36
Short answer
It is a flying lemur (there exist only 2 species). Flying lemurs and primates are together a sister clade to treeshrews.
Easy source of information
Have a look at the post The best free and most up to date phylogenetic tree on the internet?.
In short, you can have a look at onezoom.org, tolweb.org or opentreeoflife.org by yourself!
Tree of ...
25
Here is a tutorial to perfectly understand Hardy-Weinberg Rule! If you feel like you just need a brief reminder, you can skip the text until the section In short... and try out the exercises just to check your understanding.
Terms you should know a priori
I will not define the following terms, so make sure you understand them
locus
allele
(relative) ...
24
This is a very subtle question and I encourage you to read the Wikipedia articles on these different subjects (t-test, chi-squared test, p-value, etc) because the authors worked hard to combat common misconceptions about these commonly used statistical tests. Here is a rather oversimplified rule-of-thumb for these different tests:
t-test: Used when you are ...
23
The most closely related animals to primates are colugos (order Dermoptera).
The next most closely related after colugos are tree shrews (order Scandentia).
The next most closely related after tree shrews are rodents (order Rodentia) and lagomorphs (order Lagomorpha) (rabbits, hares, and pikas).
Sources: Wikipedia's section on the evolutionary history of ...
20
The terms intron and exon were coined by Walter Gilbert in a renowned 'News and Views' article, Why Genes in Pieces, published in the journal Nature in 1978.
Introns are the intragenic regions and exons are the regions which are expressed.
This is the relevant passage in full:
The notion of the cistron, the genetic unit of function that one thought ...
17
Your reasoning is sound and correct. The answer key is wrong.
An unclotted blood sample needs something to prevent clotting. Extracellular calcium is required for both the coagulation cascade and platelet activation. It even has its own name in this context, Factor IV. This why EDTA, a calcium chelator, is used in some blood collection tubes to delay ...
13
I agree with you that the question is ambiguous, and also that the most sensible answer would be C. However, one could make a more or less reasonable argument in favor of several other answers, too.
a. The common ancestor of whales and fish possessed genes for fins.
Technically, this statement is true. At least some of the fins of whales and fish are ...
13
Enzymes can catalyze a thermodynamically unfavorable reaction by coupling it with a thermodynamically favorable reaction. Most often, enzymes use ATP hydrolysis reaction (energetically favorable) as a source of energy (in simple terms) to drive the unfavorable reaction forward. One important point to keep in mind here is that enzymes don't drive a reaction ...
answered Jun 26 '17 at 8:58
another 'Homo sapien'
13.5k4 gold badges53 silver badges88 bronze badges
12
Can enzymes catalyze thermodynamically unfavourable reactions?
Enzymes don't change the equilibrium of a reaction, but the fact that an equilibrium exists means that the reaction proceeds in both the forward and reverse directions. Before equilibrium is attained, ΔG for the reaction is not 0. Thus, by definition, one direction is thermodynamically ...
11
By frame size, do you mean sliding window?
I know that if you want to predict a secondary structure of a transmembrane protein, then your window size should be 20 amino acids (this is the average length of 1 transmembrane alpha helix spanning through the membrane).
I found this paper by Chen, Kurgan, and Ruan[1].
It basically says that the window size ...
11
There are two answers if the question refers to genomic DNA (neither enucleated ova nor mature RBCs have genomic DNA). However, since the question doesn't specify genomic DNA, we can exclude enucleated ova, which would still have mitochondria and therefore mitochondrial genomic DNA. Mature RBCS (at least in most mammals) do not have mitochondria, so the ...
10
Primary oocytes are formed prenatally and reain suspended in prophase of meiosis I for years until the onset of puberty. An oocyte completes meiosis I as its follicle matures (during ovulation) resulting in a secondary oocyte and the FIRST polar body. After ovulation, each oocyte continues to metaphase of meiosis II. Meiosis II is completed only if ...
9
Every nucleotide sequence has six possible reading frames, because each codon (determining one amino acid) consists of a base triplet (3 frames), and there is a complementary strand which could be coding (3 reverse frames).
To find the possible open reading frames contained in your sequence, you have to look for start codons. That is: ATG. But, as said the ...
