A mosquito is a biological parasite, it is not a medical parasite.
There are two definitions of parasite. A biological/ecological definition and a medical/physiological interaction definition.
A parasite in biological terms is an organism that benefits from a parasitic relationship; a parasitic relationship being a non-mutual relationship between species, ...
There are multiple biological mechanisms that can be brought to bear for distinguishing between atoms. In addition to binding properties (e.g., ionic charge, electronegativity, bond strength), there is also the size of the atoms and even their vibrational properties.
For one of these mechanisms to actually be used, however, it needs to be evolutionarily ...
In short, we do not think about the uniqueness of the second part of the binomial (the species epithet) but about the uniqueness of the binomial itself (the genus and the species epithet). Thus, the unique binomial of mango is Mangifera indica and the unique binomial of bee is Apis indica. For more detail, see this question.
To complicate matters slightly, ...
Interesting question! I searched briefly and came up with an answer from this short paper.
I won't repeat all the details of the paper, but to be not a completely link-only answer I will give a brief summary:
The technology used at the time was a lot different than modern ECG leads: it used a Lippman capillary electrometer that used moving mercury to ...
The cytoplasm is like the ocean.
When you talk about the ocean, do you include the fish? What about islands? Sometimes yes, sometimes no.
You could use a cytosol/cytoplasm distinction, where cytosol is "just the liquid part outside the organelles" and cytoplasm includes all the fish, but context matters and I don't think it's actually necessary to ...
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I think you are talking about plantigrade, digitigrade and unguligrade.
Please note that the number of joints in mammals does NOT vary, but only the relative length (and shape) of the different parts of the leg.
A Plantigrade walks on the sole of the foot. 'Sole' translates to 'planta' in Latin hence the name.
Examples: Human, ...
Walnuts are classified both as nuts and drupes ('stone fruits').
According to University of Wisconsin - Madison, Department of Botany , hickory and walnut can be classified both as drupes and nuts, but are best classified as nuts.
Nuts fall into the class of indehiscent fruits: dry fruits that do not open when mature to shed their ...
Hmm, I think that the teacher is actually correct and that the previous explanation, although very nicely referring to text book diagrams, is a little misleading.
The issue here is the nature of a hydrogen bond within the DNA structure. Within a chemical context, generally a molecule is a collection of atoms primarily bonded together via covalent bonds. ...
The young scientist asks:
“What is the correct definition?”.
The old scientist answers:
“As is often the case in biology, there is no correct definition — different people adopt different usages.”
This answer attempts to explain why this is the case and how to find out other than asking people who despite greater age and knowledge, may be mistaken in ...
Anatomical terms must be able to fit a wide variety of organisms, from insects to fish, dogs, horses, chimpanzees to humans. That's why the terms are sometimes confusing to people who are thinking only of bipedal humans.
In anatomy, the dorsum is the upper side of animals that typically run fly, swim or crawl in a horizontal position. In vertebrates the ...
Such projections are more formally known as spiculations. Most commonly, we talk about spiculations with respect to the radiographic appearance of malignant breast and lung lesions. This paper* describes the correlation between the mammorgraphic appearance of spiculated breast lesions and their pathology (microscopic appearance), which is a reasonable start ...
As you can see in the above structure of ADP(Adenosine di-phosphate), the two phosphate groups in the compound are directly attached to one another. So it is named as di-phosphate. [Source] You can see this table for more examples.
In this structure of RuBP(Ribulose-1,5-bisphosphate), the two phosphate groups in the ...
This phenomenon can be (and has been) described as regressive evolution (the loss of a phenotypic trait). There are several reasons why this occurs:
Neutral mutations which become fixed through genetic drift.
Positive selection of regressive mutations that are beneficial.
Pleiotropic antagonism: positive selection for one trait may have the consequence of ...
First, for reference, see here for a discussion about the difference in directional terms between bipeds and quadrupeds as well as a fairly complete explanation of word meanings/etymology.
