Download Science Department Fourth Primary General Revision Unit one 1

Science Department
Fourth Primary
General Revision
Unit one
1- Human Digestive System
Living organisms which all have common properties and
characteristics such as nutrition, transport, respiration, excretion,
motion, sensation, reproduction...etc.
The structure of the living organism body
- A living organism body is made up of a set of systems.
- The human body is made up of a number of systems.
- Each system performs a certain function.
For examples:
1- The digestive system: digests and absorbs food.
2- The respiratory system: carries out the process of breathing.
3- The circulatory system: distributes the digested food and oxygen
all over the body cells.
4-The urinary system: helps the body get rid of harmful substances.
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5-The nervous system: lets us have the ability to feel, hear, see,
smell, and taste,
6- The reproductive system: makes us give birth for new
individuals who will look like us.
All these systems are working in full harmony and integrity together
to keep the human life goes on.
1. Mouth.
2. Esophagus.
3. Stomach.
4. Pancreas.
5. Liver.
6. Small intestine.
7. Large intestine.
8. Rectum.
9. Anus
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Digestion: Changing the food from a complex form into a simple one
to let the body get benefited.
Digestive system in a human being is made up of a set of organs which
contact with each other in a shape of a long pipe (duct) known as the
digestive canal with length of 9 - 10 m this canal starts with the mouth and
ends in the anus.
There are three types of glands are connected with this canal:1- The salivary glands.
2- The liver.
3- The pancreas.
(1) Mouth:The mouth is a cavity in where teeth and
tongue are existed and the salivary glands open
to it.
•Teeth:The teeth number in an adult is 32, each jaw has 16 teeth divided into
(4 incisors, 2 canines and 10 molars).
- Incisors and canines cut and tear food into small pieces.
- Molars grind the food to ease its swallowing
process.
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•Salivary glands :They are three pairs of glands secrete a liquid known as the saliva which
contains digestive substances called enzymes that digest starches, and
convert them into sugars.
•Tongue:It mixes food with saliva and help in the swallowing process.
(2) Pharynx:Is a common cavity leads to the esophagus and trachea.
(3) Esophagus:Is a muscular tube that allows food to pass from mouth and pharynx to
your stomach.
(4) Stomach:A muscular sac works on mixing food up by its
digestive juices. After a few hours food changes
into semi - liquid substance, in where an
incomplete digestion of protein takes place
by
a gastric juice, and then food travels to the small intestine.
(5) Small intestine:Its length is about seven meters; (7m) it coils inside the abdominal cavity.
It starts with a part known as duodenum.
- The bile juice (secreted by liver) is poured in it.
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Bile juice: helps to digest fats where it changes fats into a fatty
emulsion.
- The pancreatic juice (produced by pancreas) is poured in it.
- Duodenum is followed by a part of the small intestine known as ileum.
Intestinal juice is poured in the ileum where the digestion to different
types of food is completed.
• Absorption
Digested food is absorbed through the small intestine walls then it reaches
blood which distributes it all over the body organs.
(6) Large Intestine:Starts from the end of small intestine ending in the anus which is located
at the end of the rectum. Water is absorbed in rectum from food remains,
and then these wastes are ejected outside the body through the anus.
Keeping The Digestive System Healthy:1- Chew the food well.
2- Don't eat much food that contains large amounts of fats such as fast
meals.
3- Skip having food containing the additive compounds and flavorings.
4- Skip purchasing food from streets to avoid infectious diseases.
5- Practice sports regularly.
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2- Human Respiratory System
Man requires the process of respiration to get the needed energy from
nutrients in order to enable the body systems doing their different
functions such as transport, motion, excretion, sensation ...etc
Structure of Respiratory System.
Respiratory system consists of:
1- The nose. 2- The pharynx. 3- The trachea. 4- The two bronchi.
5- The two lungs. 6- Diaphragm.
(1) Nose:It is lined with:
1- A mucous layer: to obstruct and filter dust and microbes from air.
2- Hairs: to obstruct and filter dust and microbes from the air.
3- Blood capillaries (tiny blood vessels): to warm the air.
(2) Pharynx:A common cavity leads to the esophagus and trachea.
(3) Trachea:- Is a tube supported with:
a. incomplete cartilaginous rings: make it permanently open.
b. lined with cilia: to eject up (sweep out ) the strange objects.
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- At the top of trachea are the larynx (voice box) and epiglottis which
closes off the opening trachea during swallowing, to forbid (prevent) food
entering the trachea.
- The bottom of the trachea branches into two narrow tubes called bronchi
enter the lungs.
(4) Lungs:- Bronchus is divided into bronchioles inside each lung ending in alveoli
(air sacs) which is surrounded by a network of blood capillaries in where
gas exchange occurs.
- The two lungs occupy the thoracic (chest) cavity and they are surrounded
by the ribs.
