Plant Physiology Bio 435 Cal Poly Steinmoss Knight Exam 2 Quiz #2

Front 1

What kind of cells are the pathways for translocation in phloem?

Back 1

sieve elements, bundle sheath cells

Front 2

Are sieve elements living or dead and do they have nucleus or tonoplast?

Back 2

living, they don't have a nucleus or tonoplast

Front 3

How are damaged sieve elements sealed off?

Back 3

Structural P-proteins plug up sieve plate pores so that sap cannot escape

Front 4

What would happen to a plant without P-proteins or callose?

Back 4

A pressure release causes contents of the sieve tube (sugar-rich phloem sap) to surge toward the cut end.

Front 5

What do companion cells do for sieve elements?

Back 5

protein synthesis, and supply ATP

Front 6

Is phloem translocation always from leaves to roots? Provide an example.

Back 6

No it goes to any organ that doesn't produce enough to suppport it's own growth, Ex: tubers and immature leaves

Front 7

Are transport velocities in the phloem higher or lower than the rate of diffusion?

Back 7

higher

Front 8

Describe the pressure-flow model of phloem transport.

Back 8

In the Pressure-flow model the flow of solution in sieve elements is driven by an osmotically generated pressure gradient between source and sink

Front 9

What are four predictions of the pressure-flow model of phloem translocation?

Back 9

1) The sieve plate pores must be unobstructed
2) No true bidirectional transport in a single sieve element can occur
3) No great expenditures of energy are required in order to drive translocation in the tissues along the path.
4) The pressure-flow hypothesis demands the presence of a positive pressure gradient, with turgor pressure higher in sieve elements of sources then in sinks.

Front 10

Does phloem loading occur through the apoplast or symplast?

Back 10

both

Front 11

Describe how sugars could enter the sieve elements from the apoplast.

Back 11

Sugars enter sieve elements from the apoplast by an energy-driven, selective transporter located in the plasma membranes of these cells

Front 12

name the four primary metabolites

Back 12

carbohydrates, proteins, nucleic acids, and lipids

Front 13

What three important functions do secondary metabolites perform for plants?

Back 13

structure, defense

Front 14

Do plant secondary metabolites have limited or extensive phylogenetic distribution?

Back 14

restricted

Front 15

Plant secondary metabolites can be divided into three chemically distinct groups, name them.

Back 15

Terpenes, phenolics and nitrogen containing compounds

Front 16

What is the basic structural element of a terpene called?

Back 16

an isoprene unit

Front 17

What two pathways exist for terpene biosynthesis?

Back 17

The mevalonic acid pathway and the methylerythritol phosphate pathway

Front 18

The terpene saponin protects against what type of invader?

Back 18

Vertebrate Herbivore

Front 19

What are four roles of phenolic compounds?

Back 19

defense against herbivores and pathogens, mechanical support, attracting pollinators and fruit dispersers, in absorbing harmful ultraviolet radiation

Front 20

What is the most abundant organic substance in plants after cellulose? Describe its role

Back 20

lignin, it provides support and can be found in conducting tissues such as the cell walls of xylem

Front 21

The different types of flavonoid perform a range of functions including

Back 21

insect and animal attraction