BIOL-LEC Homework Chapter 5

During normal animal metabolism, the majority of food that is consumed is digested so that the macromolecules in the food are broken apart into monomers that can then be used to gain energy.  However, while the majority of metabolism of food is breakdown,  a small portion of the monomers that are released can be used to synthesize new macromolecules.  Given this information, what is the net effect on water--is it consumed or generated during metabolism of food? 

Hint: the net effect takes into consideration breakdown and synthesis reactions

• overall, the water consumed is exactly balanced by the that is water generated.

• overall, there is no net change in water.

• overall, water is generated during metabolism, but water is consumed during periods of growth.

•   overall, water is released by animal metabolism

•   overall, water is consumed by animal metabolism.

You briefly heat an aqueous solution containing macromolecules to 95°C.  How will heating affect the structure of the macromolecules?

•   Glycosidic bonds in starch will hydrolyze (break) leaving monomeric sugars.

•   The weak chemical bonds holding DNA duplexes together will break and the DNA will unwind and separate. Similarly, proteins will unfold (denature) because of the disruption of weak chemical bonds.

•   Peptide bonds in protein will hydrolyze (break) and leaving monomeric amino acids

•   Heating will have no effect on macromolecule structure

•   Lipids in membranes will interact with each other more strongly

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

•   different side chains (R groups) attached to the α carbon

•   different asymmetric carbons

•   different side chains (R groups) attached to a carboxyl carbon

•   different structural and optical isomers

•   different side chains (R groups) attached to the amino groups

Cellular proteins often exist in either the cytoplasm (globular shape, sitting in an aqueous environment) or in the membrane (non-aqueous environment).  In a normal cellular protein, where would you expect to find a hydrophobic amino acid like valine?

•   Valine would only be found in the transmembrane portion of a protein where it can interact with lipid fatty acid chains.  It is never found in globular, cytoplasmic proteins.

•   If it is cytoplasmic, in the interior of the folded protein, away from water. If it is a transmembrane protein, in the membrane spanning portion interacting with lipid fatty acid chains

•   If it is a cytoplasmic protein, on the exterior surface of the protein, interacting with water.  If it is a transmembrane protein, on the tail end of the protein that interacts with the cytoplasm.

•   Valine could be found anywhere regardless of the environment the protein is located in.

•   Valine will be found on the exterior of the protein regardless of environment.

The secondary structure of proteins is maintained through a specific type of bond between atoms located in two different functional groups on the chain.  What type of bond maintains the secondary structure of a protein?

•   hydrogen bonds between the R groups

•   hydrogen bonds between the H of an amino group participating in one peptide bond and the O of carboxyl group in another peptide bond

•   disulfide bonds

•   hydrophobic interactions

•   peptide bonds

Which of the following statements is true regarding the chemical reaction illustrated below?

•   It is a hydrolysis reaction and it results in formation of a glycosidic bond

•   It is an esterification reaction and results in formation of a phospholipid

•   It is a dehydration synthesis reaction and results in formation of a peptide bond.

•   It is a hydrolysis reaction and it results in formation of a peptide bond.

•   It is a dehydration synthesis reaction and results in formation of a glycosidic bond

The structure depicted below shows the

•   1-4 linkage of the α glucose monomers of starch.

•   double-helical structure of a DNA molecule.

•   β pleated sheet secondary structure of a polypeptide.

•   α helix secondary structure of a polypeptide.

•   1-4 linkage of the β glucose monomers of cellulose.

Which of the following sequences would be the complement of a strand of DNA that has the sequence 5'ATTGCA3' ?

•   5'TAACGT3'

•   3'UAACGU5'

•   3'ATTGCA5'

•   5'UAACGU3'

•   3'TAACGT5'

Refer to the figure above to answer the following question.

Which of the molecules act as building blocks (monomers) of polypeptides?

•   1, 4, and 6

•   11, 12, and 13

•   7, 8, and 13

•   2. 7, and 8

•   12, 13, and 15

Refer to the image above to answer the following question.

Which of the following combinations could be linked together to form a nucleotide?

•   5, 9, and 10

•   11, 12, and 13

•   3, 7, and 8

•   12, 14, and 15

•   1, 2, and 11