CH9 transport in plants test questions

Question 1

How are nutrients transported around the plant?

Answer 1

Phloem

Question 2

What is an example of a sink in a plant?

Answer 2

Meristem

Question 3

What is the purpose of the Casparian Strip

Answer 3

To force water from the cell wall into the cytoplasm

Question 4

What is an example of something that contributes to the movement of water up the stem of a plant

Answer 4

Root pressure

Question 5

In an experiment on translocation, swelling ocurred above the ring used to hold the stem in place - what substance caused this swelling?

Answer 5

Sucrose

Question 6

How do plants control water loss from leaves?

Answer 6

Close the stomata

Question 7

What are the steps of the transpiration stream?

Answer 7

• Water evaporates from mesophyll into air space in leaf (Water has to leave for water to come in)
• Water moves down a concentration gradient out of the leaf
• Water potential of cell is lowered and watermoves into it via osmosis
• Water moves out of the xylem via osmosis

Question 8

How does water move from the root to the xylem?

Answer 8

Down a water potential gradient.

Question 9

What is an adaptation of pine trees to reduce water loss?

Answer 9

Narrow leaves with a thick waxy coating - pines

Question 10

What is a plant adapted to live in standing water called?

Answer 10

Hydrophyte

Question 11

What is the part of a plant used to transport sucrose called?

Answer 11

Phloem

Question 12

What is the pathway of water that moves through the cell wall and not the cytoplasm called?

Answer 12

Apoplast pathway

Question 13

What is a plant that possesses transport tissues called?

Answer 13

vascular plant

Question 14

What is an apparatus to measure water uptake in a plant called?

Answer 14

Potometer

Question 15

What is the difference between transpiration and translocation?

Answer 15

• Transpiration is the movement of water from the root to the stomata on the leaf, via the xylem, using cohesion-tension theory.
• Translocation is the movement of assimilates (dissolved sucrose/amino acids) from the source to the sink (e.g. sucrose from leaf to the root), along a concentration gradient.

Question 16

What is the difference in distribution of xylem in a root versus a stem?

Answer 16

• Xylem in root forms an ‘x’ in the centre of the root, with a border of xylem. Xylem tightly packed together.
• Xylem in stem form individual vascular bundles which are arranged around the border of the stem. In one vascular bundle, there are xylem facing inwards, and phloem facing outwards, and therefore xylem are dispersed.

Question 17

What is the significance in hydrogen bonding in water for transport of water in xylem.

Answer 17

• Polar hydrogen bonds means that each water molecule has a small positive and negative charge
• The slightly negative oxygen and the slightly positive hydrogen will attract one another
• this allows for cohesion between water molecules, and also allows for adhesion to the xylem walls, which allows for the cohesion-tension theory and also allows for capillary action.

Question 18

In a vascular bundle, does the xylem or phloem face the palisade mesophyll tissue? (top of the leaf)

Answer 18

xylem faces upwards, phloem faces downwards

Question 19

What are functions of a vascular bundle?

Answer 19

• Transporting nutrients, vitamins and assimilates around the plant, for example water from root cells to leaf cells.
• Provides mechanical support to leaf
• Uses cambium to seperate the phloem and the xylem.

Question 20

Describe the different pathways of water

Answer 20

• Symplast pathway - travels via cytoplasm of cells, which are bound together by the plasmodesmata which allows water to travel from cytoplasm to cytoplasm
• Apoplast pathway - water travels in the gaps in the cell wall, uses simple diffusion to travel.

Question 21

What are the functions of the companion cell and sieve-tube cell?

Answer 21

• Phloem sieve-tube cell - Hollow, thick walls, functional for the transport of assimilates and nutrients.
• Companion Cell - Eukaryotic plant cell, facilitates the loading of sieve tubes with assimilates. Connected to sieve-tube cells via plasmodesmata.

Question 22

Why should seedlings when being transported to new soil in a bigger pot should be moved in the evening?

Answer 22

• You would cut off transpiration stream if moved during the day, due to the intake of water being interrupted, which means that the plant would lose a lot of vital water, therefore meaning it would wilt.
• If you move the plant in the evening, it still has the entire night to settle in to it’s new surroundings before being exposed to the full heat of the day. Stomata are closed at night, so there is no water loss or intake, making it the perfect settling in time.