BIO CH 3,4,5

Which of the following best summarizes the relationship between dehydration reactions and hydrolysis? A) Dehydration reactions assemble polymers, and hydrolysis reactions break down polymers. B) Dehydration reactions eliminate water from lipid membranes, and hydrolysis makes lipid membranes water permeable. C) Dehydration reactions can occur only after hydrolysis. D) Hydrolysis creates monomers, and dehydration reactions break down polymers. E) Dehydration reactions ionize water molecules and add hydroxyl groups to polymers; hydrolysis reactions release hydroxyl groups from polymers.

Dehydration reactions assemble polymers, and hydrolysis reactions break down polymers.

Why does ice float in liquid water?

Hydrogen bonds stabilize and keep the molecules of ice farther apart than the water molecules of liquid water.

A compound contains hydroxyl groups as its predominant functional group. Which of the following statements is true concerning this compound?

It should dissolve in water.

LOOK AT FIGURES IN #39, 44, 45, 46,47, 62

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How many electron pairs does carbon share in order to complete its valence shell?

4

If one strand of a DNA molecule has the sequence of bases 5'ATTGCA3', the other complementary strand would have the sequence

5'TAACGT3'

Which of the following statements about the 5' end of a polynucleotide strand of DNA is correct? A) The 5' end has a hydroxyl group attached to the number 5 carbon of ribose. B) The 5' end has a phosphate group attached to the number 5 carbon of ribose. C) The 5' end has phosphate attached to the number 5 carbon of the nitrogenous base. D) The 5' end has a carboxyl group attached to the number 5 carbon of ribose. E) The 5' end is the fifth position on one of the nitrogenous bases.

The 5' end has a phosphate group attached to the number 5 carbon of ribose.

Why are hydrocarbons insoluble in water?

The majority of their bonds are nonpolar covalent carbon-to-hydrogen linkages.

The slight negative charge at one end of one water molecule is attracted to the slight positive charge of another water molecule. What is this attraction called?

a hydrogen bond

Liquid water's high specific heat is mainly a consequence of the

absorption and release of heat when hydrogen bonds break and form.

The element present in all organic molecules is

carbon

Which of the following are nitrogenous bases of the pyrimidine type?

cytosine and uracil

There are 20 different amino acids. What makes one amino acid different from another?

different side chains (R groups) attached to an α carbon

Which of the following are nitrogenous bases of the purine type?

guanine and adenine

A strong acid like HCl

ionizes completely in an aqueous solution.

In a single molecule of water, two hydrogen atoms are bonded to a single oxygen atom by

polar covalent bonds

The bonding of two amino acid molecules to form a larger molecule requires which of the following?

removal of a water molecule

The partial negative charge in a molecule of water occurs because

the electrons shared between the oxygen and hydrogen atoms spend more time around the oxygen atom nucleus than around the hydrogen atom nucleus.

What determines whether a carbon atom's covalent bonds to other atoms are in a tetrahedral configuration or a planar configuration?

the presence or absence of double bonds between the carbon atom and other atoms