Diaphragm: separates the thoracic (chest) cavity from the abdominal
cavity. OR separates the digestive system and the respiratory system.
Respiration: is the process in where the air rich in oxygen enters into the
two lungs and the air rich in carbon dioxide released outside the two lungs.
The more active your body is, the more your respiration times increases.
Respiration process = Inhalation + Exhalation
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Mechanism of Respiration
1- Process of inhalation:
- The diaphragm muscle contracts and moves down and the thoracic cavity
enlarges.
- The air rich in oxygen enters the two lungs through the nasal passage
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2- Process of exhalation:
- The diaphragm muscle relaxes and moves up and the thoracic cavity
becomes narrow.
- The air rich in carbon dioxide moves outside the lungs through the nasal
passage.
Exchange of gases:
Exchange of gases occurs between the air existed in alveoli and the blood
flows in the capillaries via their thin walls where blood leaves carbon
dioxide and carries the oxygen and distributes it all over the body cells.
Components of exhaled air:
Exhalation air contains carbon dioxide and water vapour as products of
respiration process.
Keeping the respiratory system healthy:1- Skip being in crowded or poor ventilation places.
2- Keeping off the severe cold.
3- Having fruits rich in vitamin (c) such as oranges, guava to protect
yourself from cold.
4- Stop smoking or being a passive smoker.
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3- The cell
What is an organ made up of ?
An organ is made up of similar or different tissues
- Tissue is made up of a symmetric set of cells.
- Plants are also made up of organs such as roots, stems and leaves.
- Each organ is made up of tissues and every tissue is made up of
symmetric units known as cells.
- The animal cell is the building unit of an animal body.
- The plant cell is the building unit of a plant body.
- The epidermis tissue of the onion plant leaf is made up of similar units
known as the plant cells.
The cell: is the building unit of the living organism body.
The cell simplified structure
All cells contain:
1- Nucleus: organizes the biological operations inside the cell and it is in
charge of cell division.
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2- Cytoplasm: Fill the space and biological operation are acted by it.
3- Plasma Membrane: surrounds the cell and controls the substances
entering into the cell or leaving it.
The plant cell is characterized by the presence of:
- A cell wall surrounding it.
- Chloroplasts which are responsible for making food in a process known
as photosynthesis.
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Unicellular organisms
There are a lot of unicellular micro- organisms around us which can't be
seen by the naked eye such as bacteria and yeast.
- The unicellular organism is a model to the cell ability as a unit of
structure and function of a living organism body.
- The unicellular organism is considered as an integrated living thing has
the ability to do all the biological functions and it.
Structure of yeast fungus: It is an unicellular living organism that
made up of (a) nucleus. (b) Cytoplasm and (c) a cell wall that
determines the cell shape.
Economic importance of the yeast fungus:
- Yeast fungus is used in a
lot of industries such as:
1- Making bread.
2- Making alcohol.
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4- The importance of sunlight to living organisms
A lot of animals depend mainly on plants to get their food. Plants supply
animals with the required energy for survival. For example, we see cows
and sheep feed on the plants, and birds feed on the seeds of some plants.
How do plants manufacture their food?
Plants manufacture their food
Plant cells contain chloroplasts which give the plants the green color and
absorb sunlight as well.
Plants absorb: 1- Light energy of the sun.
2- Water and mineral salts from the soil.
3- Carbon dioxide from the air in order to form their food.
(This process is known as photosynthesis)
Photosynthesis Process: A biological process takes place in the plant
green parts to make a food of carbohydrates and starches in the existence
of sunlight, water, carbon dioxide and some mineral salts.
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Products of photosynthesis.
Plants make their food (starch-carbohydrates) through the process of
photosynthesis in the existence of sunlight, water, and carbon dioxide.
Releasing Oxygen
Oxygen is released during the process of photosynthesis
Green plants are called producers.
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Examples of producers:
• Green plants - algae.
Examples of consumers:
• Cows, sheep and chicken ... feed on producers (direct consumer)
(Herbivores consumer).
• The lion, snake, hawk.... feed on consumers that previously feed on
producers. (Indirect consumer) (Carnivores consumer)
Decomposers:
Are living organisms can't make their food by themselves since
chloroplasts are not existed in their cells.
Decomposers get their food through decomposing the organic wastes such
as dead bodies, plant remains and decayed food.
Examples of decomposers:
1- Some types of bacteria.
2- Some fungi such as bread mold fungus.
Importance of decomposers:
1- Help us get rid of the organism's dead bodies and the plant remains.
2- Increase the soil fertility.
3- Used in a lot of industries.
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5- Energy paths through living organisms
Food chain:
Is a path that the energy transmits in a form of food from a living
organism to another one.
Food chain begins with a producer then consumer then carnivore’s then
decomposer.
