Question

Nicotinamide dinucleotide (NAD) is a _____________ derived from ______________.

	a.	Cofactor; magnesium (Mg2+)
	b.	Coenzyme; vitamin B2
	c.	Cofactor; zinc (Zn2+)
	d.	Prosthetic group; non-amino molecules
	e.	Coenzyme; vitamin B3

1. Solvent X is a dry blue substance with unknown properties. In an attempt to characterize substance X, you go to the lab, then add water and substance X to a beaker to make a solution. After mixing for 20 minutes, you notice an accumulation of blue particles still on the bottom of the beaker. You measure the pH, and determine that pH = 3. What can you deduce about substance X?

   	a.	It is nonpolar and basic
   	b.	It is polar and acidic
   	c.	It is polar and has a neutral pH
   	d.	It is nonpolar and acidic
   	e.	It is polar and basic

2. Which if the following plant types would most likely lead to the greatest genetic diversity from undergoing reproduction?

   	a.	The chances of genetic diversity are equally likely in both types of plants
   	b.	A plant that reproduces asexually
   	c.	A plant that reproduces sexually

Answer 1

EXPLANATIONS:

Nicotinamide dinucleotide is a coenzyme , derived from vitamin-B3 (also known as Nicotinic acid or Niacin.)

We know that polar solvents dissolve polar substances and non-polar solvents dissolve non-polar substances. Since water is polar, and dissolves the compound X to form a solution of pH-3, the substance X must have been polar in nature. Also since the pH is less than 7, it must be acidic in nature. Accumulation of blue particles at bottom indicates that a saturated solution has been formed.

Sexual reproduction produces variations. Hence, plants reproducing through sexual modes will have greater genetic diversity compared to the plants reproducing asexually.

Thanks.