- Cloning of plant tissues requires either a piece of the plant tissue through vegetative
propagation or chemical treatment to produce calluses in tissue culture propagation. - Cloning of animal tissues occurs through the process of reproductive cloning. It can
result in the replacement of a whole organism or, through therapeutic cloning the
creation of stem cells. - There are broad legal and ethical questions regarding cloning of organisms as well as
the use of stem cells. These differ from country to country.
The leaf as an organ
- Plant leaf is an example of an organ, as it consists of a group of tissues that form part
of a structural unit performing a common function. - Plant leaves are adapted to absorb light in order for photosynthesis to occur as well as
to manufacture sugars for transport to the rest of the plant. - The major processes for which leaves are therefore adapted are photosynthesis, tran-
spiration and gaseous exchange. Leaves transport oxygen, carbon dioxide, water and
sucrose. - Water is lost from the plant through transpiration out of stomata in the leaf. The move-
ment of carbon dioxide and oxygen is through diffusion in and out of the leaf. - Sugar manufactured in the leaf is transported through the phloem vessel.
- Stomata open and close in response to a variety of environmental stimuli.
Exercise 5 – 1: End of chapter exercises- Answer the following questions based on the drawings below.
a) Provide labels for 1, 2, 3 and 4.
b) Which tissue, A or B, is found in the rib cage?
c) Which tissue, A or B, is found in the lining of blood vessels?- Tissues come together to form a/an
a) organ
b) organ system
c) body system
d) organelle - What kind of tissue can parenchyma tissue be described as being?
a) simple tissue
b) complex tissue
c) xylem
d) phloem
Chapter 5. Plant and animal tissues 155