Food chain:Producer
Consumer (1)
Consumer (2)
Decomposer
Food webs:
Food web is a group of overlapping food chains representing the flow of
energy through living organisms in the form of food.
Energy paths:
Are paths showing the energy transference in the form of food from living
organism into another within
the food web.
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Unit two
1- Force and its effect
- The motion of the car and its stopping needs an effect.
- The motion of the bicycle and its stopping needs an effect.
Force:
It is an effect that changes from the state of the object.
- The Force is measured by "Newton" unit.
You knew from the first term that the measuring unit of length is meter
and like this the measuring unit of force is Newton related the scientist
"Isaac Newton".
- Games depend on the effect of force:
1- Pulling rope game
2- Balloon and rocket game
- The motion increases by increasing the force.
- Force causes the motion of objects and their rising.
Technological applications:
- There are a lot of technological applications that depend
its motion on the effect of the motor pushing force such as:Home equipments (mixer - electric fan – electric sewing machinewashing machine)
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- There are a lot of technological applications that depend its motion on
the effect of the Engine pushing force such as:Some means of transport (cars- metro – train)
- There are technological applications that their operation depend on the
effect of force in rising of heavy objects such as:
1- Crane, electric lift, escalator and fishing tools
These machines contain:
Pulleys that make the motion easy
Gears that transfer the motion.
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Answer school book page 41
Question (1) 1- (a) .
2- (c).
3- (b).
4- (a).
5-(c).
Question (2) 1- oxygen. 2- Iodine solution. 3- sunlight, water , CO2 and
mineral salts.
Question (3)
consumer : dog-lion-human.
producers: corn plant – green algae
decomposers: yeast fungus – yoghurt bacteria.
Question (4)
1-bec they * Help us get rid of the organism's dead bodies and the plant
remains. * Increase the soil fertility.
* Used in a lot of industries.
2- To absorb the sunlight in order to make photosynthesis process.
Question (5)
Producers
Living organisms
can make its food
through
photosynthesis
process
As ( algae – corn)
Consumers
Living organisms that
feed on another living
organisms directly or
indirectly.
As( deer – cow –
rabbit –lion- tiger-owl)
decomposers.
Living organism obtain
its food through
decompose dead bodies
and can’t make its food
through photosynthesis
process as( bacteria)
Answer school book page 49
Question (1) 1- decomposers. 2- food chain. 3- producers.
4- the sun (photosynthesis process).
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Question (2) desert environment
Green plant
rabbit
snake
Hawk
aquatic environment
Aquatic plant
water beetle
fish
shark
Question (3)
1- Bec. they can make “produce” their own food by themselves by the
photosynthesis process .
2- bec.it can make their own food by themselves by the photosynthesis
process .
Question (4)
1- hawk is consumer
2-
wheat plant
wheat plant is producer
rat
snake
Hawk
3-the energy will transfer from wheat plant to rat then to snake and then to
the hawk.
4- it will die and decomposers will feed on them.
Question (5)
wheat plant
cow
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human
Answer general exercises on unit (1) school book page 51
Question (1): Complete the following sentences:
1- oxygen , carbon dioxide.
2- organs , tissues. 3- stomach , small intestine. 4- decomposers.
5- food web. 6- intestinal juice , bile juice. 7- producers , green plant.
8- yeast fungus.
9- solar , chemical. 10- consumers.
Question (2):Choose the correct answer :
1- (d).
2- (c).
3-(b).
Question (3) 1- (1).
4-(c).
5-(c).
6-(a).
2- it produce bile juice that digest fats.
3-(5) small intestine.
Question (4)
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Question (5) plant cell only has cell wall and chloroplasts.
Question (6)
Green plant
cow
Question (7) salivary glands : saliva.
lion
liver : bile juice.
Question (8)
1- cell.
3- bile juice. 4- green plastids “chloroplasts”
2- saliva.
5- producers. 6- food chain.
7- food web.
Question (9)
1- plant will not be able to absorb the sunlight and can’t make
photosynthesis process.
2- the dead bodies will be all over the Earth.
3- Food will not be completely digested and will not be absorbed.
4- food will enter the trachea and the person will die.
5- air will not filtered or moisten before entering the 2 lungs
Exercise school book page 64
Question (1) 1- (d).
2-(c).
3-(c).
question (2) canceled .
Question (3) 1- leg pushing force.
2- hand pushing force.
3- air pushing force.
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4- engine pushing force.
Question (4) pulleys ease the motion.
Question (5) 1- ease the motion .
2- transfer the motion.
3- lifting heavy objects.
question (6) canceled .
General Exercises on unit 2 book page 98
question (1,2,3,4,5,7,9,10,11,12,13) canceled
question (6) 1- (c).
2- (a).
question (8) 1- force: change the state of body from rest to motion or from
motion to rest. “ rest of the question is canceled”
question (14) 1-
“ rest of the question is canceled”
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