BIO101 Final

You are studying a new enzyme that appears to not work when phosphate accumulates. Which of the following scenarios would you predict to be responsible for deactivating this enzyme?

Responses

• Phosphate may be a competitive or allosteric inhibitor for the enzyme.

• Phosphate may be a cofactor for the enzyme.

• Phosphate may be an allosteric activator for the enzyme.

• Phosphate cleaves the enzyme to form the active conformation.

• Phosphate may be a competitive or allosteric inhibitor for the enzyme.

Which of the following types of molecules would have the highest capacity to store chemical energy?

Responses

• A two-carbon molecule rich in C–O bonds, such as ethanol

• A six-carbon molecule rich in C–O bonds, such as a hexose

• A six-carbon molecule rich in C–H bonds, such as a lipid

• A two carbon molecule rich in C–H bonds, such as ethane

• A six-carbon molecule rich in C–H bonds, such as a lipid

Which statement is true of pH buffers?

Responses

• They consist of weak acids and weak bases

• They keep the pH of the blood constant

• Both (b) and (c)

• They consist of strong acids and strong bases

• Both (a) and (b)

• They consist of weak acids and weak bases

Which of the differences listed here could be found among molecules of the same monosaccharide?  

Responses

• a difference in the overall shape of the molecule − one is a ring and the other is linear

• a difference in the orientation of an amino group in the ring form

• a difference in the number of carbons 

• a difference in the position of the carbonyl group in the linear form

• a difference in the overall shape of the molecule − one is a ring and the other is linear

How do fats differ from proteins, nucleic acids, and polysaccharides?

Responses

• Only fats are organic compounds.

• Fats are found in membranes but proteins, nucleic acids, and polysaccharides are not.

• Fats play a structural role in cells while proteins, nucleic acids, and polysaccharides don't.

• Only fats do not form from the polymerization of monomers.

• Only fats do not form from the polymerization of monomers.

Which of the following is NOT a potential function of proteins?

Responses

• Catalysis of reactions using enzymes

• Energy storage that can be easily digested and metabolized

• Immunity and defense, through molecules such as antibodies

• Diffusion and transfer of molecules, such as through aquaporins

• Energy storage that can be easily digested and metabolized

In all chemical reactions, even those that release energy, a minimal input of energy, known as activation energy, is necessary to initiate the reaction process.

 

Responses

• True

• False

• True

Increasing the substrate concentration in an enzymatic reaction could overcome which of the following?

Responses

• competitive inhibition

• the need for a coenzyme 

• allosteric inhibition

• insufficient cofactors

• competitive inhibition

A cell with a predominance of free ribosomes is most likely:

Responses

• digesting large food particles

• primarily producing proteins in the cytosol

• constructing an extensive cell wall or extracellular matrix 

• primarily producing proteins for secretion

• primarily producing proteins in the cytosol

Which of the following hypotheses best explains why membrane-bound organelles are more common in eukaryotic cells than prokaryotic cells (bacteria or archaea)?

Responses

• Membrane-bound organelles provide structural support, which is unnecessary in smaller cells.

• Bacteria and archaea lack the genetic material required to form organelles.

• Eukaryotic cells are larger, and organelles help overcome diffusion limitations by partitioning functions.

• Eukaryotic cells evolved in nutrient-rich environments where organelles were necessary for nutrient storage.

• Eukaryotic cells are larger, and organelles help overcome diffusion limitations by partitioning functions.

Your skin may shrivel if you spend too much time in salt water. What can we say about the concentration of salt in the salt water versus those in your skin cells?

Responses

• Salt water is isotonic relative to our skin cells, meaning it has higher concentration of solutes

• Salt water is hypertonic relative to our skin cells, meaning it has lower concentration of solutes

• Salt water is hypotonic relative to our skin cells, meaning it has lower concentration of solutes

• Salt water is hypertonic relative to our skin cells, meaning it has higher concentration of solutes

• Salt water is hypotonic relative to our skin cells, meaning it has higher concentration of solutes

• Salt water is hypertonic relative to our skin cells, meaning it has higher concentration of solutes

Why does the process of cellular respiration need to be regulated?

Responses

• To avoid the cell entering the process of fermentation

• To guarantee that the cell will not run out of glucose

• To sustain high levels of ATP

• To provide balanced amounts of energy in the form of ATP

• To provide balanced amounts of energy in the form of ATP

When solid tumors of animals reach a certain size, the center of the tumor begins to die. To prevent this, the tumor can recruit new blood vessels. What purpose does the recruitment of blood vessels to growing tumors serve?

Responses

• it supplies a non-oxygen electron acceptor to cells so that the cells can respire anaerobically

• it supplies glucose to the rapidly dividing cells of the tumor

• it supplies oxygen so that aerobic cellular respiration can occur instead of fermentation

• it supplies oxygen and glucose so that aerobic cellular respiration can occur instead of fermentation, in the rapidly dividingcells of the tumor

• it supplies a non-oxygen electron acceptor to cells so that the cells can respire anaerobically, and it supplies oxygen so that aerobic cellular respiration can occur instead of fermentation

• it supplies oxygen and glucose so that aerobic cellular respiration can occur instead of fermentation, in the rapidly dividingcells of the tumor

A poison that disrupts the integrity of the inner mitochondrial membrane would most directly interfere with what process of cellular respiration?

Responses

• Electron Transport Chain

• Oxidative Phosphorylation

• Krebs Cycle

• Glycolysis

• Pyruvate processing

• Oxidative Phosphorylation

During DNA replication, the leading strand is synthesized continuously while the lagging strand is synthesized in fragments. What is the primary reason for this difference?

Responses

• DNA polymerase can only add nucleotides to the 3' end of the new strand.

• Primase (RNA pol) synthesizes primers more frequently on the leading strand.

• Helicase unwinds DNA in the 3' to 5' direction, favoring the leading strand.

• DNA polymerase can only add nucleotides to the 5' end of a growing strand.

• DNA polymerase can only add nucleotides to the 3' end of the new strand.

Why do linked genes violate the law of independent assortment?

Responses

• Because segments of homologous chromosomes exchange linear segments of genetic material (crossing over)

• Because homologous chromosomes possess the same genes in the same linear order

• Because genes that are located physically close to each other are inherited independently of each other

• Because genes that are located physically close to each other on the same chromosome are more likely to be inherited as a pair

• Because genes that are located physically close to each other on the same chromosome are more likely to be inherited as a pair

In addition to splicing, additional modifications at the 5' and 3' end are required to generate a mature mRNA. What is the significance of these modifications?

Responses

• These modifications ensure that the mRNA is properly spliced.

• These modifications are required so that the mRNA is retained in the nucleus.

• These modifications allow the mRNA to be recognized by the protein synthesis machinery and protect it from degradation.

• These modifications ensure that RNA polymerase recognizes the proper promoter sequence.

• These modifications allow the mRNA to be recognized by the protein synthesis machinery and protect it from degradation.

What do genes do?

Responses

• Genes contain the genetic information for coding one or more RNAs or proteins.

• Genes are what contain the genetic information for making enzymes.

• Genes are the genetic information that is created from transcribing and translating RNA.

• Genes contain the information for replicating the entire DNA strand.

• Genes contain the genetic information for coding one or more RNAs or proteins.

Which of the following occurs in prokaryotes but not in eukaryotes?

Responses

• Posttranscriptional splicing

• Translation in the absence of a ribosome

• Concurrent transcription and translation

• Gene regulation

• Posttranscriptional splicing