What is the role of companion cells in the movement of sugars through plants?a. They are the sites of sugar production by photosynthesis.d. They are the sites where starch is converted to sucrose.c. They secrete sucrose, which draws sugars through phloem under negative pressure.d. They accumulate sucrose, which is then transferred to adjacent sieve-tube elements.

What is a sieve-tube element?a. the sugar-conducting cell found in phloemb. the widened, perforation-containing, water-conducting cell found only in angiospermsc. the nutrient- and water-absorbing cell found in root hairsd. the nucleated and organelle-rich support cell found in phloem

The innermost layer of the root cortex is thea. core.b. pericycle.c. endodermis.d. pith.

Evaluate the following statements regarding tracheids and vessel elements. Select True or False for each statement.T/F Both tracheids and vessel elements are specialized for water conduction.T/F Both tracheids and vessel elements have pits.T/F Vessel elements have perforation plates but tracheids do not.T/F Tracheids and vessel elements have to be alive in order to transport water.

Splicing begins:a. as transcription occurs.b. after transcription is complete.c. as translation occurs.d. after translation is complete.

Compared with mRNAs that have a cap and tail, predict what will be observed if a eukaryotic mRNA lacked a cap and poly(A) tail.a. The primary transcript would not be processed properly.b. Translation would occur inefficiently.c. Enzymes on the ribosome would add a cap and poly(A) tail.d. tRNAs would become more resistant to degradation.

Which of the following would not be seen in a cross section through the woody part of a root?a. sclerenchyma cellsb. parenchyma cellsc. sieve-tube elementsd. root hairs

Artichoke hearts are tender and have a strong taste. The leaves have a strong taste, too, but most of an artichoke leaf is fibrous and too difficult to chew. The leaves must contain lots of __________.

The plant tissue system most analogous to our circulatory system is the __________.