Page 30 - PRE-U STPM BIOLOGY TERM 1

Biology Term 1 STPM Chapter 2 Structure of Cells and Organelles

12. The size of these granules vary. These are the ATP synthase enzyme
that performs oxidative phosphorylation to produce ATP from ADP
and phosphate, in the presence of oxygen.
13. The colloidal interior of the mitochondria contains ribosomes, DNA,
RNA and a lot of enzymes, which are involved in the Krebs cycle and
the oxidation of fatty acids.
2
14. The functions of mitochondria are as follows:
(a) Mitochondria carry out Krebs cycle, part of cellular respiration
within their matrices.
(b) They carry out oxidation and complete breakdown of fatty acids
into carbon dioxide and water to produce ATP.
(c) They carry out oxidation and complete breakdown of amino
acids.
(d) They carry out oxidative phosphorylation, which produces ATP
from ADP and phosphate.
(e) They produce their own proteins from DNA with the help of
RNA. The proteins are those required for the oxidative process.
Golgi apparatus (Dictyosome in plant cells)

1. Golgi apparatus is an organelle consisting of a stack of flattened sacs, 2014
which produce vesicles full of secretion for internal or external uses.
2018
2. They are found in large numbers in glandular cells, neurones, muscle
tissues, root cap cells and meristems of plants. Their locations within
the cell are not fixed. They are formed from ER.
3. There is usually one of them per cell. However, there are many
in glandular cells and their number can increase as the secretory
activities increase. Meristem has more of them per cell.
4. Each consists of a stack of flattened sacs called cisternae, which are
rough and circular with a network of tubules around their periphery
as shown in Figure 2.19.

Vesicle budding off and moving
towards cell membrane
Cisterna

Inter–cisternal space
Network of
tubules

Sac from ER added to the
convex face

Figure 2.19 Golgi apparatus

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