7
votes
2answers
162 views

The Assumption of Weak Selection?

I was reading this question and I failed to fully understand the introductory part of it. The OP (@Artem Kaznatcheev) says: Most analytic models like to assume weak selection because it allows ...
3
votes
1answer
780 views

Classification of glycosidic anomeric bonds (alpha vs. beta)

In the process of studying for my upcoming biochemistry exam, I have stumbled over the classification of glycosidic bonds. I want to be able to distinguish $\alpha$- from $\beta$-glycosidic bonds. ...
1
vote
1answer
94 views

Prothrombin time when extrinsic pathway is turned off

I was searching for an answer that "why do we need intrinsic pathway when there is fast extrinsic pathway" and i found the answer in the following link: http://www.pathologystudent.com/?p=3197 It ...
0
votes
1answer
65 views

Is “monosexual” still a valid term in biology?

I read an older article where they talk about species being strictly monosexual as opposite of being hermaphrodite, etc [1]. After an extensive googling and reading about how everybody has to be at ...
3
votes
2answers
86 views

Why are dolphins so smart?

It seems that dolphins have (among?) the highest encephalization quotients found outside of humans, higher even than chimpanzees. By the "use it or lose it" principle this indicates that intelligence ...
2
votes
4answers
125 views

Does a phenotype include the presence of a recessive gene

I am trying to understand what exactly a phenotype is to try and understand a genetics database. (Ie I don't really know very much about genetics at all) I've been reading through wikipedia on what a ...
1
vote
1answer
66 views

Botany related question: liverwort sporophyte

Is perianth part of the sporophyte or gametophyte in liverworts (Marchantiophyta)?
6
votes
2answers
2k views

Very high 260/230 absorbance ratio of an RNA sample

After my most recent RNA extraction, the RNA samples had very high 260/230 absorbance ratios, (ranging from 5 to 25). I've never gotten numbers like this and I know the ratio is supposed to be ~2 in ...
3
votes
1answer
502 views

When happens when pollen grains land on the a part other than the stigma of a flower of the same species?

When happens when pollen grains land on the a part other than the stigma of a flower of the same species? Would the pollen be transported to the stigma or would it just sit where it landed and nothing ...
2
votes
1answer
506 views

Action potential and sodium channels

In this video on electro tonic potential, the tutor says that when the potassium channels open the potential drops from +40mV to -80mV, where the sodium channels have already closed at +40mV. Now in ...
-1
votes
2answers
83 views

Could a normative population ever be non-heterosexual? [closed]

In the modern documentary called "Bi the way", one American geneticist said that if modern American youngsters may as well be functionally bisexual, then some generations ahead Americans could be ...
1
vote
1answer
155 views

Determining a patients biological age?

I am looking for an algorithm that shows the exact coefficients some variables that have on a hospital patient's chronological age versus their biological age. I understand a lot of the variables ...
2
votes
1answer
48 views

maximum # of generations possible in a population of cannibalistic rats

Assume a sufficiently large population of rats (to allow genetic variation and facilitate inbreeding) in a place with abundant water, sunlight, shelter but no food. For how many generations can this ...
-1
votes
1answer
93 views

Can pheromones in perfume be formulated to cause agitation? [closed]

I generally don't care for female perfume. I have very sensitive olfactory receptors and in general, I just find perfume overwhelming. A couple weeks ago, my wife of almost 14 years and I were ...
2
votes
1answer
68 views

How good is information transfer between the hemispheres of the brain?

I sometimes listen to lectures on my phone using ear buds, but occasionally with only one ear bud in. Is the other half of my brain losing out on any aspect of the lecture? Just how good is the corpus ...
11
votes
3answers
3k views

How long can E. coli stocks be stored at -20°C?

I'm volunteering for a biohacker lab - biocurious in Sunnyvale. The have a pretty good set of equipment - gel boxes, incubators, but they don't have a -80°C freezer yet. I'd like to set up some ...
2
votes
2answers
96 views

Is it possible to create an experiment in house conditions to prove the existence of germs?

I realise that the best way to prove the existence of germs or single-celled organisms is by looking at them through a microscope. But I don't have a microscope at my home, how can I design an ...
6
votes
3answers
5k views

What's the difference between a plant and an animal?

Are there some living things where the distinction between plant and animal is blurry or unclear? I wouldn't know where to put something like yeast. I also thought of photosynthesis, but then I ...
1
vote
2answers
100 views

Removing a restriction site and introducing other at its place

What would you do if you want to remove an EcoRI restriction site and introduce BamHI restriction site at apprx. the same location ? One of the answers in my textbook was : To construct a DNA ...
2
votes
1answer
86 views

What is the name of the smallest self-replicating thing?

Some time last year, I found an article on Wikipedia about the smallest something to be able to reproduce. I don't remember exactly what it was, but I am fairly certain that after the initial ...
0
votes
1answer
159 views

How does human body deal with inert solid material in the bloodstream?

How does human body deal with inert solid material in the bloodstream? For example, if there is a powder of glass injected into our bloodstream, will the white blood cells do anything or will kidney ...
3
votes
2answers
7k views

Can all mammals swim?

When I checked it seemed trivial to answer: yes, all mammals can swim. But research on the internet provided different information. I found: people and primates cannot swim, but can be taught how to ...
1
vote
4answers
160 views

Significance of having goosebumps?

What help does goosebumps do to us? I don't think it helps us noticeably when we are scared or shivering.
4
votes
1answer
48 views

Where are newly discovered medicines tested

When a medicine is prepared by a biologist,then where does he first test on? And how does he know that this is the exact combination for a disease to get cured? Does he test that medicine on a human ...
1
vote
1answer
1k views

What are the differences between G+ and G- bacteria?

