5. Transport in plants

Question 1

Plant cells, like animal cells, need a regular supply of

Answer 1

oxygen and nutrients

Question 2

All plants are multicellular and some of them are very large. Most plants however, have a much more branching shape than animals, and this provides

Answer 2

a much larger surface area: volume ratio for exchange with their environment than in an animal of the same
body mass

Question 3

The requirements of plants differ from those of

animals in several ways, both in

Answer 3

the nature of the nutrients and gases required and the rate at which these need to be supplied

Question 4

requirements plants need (4)

Answer 4

Carbon dioxide during daylight
oxygen for respiration
Organic nutrients
Inorganic ions and water

Question 5

Plants photosynthesise in sunlight and produce sugars that are used as

Answer 5

food

Question 6

Sugars produced by plants are converted to

Answer 6

useful metabolites necessary for plant growth

Question 7

The phloem transports

Answer 7

sugar and other organic substances from the site of production to parts of the plant where they are stored or metabolised

Question 8

Translocation is

Answer 8

the transport of the products of photosynthesis via the phloem

Question 9

What is the by-product of photosynthesis?

Answer 9

oxygen

Question 10

Transpiration is

Answer 10

the loss of water from the plant leaves

Question 11

what helps regulate the rate of transpiration

Answer 11

Stomata help regulate the rate of transpiration

Question 12

Roots absorb water and minerals from where?

Answer 12

the soil

Question 13

Water and minerals are transported from the roots to the leaves and stems via the

Answer 13

xylem

Question 14

A mineral is

Answer 14

an inorganic substance usually containing two or more elements

Question 15

Flowering plants have specialised transport systems for water and nutrients, but do not have one for oxygen and carbon dioxide because

Answer 15

These gases simply diffuse through air spaces within the plant body – even through seemingly solid structures like the trunks of trees

Question 16

Transport is the movement of substances throughout the bodies of organisms. This is achieved by specialised tissues and organs that make up transport systems. These are

Answer 16

mammals – circulatory system consisting of blood, blood vessels and a heart

flowering plants – transport systems consisting of xylem tissue and phloem tissue

Question 17

transport systems rely on

Answer 17

the movement of fluids inside tubes in a single direction. This type of transport is known as mass flow

Question 18

The regions of xylem and phloem in stems and leaves are known as

Answer 18

vascular bundles

Question 19

how Aquatic plants get carbon dioxide

Answer 19

Aquatic plants get carbon dioxide from the water that surrounds them.

Question 20

what do plant cells that do not photosynthesise need

Answer 20

organic nutrients from photosynthetic or storage cells

Question 21

All plant cells require a range of inorganic ions and also water that are taken up from

Answer 21

the soil, by roots, and are transported to all areas of the plant

Question 22

why plants have a much slower transport system?

Answer 22

The energy requirements of plant cells are, on average, far lower than those of cells in a mammal.

This means that their rate of respiration and, therefore, their requirement for oxygen and glucose are considerably less than those of mammals.

Question 23

Plants have evolved thin, flat leaves which present

a

Answer 23

large surface area to the Sun

Question 24

why plants don’t need a transport system to carry gases

Answer 24

Plants have evolved thin, flat leaves which present a large surface area to the Sun. This also makes it easy for oxygen and carbon dioxide to diffuse into and out of the leaves, reaching and leaving every cell quickly enough so that there is no need for a transport system to carry gases

Question 25

the 2 transport systems in plants

Answer 25

xylem- for carrying mainly water and inorganic ions from the roots to the parts above ground

phloem- for carrying substances made by photosynthesis from the leaves to other areas

Question 26

why plants don’t need a transport system for gases

Answer 26

Neither plant transport system carries oxygen or carbon dioxide, which travel to and from cells and the environment by diffusion alone

Question 27

mass flow is the

Answer 27

bulk transport of materials from one point to another as a result of a pressure difference between two points

Question 28

osmotic pressure (OP) is the

Answer 28

pressure a solution generates when enclosed within an osmometer and allowed to come to equilibrium with pure water

Question 29

guttation is the

Answer 29

loss of liquid water from the surface of a plant

Question 30

why long-distance mass-flow transport systems have been developed

Answer 30

unicellular organisms and individual cells of multicellular organisms possess a large surface-area-to-volume ratio.

Efficient exchange of materials between these cells and their environment takes place by diffusion, active transport and endo and exocytosis.

The distances that materials travel within the cell are small enough for diffusion and cytoplasmic streaming to be fast and efficient.

However, in the bodies of large multicellular organisms different cells are far apart from each other and/or their external environment and diffusion is inadequate. Thus long-distance mass-flow transport systems have been developed.

Question 31

If an organism is small and has a large surface area to volume ratio, all the nutrients and respiratory gases can be taken in by

Answer 31

diffusion across the body surface

Most multicellular plants and animals have too small a surface area to volume ratio so diffusion would be too
slow to provide the necessary molecules.
Therefore, they require a system to transport nutrients and waste products around the organism

Question 32

Plants can be very large, but they have a branching shape that helps to

Answer 32

keep the surface area-to-volume ratio fairly large

Question 33

Their energy needs are generally small compared with those of animals, so respiration does not take place so quickly.

They can therefore rely on

Answer 33

on diffusion to supply their cells with oxygen and to remove carbon dioxide

Question 34

plant leaves are very thin and have a large surface area inside them in contact with the air spaces. This means that

Answer 34

diffusion is sufficient to supply the mesophyll cells with carbon dioxide for photosynthesis, and to remove oxygen