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arise when an individual or organization faces a situation in
which different moral principles conflict, or where there is no
clear "right" answer. Legal issues, meanwhile, come into play
when actions conflict with established laws or legal norms. The
challenge arises in balancing both ethical and legal
considerations when making decisions.### 2. **Ethical Issues
in Healthcare**Healthcare is one of the sectors where ethical
and legal issues are particularly pronounced. Medical
professionals regularly face situations that require them to
make complex decisions that not only have life-altering
consequences for patients but also raise profound moral
questions. These issues include:#### 2.1 **Patient Autonomy
and Informed Consent**One of the fundamental ethical
principles in healthcare is respect for patient
CONTENTS
‗O‘ LEVEL BIOLOGY
Unit Description Page
1 Cells 1
2 Movement of Substances 10
3 Nutrients 19
4 Enzymes 27
5 Nutrition in Humans 36
6 Nutrition in Plants 51
7 Transport in Humans 60
8 Transport in Plants 72
9 Respiration 80
10 Excretion 87
11 Homeostasis 97
12 The Nervous System 105
13 The Human Eye 113
14 Hormones 121
15 Reproduction in Plants 129
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16 Reproduction in Animals 137
17 Cell Division 146
18 Heredity 152
19 Molecular Genetics 160
20 Ecology 166
21 Our Impact on the Ecosystem 173
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Unit 1
Notes
Cells are the building blocks of life. They are the simplest units that have all the characteristics of life.
What does a cell consists of?
mitochondrion
lysosome
golgi
vesicle apparatus
rough
endoplasmic
reticulam nucleus
smooth
endoplasmic
reticulum centrioles (2)
each composed of 9
microtubule triplets
cell (surface)
membrane cytoplasm
ribosome
Parts of an animal cell
cell wall
cell
vesicle surface membrane
golgi
apparatus
chloroplast
tonoplast
vacuole
mitochondrion
Parts of a plant cell
1
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Part of a cell Function
Cellulose cell wall (plant cell) Non-living, thick, rigid layer around the cell membrane
Helps the plant to support itself
Vary the shape of the cell – angular, rectangular or rounded
Permeable – allows all substances to move in and out of the cell
Cell surface membrane Surrounds the cytoplasm – keeping cells separate from one another
Made up of layers of lipid and protein – 0.00001 mm thick
Semi-permeable – allows only some substances to move in or out of
the cell
Nucleus Controls all activities of the cell
Round and surrounded by two membranes which together form the
nuclear nuclear membrane
envelope
nucleolus (Note: Nuclear membrance has several nuclear pores to allow nuclear
nucleoplasm material to pass through.)
chromatin Contains chromosomes and nucleolus
Chromosomes
Parts of a nucleus
Made up of chemical DNA – provides information for the formation of
proteins in cells
Nucleolus
Spherical structure involved in cell division
Produces RNA – takes information from the DNA out of the nucleus to
make proteins in the cytoplasm
Centrioles Paired cylindrical organelles near the nucleus
Composed of nine tubes – each with three tubules
Involved in cellular division
Cytoplasm Made up of 75% water and 25% structures
Structures can be inclusions or organelles
Inclusions
Substances that are stored temporarily in the cell which includes fat
globules and starch grains
Organelles
Permanent structures that are important for life of the cell
Help to carry out all its activities
Make useful substances that can be exported to other cells
Mitochondrion Also known as the ‗power house‘ of the cell
Generates energy that is needed to keep the cell‘s essential living
processes going
Energy is produced on the folded inner membrane by a process called
internal or cellular respiration
Quantity present in the cell depends on the cell‘s activities – muscle
cells contain more mitochondria than other parts of the body
Endoplasmic reticulum (ER) Rough ER
nuclear rough endoplasmic
reticulum flattened space Contains ribosomes attached to its surface
envelope
(filled with fluid)
tube of smooth Smooth ER
endoplasmic reticulum
No ribosomes attached; connected to rough ER and more tubular than
ribosome rough ER
Synthesises substances such as fats and steroids
Parts of an endoplasmic reticulum
Converts harmful substances into harmless materials – detoxification
‘O’ Level Biology 2
eskulu.com - The Free Zambian Online School
