36 votes
Accepted

Why is a mosquito feeding on human blood not a parasite?

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 ...
  • 13.5k
35 votes
Accepted

Why do animal cells "mistake" rubidium ions for potassium ions?

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 ...
  • 6,967
31 votes
Accepted

Why do both the mango and the bee have "Indica" in their binomial name?

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 ...
  • 930
24 votes
Accepted

ECG wave names origin

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 ...
  • 38.1k
24 votes

Does the cytoplasm include the organelles?

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 ...
  • 38.1k
21 votes
Accepted

What is the anatomical term for a two jointed leg?

Welcome to Biology.SE! 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)...
  • 67.8k
21 votes
Accepted

What does rescue mean in the context of biological experiments?

"Rescue" in an experimental context means you're capable of undoing some experimental manipulation. It's considered evidence towards identifying a causal mechanism or verifying that your ...
  • 38.1k
20 votes

Is a walnut a nut or a drupe?

Short answer Walnuts are classified both as nuts and drupes ('stone fruits'). background According to University of Wisconsin - Madison, Department of Botany , hickory and walnut can be classified ...
  • 51.6k
19 votes

Is a DNA molecule a single strand of polynucleotide or two of them linked together?

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 ...
  • 191
18 votes

Does the cytoplasm include the organelles?

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.” ...
  • 22.9k
17 votes
Accepted

Why is the opposite of plantar flexion called "dorsiflexion"?

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 ...
16 votes
Accepted

Why should a tumor look like a crab?

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* ...
  • 3,139
16 votes
Accepted

What is the difference between "Bisphosphate" and "Diphosphate" in biochemistry?

[Source:Wikipedia] 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. ...
  • 3,249
14 votes
Accepted

Is there a name for the evolutionary loss of vestigial structures?

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 ...
  • 17.5k
14 votes
Accepted

Using anatomical terms for human organs and parts of plants

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 ...
14 votes
Accepted

What is the difference between cytosol and cytoplasm?

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 ...
  • 4,648
14 votes
Accepted

What is the definition of "Natural Selection"?

Official definition 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 "...
  • 67.8k
13 votes

Are all carcinogens mutagens?

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 ...
  • 35.1k
13 votes
Accepted

How to decipher references in natural history works of the late Renaissance and early Modernity?

I have found what may be the holy grail. It is a book known as "A Botanical Materia Medica" by Jonathan Stokes. This has several volumes, but the one you want is volume 1, which has no ...
  • 8,421
12 votes
Accepted

Are sensory receptors neurons?

Short answer Receptor cells are specialized neurons Background There are, globally, three types of neurons (Eckert's Animal Physiology): Sensory neurons: these cells transmit information from ...
  • 51.6k
12 votes

Are blood vessels organs?

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 ...
  • 7,097
12 votes

Is a walnut a nut or a drupe?

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 ...
  • 2,723
12 votes
Accepted

What is the meaning of multicellularity?

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 ...
  • 2,721
12 votes

What is the difference between a protein and a factor?

Short Answer 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 ...
  • 38.1k
12 votes
Accepted

What is the difference between a protein and a factor?

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. ...
  • 1,495
12 votes

Why do both the mango and the bee have "Indica" in their binomial name?

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. ...
  • 13.5k
12 votes
Accepted

What is a synonym of the word design that can be used in context of evolution?

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,...
  • 38.1k

Only top scored, non community-wiki answers of a minimum length are eligible