Science High School Reviewer | Grade 4 Science | Life Science | Kingdoms of Life | Lesson 1: Cells
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Lesson 1 Cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
What are living things?
Credit: https://www.teacherspayteachers.com/FreeDownload/Characteristics-of-Living-Things-Notes-Quiz-PPT-5512683
All living things are made up of cells. A cell is the building block of life.
A cell is the smallest unit of living matter that can perform all life processes.
Living things have needs. Living things need water, food, and a place to live.
Living things use food to carry out life functions.
Living things breathe or respirate.
Living things get rid of waste.
Living things reproduce.
Scientists use organism to refer to living thing.
An organism is an organism that carries out five basic jobs, or life functions.
One life function of an organism is to make more of its own kind. To make more of one’s own kind is to reproduce.
Offspring is refers to the young of living things.
Living things grow and develop.
Living things react to changes in the environment.
Parts of a cell
Cell wall – This stiff structure protects and supports the plant cell. Only plant cells have a cell wall.
Mitochondria – Food is burned here to give the cell energy.
Chloroplasts – This substance helps plants make food using the Sun’s energy. Only plant cells have chloroplasts.
Nucleus – This controls all the cell’s activities.
Chromosomes – These control how the cell develops.
Cell membrane – This thin covering is found outside the cell. In plants, it is inside the cell wall.
Vacuole – This structure stores the cell’s food, water, and wastes. Plant cells have one or two vacuoles. Animal cells have many.
Cytoplasm – Filling the cell is a substance that is like jelly. It is mostly water. It also has important chemicals.
Comparing plant and animal cells
Plant cells have chlorophyll.
Most plants have green parts called chloroplasts. Chloroplasts are filled with a green substance called chlorophyll.
Chlorophyll helps plants make food using the Sun’s energy. This process is called photosynthesis.
Animal cells do not
have chloroplasts or chlorophyll.
Plant cells have cell walls.
Plant cells also have sturdy cell walls. Cell walls give the cell a shape like a box. Animal cells have a cell membrane, but not a cell wall. Animal cells tend to have a round shape.
Plant cells have large vacuoles. Animal cells have small vacuoles.
The organization of cells
In a many-celled plant or animal, cells are organized to work together. Different types of cells do different kinds of work.
Groups of the same type of cell form a tissue.
Groups of tissues that work together form an organ.
Groups of organs that work together form systems.
An organism is the highest level of cell organization. It is a complete living thing that is made from all parts in all of the systems working together.
