Transport in Plants

Question 1

Over small distances, substances move by

Answer 1

Diffusion and cytoplasmic streaming supplemented by active transport

Question 2

Transport over longer distances proceeds through

Answer 2

Vascular system - translocation

Question 3

Transport in xylem is

Answer 3

Unidirectional - root—->stem

Question 4

Transport of PGRs is

Answer 4

Sometimes in a strictly polarized or unidirectional manner

Question 5

Only means of gaseous movement within plant body

Answer 5

Diffusion

Question 6

Diffusion of any substance across cell membrane depends on

Answer 6

Its solubility in lipids

Question 7

Hydrophilic substances can easily pass through cell membrane - true/false

Answer 7

False

Question 8

Facilitated diffusion is sensitive to

Answer 8

Inhibitors which react with protein side chains

Question 9

Porins are

Answer 9

Proteins that form large pores in outer membrane of plastids, mitochondria, some bacteria

Question 10

Water channels are made up of

Answer 10

8 different types of aquaporins

Question 11

Pumps are

Answer 11

Proteins that use energy to transport substances across cell membrane

Question 12

Facilitated diffusion and active transport are under

Answer 12

Hormonal regulation

Question 13

Watermelon has over ____ % water

Answer 13

92

Question 14

Most herbaceous plants have ___ to ___ % of fresh weight as dry weight

Answer 14

10 to 15%

Question 15

Mature corn plant absorbs ___ litres of water per day

Answer 15

3

Question 16

Mustard plant absorbs water

Answer 16

Equal to its own weight in 5 hours

Question 17

Water potential of pure water at standard temperature and pressure is

Answer 17

Zero

Question 18

Solute potential is

Answer 18

Always negative

Question 19

The more the solute molecules the ______ is the solute potential

Answer 19

Lower (more negative)

Question 20

For a solution at atmospheric pressure

Answer 20

Solute potential = Water potential

Question 21

Pressure potential is usually

Answer 21

Positive

Question 22

Water potential =

Answer 22

Pressure potential + Solute potential

Question 23

Osmosis occurs through

Answer 23

Selectively permeable membrane

Question 24

Osmotic pressure =

Answer 24

• Osmotic potential

Question 25

Plasmolysis occurs when

Answer 25

Water moves out of the cell and the cell membrane shrinks AWAY from the cell wall

Question 26

Water is lost first from ______ and then from _____

Answer 26

Cytoplasm, vacuole

Question 27

Pressure responsible for enlargement and extension growth of cells

Answer 27

Turgor pressure

Question 28

Imbibition is a special type of diffusion when water is absorbed by

Answer 28

Solids - colloids

Question 29

Water potential gradient is not essential for imbibition - true/false

Answer 29

False - imbibition is similar to diffusion

Question 30

Size of typical plant cell

Answer 30

50 micrometer

Question 31

The time taken by a molecule to move across a plant cell (50 micrometer) by diffusion is

Answer 31

2.5 seconds

Question 32

Translocation

Answer 32

Bulk movement of substances through vascular tissues

Question 33

Xylem is associated with translocation of

Answer 33

Water, mineral salts, organic nitrogen and hormones (PGRs)

Question 34

Phloem is associated with translocation of

Answer 34

Organic and inorganic solutes

Question 35

Water, along with mineral solutes in plants is absorbed by

Answer 35

Root hairs, PURELY by DIFFUSION

Question 36

Apoplast is continuous throughout the plant except

Answer 36

Casparian strips of endodermis in the root

Question 37

Mass flow occurs in apoplast due to

Answer 37

Adhesive and cohesive properties of water

Question 38

Symplastic movement may be aided by

Answer 38

Cytoplasmic streaming

Question 39

Most water flow in roots occurs via

Answer 39

Apoplast

Question 40

In young roots, water enters directly into

Answer 40

Xylem vessels/tracheids (apoplast)

Question 41

Greatest contribution of root pressure is to

Answer 41

Reestablish the continuous chains of water molecules in xylem

Question 42

Rate of upward flow of water through xylem

Answer 42

15 metres/hour

Question 43

Less than __ % of water reaching the leaves is used in photosynthesis and plant growth

Answer 43

1%

Question 44

Inner wall of each guard cell is

Answer 44

Thick and elastic

Question 45

Opening of stomata is also aided due to

Answer 45

Orientation of microfibrils in cell WALL of guard cells - cellulose microfibrils are oriented radially rather than longitudinally

Question 46

Adhesion is

Answer 46

Attraction of water molecules to polar surfaces (surface of tracheary elements)

Question 47

Tracheids and vessel elements have

Answer 47

Small diameter

Question 48

Forces generated by transpiration can lift a xylem sized column of water upto

Answer 48

130 metres

Question 49

What supplies water for photosynthesis

Answer 49

Transpiration

Question 50

Transpiration can cool leaf surfaces by upto

Answer 50

10 to 15 degrees

Question 51

C4 plant loses only ___ % water as compared to a C3 plant

Answer 51

50%

Question 52

Most minerals enter the root by

Answer 52

Active absorption

Question 53

Root endodermis can actively transport ions in

Answer 53

ONLY ONE DIRECTION

Question 54

Unloading of mineral ions occurs at fine vein endings through

Answer 54

Diffusion and active uptake

Question 55

Elements most readily mobilized are

Answer 55

Phosphorous, sulphur, nitrogen, potassium

Question 56

Most of the nitrogen is carried as

Answer 56

Organic nitrogen - amino acids, etc.

Question 57

Substances translocated through phloem

Answer 57

Water, sucrose, other sugars, hormones, amino acids

Question 58

Sucrose is moved into companion cells and sieve tube cells by

Answer 58

Active transport