الأسبوع 15 · مراجعة الفصل الدراسي الأول (الوحدات ١–٤) ومهام مراجعة من إعداد Darslab · 3 دروس
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Review: living things, microbes, Earth and Moon
Science Prep 1 Term 1, Units 1–4: Review
GoalReview cells, living things, microbes, the Earth and the Moon with new tasks.
New words
cell · the basic unit of living thingsphotosynthesis · making food from light, carbon dioxide and watermicrobe · a living thing too small to see without a microscope
Explanation
Living things are made of cells. Plant cells have a cell wall and chloroplasts, and animal cells do not. Bacteria are prokaryotes with no nucleus in a membrane. Living things feed, respire, grow, move, make waste, respond and reproduce. Plants make food by photosynthesis using light, and all living things release energy by respiration. Microbes are bacteria, fungi and protozoa. Some are helpful, such as yeast in bread and penicillin from a fungus. Some cause disease, such as the microbes behind dysentery and typhoid. Washing hands helps to stop their spread. The planets are eight; the inner four are rocky. Day and night come from the Earth’s spin. Seasons come from the tilt of its axis. The Moon shows phases and can enter the Earth’s shadow in an eclipse.
Worked examples
Clue
Cell
cell wall and chloroplasts
plant
nucleus, no cell wall
animal
no nucleus in a membrane
bacterium
Plant cell or animal cell? A cell with a cell wall and chloroplasts: plant. A cell with a nucleus and no cell wall: animal. A cell with no nucleus in a membrane: bacterium.
Photosynthesis
Respiration
uses
CO₂, water, light
sugar, O₂
makes
sugar, O₂
energy, CO₂, water
Compare. Photosynthesis uses light, carbon dioxide and water and makes sugar and oxygen. Respiration uses sugar and oxygen and releases energy, with carbon dioxide and water.
Helpful or harmful? Yeast in dough: helpful. Penicillin: helpful. The microbe causing typhoid: harmful. Mould on old bread: harmful if eaten.
Order the planets by size, smallest first, from the diameters: Earth 12756 km, Mars 6787 km, Mercury 4878 km, Venus 12120 km. Answer: Mercury, Mars, Venus, Earth.
A day in Egypt in midsummer has about 14 hours of daylight and in midwinter about 10. The tilt of the Earth’s axis explains the difference, not distance from the Sun. A full moon inside the Earth’s shadow is a lunar eclipse; the line-up is Sun, Earth, Moon.
Class activity
Make a mind map with the Earth in the middle. Draw branches for the planets, day and night, the seasons, the Moon’s phases and eclipses. Add one fact to each branch, and one question for a friend. Never look at the Sun.
Practice
1
Name two things a plant cell has that an animal cell does not.
A cell wall and chloroplasts.
2
Write the line-up of the Sun, Earth and Moon for a lunar eclipse.
Sun, Earth, Moon.
3
Give one helpful and one harmful microbe example.
Helpful: yeast. Harmful: the microbe that causes typhoid.
4
What causes the seasons?
The tilt of the Earth’s axis during its year-long trip around the Sun.
