Vascular System

Question 1

What are tracheids and vessel elements together called

Answer 1

Tracheary element

Question 2

What kind of cell wall do to tracheids and vessel element have

Answer 2

Lignified cell wall

Question 3

Where does differentiation takes place in xylem

Answer 3

In tracheary element

Question 4

What happens in differentiation

Answer 4

Specification, enlargement, patterned cell wall deposition, programmed cell death and cell wall removal

Question 5

How are pits different from pores?

Answer 5

Pits are the cavity in the secondary cell wall and pores do not have any wall.

Question 6

What are the two types of perforation in the vessel element?

Answer 6

Simple and compound perforations are found. Compound perforation all of three types: -
Reticulate
Scalariform
Foraminate

Question 7

Who lacks vessel in the xylem?

Answer 7

Gymnosperm

Question 8

What kind of cell is xylem parenchyma? What is its function?

Answer 8

Xylem parenchyma is a living and thin walled cell. It helps in storage of starch or fat.

Question 9

What are xylem fibres? What are their function?

Answer 9

They are highly thick and dead cells. They help in mechanical function. They are either septate or aseptate.

Question 10

What are the two types of xylem fibres?

Answer 10

Fibre tracheids and libriform fibre

Question 11

What are sieve tube elements?

Answer 11

They are elongated living cells.

Question 12

What are the organelles that are lost after maturation of seive tube element?

Answer 12

They lose a nucleus tonoplast, golgi bodies and ribosomes.

Question 13

What do mature seive tube element have?

Answer 13

They have SER, mitochondria and plastids.

Question 14

What does a gymnosperm have instead of seive tube element and companion cell?

Answer 14

They have seive cells and albuminous cells.

Question 15

What is the name of protein that phloem has that help in plugging the phloem?

Answer 15

P protein and callose

Question 16

Where is p protein and callose are synthesized?

Answer 16

P protein synthesized in immature seive cells and callose synthesized in plasma membrane by callose synthase.

Question 17

Which one is a reversible mechanism for plugging the sieve tube element?

Answer 17

P protein

Question 18

What organelles does companion cells have?

Answer 18

They have a dense cytoplasm, mitochondria, nucleus, golgi bodies, ER and chloroplast.

Question 19

What are the three types of companion cells?

Answer 19

Ordinary companion cell, transfer companion cell and intermediary companion cell

Question 20

Where is phloem parenchyma absent in

Answer 20

Monocotyledons

Question 21

What is Fick’s law?

Answer 21

J = -D (∆c/∆x)

Question 22

What is a turgor pressure?

Answer 22

Pressure exerted outwards against the cell wall.

Question 23

What is incipient plasmolysis ?

Answer 23

The first sign of shrinkage of protoplast

Question 24

What is the relationship of water potential with solute potential

Answer 24

Inversely proportional

Question 25

What are the three zones of development in roots

Answer 25

Zone of differentiation, elongation zone and meristematic zone

Question 26

What are the two pressures that help in the absorption of water in the roots?

Answer 26

Hydrostatic pressure and transpiration

Question 27

What are the three pathways in which the water moves from the cell?

Answer 27

Apoplastic, symplastic and transmembrane pathway

Question 28

What is casparian strip made of?

Answer 28

Suberin

Question 29

Who proposed cohesion tension theory?

Answer 29

Dixon and Jolly

Question 30

What is cavitation or embolism?

Answer 30

Presence of a bubble in the xylem sap.

Question 31

What are the three types of transpiration?

Answer 31

Stomatal, cuticular and lenticular transpiration

Question 32

What happens when the blue light falls on the stomata?

Answer 32

When the blue light falls on the stomata, zeaxanthin activates signal transduction cascade that activates serine and threonine. They activate H+ ATPase and protons get pumped out. K+ and Cl- is taken in by proton chloride symporter. Malate synthesis and sucrose synthesis occur.

Question 33

Why does stomata opens?

Answer 33

Due to turgor pressure

Question 34

Transpiration ratio?

Answer 34

The ratio of the number of water molecules transpired to form a CO2.

Question 35

What is the transpiration ratio of C3 C4 and cam plants

Answer 35

C3 500 C4 250 CAM 50

Question 36

What is guttation

Answer 36

Exudation of water molecule via hydathodes at night

Question 37

Why does guttation occur?

Answer 37

Due to positive hydrostatic pressure

Question 38

What is the major pathway taken by water to reach xylem

Answer 38

Apoplastic

Question 39

What is the major pathway to reach xylem taken by ions?

Answer 39

Symplastic

Question 40

Functional unit of phloem

Answer 40

SE-CC complex

Question 41

Major sink during early stage and major sink during reproductive stage

Answer 41

During early stage: Roots and leaves Reproductive stage: tubers, seeds and fruit

Question 42

What kind of sugars are present in the phloem sap

Answer 42

Sucrose, raffinose, stachyose and verbascose.

Question 43

What are present in the phloem sap

Answer 43

Organic solutes, amino acids, inorganic acids, hormone, RNAs

Question 44

Is sugar alcohol present in the phloem sap

Answer 44

Yes

Question 45

Which sugar isn't tolerated in the phloem sap

Answer 45

Glucose

Question 46

Who gave pressure flow hypothesis and what was in it?

Answer 46

Münch gave the hypothesis. It said that mass flow of phloem sap occurred due to the pressure gradient between source and sink.

Question 47

What is leakage retrieval mechanism

Answer 47

Loading and unloading occurs throughout the whole seive tube element

Question 48

What is the name of the uniporter that transfers sucrose down the concentration gradient from mesophyll cell

Answer 48

SWEET

Question 49

What is polymer trapping mechanism

Answer 49

Sucrose when symplatically enters the companion cell, it becomes raffinose. Since raffinose is a large molecule it can't go back, hence it has to go to the seive tube element.

Question 50

What is the major path from which phloem loading takes place

Answer 50

Symplastic loading

Question 51

Nitrogen is found in which form in phloem?

Answer 51

Glutamate and aspartate

Question 52

Which ion is most abundant in phloem?

Answer 52

Potassium