1
vote
1answer
23 views

tetrads in meiosis are held together by what

This is from SAT subject biology test practice question. The answer it gave me was both chiasmata and centromeres. I can understand they are held by chiasmata but why also centromeres? I looked it up, ...
0
votes
0answers
15 views

interphase of meiosis 1 and meiosis 2

I saw a question asking "in both meiosis 1 and meiosis 2, the interphase include?" the answer they gave me was "chromosome uncoiling" I have several questions : is there interphase for meiosis 2? ...
1
vote
1answer
28 views

What are the internal surfaces of body cavities actually made of?

In Ross's book of histology it says that the mesothelium that includes all body cavities is made of simple squamous epithelium but in other places it says that in the gastrointestinal tract it is made ...
0
votes
0answers
4 views

Grouped Frequency distribution plot in R [migrated]

I have a dataset with Butterfly species as rows and the number of plant family-genera-species that they feed on in different columns. I tried to get a frequency plot in R but encountered problems in ...
2
votes
1answer
18 views

phylogenetic Independent contrasts with unresolved tree

I have a dataset containing morphological and performance measures of species from various groups, including insects, lizards, frogs, spiders etc, and want to analyse the relationship between these ...
0
votes
1answer
17 views

is there a way to do batch download for all gene pathways?

I would like to download all the gene pathways and genes of each pathway. Preferably, gene length of each gene as well. It would be a lot more convenient if there is an R package.
8
votes
1answer
852 views

Is there a protein in the eye that gets kinked by photons and shipped down to the liver to get un-kinked?

My friend made the claim that there exists a protein in your eye responsible for vision. This protein is sensitive to different wavelengths of light, and when it gets hit by the right wavelength, it ...
1
vote
1answer
40 views

What is reductive deamination?

This presentation on anaerobic digestion mentions (pg. 19) two major pathways for the digestion of amino acids: Stickland reaction and reductive deamination. While I find some info on the former, what ...
3
votes
1answer
82 views

What's the difference between naive and memory B cells?

I understand that when naive B cells are exposed to antigens, they become memory B cells, but what is the functional difference between the two? I've looked at the quite a few article on B cells, but ...
0
votes
0answers
33 views

Width of vein in finger

I am working on my bachelors thesis, where one part of it is to find width of vein in fingertip. I use database images and extract vein patterns from it, but i have to calculate the width of vein and ...
2
votes
3answers
38 views

Why doesn't the cytosol dissolve the polar structures?

we know that cytoplasm of cells are filled with water molecules and other hydrophilic molecules so my question is why the water of cytosol doesn't dissolve the ionic part of the lipid bilayer or why ...
2
votes
1answer
28 views

Role of isopropanol in plasmid isolation

In plasmid isolation, isopropanol is used to renature only the plasmid macromolecules after we precipitate all macromolecules(DNA, RNA, plasmids) using sodium acetate solution. How does it do that? ...
2
votes
2answers
58 views

introduction to Chip Seq

I hope this question is suitable for this site. I am concerned about the Chip experiment part so I think it should be okay. I am a Applied Math student starting to get into bioinformatics and so I've ...
1
vote
0answers
19 views

How to make a concentrated solution of the common lab glassware cleaner Alconox

I'm using the all famous Alconox powder detergent to clean my laboratory glassware, the powder is a pain to store near the sink and to use. Would like to make a more friendly concentrated liquid to ...
1
vote
1answer
32 views

Advantage of cup-like shape of blood cells, spores?

Mold spores sometimes have the same shape as platelets in blood. If I were designing a spore it would probably be spherical. Is there any advantage to this cup-like shape? Maybe there is some ...
2
votes
1answer
18 views

How much of the jejunum is bypassed during gastric bypass?

There is both long and short limb bypass surgeries. I want to know how much of the jejunum is bypassed with each procedure.
0
votes
1answer
13 views

What is Saccus in Embryology?

