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 ...
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
1answer
69 views

Statistics on energy consumption breakdown per biological functions across organisms?

Are there any statistics available on how much energy organisms use for each biological functions (i.e. something similar to the line of "Bacteria spend X% of energy on information processing, Y% for ...
5
votes
4answers
565 views

What is the advantage of restriction enzymes cutting only at specific sites?

Bacteriophages have sequences which often do not have specific sites for restriction enzymes of bacteria to cut at and so can attack the bacteria. Wouldn't it be better if bacteria had something ...
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)?
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
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 ...
2
votes
2answers
758 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 ...
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 ...
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?
4
votes
2answers
97 views

Why do plasmids replicate on their own?

I know how plasmids can replicate independently of the main genome and know that they confer various properties to the bacteria and are useful in conjugation. My question is - what is the advantage ...
3
votes
1answer
140 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 ...
5
votes
2answers
1k views

What is the evidence that australopithecines were bipedal?

Before the discovery of Australopithecus afarensis in the 1970s, most anthropologists believed that an increase in brain capacity had preceded bipedal locomotion. However, this reconstruction of the ...
6
votes
1answer
55 views

How to search for organisms by criteria such as growth substrate and overflow metabolites?

I'm looking for a database or a systematic way to search for organisms which meet certain criteria. My criteria descending importance are: growth substrate chemolithoautotrophy (on which substrate) ...
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?
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 ...
4
votes
1answer
119 views

Was life less colorful before color vision evolved?

According to Wikipedia, we know that color-vision photopigments appeared in the common ancestors of tetrapods and fish at least 360 MY ago. Would life have been less colorful before the evolution of ...
0
votes
1answer
561 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?
2
votes
2answers
653 views

What can cause incompatible sticky ends to be ligated?

Actual question I have reason to believe (details see below) that in a ligation I carried out, an EcoRI sticky end (EcoRI: G'AATT_C) and an XmaI sticky end (XmaI: C'CCGG_G) were somehow ligated ...
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 ...
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?
2
votes
1answer
224 views

Why are some fungi poisonous?

There are many poisonous fungi in nature. For example Amanita Phalloides. What reasons could a fungus need poison for? Some species, like venomous snakes, use poison to kill other species as prey. ...
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 ?
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
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 ...
3
votes
1answer
83 views

What happens if we continuously stimulate a mimosa plant?

I know there is some mechanism in humans by which we start to ignore a certain stimuli if it persists for a long time (e.g., we don't feel our shoes all the time !). Can the same thing happen in ...
2
votes
0answers
1k views

What are potential side effects of myostatin inhibitors?

Myostatin inhibitors, which are being developed to treat muscle wasting diseases like muscular dystrophy, are likely to be abused by athletes. What are the potential long-term side-effects of taking a ...
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?
3
votes
1answer
2k views

Neuromediator, Neuromodulator, Neurotransmitter?

Of these three words, perhaps Neurotransmitter is the most obvious. I took a look at Wikipedia page for Neuromodulation and found that this is pretty similar to Neurotransmitter too. I guess ...
3
votes
0answers
60 views

Is there a realtime molecular clock within the genome to co-ordinate the developmental sequences in an embryo?

It is difficult to assume that the massive number of co-ordinated developmental sequences in a developing embryo is controlled by molecular signalling alone. Is anyone aware of a molecular or ...
4
votes
2answers
166 views

Plant identification?

Can anyone identify the plant below? It's in a backyard in Pennsylvania, and the photo was taken today.
7
votes
4answers
580 views

Are there any scientifically based predictions or theories of future human evolution?

Reading this question of the stack exchange got me thinking. I believe human evolution is an ongoing process and will not stop. Are there any predictions/theories about the phenotypes and genotypes of ...
5
votes
1answer
459 views

Do hormones make men think of sex?

I remember hearing a saying that goes like "men think of sex every 7 minutes (or seconds?)". I take this saying to mean that men have sex related thoughts more often than women. I'm interested if ...
5
votes
1answer
9k views

What is the standard deviation of adult human heights within sexes?

The wikipedia article on human height reports mean height for many different countries by sex but it does not report standard deviations. What is the standard deviation of adult human heights within ...
1
vote
0answers
27 views

Is there a database of pollen-seed distances across plant species?

I was enjoying Richard Smith's excellent answer to this question, and wondered: If you consider the pollen/seed distribution range to be plant locomotion, is there a database that compares these ...
5
votes
2answers
333 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 ...
5
votes
0answers
55 views

Honeybee decision process: new food, new home, new threat [closed]

I have heard that honeybees send out scouts, then based on the scout reports more bees go then come back and report and so they are supposed to be efficient decision makers. Can you give as complete ...
2
votes
1answer
43 views

Why are dreams sometimes remembered and sometimes forgotten?

Why is it that sometimes, when we wake up, we are able to remember what we were just dreaming, but sometimes we don't remember any of it?
5
votes
0answers
339 views

Reason for seeing grid-like patterns when strobing a solid black-white image?

I was trying to do some stimulation for SSVEPs by strobing a solid black square and a solid white square. Weird thing was, I ended up seeing weird grid like patterns that looked like this, always of ...
2
votes
1answer
82 views

Can plants survive indefinitely without external supply of gases at compensation point?

During photosynthesis, there is a point at which the light intensity is such that the rate of photosynthesis exactly matches the rate of respiration called the compensation point. What this means is ...
7
votes
1answer
457 views

Why do people sleep with their eyes open?

It's a fact that some people sleep with their eyes open, but why does that happen? Is it normal behavior, not a symptom of any sort of disorder? Are there any (dis)advantages to sleeping with eyes ...
6
votes
2answers
949 views

Do animals get sick from eating dirty food or eating off the floor?

Humans have very strict tradition of hygiene, such as washing hands before eating, using utensils, and in general keeping as much distance between food and dirt as possible. At the same time, most ...
2
votes
1answer
132 views

What's the difference between Cytoplasmic pool and Granular storage pool?

What's the difference between Cytoplasmic pool and Granular storage pool when speaking about neurotransmitters and synaptic cleft. I encountered this here: Amphetamine’s mechanism of action thus ...
3
votes
1answer
115 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
66 views

Why is duck fat less saturated than cow fat?

Why does the composition of fat in animals vary? Is there an evolutionary advantage to producing fat that is less or more saturated?
0
votes
1answer
26 views

Known MicroRNA - Gene Systems?

Have there been any experimentally-verified systems of microRNAs targeting a gene set (e.g., in cancer, perhaps)?
3
votes
1answer
127 views

Do insects respond to the detection of dead insects?

Are there insects that change their behavior upon detecting the nearby presence of other dead insects? If there are, can you provide an example?
3
votes
1answer
991 views

Why does the stomach ache if you take a brisk walk after lunch or dinner

After eating your lunch or dinner, if you take a brisk walk, most of the time your stomach aches. Why does that happen? What happens with respect to the body metabolism?
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 ...

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