USABO OPEN EXAM NEWEST 2025 ACTUAL EXAM COMPLETE
150 QUESTIONS AND CORRECT DETAILED ANSWERS
(VERIFIED ANSWERS) |ALREADY GRADED A+ .
A lichen is composed of a fungus and a protobiont. The
protobiont is most likely to be a:
A. green or red algae.
B. sponge.
C. green alga or a cyanobacterium.
D. bryophyte or brown algae.
E. moss or a cyanobacterium. - ANSWER-C. green alga or a
cyanobacterium.
Which of the following represents the correct sequence for
protein digestion in humans?
A. Aminopeptidase, carboxypeptidase, chymotrypsin, pepsin
B. Aminopeptidase, pepsin, chymotrypsin, carboxypeptidase
C. Pepsin, carboxypeptidase, aminopeptidase, chymotrypsin
D. Chemotrypsin, aminopeptidase, carboxypeptidase, pepsin
E. Pepsin, chymotrypsin, carboxypeptidase, aminopeptidase -
ANSWER-E. Pepsin, chymotrypsin, carboxypeptidase,
aminopeptidase
,Which of the following situations would result in the greatest
degree of O2 saturation for hemoglobin, assuming PO2 remains
constant?
A. Decreased PCO2, decreased temperature
B. Elevated levels of 2, 3 - DPG
C. Low pH
D. Decreased PCO2, increased temperature
E. Increased PCO2, decreased temperature - ANSWER-A.
Decreased PCO2, decreased temperature
A biologist collected seeds from 10 different plants, keeping all
seeds under optimal conditions of storage. Within a week after
collection the seeds were germinated under laboratory
conditions. Each set of seeds was placed onto moist filter paper
which was remoistened as necessary and subjected to room
temperature of 23˚C. Half the seeds of each group received 24
hours of light, the other half were kept in darkness. Within
variable periods of time the seeds of certain plants kept in the
light germinated. The seeds of other plants kept in the dark
germinated. Some sets of seeds germinated under both light
regimes. One set of seeds did not germinate under either light
condition. What might be a LOGICAL hypothesis, consistent
with the data, for the lack of germination of the one set of
seeds?
, A. The seeds required 12 hours of light and 12 hours of
darkness in order to germinate.
B. All the seeds of that group were dea - ANSWER-D. The
seeds required vernalization in order to germinate.
Which of the following fibers binds to the cytoplasmic site of the
cell-matrix adherens junctions?
A. Elastin
B. Actin
C. Tubulin
D. Reticular
E. Collagen - ANSWER-B. Actin
Which of the following are NOT imbedded in the thylakoid
membrane?
A. Enzymes associated with carbon dioxide fixation
B. Molecules of chlorophyll a and chlorophyll b
C. P700 and P680 molecules
D. Proton channels of the ATP synthase
E. Ferredoxin-NADP+ - ANSWER-A. Enzymes associated with
carbon dioxide fixation
150 QUESTIONS AND CORRECT DETAILED ANSWERS
(VERIFIED ANSWERS) |ALREADY GRADED A+ .
A lichen is composed of a fungus and a protobiont. The
protobiont is most likely to be a:
A. green or red algae.
B. sponge.
C. green alga or a cyanobacterium.
D. bryophyte or brown algae.
E. moss or a cyanobacterium. - ANSWER-C. green alga or a
cyanobacterium.
Which of the following represents the correct sequence for
protein digestion in humans?
A. Aminopeptidase, carboxypeptidase, chymotrypsin, pepsin
B. Aminopeptidase, pepsin, chymotrypsin, carboxypeptidase
C. Pepsin, carboxypeptidase, aminopeptidase, chymotrypsin
D. Chemotrypsin, aminopeptidase, carboxypeptidase, pepsin
E. Pepsin, chymotrypsin, carboxypeptidase, aminopeptidase -
ANSWER-E. Pepsin, chymotrypsin, carboxypeptidase,
aminopeptidase
,Which of the following situations would result in the greatest
degree of O2 saturation for hemoglobin, assuming PO2 remains
constant?
A. Decreased PCO2, decreased temperature
B. Elevated levels of 2, 3 - DPG
C. Low pH
D. Decreased PCO2, increased temperature
E. Increased PCO2, decreased temperature - ANSWER-A.
Decreased PCO2, decreased temperature
A biologist collected seeds from 10 different plants, keeping all
seeds under optimal conditions of storage. Within a week after
collection the seeds were germinated under laboratory
conditions. Each set of seeds was placed onto moist filter paper
which was remoistened as necessary and subjected to room
temperature of 23˚C. Half the seeds of each group received 24
hours of light, the other half were kept in darkness. Within
variable periods of time the seeds of certain plants kept in the
light germinated. The seeds of other plants kept in the dark
germinated. Some sets of seeds germinated under both light
regimes. One set of seeds did not germinate under either light
condition. What might be a LOGICAL hypothesis, consistent
with the data, for the lack of germination of the one set of
seeds?
, A. The seeds required 12 hours of light and 12 hours of
darkness in order to germinate.
B. All the seeds of that group were dea - ANSWER-D. The
seeds required vernalization in order to germinate.
Which of the following fibers binds to the cytoplasmic site of the
cell-matrix adherens junctions?
A. Elastin
B. Actin
C. Tubulin
D. Reticular
E. Collagen - ANSWER-B. Actin
Which of the following are NOT imbedded in the thylakoid
membrane?
A. Enzymes associated with carbon dioxide fixation
B. Molecules of chlorophyll a and chlorophyll b
C. P700 and P680 molecules
D. Proton channels of the ATP synthase
E. Ferredoxin-NADP+ - ANSWER-A. Enzymes associated with
carbon dioxide fixation