The distinction between Gram-positive and Gram-negative bacteria is based upon the Gram staining method, that reflects the bacterial wall physical properties. However, this classification involves ...
1
vote
1answer
57 views

Constitutive mutation in operator gene

If a constitutive mutation happens in the operator of an inducible operon, does that mean that repressors won't be able to bind them ? Or does it mean that even if repressors are bound, they will not ...
1
vote
1answer
94 views

Insect identification

It is found in my apartment in Finland. I had to kill it to stop it from getting away before looking for the camera, but it looked pretty much the same alive and intact. It's length is about half a ...
15
votes
5answers
8k views

Origin, or source, of rhesus negative in human blood

This is my first post here, so please be gentle. I recently learned that I have Rh- blood (I'm A-), and was idly looking into blood types on Wikipedia. I was surprised to find that relatively few ...
2
votes
1answer
53 views

Evolutionary conservativeness

List the following proteins in the order of decreasing evolutionary conservativeness of their primary structure: Somatotropin. Catalytic subunit of a DNA – polymerase. Histone H1. ...
3
votes
0answers
84 views

Why don't surfactants destroy or incorporate into cell membranes?

How do surfactants remain on the surface of pneumocytes without (1) acting as a detergent or (2) the phospholipids getting incorporated into the membranes of pneumocytes... I'm guessing the answer ...
0
votes
0answers
35 views

How to predict the position of the femoral head center given surface anthropometric data?

Given surface measurements such as hip breadth and hip depth, how would you predict the location of the femoral head center?
5
votes
2answers
3k views

Why do we assume that the first humans were dark-skinned?

According to the article Dark skin and blue eyes: How Europeans once looked: It is widely accepted that Man's oldest common forefather was dark skinned, and that people became more pale as they ...
2
votes
1answer
788 views

Telomere shortening during replication

It is widely know that each cell cycle during DNA replication some fraction of the telomeres is lost, and this phenomenon is called the end replication problem. Well this is due to the fact that the ...
2
votes
1answer
67 views

Mites on ginger root

I was just looking at some mouldy ginger found in the fridge under the microscope and was horrified/delighted to find (what looked to be) mites growing in it. I have searched the web and can only find ...
1
vote
1answer
70 views

Why do peas change colour?

I am doing an experiment on preservation of peas. The first notable change to the peas over a period of one week is that they have changed colour from bright green to a dull colour... Why is this ...
1
vote
0answers
16 views

Phylogentic Footprinting Project

I'm working on performing phylogentic footprinting to figure out how many TRE sequences there are in the TWIST1 gene. (Sequence motifs). I'm trying to use ENSEMBL to gather orthologues of species in ...
1
vote
1answer
216 views

Genetic Epistasis Question

I need help with this practice question. I'm assuming that would a epsitatic recessive question since the parents are true breeding and then the ratio would be 9.3.4. But I am not so sure. Any ...
1
vote
1answer
112 views

Pedigree Diagram help

I am asked to fill the genotypes in the spaces provided but looks like I am aving a little bit of trouble. can anyone help? thanks in advance!
0
votes
1answer
121 views

PedigreeAnalysis Genetics [duplicate]

Hello! I need help with this exercise question. I am not really sure which pedigree diagram is autosomal and which is not. But, is question b 1/2. Can someone give an explanation? Thanks very much ...
4
votes
1answer
54 views

Where can I find histograms and tables of prevalence of mutations in cancer?

At some point in the past I found a cancer portal site which had aggregated data for the relationships between various mutations and their prevalence in cancer types and tumor data. The data was ...
5
votes
2answers
94 views

How extensive is CD47?

CD47 aka the "don't eat me" signal has recently been claimed to be expressed on all tumor cells. This doesn't seem to corroborate with other cell-biology experiments. On what other cells is CD47 ...
2
votes
1answer
51 views

Need help distinguishing between a primary and secondary source

I am trying to figure out if the following article is a primary or secondary source. I'm leaning towards secondary but here are my cases for both. Primary: Published in a peer-reviewed ...
1
vote
1answer
35 views

Why all particles have same influence on osmosis

When people talk about osmosis, they say that when we add a mole of NaCl, then each its molecule gets dissolved into 2 separate particles and therefore we have 2osM/L solution. But both Na & Cl ...
3
votes
1answer
102 views

Why is Turner syndrome rarer than Klinefelter syndrome?

Turner syndrome occurs in 1-1000 to 1-5000 females, and Klinefelter syndrome occurs in 1-500 to 1-1000 males. Why is Turner so rare even though they both are caused basically by the same mechanism?
2
votes
0answers
27 views

Are human infants inherently frightened by anything?

Naïve question - feel free to shoot it down. To the best of my knowledge an infant doesn't really 'shrink' from something without first trying it. Even the action of looking at the fierce expression ...
1
vote
1answer
57 views

Molting in arthropods

Do all the arthropods molt ? Which ones do not molt ? Why don't they need to molt ? I tried googling this - but did not get satisfactory answers.
2
votes
1answer
85 views

What is this image?

What I understand is- I think this is picture of DNA. But why is it in this conformation ? What types of cells have this type of DNA ?
2
votes
1answer
55 views

Determining whether X chromosome from sperm or egg

Is there any way of determining which X chromosome a female inherited from her father and which from her mom ?
5
votes
2answers
125 views

Can you tell the sex of a white willow when it's not flowering?

Can you tell whether a salix alba tree will produce male flowers or female flowers by looking at it, touching it or generally using your unaided senses? If not, is there any way to do that without ...
0
votes
1answer
56 views

probability of having normal daughter

If father has hemophilia, mother is a carrier of the disease, then what is the probability of having a normal daughter ? My question: Should the probability of having a daughter be also ...

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