Cell Structure

Question 1

What are cells?

Answer 1

Cells are the basic functional unit of life.

Question 2

What is an organelle?

Answer 2

A specialised, membrane-bound compartment within a cell, that has a specific function.

Question 3

(2 points)

What is a cell membrane?

Answer 3

-The boundary of the cell and controls what enters and leaves the cell.
-Also maintains the integrity of the cell and holds the contents in.

Question 4

What is the cytoplasm?

Answer 4

The medium in which all chemical reactions occur.

Question 5

(3 points)

What is the function of the nucleus?

Answer 5

• Contains the DNA, organised into chromosomes.
• Chromsomes are usually in a thin, thread-like form called chromatin.
• The nucleus is the control-centre of the cell and sends chemical signals to all areas of the cell.

Question 6

(2 points)

What is the structure of the nucleus?

Answer 6

• It has a double membrane (nuclear envelope) separating it from the rest of the cell’s contents.
• There are many nuclear pores in the nuclear envelope. These are small holes in the double membrane that allows chemicals to pass in and out of the nucelus.

Question 7

What is deoxyribonucleic acid (DNA)?

Answer 7

Contains the genetic code for the manufacture of all proteins needed by the organism.

Question 8

(3 points)

What is the function of the nucleolus?

Answer 8

• Found within the nucleus
• There may be more than one nucleolus
• They assemble ribosomes, which are then transported to the cytoplasm.

Question 9

What are ribosomes?

Answer 9

Made from RNA. Responsible for making the proteins needed by the cell or surrounding cells.

Question 10

(2 points)

What is the function of mitochondria?

Answer 10

-Powerhouses of the cell.
-Responsible for carrying out major metabolic processes, such as respiration.

Question 11

What are lysosomes?

Answer 11

Contain enzymes. Responsible for breaking down any cell debris e.g. viruses, bacteria or worn-out organelles.

Question 12

What is the function of chloroplasts?

Answer 12

Responsible for making food using sunlight, water and CO2. This food is burned or stored.

Question 13

What is the cell wall and what is its function?

Answer 13

The strong and rigid structure responsible for giving plants their strength and shape. Also acts as a protective layer against pathogens.

Question 14

What is the middle lamella?

Answer 14

The cement that binds cell walls together - maintains structure of the plant.

Question 15

(2 points)

What is the vacuole and what is its function?

Answer 15

-Large, fluid filled sac that takes up most of the plant cell.
-Has many different functions including:
- Storage of food, water and wastes
- Maintaining the shape of the plant cell
- Isolating harmful substances

Question 16

What type of microscope is used to get higher magnifications?

Answer 16

A transmission electron microscope (TEM).

Question 17

(3 points)

How do transmission electron microscopes work?

Answer 17

• Transmission electron microscopes use a particle beam of electrons that strikes the specimen and travels right through it and is diffracted (or deflected) along the way.
• The electrons are brought into focus using magnets (instead of glass lens as for light).
• The image is produced on an electron-detecting screen or photographic film.

Question 18

What is a prokaryotic cell?

Answer 18

A tiny cell that has neither a membrane-bound nucleus nor membrane-bound organelles.

Question 19

What is an example of a prokaryotic organism?

Answer 19

Bacteria.

Question 20

What is a eukaryotic cell?

Answer 20

A cell that has a membrane-bound nucleus and membrane-bound organelles.