B7- Adaptations For Transport: Plants

Front 1

Word equation for photosynthesis

Back 1

Carbon dioxide + water -> glucose + oxygen

Front 2

What do xylem vessels carry?

Back 2

Xylem vessels carry water and mineral ions from the roofs to the leaves

Front 3

What is the glucose produced during photosynthesis used to make?

Back 3

Sucrose and amino acids (photosynthates)

Front 4

What do the phloem vessels carry?

Back 4

Phloem transport photosynthates upwards and downwards.

Front 5

What is the name for the fact the movement in phloem is both upwards and downwards?

Back 5

Bi- directional movement

Front 6

Name the six main parts of the stem.

Back 6

Epidermis, Cortex, Phloem, Cambium, Xylem and Pith

Front 7

Name the 8 main parts of the root.

Back 7

Epidermis, Pericycle, endodermis, phloem, xylem, Steele, Cortex and to root hair cells

Front 8

How do mineral ions such as nitrates enter the roots?

Back 8

They are actively transported from the soil into root hair cells.

Front 9

How is water transported into the roots?

Back 9

When mineral ions are transported into the roots this lowers the water potential so water enters by osmosis

Front 10

Name the three pathways water and dissolved mineral ions can take when travelling through the root hair cells.

Back 10

Apoplast, Symplast, Vacuolar

Front 11

Describes the apoplast pathway.

Back 11

Water is taken up by the root hair cell and moves across the cortex by cohesion via cell walls.

Front 12

Describe the symplast pathway.

Back 12

Water moves from the cytoplasm of one cell to the next by osmosis via plasmodesmata

Front 13

Describe the vacuolar pathway.

Back 13

Water can move via the cytoplasm and vacuoles

Front 14

Why once the water and mineral ions reach the endodermis are they all forced to travel along the symplast pathway?

Back 14

The cell walls of the endodermis contain a waxy substance called Suberin (the Casparian Strip). Suberin is impermeable to water and mineral ions meaning the apoplast pathway is blocked.

Front 15

How do mineral ions enter the xylem from the endodermis?

Back 15

Mineral ions are actively transported from outside the endodermal cells into the cytoplasm and diffuse from there to the pericycle and then into the xylem.

Front 16

How does water enter the xylem from the endodermis?

Back 16

Water moves by osmosis down a water potential gradient

Front 17

Why does a plant need to control the entry of mineral ions into the xylem?

Back 17

Once a particle enters the xylem it can travel all over the plant, therefore plants new a control mechanism as some minerals can be toxic, e.g. copper ions

Front 18

Give three reasons plants need to absorb nitrates from the soil?

Back 18

To make amino acids needed to make proteins for growth and to make nucleic acids and ATP

Front 19

Why do plants need to absorb potassium?

Back 19

For stomatal opening and closing

Front 20

Why do plants need to absorb magnesium

Back 20

To make chlorophyll

Front 21

Why do plants need to absorb phosphates?

Back 21

For the production of ATP

Front 22

Give two adaptations of root hair cells

Back 22

Large surface area and lots of mitochondria

Front 23

Definition of transpiration.

Back 23

Transpiration is the evaporation of water from inside the leaves through the stomata to the atmosphere

Front 24

Give the four steps of the transpiration stream.

Back 24

1. Water is absorbed by the root hair cells 2. Water moves through the room tissue into xylem and is transported up the xylem in the plant stem to the leaves 3. Water is transported by osmosis from the xylem into the spongy mesophyll where it evaporates into air spaces 4. Water vapour then diffuses from the air spaces out of the leaf through stomata down a water potential gradient

Front 25

Definition of cohesion.

Back 25

Cohesion is when water molecules are attracted to each other by hydrogen bonding.

Front 26

Definition of adhesion.

Back 26

Water molecules are attracted to the hydrophilic lining of the lignified xylem vessels walls

Front 27

Describe how capillarity allows water to travel up the xylem.

Back 27

The forces of adhesion and cohesion allow water molecules to rise up narrow tubes for a short distance which is useful in small plants

Front 28

Describe how root pressure helps transport water upwards in the xylem.

Back 28

Water moves from the endodermal cells of the root into the xylem by osmosis, generating hydrostatic pressure.

Front 29

Describe the cohesion- tension theory (transpiration pull)give

Back 29

As water vapour diffuses out of the stomata by transportation water molecules are drawn up behind to replace them. The water molecules are drawn up the xylem which is possible due cohesion between water molecules due to hydrogen bonds and adhesion between the water molecules are xylem walls. This upwards movement creates tension.

Front 30

Name the four factors affecting transpiration.

Back 30

Temperature, Wind speed, Humidity and Light Intensity

Front 31

How does a ride in temperature affect the rate in transpiration?

Back 31

A rise in temperature increases the kinetic energy of the water molecules and increases the rate of evaporation and diffusion. The water potential of the atmosphere is also lower increasing the water potential gradient.

Front 32

Describe how low wind speed affects the rate of transpiration.

Back 32

Still air results in a layer of water vapour around the stomata of the leaf (diffusion shell). This reduces the water potential gradient between the inside and outside.

Front 33

Describe how a high wind speed affects the rate of transpiration.

Back 33

Air movement blows away the diffusion shell and increases the rate of transpiration.

Front 34

Describe how a high humidity affects the rate of transpiration.

Back 34

The water potential gradient between the inside and out decreases as there is more water in the atmosphere.

Front 35

Describe how light intensity affects the rate of transpiration.

Back 35

Light causes the stomata to open to allow gas exchange for photosynthesis.

Front 36

What does a photometer measure?

Back 36

The rate of uptake of water

Front 37

Describe the six steps in setting up a potometer.

Back 37

1. Cut a leafy shoot under water (prevent the entry of air into the xylem vessel) 2. Completely full the apparatus with water 3. Fit the leaf tightly and seal the joints with vaseline 4. Pat the leaves dry 5. Introduce one air bubble to the capillary tube 6. Measure the distance the air bubble moves along the scale in a specific time.

Front 38

What is the structure of vessel tissue in xylem?

Back 38

Continuous columns of dead cells arranged end to end with completely dissolved cross walls to form long hollow tubes

Front 39

Why are xylems walls thickened with lignin?

Back 39

As it is impermeable to water and strengthens and supports the plants.

Front 40

What is the function of tracheids?

Back 40

They also conduct water but less efficiently than vessels.

Front 41

How do tracheids differ from vessels?

Back 41

Tracheids have tapering ends.

Front 42

Continue on page 11

Back 42

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