9
Databases
There are too many databases to list here, but Wikipedia has a decent list of the genome databases. For example, there are databases dedicated to genes of individual species, like Wormbase, SGDB and countless others. Alternatively, as others mention a great place to kick off your search is the NCBI.
Finding your nucleotide sequence in databases
...
8
Starting with the left hand side of the diagram:
III:2 is definitely a carrier (Tt) as one parent (II:2) is affected (tt).
III:1 is also definitely a carrier (Tt) as when mating with III:2 they produce an affected (tt) offspring (IV:1)
This means that we can work out the possibilities for IV:4 as we know the parent genotypes. It follows the standard ...
8
The mechanism is called "capillary action". It requires a tube of a small diameter and happens because of the adhesion of water to the walls and the cohesion within the water (=surface tension).
8
NCBI is a good option.
http://www.ncbi.nlm.nih.gov
If you're looking for a gene sequence, you can search for the gene name in the nucleotide database. For example, here is the annotated human insulin gene;
http://www.ncbi.nlm.nih.gov/nuccore/J00265.1
8
The reason why the cell would shrink more in CaCl2 solution is because it has a higher van't Hoff factor i.e. total number of dissociated ionic species per solute molecule (it is 2 for NaCl whereas it is 3 for CaCl2).
(Nonionic solutes do not dissociate and will therefore have a van't Hoff factor of 1)
Osmotic pressure (and other colligative properties) ...
8
The key here is that it is a question about mitochondrial DNA. mtDNA in humans is inherited maternally (from the mother). Both sons and daughters inherit mtDNA, but only the daughters will pass it on to the next generation.
A child's mtDNA has to come from his or her mother, and all of a person's mitochondria are genetically identical. Therefore, children ...
8
If you think about the boiling of water, I'm sure you can understand that heat breaks hydrogen bonds. Next consider that the hydrophobic effect is driven entropically and so, by the equation $\Delta G=\Delta H-T\Delta S$, its strength increases with temperature (to a point). See here and here for further explanation. Also, this paper for a more empirical ...
8
There is no answer to your question
The doubling time of a bacterium is dependent on the conditions: primarily on the temperature and the availability of nutrients, but other factors can apply. Because of this, the doubling time of any particular bacterial strain cannot be considered in the abstract, thus to give a single number we can consider the optimum ...
7
If the question is about the one and only most important difference between mitosis and meiosis, then the answer "meiosis reduces ploidy" is probably correct. But if the list of important differences is open, it would be critical to add that mitosis generates identical cells (identical to each other and any ancestral cells, barring rare new mutations), while ...
7
Still if you change your question as (If histidine is abundant, HisP's job is to stop the histidine pathway as a "repressor." If HisP binds less tightly to promotors, the pathway should not produce as much histidine.)
Then it should be under another assumption that what is the effect of HisP binding promoter of enzyme's gene. Is it suppressing the ...
7
In high school, we did an experiment that showed this.
Basically, if you take a glass of water, and let it sit out, perhaps in front of an open window, it will eventually lose water due to evaporation. It may take a few days/weeks to really see a large difference, but the level will go down. But, if you take a few flexible straws, put them in so the bendy ...
7
Assumptions: Blonde hair is Homozygous Recessive and that the traits are strictly Mendelian.
The parental generation must be both heterozygotes as at least one child is Blonde (bb). So your cross is Bb x Bb.
Your square is going to look like this:
_B_ _b_
_B_ BB Bb
_b_ bB bb
So of the question ...
7
I got $26$% as the answer.
To get a recombination between C and E, there are two possible mechanisms:-
C and D produce a recombinant, but D and E remain linked, therefore the final genotype will be a recombinant considering C and E(Chiasmata between C and D). Here $P_1=P_{CD}\times P'_{DE}$ where $P$ is the probability of recombination and $P'=1-P$ is ...
7
There are actually very few situations where organs can be harvested from donors. For all deceased donor transplants, the donor must be confirmed as being brain dead (both brain stem and higher cortical functions). However, in order for the organs to remain viable they must not become ischaemic - which is obviously a huge problem when the patients heart has ...
Only top voted, non community-wiki answers of a minimum length are eligible
