Bitwise
  • Member for 9 years, 4 months
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How do prokaryotes perform cellular respiration without membrane-bound organelles?
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15 votes

Mitochondria are very similar to bacteria and are thought to have originated from bacteria. This points you to the answer: bacteria produce ATPs the same way mitochondria do, with the oxidation ...

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Differences Between Protein Motifs and Protein Domains?
13 votes

These are completely different concepts, which sometimes may be connected. A motif in biology is a mathematical model, typically of a sequence, that predicts which sequences belong to some defined ...

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Scoring sequence against position weight matrix
12 votes

The probabilities are correct. You must take the product (in log space this is equivalent to sum). The reason the probability looks small is just that you are perhaps thinking the score should be ...

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What does phasing mean?
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9 votes

This refers to haplotype phase (aka gametic phase). This essentially means knowing which allele belongs to which copy of the chromosome, or alternatively, which alleles appear together on the same ...

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Why are antibiotics prescribed with a viral infection like a cold?
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9 votes

In general antibiotics don't help with viruses. However, sometimes a bacterial infection may follow a cold virus, so there might be some scenarios in which antibiotics would be needed. However in many ...

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A mathematician's confusion regarding parametric $t$ tests for gene expression data
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8 votes

I understand this in the following way: For each probe you have two sets of measurements, one for ER+ and one for ER-. What you do is a T-test (to my understanding is that the "parametric" just ...

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Are there genes in humans from the common ancestor of all organisms?
7 votes

Depends on what you mean by unchanged. If you mean a gene that maintained the same nucleotide sequence, then the answer is no. If you meant a gene that descends from a very ancient gene, i.e. one can ...

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Does the Heart Require Gold?
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6 votes

According to this source, gold is not a necessary trace element for living organisms. Would have been cool, though...

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Is warmth/temperature sensed linearly or on a different scale?
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5 votes

A more general answer/comment is that technically almost nothing in biology is really linear. In a linear relation, when one variable increases the other increases proportionally. In biological ...

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Are there special constants in biology that define organism's morphology?
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5 votes

I don't know if this is what you mean, but take a look at BioNumbers. Also, mathematical constants like pi are different from physical constants. Mathematical constants are true in a mathematical (...

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Is it possible to make bacteria vulnerable to antibiotics it's resistant to?
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5 votes

Perhaps it is useful to first consider how resistance is gained: If you treat a population of bacteria with an antibiotic, some may die and some may live. If none die, they are obviously resistant. ...

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Expanding the SETI initiative to seek intelligent data within DNA sequences?
5 votes

Let's extend your idea a bit... Ok, there are conserved sequences that we may not know what their function is. Let's assume that they are indeed not functional and are some kind of message left by an ...

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What is the known maximum ranging distance of a bat's sonar?
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5 votes

This paper finds some species can detect as far as 67 meters, but the range varies between species. Note that the bats can actively change their range of detection and trade off range for resolution (...

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How and when did sex evolve?
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4 votes

Sex (depending on how you define it), evolved very early (more than a billion years ago). Even species like yeast have a type of "sex" (see below). Also, this doesn't mean there is necessarily a big ...

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Suitable introductory book on Bioinformatics for a computer scientist?
4 votes

Systems biology and bioinformatics are quite diverse subjects, but here are some options: Biological Sequence Analysis by Durbin et al.: the classic bioinformatics text for people with a CS ...

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Why is the Hydra Biologically Immortal?
4 votes

Actually, most adult cells do not express telomerase or express it only at a very low levels. Telmoerase is highly expressed only in cells that need to divide (e.g. stem cells), thus "immortalizing" ...

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Can children restore brain cells?
3 votes

I am not an expert in neurobiology, but this is what I have been able to find: In general, the PNS (peripheral nervous system) does have remarkable neuroregeneration capabilities. However, the CNS (...

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How easy is it to carry out de novo sequence assembly?
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3 votes

If you only want to use only sequencing techniques, you have a problem. To get a feeling of what kind of results to expect, consider this paper published recently in Nature Genetics. They tried to ...

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Why isn't a virus "alive"?
3 votes

In addition to the good answers given here, I would like to propose a more intuitive argument against viruses being alive. Viruses are, at one point of their "life", simply a piece of DNA (or RNA). ...

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Are there beneficial genetic mutations identified by consumer DNA genotyping?
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3 votes

First of all, I think it is, to a large extent, the way you perceive it. Instead of cancer-causing allele and hair-loss allele, you can think of them as cancer-protection and great-hair alleles. If ...

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What is the difference between abiogenesis and spontaneous generation?
3 votes

One important difference is that spontaneous generation is a form of "mechanism" by which a certain species is "born", so it is repeated many times. For such complex organisms this would be part of ...

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Does the DNA sequence of a butterfly match that of the caterpillar it used to be?
3 votes

I would like to expand on Rory's answer. You can think about the DNA like a very complex book of recipes (genes) for constructing cellular machinery (e.g. proteins). Every genome has a large ...

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"Acellular" designation for organisms
3 votes

From Wikipedia: Some biologists refer to wholly syncytial organisms as "acellular" because their bodies contain multiple nuclei which are not separated by cell walls. As Albano pointed out, "cell ...

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What determines the fate of a cell with respect to differentiation?
3 votes

I would like to add to Lo Sauer's nice answer but give a slightly different perspective. What you referred to as the "brain" of the cell, is mostly its regulatory program. An abstract way to think ...

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Why don't housekeeping genes have TATA Box regions in their promoter sequences?
2 votes

Two possible answers: First, TATA boxes has been found to cause increased "noise" in gene expression, such that the expression of genes that have a TATA box is highly variable. See this review for ...

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Looking for a gene in my raw genetic data. What are the possible causes for this?
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2 votes

Let's set things straight. The genomes of humans are highly similar and in general everyone shares the same genes. SNPs, or Single Nucleotide Polymorphisms, are single basepair positions in the genome ...

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Modern alternatives of DNA footprinting
2 votes

DNAse-seq is the most obvious choice. It uses the same idea as DNAse footprinting but measures output using high-throughput sequencing, so it can be done on a whole genome in one shot.

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DNA preparation for sequencing
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2 votes

I hope I understood your question correctly. I think what you are missing is that after you break up the DNA, you dilute the concentration so that each bacteria will incorporate ~1 DNA molecule. Then,...

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What is range of the number of individual organelles in cells
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2 votes

BioNumbers is a database that contains exactly this sort of stuff. For example, I took this from this site: Number of mitochondria per cell: Yeast Cryptococcus neoformans cell: ~34 Human HELA cell:...

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What are the limitations of commercial-grade DNA genotyping compared to full sequencing?
2 votes

I want to give the OP a slight variation on Steve's answer. It is important to note that most of the genome is the same between different people. That isn't surprising, since we belong to the same ...

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