Page 62 - PRE-U STPM BIOLOGY TERM 1

Biology Term 1 STPM Chapter 2 Structure of Cells and Organelles

2. (a) Distinguish the chromosome of a bacterium with that of a eukaryote. [4]
(b) Describe the structure and functions of the Golgi apparatus with the help of a labelled
diagram. [11]
3. (a) Two ultra-structures of xylem are important in transport and mechanical support.
Explain. [6]
(b) Describe the distribution and functions of three types of simple epithelia. [9]
4. Explain the meaning of meristem. Describe the structure, locations and functions of different
types of meristem with reference to suitable examples. [15]

ANSWERS

1 (e) Both have ribosomes. They are required to
produce proteins especially enzymes to control
1. They are simpler and smaller cells. They contain fewer cellular reactions.
genes, unable to carry out complicated processes at the
same time. They contain fewer organelles, not capable 3
of carrying out reactions in compartments with little
or no interference. They have no enveloped organelle 1. Both contain DNA with genes and ribosomes, capable
like nucleus, mitochondria and chloroplast where of independent survival like bacteria. They can divide
specialised processes occur with high efficiency. Their like bacteria. Mitochondria require pyruvic and other
cell wall is less rigid to support greater load. organic acids, ADP, phosphate, NADH to produce
ATP required by the cell. Chloroplasts require carbon
2. They can be both autotrophs and heterotrophs. dioxide and mineral ions to produce glucose and fatty
Autotrophs can be photoautotrophs which are capable acids for the cells.
of photosynthesis, and chemoautotrophs which are
capable of chemosynthesis. Heterotrophs can be 2. Nucleus contains DNA that codes for the production
saprophytes which feed on ‘dead’ organic substances, of enzymes. It is the place where RNA and ribosomes
or parasites that feed on ‘living’ organic substances. are also produced. The mRNA from the nucleus
is translated by the ribosomes on the rough ER to
become proteins inside its cisternae. From here the
2 proteins will be sent to the Golgi apparatus where they
are packed in the form of vesicles for export out of the
1. (a) Both have cytoplasm. It is the cell body where all cell. However, if the proteins exported are hydrolases,
reactions of the cells occur. they are required to be packed like lysosome so the
(b) Both have nucleus. It contains DNA and genes, hydrolases will not digest the membrane packing them.
which are required to control all cellular activities
through the productions of proteins. 4
(c) Both have plasma membrane. It is the structure
15
that controls the exchange of substances between 1. Radioactive DNA contains N instead of the normal
the cell and the environment. 14 N. As a result, the radioactive DNA is heavier than
(d) Both have mitochondria. They are the power the normal DNA. Such minor weight difference can be
generators of the cell where they produce ATP as separated by ultra-centrifuge, which revolves 100,000
energy source for cellular activities. times gravitational force.

107

02[STPM Bio T1].indd 107 3/29/18 5:08 PM