Question

AJ by oxygen Donas Bjoy nyarogen bonas ionic bonds D) by nonpolar covalent bonds Coy E) by isotopes 29) Which answer below best describes H,0? A) Water molecule bonds are ionic bonds, in which electrons are gained and lost to create the bond. B) Water molecule bonds are oxygen bonds, in which oxygen atoms form bonds together. C) Water molecule bonds are polar covalent bonds, in which unequal sharing of electrons occurs. D) Water molecule bonds are nonpolar covalent bonds, in which equal sharing of electrons occurs. E) Water molecules bonds are nonpolar ionic bonds, in which equal movement of electrons occurs. 30) Which answer below best describes one of the main differences between hydrophilic and hydrophobic substances? A) Hydrophilic molecules are attracted to water, whereas hydrophobic molecules do not interact with water molecules. B) Hydrophilic molecules do not interact with water molecules, whereas hydrophobic molecules are attracted to water. C) Hydrophilic molecules are inorganic, whereas hydrophobic molecules are organic. D) Hydrophilic molecules are organic, whereas hydrophobic molecules are inorganic. E) Hydrophilic molecules are monomers, whereas hydrophobic molecules are polymers. 31) Why is it very important to have cholesterol in our body? A) Very important for energy. B) Very important for enzymes. C) Very important for synthesizing proteins. D) Very important to maintain correct fluidity of plasma membrane. E) Very important for genetic material. 32) As water goes from liquid to solid ice: A) its molecules move farther apart it cools the surrounding environment C) its hydrogen bonds break apart polarity D) it loses its 33) Relative to a pH of 4, a pH of I has a A) 3000 times higher H+ concentration B) 3 times higher H+ concentration C) 3 times lower H+ concentration 30 times lower H+ concentration E) None of the above 34) One difference between eukaryotic and prokaryotic cells

Answer 1

29) H2O is an example of a polar covalent bond. In a H2O molecule electrons are unequally shared, with the oxygen atom. Since electrons spend more time with the oxygen atom and that is why it carries a partial negative charge.

So option (c) is the correct answer.

30)

Hydro = water

Philic = loving

Phobic= hating

So, Hydrophilic = Water loving

Hydrophobic = Water hating

Option (a) is the correct answer.

31) The body uses cholesterol to build the structure of cell membranes. It also makes hormones like oestrogen, testosterone and adrenal hormones.

So option (e) is the correct one.

32) When the water freezes then water molecules slowe down and their attractions arrange them in fixed positions as a result these molecules freeze in a hexagonal pattern and go further apart than they were in liquid form.

So option (a) is the correct one.