth get darker if exposed?

I was wondering why the teeth of cats (And dogs, as far as I know, plus possibly some other animals or even humans) get darker if they are exposed to air / light? Example: (See the lower end of ...
1
vote
1answer
56 views

Method to inject genes into cells

The famous Hershey and Chase Experiment uses phages to inject genes into cells. In the beginning, Professor Yamanaka injected 24 types of genes into cells to figure out which genes turn a cell into ...
9
votes
1answer
334 views

Structure of fitness landscapes in the NK model

The NK model of rugged fitness landscapes consists of $N$ sites where fitness contribution of each site depends on its state $\{0,1\}$ and is epistatically affected by $K$ other sites. When defining ...
1
vote
0answers
59 views

Does pain scale with mammal mass?

Some biological features scale with the animal mass (see previous Q&A). Assuming the same concentration of nociceptors on the skin surface, I'm wondering how painful a 1 cm wound will be ...
6
votes
2answers
229 views

Is local equilibrium a reasonable assumption for evolutionary processes?

Whenever I look at discussions of fitness landscapes (in particular, Kauffman's NK model) the questions tend to resemble: The population is at a local equilibrium, but another equilibrium of ...
3
votes
2answers
445 views

How can fruit flies and mice share the same gene that says to build an eye if they evolved separately?

I saw a documentary where they inserted the gene of a mouse that basically is the starting "build an eye" command into a fruit fly, and a fruit fly eye grew. My question is, if eyes of different types ...
0
votes
3answers
2k views

How come that we “feel” it when someone's watching us [closed]

The question is relatively easy (the answer however..). We all know this feeling "being watched" and more often than not this is a real thing. If someone is staring at us from the side or from the ...
1
vote
1answer
94 views

Is iodised salt harmful to the lactofermentation process?

I was discussing sauerkraut recipes with someone on IRC a minute ago, and they warned me not to use iodised salt in the process. My first (and so far, the only successful) batch is one I made with ...
5
votes
2answers
334 views

What are common causes of unexpected ligation products?

I digested two plasmids, one with EcoRI and AgeI and the other with EcoRI and XmaI. Digests looked as expected, so I purified the respective fragments and set up the T4 DNA ligation (AgeI and XmaI ...
3
votes
1answer
88 views

What is a good source for info on disease frequency distribution among age groups?

I need information on the disease frequency distribution among age groups for an Android app I'm building... Hopefully I've come to the right place. Is there a good data source for this? Like a ...
1
vote
1answer
74 views

How do plasmids protect themselves against restriction enzymes?

How do plasmids protect themselves from restriction enzymes released by bacteria (i.e., against bacteriophages)?
3
votes
1answer
2k views

What is DNA binding domain? It is not clear what the domain means

I am confused about the term DNA binding domain. Does it mean that there are some parts of the DNA that tends to coil up? Does it happen because some proteins tend to stick around that area? Also it ...
1
vote
1answer
2k views

Are there more/less favourable phases of menstrual cycle to donate blood?

I was wondering whether it makes a difference when during the menstrual cycle a female is donating blood in terms of: Blood quality (iron or hormones levels) Her health/safety I am aware that ...
18
votes
3answers
473 views

Are human fetuses more likely to be male? [duplicate]

Question: From a physiological point of view, when sex is determined in a human fetus, is it equally likely to be male or female? Studies in this area typically measure age at birth, where the data ...
4
votes
1answer
46 views

Are there any studies on the fertility levels of humans/mammals as a function of their stay at Antarctica?

Wikipedia, and Space.SE seem to indicate humans become infertile in space due to the increased exposure to cosmic rays. Knowing as we do that Antarctica is holey, and subject to increased radiation ...
2
votes
2answers
761 views

What is the best color for a PPG signal (photoplethysmography)?

What is the best color for a PPG signal? Red, green, blue or infra-red? I'm asking because commercial oximeter sensors usually use a pair of red and infra-red LEDs. But recently, I've seen a lot of ...
1
vote
0answers
37 views

Visualizing secondary RNA structure binding to target

I am designing synthetic ribozymes, and need to see the secondary structure that arises from its flanking arms binding to a target mRNA. I've used Mfold as well as IDT's OligoAnalyzer (Hairpin), but ...
8
votes
1answer
99 views

Why pouring salt in the wounds is painful?

Pouring salt in the wounds is so painful. I am sure you all experienced this. whats happend there?
3
votes
1answer
141 views

What are these stars in my microscopic image?

