Page 34 - Biology_F5

Cytology

are particularly predominant in the liver and of germinating seeds and in filamentous
kidney cells of vertebrates, while in plants fungi. Glycosomes are microbodies which
they are found mostly in plant cells where contain glycolytic enzymes in its matrix,
photorespiration occurs. Glyoxosomes and they are believed to have evolved from
are specialised microbodies found in the peroxisomes. They are found in few
plants, particularly in fat storage tissues species of protozoa, such as Trypanosoma.
FOR ONLINE READING ONLY

Figure 1.33 Structure of the zwitterion

Crystalline core

Lipid bilayer
Figure 1.34 Formation of dipeptide molecule linked by the peptide bond

Figure 1.15: Structure of microbody

Functions of microbodies into carbohydrate, especially in
(a) Microbodies, such as peroxisomes germinating seeds.
found in plant and animal cells, (d) Microbodies also help in conversion

are involved in the breakdown of of stored lipid in germinating oil

poisonous hydrogen peroxide to seeds and liver cells into glucose in

water and oxygen in the presence of the process called gluconeogenesis.

peroxidase enzyme.

Golgi apparatus

The name of this organelle was derived
(b) The peroxisomes contain enzyme from its founder, Camillo Golgi, in 1898.
glycolic acid oxidase that oxidises He identified it in the nerve cells of the
glycolic acid, a product of owl and cat. This happened long before the
photosynthesis, to glyoxylic acid, by discovery of the endoplasmic reticulum.
the process called photorespiration. Golgi apparati are involved in important
cellular functions, such as biosynthesis
(c) In plants, there is special microbody of polysaccharides, packaging of cellular
called glyoxysomes that are the centre synthetic products, production of
for the glyoxylate cycle. Glyoxylate exocytotic vesicles, and differentiation of
cycle involves conversion of fats

Form Five Student’s Book
27