The accepted model of the atom was changed.
Answer:
1,2 and 4 are correct
Explanation:
Enzymes that show cooperativity are defined as Allosteric enzymes. This cooperativity is of several types.
1) homotropic/homoallestery - positive cooperation
2) heterotropic/heteroallestery - negative cooperation
Activity of allosteric enzymes is regulated by other molecules (effector molecules)
Hence, statement 1 and 2 are correct.
Binding curve of allosteric enzymes:
For cooperative binding, binding curve is Sigmoidal curve
For non cooperative binding, binding curve is Hyperboilc curve.
Hence, statement 3 is wrong.
Allosteric enzymes have multiple active sites.
Allosteric enzymes are often multi sub unit proteins.
Hence, statement 4 is correct.
Answer:
Isoelectronicity may be used to predict the properties and reactions of a species. It is used to identify hydrogen-like atoms, which have one valence electron and are thus isoelectronic to hydrogen.
Explanation:
A. Outer energy level electrons are shared.
In electrovalent combination, after donating their valence electrons, metallic particles become positively charged; non metallic particles become negatively charged after acquiring extra electrons.
The electrons involved reside in the outermost shells of the atoms.
PeAcE.
Answer:
A
Explanation:
You can eliminate C because you need to consult a periodic table to determine the mass (not the weight).
There are other answers you could use. The wording is awfully sloppy. D is an example of that. The elements part is true, the atoms part is not really true in all cases. For example NaCl is table salt and both the elements are ions, not atoms. Na is plus ion and Cl is minus one. B is wrong for the same reason.
I think in the end I would choose A. I think this is a very sly question. It is not really testing chemistry. It is testing how well you know your definitions.