I see this very curious patterns on the sun-facing side of a jasmine (probably) leaf - visible with a makeshift microscope (about 50x) What are them? Pores? Are there other plants with similar ...
6
votes
2answers
828 views

Why did the urinary bladder evolve?

Sure it's convenient to decide when to urinate but not essential for survival or reproduction, as I understand. But just convenience is not a drive for evolution. Does the bladder serve any essential ...
0
votes
1answer
3k views

What decides whether a lysogenic cycle or a lytic cycle will take place?

A virus can either participate in a lysogenic cycle or a lytic cycle. What decides that?
1
vote
2answers
246 views

Does evolution destroy functional sequences much faster than it creates them in any large-genome animal with low reproductive rates?

Recently I have found myself in a discussion with a guy that isn't a creationist, but denies evolution. He cites several studies that show problems like this one, but I do not have the knowledge to ...
3
votes
2answers
46 views

Have novel interactions or pathways been predicted by GRN or PPI data and later confirmed by experiment?

I've been learning about the gene regulatory network (GRN) and protein-protein interaction network (PPI) recently. I've found a huge amount of extremely interesting papers about how biological network ...
2
votes
1answer
36 views

Material on the analysis of (micro)array data

I'm at the moment analyzing cytokine array data. The available material on the statistical analysis of these data is more than unsatisfactory. Since a lot of effort is being made in the analysis of ...
5
votes
3answers
2k views

Fetal development, gastrulation and embryonic disc

I am completely confused by the images circulating on the internet of human gastrulation. First, lets see how it happens in deuterostomes. This image depicts the process: (image is from Wikipedia) ...
2
votes
1answer
89 views

Expression of bidirectional promoters

How are bidirectional promoters expressed ? (Won't RNA Pol have to go in 3'-5' direction?) Why are they more commonly found in eukaryotes than prokaryotes?
2
votes
1answer
248 views

How can a continuous RNA be transcribed in the lac operon?

The lac operon has 3 genes: lacZ , lacY and lacA. I have seen that the m-RNA transcript of these genes has stop codons in between. So, how can the RNA be made continuously? Won't the RNA Pol detach if ...
8
votes
3answers
422 views

Why people like to see pornographic scenes, but do not feel the same about eating scenes?

This question may seem funny, but I think biology must have good answers. I think no more explanation is needed. I really thought about this and searched for an answer, but there is nothing yet. If ...
1
vote
1answer
2k views

Why do I always close my eyes when someone takes a photo of me using a flash?

Everytime some tries to take a photo of me with a flash I manage to close my eyes (blink). It's not intentional and it's quite annoying. Why am I doing it?
0
votes
1answer
563 views

Why does air from the nasal cavity not go into the oesophagus?

When we ingest food, the epiglottis covers the trachea and the uvula covers the nasal passage. But what happens when we breathe? Why does the air go into our trachea and not the oesophagus?
5
votes
4answers
5k views

RNA or ribosome, which one moves during translation?

During translation ribosomes decode the genetic information present in the mRNA and protein synthesis takes place. During this process which of those two does move, the ribosome or the mRNA?
2
votes
1answer
237 views

Are there natural selection experiments that quantitatively agree with theoretical modeling?

Has anyone ever conducted an evolution experiment and quantitatively compared it to theory? For example, has anyone ever put bacteria in a million petri dishes filled with antibiotics and calculated ...
1
vote
1answer
167 views

Can viruses protect themselves against restriction enzymes?

Restriction enzymes cut the DNA of bacteriophages. Have bacteriophages evolved any mechanism to protect themselves from it ?
2
votes
2answers
4k views

What is genomic imprinting?

What is a genomic imprint? How does genomic imprinting take place? If I say that "this" allele is maternally imprinted does it mean that the allele of the gene is passed only by the mother? If a ...
3
votes
1answer
116 views

What causes sinus pain and congestion?

When the sinuses flare up, it can get very painful. Thus, my question - what biological mechanisms cause the congestion and especially the pain associated with sinusitis?
2
votes
1answer
80 views

Bioluminescence and photovoltaics

I work in the PV industry and was asked a question recently during a presentation. Could Bioluminescence provide enough light to power a PV array during off peak hours? I understand the PV portion and ...
6
votes
1answer
1k views

How do lilies sense day and night and open and close their flowers?

We have lots of lily flowers inside our garden. Their flowers are open in day and closed in night. How do lilies sense day and night and open and close their flowers?

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