The etymological meanings of the various anatomical directional terms should help explain their usage in body organs. For example:
Ventral -> "belly" side
IMO, the definitive answer to this question is given in a paper by J. S Clegg. He traced the origin of the term cytosol to a book chapter by H. A. Lardy, and confirmed by email that Lardy had indeed coined the term. Their definition of cytosol is as follows:
... that portion of the cell which is found in the supernatant fraction after centrifuging the ...
Is there an official definition of natural selection that is adopted by biologists nowadays? and what is that definition exactly?
I don't think there is such a concept as an "official definition" of any concept in science. There are common definitions though.
The definitions you cite
Let's go through your three definitions
All mutagens are potential carcinogens unless the mutagen is highly specific to a site. As noted in the question, carcinogens need not be mutagenic.
HPV causes oncogenic transformation of a cell because of certain proteins that it expresses. HPV is considered a carcinogen by the IARC. Some retroviruses are oncogenic: they might carry an ...
How can a non-mutagenic agent be carcinogenic?
An agent that causes overexpression of oncogenes or inhibition of tumor suppressors, would be carcinogenic but not mutagenic.
HPV, for instance, produces proteins that cause inactivation and degradation of tumor suppressors, p53 and pRb.
Regarding alcohol. As you guessed, alcohol is metabolized to form ...
Receptor cells are specialized neurons
There are, globally, three types of neurons (Eckert's Animal Physiology):
Sensory neurons: these cells transmit information from external stimuli (e.g., sound, light, pressure), or from internal stimuli (e.g., blood oxygen level or head orientation);
Interneurons: these cells connect ...
I don't know if they are classified as organs, but basically, blood vessels match the criteria for being organs.
Quoting SIU School of Medicine:
Blood vessels are basically tubular organs found within other organs.
Biology Reference states the same:
Even the glands within the integument can be considered organs; any gland is primarily secretory ...
A true nut, botanically speaking, is a hard-shelled pod that contains
both the fruit and seed of the plant, where the fruit does not open to
release the seed to the world. Some examples of botanical nuts are
chestnuts, hazelnuts, and acorns.
A drupe is a type of fruit in which an outer fleshy part surrounds a
shell (what we sometimes call a pit) ...
Bacteria are, as a general rule, unicellular. However, there are some, like the cyanobacteria which you referenced, which are kind of border line. Wikipedia's definition of multicellularity is a very broad sweeping definition, and its statement that bacteria are unicellular is also a broad sweeping statement.
The fact is, that as a general rule, bacteria ...
There is no agreed upon naming convention for proteins - there are some rough standards because in language people usually try to convey their ideas in a way others can understand, but that doesn't necessarily mean fixed rules.
I think it's important to recognize the process for understanding what proteins do is not always ...
TLDR: As far as I know, there's no specific reason some proteins are called "factors"; it's just a matter of what name was chosen.
"Protein" is a specific term meaning a long chain of amino acids. They are typically at least 50 amino acids long.
Conversely, the word "factor" is quite a loose term and is as broad as even being "an element of something". So, ...
That is the species name it is often the same for unrelated organisms, that is why we use a two name system. Binomial nomenclature (literally, two term naming system) goes Genus species respectively.
The first part of the binomial identifies the genus (which should not be the same unless they are closely related) and the second is the species name which is ...
Although not ideal, "adaptation" is more appropriate than "design" as a noun describing something that has come about in an evolutionary context, even though not all evolution is adaptive.
In writing, though, I would not phrase it as you have, rather I would change the agency from something evolution does as some sort of "entity" which makes it sound like a ...
Alcohol itself is non-mutagenic because it does not directly alter DNA. (Additionally ethanol enhances carcinogenesis and is itself not a carcinogen - updated) There are similar non-mutagenic carcinogens such as estrogen - which is a carcinogen. Another important thing to realize is that a non-mutagenic carcinogen may not alter DNA, but instead alter ...