Skibidi sigma Flashcards
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- What are cells? Provide an example.
If you look carefully at the houses above, you will find that they are made of many small plastic bricks. Different number and types of bricks are used to build a variey of houses. Each house can be broken down into single pieces of brick. Each brick is therefore a basic building block of the houses.
Similarly, cells are the basic building blocks of living things. The living things around us, from the smallest bacterium to the largest animal or tree, are all made up of one or more cells.
A cell is the basic unit of life. It is the smallest part of a living thing which is capable of carrying out basic life processes.
- Who discovered cells?
More than 300 years ago, a scientist, Robert Hooke, used a microscope to observe thin slices of cork. He found that the cork was made up of tiny boxes which he called ‘cells’.
- Describe what the number of cells an organism has and how it can classify it.
Some living things, such as bacteria and yeasts, are made up of only one cell. An organism or a living thing that is made up of only one cell is called a unicellular organism. Living things such as plants and animals are made up of many cells. They are called multicellular organisms. A large animal, such as an elephant, is made up of many more cells than a small animal like a frog.
- What is the biggest cell in the human body?
To find out, observe the thickness of a strand of hair. The largest human cell in terms of volume is an egg cell, which has a diameter similar to that of a strand of hair. Most other cells are about ten times smaller.
- What is the cell theory and who discovered it?
In 1839, two scientists, Scheiden and Schwann, proposed the cell theory. The cell theory states that:
- all living things are made from one or more cells;
- cells come trom pre-existing cells;
- cells are the basic units of life.
- What is the object placed on the slide called? What is the slide made off and why?
The object to be observed is called the specimen. It is placed on a microscope slide which is then placed on the microscope stage. The focus knobs are turned to adjus the sharpness of the image.
- What are the similarities and differences between Animal Cells and Plant Cells.
As you have seen, an animal cell has a nucleus, cell membrane and cytoplasm, just like a plant cell. These parts have similar functions as those in a plant cell.
However, unlike a typical plant cell, an animal cell does not have chloroplasts. This is one reason why plants can make food using light energy but animals cannot. The cell wall is also absent in an animal cell. This explains why animal cells do not have regular shapes, unlike plant cells. In general, plant cells are bigger than animal cells.
What is a microscope? Why is it used? State its parts.
Page 5
What is each box-like shape observed under the microscope when looking at a plant called? State its properties. Give an example. Also, state an example of an animal cell. How can it be obtained?
Last part of page 7 & first part of Page 9.
Differentiate between a plant cell and an animal cell by using both of their parts. Then, draw an example of both types of cells as best as you can.
You may use a table to solve this question.
Table 1.1 and Table 1.2
Think About It Page 9.
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