Biology - 2.2 Transportation Plants

Question 1

Cellular uptake

Answer 1

Uptake and release of water by individual cells
Absorption of water and minerals from the soil by root cells
Control of water movement across endodermis

Question 1

Epidermis

Answer 1

Presence of root hairs for uptake of water

Question 2

Tissue Transport

Answer 2

Short distance from cell to cell
Transport across root cortex into xylem

Question 3

Whole plant transport

Answer 3

Long distance transport of sap within xylem and phloem

Question 4

Cortex parenchyma

Answer 4

Intercellular spaces allow movement of water

Question 5

Endodermis

Answer 5

Waterproof layer that forces water into the cytoplasm of endodermal cells and controls transport in xylem

Question 6

Xylem

Answer 6

Transports water and ions from roots to stem and leaves, support

Question 7

Phloem

Answer 7

Transports the products of photosynthesis to roots from leaves

Question 8

Cambium

Answer 8

Meristematic tissue undergoes mitosis to produce more xylem and phloem

Question 9

Adaptations of root hair cells for absorption

Answer 9

Thin cellulose cell wall for shorter diffusion distance
Mitochondria to produce more ATP for active transport of ions
Lots of root hairs for increase in surface area

Question 10

How can water and ions be absorbed into cell?

Answer 10

Passively by into sponge like cell wall
Osmosis - water
Active transport - ions

Question 11

What does cuticle do?

Answer 11

Reduces water loss from evaporation
Transparent to allow photosynthesis

Question 12

Collenchyma

Answer 12

Cell walls thicken with cellulose to strengthen stem

Question 13

Structure of xylem

Answer 13

Xylem vessels - transport of water to other parts of the plant
Tracheids - provide strength to tissue
Xylem parenchyma - packing tissue between xylem vessels

Question 14

What are xylem cell walls made of

Answer 14

Lignin - impermeable to water, water leaves xylem through pits

Question 15

Structure of phloem

Answer 15

Phloem sieve tubes - cell walls made of cellulose
Companion cells - provide support to keep sieve cells alive, produce ATP from mitochondria for active transport

Question 16

How are sieve and companion cells combined?

Answer 16

Plasmodesmata

Question 17

Sieve plates in phloem

Answer 17

Perforations in sieve tube walls, strands of cytoplasm can pass through these pores for one sieve to next

Question 18

Vascular bundles

Answer 18

Contain xylem, phloem, cambium with other cells

Question 19

Apoplast Route

Answer 19

Water soaked into cellulose can travel from cell wall to cell wall by diffusion
Passive movement from cohesion

Question 20

Apoplast route fastest?

Answer 20

Fastest across the cortex
Forced into symplast route at endodermis and endodermis is waterproof

Question 21

Casparian Strip

Answer 21

Made of Suberin - waterproof

Question 22

Symplast Route

Answer 22

Can move into cytoplasm by osmosis
Water can take place between cells through plasmodesmata

Question 23

Vacuolar Route

Answer 23

Water moves between cytoplasm and large central vacuole via plasmodesmata
Slowest route - resistance to movement

Question 24

How are ions absorbed?

Answer 24

cations by ion exchange using proton pump cotransport with anions active transport at root hair cells

Question 25

Root pressure (pushes water up the xylem)

Answer 25

Active transport of ions into the stele which lowers water potential Water passively flows into roots Gravity acts against root pressure

Question 26

Cohesion Tension theory

Answer 26

Water is polar molecule Hydrogen bonds form between o and H Forces of attraction generated between molecules which makes them stick together

Question 27

Where plants live

Answer 27

Mesophytes - sufficient water available Hydrophytes - live on water Xerophytes - low water availability

Question 28

Adaptations of xerophytes

Answer 28

Succulent leaves store water Thick waxy cuticles to reduce water loss Rolled leaves - creates humid microenvironment to reduce water loss Reduced stomata Trichomes - hair that trap water vapour Sunken stomata

Question 29

Adaptations for hydrophytes

Answer 29

Floating leaves/stems Increased leaf surface area Smaller roots Lack of protective tissues

Question 30

Translocation Part 1

Answer 30

1. Sucrose enters phloem in active loading 2. Companion cells transport H+ ions out creating a diffusion gradient 3. H+ go back into companion cells by facilitated diffusion bringing in sucrose 4. Conc of sucrose in companion cells increase 5. Sucrose diffuses down the gradient into sieve tubes through plasmodesmata

Question 31

Translocation Part 2

Answer 31

1. As sucrose enters sieve, water potential inside reduced 2. Water enters via osmosis because of hydrostatic pressure of sieve 3. Water moves down sieve from high to low pressure 4. Sucrose removed by diffusion into surrounding cells 5. Water leaves sieve by osmosis, reducing pressure of phloem at the sink