Plant Transport

Question 1

What does xylem tissue consist of?

Answer 1

Hollow tubes

Question 2

What are the functions of xylem?

Answer 2

Transporting water and dissolved mineral ions from the roots to the leaves. Providing support for the plant. Xylem helps keep the plant upright.

This process is essential for plant hydration and nutrient distribution.

Question 3

What does phloem tissue consist of?

Answer 3

Living cells

Question 4

What are the functions of phloem?

Answer 4

Transporting sucrose. Transporting amino acids.

Sucrose is a key carbohydrate in plants.
Amino acids are vital for protein synthesis in plants.

Question 5

What are vascular bundles?

Answer 5

Transport tissue in plants made up of xylem and phloem.

Question 6

Where are xylem and phloem located?

Answer 6

Xylem and phloem are located in vascular bundles in different positions, depending on the part of the plant.

Question 7

What are dicotyledonous plants?

Answer 7

Flowering plants with two embryo leaves (cotyledons) in the seed, characterised by broad leaves with a network of veins.

Question 8

Where are xylem and phloem located in the cross-section of a stem?

Answer 8

When identifying xylem and phloem from a cross-section of a stem, remember phloem is always on the outside of the ring and xylem on the inside.

Question 9

Explain the positioning of xylem and phloem in different roots, stems and leaves

Answer 9

The position of xylem and phloem is different in roots, stems and leaves. In the stem their position gives protection against bending sideways due to wind.

Question 10

Provide examples of plant organs.

Answer 10

Leaves, roots the stem…

Question 11

What are the functions of root hair cells?

Answer 11

Root hair cells are adapted to absorb water and mineral ions from the soil. Their function is to increase the surface area of the roots for increased absorption of nutrients.

Question 12

Describe a microscopic image of root hair cells.

Answer 12

Question 13

Describe the pathway taken by water throughout a plant.

Answer 13

• root hair cells on the surface of a root
• root cortex cells inside the root
• xylem vessels from the roots, through the stem and into mesophyll cells in the leaf.
  soil -> root hair cells -> root cortex cells -> xylem -> mesophyll cells

Question 14

What is likely to happen if root cortex cells are damaged and water cannot pass through them?

Answer 14

The root cortex connects root hair cells and xylem. If water cannot pass through the root cortex it will not get into the xylem.

Question 15

What is transpiration?

Answer 15

The loss of water vapour from plant leaves by evaporation at the surface of mesophyll cells, followed by diffusion of water vapour through the stomata.

Question 16

All leaves have microscopic openings that allow loss of water by evaporation and diffusion of gases into and out of the leaves. What are these openings called?

Answer 16

Stomata?

Question 17

What are the two things that happen when

Question 18

What are the spongy mesophyll cells (the cells found between the upper epidermis and the lower epidermis of the leaf)

Answer 18

The site of gas exchange within a leaf. It is has a loosely packed (spongy) structure to create air spaces.

Question 19

What are the two processes of transpiration?

Answer 19

Evaporation at the surfaces of the spongy mesophyll cells (the cells found between the upper epidermis and the lower epidermis of the leaf) to form water vapour.
The loss of water vapour from the leaf by diffusion through the stomata.

Question 20

Explain Transpiration.

Answer 20

The cells in spongy mesophyll tissue are loosely arranged. This creates air spaces in the leaf and a large area of cell surfaces. These features allow for the rapid evaporation of water from the surface of mesophyll cells.

The air spaces in the mesophyll tissue are connected to stomata, through which water vapour diffuses out of the leaf

Question 21

Name an advantage and disadvantage of transpiration.

Answer 21

Advantage: it helps cool the plant on a hot day as water evaporates.

Disadvantage: the plant can lose too much water.

Question 22

What affects the transpiration rate.

Answer 22

An increase in temperature results in a high rate of transpiration. The higher temperature increases evaporation and this cools the plant.
Wind is moving air. It sweeps away water vapour from the surface of leaves surface. The faster the wind speed the more evaporation from the leaves.