The word seems to be of German origin. I have it here Saccus lymphaticus inguinalis, Saccus lymphaticus jugularis, Saccus lymphaticus posterior, Saccus lymphaticus retroperitonaealis. I ...
3
votes
1answer
18 views

PCR master mix contents

I am running PCR reactions with different sets of degenerate primers and I want to know what should go into the master mix My usual master mix: DEPC water PCR buffer (-Mg) 25mM MgCl2 10mM ...
1
vote
1answer
9 views

Why is oxygen used up in eutrophication?

This probably sounds pretty dumb, but wouldn't algae blooms produce a lot of oxygen? Although they would die out and decomposers would use up oxygen, is that more than what the algae produced?
-3
votes
0answers
26 views

Can glycogen have structural roles ? [on hold]

Does glycogen and starch provide structural support? I know cellulose as polysaccharides does.
2
votes
2answers
19 views

Gel Electrophoresis - loading dye and more

I'm a student new to molecular biology coming in from an eco-evo background looking for tips from you molecular pros! It seems that I'm running quite a few gels. The loading dye I'm using is Gel ...
1
vote
1answer
27 views

Is a naive immune system equally able to handle new antigens as an educated one?

This is a variation of the "does the immune system run out of memory" question. Here's a (possibly imperfect) thought experiment: You take two twins. One of them lives in a bubble from birth. One of ...
3
votes
0answers
10 views

How is nutrient uptake in humans measured?

There are many claims made about nutrient absorption, eg "Juicing helps you absorb all the nutrients from the vegetables". I'm curious to know how nutrient uptake is measured. Eg is it a pure ...
3
votes
1answer
45 views

What is meant by single molecule sequencing?

When sequencing papers refer to single molecule sequencing, what is their definition of a "molecule". Are they saying base by base? The entire DNA chain in a chromosome can also be though of as a ...
2
votes
2answers
44 views

How were the first primers made

I keep reading about how primers are useful in pcr -- they allow you to select a specific dna region. Similarly, in NGS or Sanger sequencing they give you a starting point. The primers I see are about ...
3
votes
1answer
38 views

How does regurgitated food go to the 3rd stomach chamber instead of going to the 1st?

Ruminants are known for their regurgitation of food; the food goes through the 1st and 2nd stomach chambers, then returns to the oral cavity in cuds. The cuds then come back into the stomach, but this ...
4
votes
1answer
18 views

When does exposure to an allergen increase / decrease allergy?

In immunotherapy a person is regularly exposed to an allergen to decrease the allergy. Yet apparently "repeated intranasal challenges ... induces robust allergic airway inflammation, " [0] So when ...
1
vote
0answers
19 views

Planar circular DNA and protein

I am trying to develop a planar (two dimensional) lattice based framework to simulate ring (circular) DNA and proteins. To verify my model, I need to simulate real DNA and proteins. The base idea for ...
-2
votes
0answers
34 views

Chronic fatigue causes low parasympatheticus and high sympatheticus in allergies

Chronic fatigue can be felt as malaise. Assume the cause is here allergies. My conjuncture is that the heart uses more energy in chronic fatigue, felt as malaise - measured as Asthma-Quality-Of-Life ...
0
votes
4answers
220 views

Strictly from a biological perspective, what is the functional expectation of a human being [closed]

Just like the title says: Strictly from a biological perspective, what is the functional expectation of a human being. No religious or philosophy-based answers will be accepted, we are talking ...
0
votes
1answer
25 views

What is accumulation and release centre of neurohormones?

What is accumulation and release centre of neurohormones? Is it hypothalamus?
4
votes
1answer
473 views

Identical twins' genders

Can identical twins have different genders (as in biological sex)? I thought they should have absolutely the same genes. If they can, what caused it? I'd assume it MAY be because of errors in ...
0
votes
0answers
40 views

Effect of natural selection on phenotypic variance

Short background Theoretically speaking, natural selection causes a decrease in genetic variance and because the environmental variance should remain unchanged, natural selection causes a decrease of ...
-1
votes
0answers
11 views

Effect of axillary stretching on prevention of congestion from hyperemia

In exercising not-opposing muscles of arms (biceps, not triceps), hyperemia of tissues occurs i.e. active process in arteries. I feel personally sour muscles many days afterwards if I do not stretch ...
1
vote
1answer
41 views

What kind of small insect is this?

