There are at least three different types of companion cells in the minor veins of mature, exporting leaves. Which of the following statements about these companion cells is CORRECT?

 a.) transfer cells are transport sugars enter the apoplast during the movement of sugars from mesophyll cells to sieve elements. Transfer cells transport sugars from the apoplast to the symplast of the sieve elements and companion cells in the source.

 b.) the numerous mitochondria in companion cells may supply energy as ATP to the sieve elements

 c.) Ordinary companion cells can function in either symplastic or apoplastic short-distance transport in source leaves, depending in part on plasmodesmatal frequencies

 d.) Intermediary cells, by contrast, function in symplastic transport of sugars from mesophyll cells to sieve elements

#Question id: 534

#Unit 1. Molecules and their Interaction Relevant to Biology

If glucose labeled with 14C in C-3 is metabolized to lactate via fermentation, the lactate will contain 14C in:

#Question id: 535

#Unit 1. Molecules and their Interaction Relevant to Biology

In some diabetic patients, glucose increases disproportionately and is unresponsive to an insulin challenge; under these conditions, how would oneʹs liver normally respond?

A) phosphorylating glucose for entry into the glycolytic pathway

B) saturating glucokinase with glucose

C) phosphorylating glucose for entry into the glycogen synthesis pathways

#Question id: 536

#Unit 1. Molecules and their Interaction Relevant to Biology

Glucose 6-phosphate allosterically inhibits

A) hexokinase I.

B) glucokinase.

C) hexokinase II.

#Question id: 537

#Unit 1. Molecules and their Interaction Relevant to Biology

Substrate level phosphorylation

A) describes the conversion of ADP into ATP with the addition of inorganic phosphate every place throughout the cell.

B) describes the formation of ADP by phosphoryl group transfer from 1,3 bisphosphoglycerate.

C) is the formation of ATP by phosphoryl group transfer from a higher energy compound.

#Question id: 538

#Unit 1. Molecules and their Interaction Relevant to Biology

Which of the following statements are correct about cells that form ATP mainly by glycolysis are

A) anaerobic yeasts.

B) lactic acid bacteria.

C) kidney medulla cells.

#Question id: 539

#Unit 1. Molecules and their Interaction Relevant to Biology

Which of the following mutases catalyze the formation of a 2,3-BPG intermediate?

A) muscle phosphoglycerate mutases

B) plant phosphoglycerate mutases

C) yeast phosphoglycerate mutases