Chapter: Transport In Plants

Question 1

Flashcard 1:
Q: What are the main functions of roots in dicotyledonous plants?

Answer 1

A: Roots are responsible for the absorption of water and mineral salts/ions, and they anchor the plant firmly in the soil.

Question 2

Flashcard 2:
Q: Describe the epidermis of a dicotyledonous root.

Answer 2

A: The epidermis is a single-celled layer surrounding the outer part of the root, protecting the underlying tissues.

Question 3

Flashcard 3:
Q: What is a root hair cell?

Answer 3

A: A root hair cell is an epidermal cell with a finger-like outgrowth that increases the absorption surface area for water and mineral salts.

Question 4

Flashcard 4:
Q: What is the function of the cortex in a dicotyledonous root?

Answer 4

A: The cortex allows water and mineral ions to pass through to the xylem and stores starch.

Question 5

Flashcard 5:
Q: What role does the endodermis play in a dicotyledonous root?

Answer 5

A: The endodermis regulates the passage of water from the cortex to the xylem.

Question 6

Flashcard 6:
Q: Where are the xylem and phloem located in a dicotyledonous root?

Answer 6

A: The xylem is in the center of the vascular bundle, arranged in a cross, while the phloem is found between the “arms” of the xylem cross, closer to the endodermis.

Question 7

Flashcard 7:
Q: What is the cambium in a dicotyledonous root?

Answer 7

A: The cambium is tissue located between the xylem and phloem.

Question 8

Flashcard 8:
Q: What are the main functions of stems in dicotyledonous plants?

Answer 8

A: Stems expose leaves for photosynthesis, bear flowers for pollination, bear fruits for seed dispersal, transport water and nutrients, and store reserve nutrients and water.

Question 9

Flashcard 9:
Q: Describe the epidermis of a dicotyledonous stem.

Answer 9

A: The epidermis is a single-celled layer surrounding the stem, with some cells modified to form lenticels for gaseous exchange.

Question 10

Flashcard 10:
Q: What is the role of the cortex in a dicotyledonous stem?

Answer 10

A: The cortex allows gaseous exchange through intracellular spaces and contains vascular bundles arranged in a circle for structural support.

Question 11

Flashcard 11:
Q: How are xylem and phloem tissues arranged in a dicotyledonous stem?

Answer 11

A: The xylem is located on the inside of the vascular bundle, while the phloem is on the outside, separated by the cambium.

Question 12

Flashcard 12:
Q: Explain the pathway of water through a plant starting from the soil.

Answer 12

A: Water is absorbed by root hairs via osmosis, moves through the epidermis and cortex, crosses the endodermis into the xylem, travels up the stem, enters leaf cells, and exits through stomata via transpiration.

Question 13

Flashcard 13:
Q: What are the three pathways water can follow through the root?

Answer 13

A: Apoplast pathway (through cell walls), symplast pathway (through cytoplasm and plasmodesmata), and vacuolar pathway (through vacuoles).

Question 14

Flashcard 14:
Q: How does water move up the xylem?

Answer 14

A: Water moves up the xylem due to root pressure, cohesion of water molecules, transpiration pull, and adhesion to the xylem walls, resulting in capillarity.

Question 15

Flashcard 15:
Q: What adaptations do root hair cells have for water absorption?

Answer 15

A: They have a large surface area, a partially permeable membrane, and a large vacuole to increase the concentration of salts and sugars.

Question 16

Flashcard 16:
Q: What is the function of xylem in plants?

Answer 16

A: Xylem transports water and mineral ions upwards and provides structural support.

Question 17

Flashcard 17:
Q: Describe the structure of xylem vessels.

Answer 17

A: Xylem vessels are long cylindrical tubes with no end walls, thick lignified walls, and pits for lateral water movement.

Question 18

Flashcard 18:
Q: What is the function of phloem in plants?

Answer 18

A: Phloem transports sucrose and amino acids upwards and downwards within the plant.

Question 19

Flashcard 19:
Q: Describe the structure of phloem sieve tubes.

Answer 19

A: Phloem sieve tubes are living cells with cytoplasm, end walls with sieve plates, and companion cells, allowing efficient transport of organic molecules.

Question 20

Flashcard 20:
Q: What is transpiration?

Answer 20

A: Transpiration is the loss of water vapor from plant leaves through evaporation at the mesophyll cell surfaces followed by diffusion through the stomata.

Question 21

Flashcard 21:
Q: How do environmental conditions affect the rate of transpiration?

Answer 21

A: Temperature, wind speed, humidity, and light intensity affect the rate of water vapor diffusion out of the stomata and the rate of water uptake.

Question 22

Flashcard 22:
Q: What is the role of a potometer in plant studies?

Answer 22

A: A potometer measures the rate of water uptake in a shoot, which is almost the same as the rate of transpiration.

Question 23

Flashcard 23:
Q: What precautions should be taken when setting up a potometer?

Answer 23

A: Use a healthy shoot, cut the shoot underwater, ensure no air bubbles, dry the leaves, and acclimate the shoot to the experimental conditions.

Question 24

Flashcard 24:
Q: Describe how wilting occurs in plants.

Answer 24

A: Wilting occurs when the rate of water loss exceeds water absorption, causing cells to lose turgidity and become flaccid.

Question 25

**Flashcard 25:** Q: What adaptations do xerophytes have to reduce water loss?

Answer 25

A: Xerophytes have thick stems or leaves to store water, fewer stomata in pits, hairs on the epidermis, rolled leaves, smaller leaves, and may lose leaves during dry periods.

Question 26

**Flashcard 26:** Q: Define translocation in plants.

Answer 26

A: Translocation is the movement of sucrose and amino acids from production or storage regions to areas of utilization or demand in respiration or growth.

Question 27

**Flashcard 27:** Q: How do systemic pesticides move through a plant?

Answer 27

A: Systemic pesticides are absorbed through leaves, transported in the phloem, and ingested by pests, leading to their death.

Question 28

**Flashcard 28:** Q: How can the effects of temperature and humidity on transpiration be investigated?

Answer 28

A: Using a potometer, variation in temperature can be tested with heaters, and humidity effects can be tested by enclosing the plant in a plastic bag.