83 Answered Questions for the topic molecular biology
When running a gel, what could cause a standard to run "faster" than usual?
We are running a gel on the products of a restriction digest to determine the size of an insert. We know the vector backbone size should be ~2.9kb; however, the standard appears to be running too... more
True or False. The gene is the basic unit of genetic information.
How do antioxidants affect human metabolism?
I'd like to know how antioxidants affect human metabolism and which ones are essential for metabolic processes.
True or False. Prokaryotic genes are often regulated in response to external signals such as nutrient availability.
The flow of genetic information is from DNA to RNA to protein, via the processes of transcription (TC) and translation (TL). This concept is known as the Central Dogma of molecular biology.
How does the body switch between aerobic and anaerobic respiration?
Lets take the case of a person doing heavy exercise. Aerobic respiration is taking place, but oxygen is about to be finished up. Glycolysis occurs, Krebs cycle finishes. Now NADH and... more
True or False. In DNA, the bases pair A T and G C; this complementary base pairing is the key to storage, transfer, and use.
What is the relationship between the light and dark reactions of photosynthesis?
My main concern is why are the dark reactions (those that produce hexose) needed? As far as I understand, the sole purpose of photosynthesis is to synthesize carbohydrates, which are only used for... more
A photosynthesizing mouse?
N. Shubin's *Your Inner Fish* makes the point several times that there is a lot of functional similarity between some seemingly remote gene cousins. If that needed reinforcing we have the... more
Why do we have no enzyme to digest cellulose?
As we know, cellulose is the most abundant polysaccharide in nature. Why don't we have an enzyme to digest cellulose?
Is HSV-vector-mediated miRNA expression in dorsal root ganglia stable?
My question is on the following article: "*[Reduction of voltage gated sodium channel protein in DRG by vector mediated miRNA reduces pain in rats with painful diabetic... more
Is there a double helix RNA?
I wonder what is its function and if it can be the genetic material for a living organism. If not, why?
How do ion channels transport only specific ions?
Ion channels, such as $Na^+$ channels and $K^+$ channels, are higly specific for ion permeability. But how do these channels achieve and maintain this specificity? Like how does a $K^+$ channel... more
True or False. Genes in prokaryotes tend to be grouped together in operons, with several genes under the control of a single regulatory region.
True of False. Three important types of RNA are copy of RNA (cRNA), messenger RNA (mRNA), and transfer RNA (tRNA).
What is the functional and structural distinction between core (H2A, H2B, H3,H4) and linker(H1/H5) histones?
Many explanations of histone biochemistry isn't quite elucidating for the undergraduate student. How does histone structure (dimers, octomers) relate to their specific functions as core or linker... more
In mitochondria, what is the mechanism by which electrons are transferred between different cytochromes?
And how is the energy gained from the lowering of the "energy level" of the electron used to generate the chemiosmotic gradient?
Does any molecule other than DNA have a double-helical structure?
DNA is known to have a double-helical structure. Do any other molecules have this structure?
Why do 60S & 40S ribosomal subunits make an 80S ribosome (not 100S)?
Why do 60S & 40S subunits make an 80S (not 100S) ribosome and, similarly, 50S & 30S make 70S? 60+40 is not equal to 80, nor is 50+30 equal to 70, so why are the subunits of the 80S and 70S... more
Photosynthesis: What Powers the Splitting of Water?
The splitting of water is an endergonic (non-spontaneous) reaction, and thus would require energy (chemical work to be done) in order to happen. In Photosystem II, an enzyme catalyzes this... more
True or False. A promoter is necessary for RNA polymerase binding, with the codon start and stop sites defining the transcriptional unit.
What happens to the precursor protein's signal sequence after it is cleaved?
Where does this signal sequence "go" after it has been cleaved by signal peptidase and what is its next function?
How, on a physical level, does ATP confer energy?
When ATP is used as the energy currency to make, say, reaction X + Y → Z happen, is what happens on a physical level down at the molecular scale that during the reaction---**ATP + H2O → ADP + Pi** ... more
What is the purpose of the outer mitochondrial membrane?
The purpose of mitochondria is to generate ATP, utilising a chemiosmotic gradient across the inner mitochondrial membrane. Protons are pumped out of the mitochondria into the intermembrane space,... more