#Question id: 1393
#Unit 4. Cell Communication and Cell Signaling
In research on aging (both cellular aging and organismal aging), it has been found that aged cells do not progress through the cell cycle as they had previously. Which of the following, if found in cells or organisms as they age, would provide evidence that this is related to cell signalling?
#Question id: 381
#Unit 1. Molecules and their Interaction Relevant to Biology
Consider an acetate buffer, initially at the same pH as its pKa (4.76). When sodium hydroxide (NaOH) is mixed with this buffer, the:
#Question id: 10134
#Unit 6. System Physiology – Plant
Some herbicides such as dichlorophenyldimethylurea (DCMU, also known as diuron) and paraquat, block photosynthetic electron flow from where ?
a.) DCMU blocks electron flow at the quinone acceptors of PSII, by competing for the binding site of plastoquinone that is normally occupied by PQB
b.) Paraquat accepts electrons from the early acceptors of PSI and then reacts with oxygen to form superoxide, O2 – , a species that is very damaging to chloroplast components
c.) DCMU blocks electron flow at the pheophytin acceptors of PSII, by competing for the binding site of pheophytin
d.) Paraquat accepts electrons from the Iron-sulfur system of PSI and then reacts with oxygen to form superoxide, O2 – , a species that is very damaging to chloroplast components
Which of the following combination is true?
#Question id: 6979
#Unit 5. Developmental Biology
The muscle-forming cells of the vertebrate limb come from:
#Question id: 711
#Unit 1. Molecules and their Interaction Relevant to Biology
The shortest alpha helix segment in a protein that will span a membrane bilayer has about.