Question 23

The loss of water from the leaf is through what process?

Answer 23

The process of diffusion.

Question 24

What’s a potometer?

Answer 24

Apparatus used to measure the uptake of water by a plant.

Question 25

As the temperature increases, the rate of transpiration increases. Why is this?

Answer 25

- water molecules gain energy - the rate of evaporation of water from the mesophyll cells increases - the diffusion of water through the stomata increases - the rate of transpiration increases.

Question 26

As the wind speed increases, the rate of transpiration increases. Why is this?

Answer 26

This is because the wind removes water vapour from just outside the stomata so the diffusion gradient is maintained and water continues to diffuse out.

Question 27

As the humidity increases, the rate of transpiration decreases. Why is this?

Answer 27

As humidity increases and the leaf is surrounded by moist air, the concentration gradient decreases resulting in less transpiration at a higher humidity.

Question 28

Wind blows away water vapour from around the leaves and reduces humidity. This results in an increase or decrease in the rate of transpiration.

Answer 28

Increase

Question 29

In which of the following conditions is the rate of transpiration higher? - Humid and still air - Humid and cold air - Dry and hot air - Cold and windy air

Answer 29

Dry and hot air

Question 30

How does a potometer work?

Answer 30

Question 31

Define turgidity.

Answer 31

Describes the point in a plant cell when the cell membrane presses against the cell wall due to high turgor pressure.

Question 32

Explain what occurs when a plants stems and leaves wilts.

Answer 32

Stems and leaves of young plants rely on the turgidity of their cells to remain upright and rigid. If plant cells lose more water than they are gaining, they become flaccid. Flaccid cells lose their rigidity and the stems and leaves wilt.

Question 33

What does it mean if a plant cells are flaccid?

Answer 33

A cell lacking water, therefore its cell membrane dosen't press against the cell wall.

Question 34

When a plant wilts, the stem can be described as what?

Answer 34

Flaccid

Question 35

What's Translocation?

Answer 35

The movement of sucrose and amino acids in phloem. They move from a source (where they are produced) to a sink (where they are stored or used in respiration or growth). ## Footnote Food crops grown on farms need to be transported to a factory for processing and storage. Think of phloem as a sugar highway transporting sugar to a storage region.

Question 36

How is the movement of substances in phloem and xylem different?

Answer 36

In xylem, the direction of movement is always from the roots to the leaves. In phloem, the direction of movement depends on the circumstances.

Question 37

In a plant, a sink can be:

Answer 37

- a region of storage - a region of use in respiration or growth.

Question 38

What is a source?

Answer 38

A source is a region of production in a plant. For example, glucose is made by photosynthesis in the leaves. It is then converted into sucrose for transport around the plant. In this example, the leaves are the source of sucrose.

Question 39

Considering the direction of translocation of a substance, what must you identify?

Answer 39

You need to identify its source and its sink.

Question 40

What does aerobic respiration mean?

Answer 40

Chemical reactions in cells in which nutrient molecules are broken down using oxygen to release energy.

Question 41

Glucose is created during photosynthesis and converted to __ for transport by phloem.

Answer 41

Glucose is created during photosynthesis and converted to sucrose for transport by phloem.

Question 42

The movement of substances, such as sucrose and amino acids, around a plant is called __.

Answer 42

The movement of substances, such as sucrose and amino acids, around a plant is called translocation.

Question 43

What term is used to describe the movement of sucrose and amino acids around a plant?

Answer 43

Translocation

Question 44

How is water absorbed? How are ions absorbed?

Answer 44

Water is absorbed by osmosis while ions are absorbed by active transport.

Question 45

What is active transport?

Answer 45

Active transport is the movement of particles through a cell membrane from a region of lower concentration to a region of higher concentration, which requires energy from respiration.

Question 46

What is osmosis?

Answer 46

The net movement of water molecules from a region of higher concentration to a region of lower concentration (along the concentration gradient) through a partially permeable membrane is osmosis and requires no energy.