36 votes
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Who are humans' closest relatives, after primates?

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 ...
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29 votes

Solving Hardy Weinberg problems

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 ...
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24 votes

Who are humans' closest relatives, after primates?

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 ...
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20 votes
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Why aren't 'exons' named 'introns'?

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 ...
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17 votes
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Which type of test tube should not be used for blood collection?

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 ...
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13 votes

What is the difference between the evolution of fins in whales and fish?

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. ...
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13 votes
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Can enzymes catalyze thermodynamically unfavorable reactions?

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 ...
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12 votes

Can enzymes catalyze thermodynamically unfavorable reactions?

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 ...
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11 votes

Which of the following lacks DNA?

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 ...
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10 votes
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Which bacteria takes the longest to double?

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. ...
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10 votes

why does translation occur more frequently than transcription?

The simple answer Under the assumption that each mRNA molecule is translated at least once, by necessity translation will happen more often than transcription. This is because the only way to get a ...
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9 votes

Where should I start looking for an online gene library?

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, ...
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9 votes
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Pedigree Analysis: Problem

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 ...
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8 votes

Where should I start looking for an online gene library?

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 ...
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8 votes
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What happens to the red blood cell in CaCl₂ solution?

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 ...
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8 votes
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Denaturation of protein

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=...
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8 votes
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What’s the Difference Between Grass and Sedge?

Short answer Sedges have edges, and they're in different families. See Minnesota Wildflowers for a great summary with images. Long answer Both are in the order Poales, but they are in different ...
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8 votes
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How does increased resistance to flow decrease blood pressure?

There is not enough information in the question to solve it. The answer key from the original question makes a logical error: Viscosity is directly proportional to resistance. This is true. An ...
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7 votes
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How to do multiple sequence alignment?

MSA Tools compare the amino acid sequence of protein 1 with nine homologous proteins and make a multi-alignment of the sequences. EBI have a portal for many MSA tools and there are also other MSA ...
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7 votes
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Gene and alleles

Alleles are basically subtypes of a gene. At the time of Mendel, the molecular nature of inheritance was not known so the original definition of gene refers to "some" inheritable molecular entity ...
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7 votes
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Is the start codon regarded as part of the UTR (untranslated region)?

Because the start codon is translated into methionine, it clearly can not be part of the 5'-untranslated region, as @Johnny writes in his answer. The more contentious question would be for the stop ...
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7 votes

Solving Hardy Weinberg problems

Lets say there are 2 alleles. One of them is represented by B and other by b. Both will have some frequency at a specific time in a population. Now, frequency is number of that allele divided by total ...
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  • 1,679
7 votes

Frequency of dominant phenotype (Hardy-Weinberg)

p = p(a) = 0.6 q = p(A) = 0.4 Frequency of homozygous recessive, aa = p2 = 0.36 All other genotypes have dominant phenotype therefore the frequency of the dominant phenotype is 1-0.36 = 0.64 (...
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6 votes

Question about what the liver does NOT do

Liver does all those functions as far as I know. The liver hepatocyctes are stimulated to create the enzyme glycogen synthase which promotes the conversion of glucose to glycogen in the presence of ...
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6 votes

which signalling pathway is involved in cancer?

The answer is b, as the mutation constantly activates the RAS protein. RAS is part of the MAP-Kinase pathway, constant signaling of it permanently activates this pathway and leads to changes in gene ...
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6 votes
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HIV and effectiveness of inhibitor cocktail over single inhibitor

Your answer is correct. HIV-1 encodes a single homodimeric aspartic protease, with each monomer containing the classic Asp-Thr-Gly motif, and the dimer's active site being formed with the two ...
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6 votes
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Restriction Mapping - Homework question

This is not as hard, as it first seems. Lets have a look at the single enzyme digests first: The digest with enzyme A and B only leads to products which are 5kB (5000 bp) away from each other. Since ...
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6 votes
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Can someone help me analyze this article?

I will answer the questions one by one- Why does this miniaturization necessitates insulation ? An organism's volume determines the total amount of heat that can be stored. The loss (exchange) of ...
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6 votes
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What is enantiostasis?

Both are ways for an organism to adapt to the environment, but enantiostasis focuses on maintaining functionality while homeostasis focuses on maintaining a stable internal environment. For example, ...
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