Found in central florida in the bath tub. Its about the size of a pencil marking, very small. What is it?
1
vote
2answers
47 views

Is there a name for this principle in biological contexts?

This is mostly a question about usage. There is a probability-related idea that has been used in at least two biological contexts. The idea is that if something happened, it was probably likely to ...
2
votes
2answers
41 views

How would the human body adjust to sleep times if we were to live in a place with different day lengths?

You sleep at night and are active during the day that's how things work for humans, but theoretically if a human whose parents lived on earth were to be born in another planet resembling earth but the ...
2
votes
0answers
13 views

Effect of Aging on SA node's sympathetic fibers

I am trying to understand the effect of aging on the sympathetic fibers of SA node. I know that aging shifts the vagal curve to left in frequency due to aging. However, I am interested if aging has ...
3
votes
3answers
122 views

What does “kcal/mol” mean when speaking of enzyme catalysis?

After thinking about it, I'm confused by what the reaction barrier of an enzyme actually means. Imagine a reactor containing enzyme and substrate. If the enzyme in the reactor has a reaction barrier ...
1
vote
1answer
22 views

Detecting a Fasting State in the Body via Lasers

I was just wondering wether it would be possible to detect if the body is in a "fasting" state, via lasers attached to the body. If it is possible, what sort of laser would be needed?
1
vote
2answers
31 views

How do exon tandem exon duplications occur in the genome?

By this I mean in cases where tandem exons are introduced by replication slippage how would a DNA polymerase by chance duplicate an entire exon cleanly (i.e. from exact start to exact end) when it ...
1
vote
1answer
108 views

Heterozygosity and overdominance

Consider $m$ loci with heterozygote advantage (overdominance) such that the fitness of the two homozygotes is $1-\frac{s}{2}$ and the fitness of the heterozygotes is $1+\frac{s}{2}$, where $s>0$. ...
2
votes
1answer
79 views

Why haven't land animals evolved beyond urination?

It occurred to me (while urinating) that this would seem to be selected against because water is a scarce resource. Why are we constantly losing water we don't need to through urination? What is ...
1
vote
1answer
28 views

How are new chromosomes replicated into the next generation via sexual reproduction?

If an individual has a new chromosome, which is very unlikely to happen, he will not have any luck in finding a sexual partner with this same trait. How will the offspring inherit this trait. And ...
2
votes
0answers
52 views

List of np-hard problems in biology/bioinformatics

I'm not sure if this is the right place for this but... I am looking for a list of computationally "hard" problems such that if a problem from this list could be solved effectively, it would be ...
1
vote
1answer
43 views

Could someone Identify this Insect Hive on my Balcony Grill

A smallish insect hive has been forming on the grill of my balcony in the last month or two, and I wanted to know should I be worried or can I just let it be. Its 13th floor in Singapore, if the ...
0
votes
0answers
27 views

Cells and their characteristic properties

Could a culture of cells of a certain type be 'forced' to attain certain properties in successive generations that would have been harmful to the cell culture as they are now?
1
vote
1answer
32 views

In an open circulatory system, how is blood moved?

In the mollusks section, the powerpoint mentioned that gastropods and bivalves have an open circulatory system. According to the note, this means that the blood does not travel in vessels. How, then, ...
2
votes
2answers
43 views

How can CI repressor both activate and repress $P_{RM}$ promoter found in $\lambda$ phage?

I'm reading a paper where the authors constructed a toggle switch that uses bidirectional $P_R/P_{RM}$ promoter found in the $\lambda$ phage. There are 3 binding sites - $O_R1$, $O_R2$, $O_R3$ - ...
-2
votes
2answers
42 views

Punnett square and hybrid cross [closed]

A plant breeder crossed two plants, one with red flowers, and the other with white flowers. Red is dominant. Calculate the phenotype and genotype ratios of the F2 generation of this cross. Is this a ...

15 30 50 per page