arise when an individual or organization faces a situation in
which different moral principles conflict, or where there is no
clear "right" answer. Legal issues, meanwhile, come into play
when actions conflict with established laws or legal norms. The
challenge arises in balancing both ethical and legal
considerations when making decisions.### 2. **Ethical Issues
in Healthcare**Healthcare is one of the sectors where ethical
and legal issues are particularly pronounced. Medical
professionals regularly face situations that require them to
make complex decisions that not only have life-altering
consequences for patients but also raise profound moral
questions. These issues include:#### 2.1 **Patient Autonomy
and Informed Consent**One of the fundamental ethical
principles in healthcare is respect for patient
CONTENTS
‗O‘ LEVEL BIOLOGY
Unit Description Page
1 Cells 1
2 Movement of Substances 10
3 Nutrients 19
4 Enzymes 27
5 Nutrition in Humans 36
6 Nutrition in Plants 51
7 Transport in Humans 60
8 Transport in Plants 72
9 Respiration 80
10 Excretion 87
11 Homeostasis 97
12 The Nervous System 105
13 The Human Eye 113
14 Hormones 121
15 Reproduction in Plants 129
eskulu.com - The Free Zambian Online School
,goto eskulu.com for more
16 Reproduction in Animals 137
17 Cell Division 146
18 Heredity 152
19 Molecular Genetics 160
20 Ecology 166
21 Our Impact on the Ecosystem 173
eskulu.com - The Free Zambian Online School
, goto eskulu.com for more
Unit 1
Notes
Cells are the building blocks of life. They are the simplest units that have all the characteristics of life.
What does a cell consists of?
mitochondrion
lysosome
golgi
vesicle apparatus
rough
endoplasmic
reticulam nucleus
smooth
endoplasmic
reticulum centrioles (2)
each composed of 9
microtubule triplets
cell (surface)
membrane cytoplasm
ribosome
Parts of an animal cell
cell wall
cell
vesicle surface membrane
golgi
apparatus
chloroplast
tonoplast
vacuole
mitochondrion
Parts of a plant cell
1
eskulu.com - The Free Zambian Online School
, goto eskulu.com for more
Part of a cell Function
Cellulose cell wall (plant cell) Non-living, thick, rigid layer around the cell membrane
Helps the plant to support itself
Vary the shape of the cell – angular, rectangular or rounded
Permeable – allows all substances to move in and out of the cell
Cell surface membrane Surrounds the cytoplasm – keeping cells separate from one another
Made up of layers of lipid and protein – 0.00001 mm thick
Semi-permeable – allows only some substances to move in or out of
the cell
Nucleus Controls all activities of the cell
Round and surrounded by two membranes which together form the
nuclear nuclear membrane
envelope
nucleolus (Note: Nuclear membrance has several nuclear pores to allow nuclear
nucleoplasm material to pass through.)
chromatin Contains chromosomes and nucleolus
Chromosomes
Parts of a nucleus
Made up of chemical DNA – provides information for the formation of
proteins in cells
Nucleolus
Spherical structure involved in cell division
Produces RNA – takes information from the DNA out of the nucleus to
make proteins in the cytoplasm
Centrioles Paired cylindrical organelles near the nucleus
Composed of nine tubes – each with three tubules
Involved in cellular division
Cytoplasm Made up of 75% water and 25% structures
Structures can be inclusions or organelles
Inclusions
Substances that are stored temporarily in the cell which includes fat
globules and starch grains
Organelles
Permanent structures that are important for life of the cell
Help to carry out all its activities
Make useful substances that can be exported to other cells
Mitochondrion Also known as the ‗power house‘ of the cell
Generates energy that is needed to keep the cell‘s essential living
processes going
Energy is produced on the folded inner membrane by a process called
internal or cellular respiration
Quantity present in the cell depends on the cell‘s activities – muscle
cells contain more mitochondria than other parts of the body
Endoplasmic reticulum (ER) Rough ER
nuclear rough endoplasmic
reticulum flattened space Contains ribosomes attached to its surface
envelope
(filled with fluid)
tube of smooth Smooth ER
endoplasmic reticulum
No ribosomes attached; connected to rough ER and more tubular than
ribosome rough ER
Synthesises substances such as fats and steroids
Parts of an endoplasmic reticulum
Converts harmful substances into harmless materials – detoxification
‘O’ Level Biology 2
eskulu.com - The Free Zambian Online School
