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20

The best ratio between weight and energy content (and of course also stability) has indeed fat. It's energy content is more than twice as high as for carbohydrates (sugars). See this table from here on the energy contents: This is the reason why animals which hibernate or migrate fed up to build up fat resources before the winter or their journey. With ...


8

The pKas of (neutral) guanine and thymine are 9-10 (ref). At high pH (>~10), those bases will be deprotonated and exist as negatively charged conjugate bases. As the deprotonated species, part of the G/C and A/T hydrogen bonding networks are eliminated. In the figure below, green dotted lines represent the hydrogen bonds that explain the observed base ...


6

The human skin is indeed made off a number of different layers, the three most important are epidermis, dermis and hypodermis (also called subcutaneous fat), see the figure (from here) for details: All three layers can be subcategorized further, I'll only give a few details here. More can be found for example in the Wikipedia article on skin. Epidermis: ...


4

According to this study, model data shows a maximum pressure of 110 kPa, that's 16 psi and only 1.086 atm: The three-phase process involved in the beetles explosive secretory discharge (ESD) process. The inlet size is shown as a proportion of the inlet radius. During the first phase of refill and heating (blue), only the inlet valve is open. ...


4

The following answer was giving by Michael D. Dryden from http://chemistry.stackexchange.com/questions/24797/what-is-a-triglyceride/24799#24799 There is some minor argument as far as nomenclature goes for these lipids. Most sources I can find, including IUPAC have glycerides as only including esters of glycerol with fatty acids. Monoglycerides have a single ...


3

The enzymes don't need physical interactions to couple reactions. Some enzymes do share subunits which are physically associated, but this is a special case. The following review gives a sort of general example during glycolysis, For example, in the biochemical pathway that breaks down glucose for energy, two enzymes work one after the other to create a ...


3

You are looking at a protein here, which is mutated in the higher host specificity, so glucose is not involved here. What is written here are the amino acids in the three-letter-code, the notation Pro→Glu means that Proline (Pro) is replaced by Glutamic acid (Glu). The notation Pro16 means the proline on amino acid position 16 in the protein. You often find ...


2

Short answer (A) is a possible answer and is indeed cause for fatigue, as pyruvate is needed for the Krebs cycle to run. The krebs cycle is an essential step in the generation of ATP in aerobic organisms. (B) is incorrect because NADH is never transported into the mitochondria in any organism (it is a nonsense answer). Background NADH is not transported ...


2

You may want to see: Mark W. Chase, Harold H. Hills; Taxon, Vol. 40, No. 2, 1991, pp. 215-220: 'Silica Gel: An Ideal Material for Field Preservation of Leaf Samples for DNA Studies' Summarized, the process would be the following: Place the leaves inside ziplock plastic bags; Add ten times (minium) the weight of the leaves in silica gel; After 12 hours ...


2

Ignoring parameters such as: Leaf shapes Difference in photosynthetic efficiency due to other metabolic factors Unequal illumination of leaves Nutrient content of the soil Photosynthesis rate of a plant1 depends on the [total number of leaves] × [surface area of a leaf]. Assuming that a tree occupies same ground area as a shrub, there will be same ...


2

There are two antipodes: The molecular (or makromolecular) biology, which has the concept of large macromolecules which fulfill one task. This can for example be an enzyme which breaks down its subtrate. The properties and the structure of all molecules of the enzyme are the same and the factor determining the function of the enzyme. The coloidal biology ...


2

No it isn't necessary to breathe in CO2 from the atmosphere. For the buffer system your brain detects the amount of CO2 (H+ which is an indicator of excess or too little CO2) and adjusts your breathing automatically to compensate so that your blood's pH stays normal. No outside CO2 is needed. Your kidneys also play a similar role but the lungs are what ...


2

You should not actually homogenize samples because histamine works locally. If you know which region is releasing histamine then you can just study those regions. You can actually create a transgenic fish with GFP that is a target of histamine receptor signaling. Using mathematical models or statistical correlations you can obtain the level of histamine ...


2

As user137 said, the general base abstracts a proton from the 2'OH and subsequently the 2'O- renders a nucleophilic attack on the δ+ Phosphorous, leading to the hydrolysis of the phosphodiester bond. There can be slight variations in the mechanism and the intermediates; for details see this review. ...


2

The gram staining relies on the differences in the bacterial membranes. The gram positive bacteria have a thick peptidoglycan layer on top of the cell membrane, the gram negative bacteria have a lipid layer on the outside followed by a thin peptidoglycan layer and then the cell membrane. See the image for clarification (from here): Crytall violet ...


1

I would suggest following: take any one-dimensional process that is described by gaussian function. If you integrate such process along variable, you will get a sigmoidal curve. For details see normal and cumulative distribution. Now, the question is: how many biological processes are described/modeled by Gaussian distribution and dependencies? A lot! ...


1

No, mammals need not take in CO2 from atmosphere. The body's homeostatic function will maintain its composition by checking the amount of CO2 released out by lungs. So certainly animals would survive if put in a CO2 free atmosphere.


1

Rubisco is an enzyme that is involved in the biochemical process of carbon fixation in photosynthesis, but also has an economically important error (photorespiration) which incorporates the wrong molecule (oxygen) into RuBP, therefore wasting the energy captured by the plant and producing toxic downstream products. Rubisco's error rate in carbon fixation ...


1

First it is important to define what actually an error is. What you call misproduct is actually a right product for a different substrate. The enzyme has a low specificity; but you won't say hexokinase is error prone because it has wide substrate specificity. The question is — is specificity critical? Coming to the example of DNA polymerase, you should note ...


1

Lets just go with the basic Hodgkin-Huxley equation: $$C_M \frac{\text{d}V}{\text{d}t}=-g_{Na}(V-E_{Na}) -g_K(V-E_K) -g_L(V-E_L)$$ At rest ${\large\frac{\text{d}V}{\text{d}t}}=0$ and therefore $V$ is dependent on the conductances ($g_X$) of different ions. Since $g_K \sim 30\times g_{Na}$, the resting potential is closer to $E_K$ (Nernst equilibrium ...


1

Yes, there are: this is a feature of bacterial intrinsic termination. The mechanism of pausing is not as you describe, though. In bacterial transcription, two forms of termination are recognised (to my knowledge): Intrinsic termination, consisting of a hairpin and a stretch of Uridines. Rho-dependent termination, consisting of a 'loading' site for ...



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