Why do phospholipids form of bilayer in water ? a. the phosphate portions repel each other b. the hydrophilic and hydrophobic parts attract each other c. the phosphate portions attract water, and the lipid portions repel water d. the lipid portions attract water, and the phosphate portions repel water

The right answer is C.

A lipid bilayer, or lipid bilayer, is a thin polar membrane consisting of two layers of lipid molecules.

The outer region on each side of the lipid bilayer is constituted by the hydrophilic heads of the lipids (phosphate group). This region is fully hydrated. The inner region is the hydrophobic core (long fatty acid chains), the water molecules cannot access.

The answer is C. The phosphate portions attract water, and the lipid portions repel water.

This is because the phosphate portions are negatively charged, hence making it polar and hydrophilic. On the other hand, the lipid portions are uncharged and nonpolar, hence making it hydrophobic.

a neutral ph of 7 and normal organism temperature is needed for a certain enzyme to be effective.  

what would happen to the enzyme if the ph and/or temperature fluctuate greatly from the norm?  

a.the enzyme’s hydrogen bonds will break.  

b.the activation energy will increase.  

c.more product will be formed.

d.the ideal temperature and ph for the enzyme function will decrease.  

9.9 years

a = p(1 + rt) . . account balance after time t at rate r starting with principal p

3000 = 2500(1 + 0.0202t) . . filling in the given numbers

1.2 = 1 + 0.0202t . . divide by 2500

0.2 = 0.0202t . . . subtract 1

0.2/0.0202 = t ≈ 9.901

it will take about 9.9 years for the account balance to reach $3000.