SCIENCE 1(FDC 114)

STRUCTURE AND FUNCTION OF CELLS,
TISSUES AND ORGANS
The cell
Is the basic unit of life. It was discovered by
Robert Hook in 1665. Is the basic unit of life
because it can carry out life activities such as
feeding, excretion, reproduction, etc
Living things which are made up with one cell
are called UNICELLULAR organisms and those
with two more cells are called MULTCELLULAR
organisms.

BOTH PLANTS AND ANIMALS CELLS HAVE
THESE IN COMMON
1. Cytoplasm
2. Cell membrane
3. Mitochondria
4. Ribosome
5. Endoplasmic recticulum
6. Nucleus

DIFFERENCES
1. PLANTS
a. Have cellulose cell wall
b. Stores food as starch
c. Cells have definite shapes
d. Have less dense protoplasm
2. ANIMALS
a. Have No cellulose cell wall
b. Stores food as glycogen
c. Cell have No definite shapes
d. Have dense protoplasm

SPECIALIZED CELLS
These are structurally adapted to perform a
specific function.
Specialized cells in plants include –
1. Palisade mesophyll cell
2. Root tip cells
3. Leaf epidemics
Specialized cells in animals include –
1. Nerve cells
2. Muscle cells
3. Red blood cells
4. A sperm cells

TISSUES
A Tissue is a group of specialized similar cells
that perform the some function.
Examples of plant tissues
1. Epidermal tissue
2. Vascular tissue
3. Photosynthetic tissue
4. Strengthening tissue
Examples of animals tissue
1. Skeletal tissue
2. Muscle tissue
3. Nerve tissue
4. Blood tissue

ORGANS
An organ is a group of different tissues which
perform the same function or functions.
Examples of plants organs includes
1. Leaf
2. Root
3. Stem
Examples of animals organs are
1. kidney
2. Heart

ORGAN SYSTEM
These consists of two or more organs working
together to perform a specific function.
Examples of plants organ system include
1. Root system
2. Shoot system
Examples of animals organ system include
1. Circulatory system
2. Sensory system
3. Digestive system

ORGANISMS
The coordination of the organ system to carry
out life processes.
The levels of cell organization in plants and
animals
Cells>tissues>organs>organ
systems>organisms.

HEALTH AND DISEASES
Disease
Is is any disorder which interferes with normal
functioning of the body of an organism.
They are two groups of disease,
infectious and non-infectious diseases
Diseases which are caused by pathogens which
enter the body and trigger the development of
an infection is called infectious disease
These diseases are communicable or
contagious.
They can be transfer / passed from person to
person.
Non-infectious diseases Are not caused by
pathogens and therefore cannot be transfer
from person to person. Examples are
kwashiorkor, asthma and diabetes.
The period between entry of pathogen and the
start of the disease is known as the period of
incubation .
Differences between infectious and non-
infectious diseases
1. Infectious disease can be treated by killing
the germ, whiles Non-infectious can be treated
by the supply of deficient nutrient.
2.Infectious disease are caused by micro-
organism whiles Non is caused by lack of an
enssential food nutrient.
3.Infectious can be transmitted from person to
person while Non can not be transmitted.
IMMUNITY
Is s state in which the body is protected from
infectious diseases.
These state can be conferred by the immune
system.
Immunity can be :
1. Natural or artificial
2.Innate or acquired
3.Active or passive
It can also be mix and match to produce.
Examples :natural passive or artificial passive.
Immunization
Is the process by which an individual immune
system become fortified against a disease
causing agent.
Antigens
They are substances that under appropriate
conditions induce the formation of antibodies.
Is also any substance capable of triggering
immune response.
They have got antigenic determinants.
Antiseptic
Is any variety of agents apply to living tissues
to inhibit the growth of infectious micro-
organisms.
Many antiseptics inhibit specific types or forms
of micro-organisms.
Antibiotics
Is described as any substance produced by a
micro-organism that is antagonistic to growth
of other micro-organism in high dilution
(Waksman 1942)
It can also be a substance or compound that
kills or inhibits the growth of bacteria.
Many antibiotics are relatively small molecules
with a molecular weight less than 2000.
Differences between antiseptic and
antibiotics
1.Antiseptic is used externally while Antibiotics
are used internally.
2.Antiseptic are used to prevent infections
while Antibiotics are used to treat infections.
Congenital and Genetic Diseases
congenital diseases include
1.Congenital Physical abnormaly
2.Congenital Metabolic disorder
3.Congenital Malformation
4.Congenital Disorder
Causes
* Cell division
*Antibodies
Genetic diseases include
1.Mental illness
2. Y-linked
3.X-linked recessive
4.Mitochondrial disease
5.X-link Dominant
6.Single genetic disorder
7.Autosomal Dominant
8.Autosomal recessive
9.Neurosis

RESPIRATORY SYSTEM OF HUMAN

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