Cells : The Living Units

Question 1

What is a cell?

Answer 1

It is the basic unit structure of the body.

Note: -It is the smallest unit of life.
-The human body is composed of about 100 trillion cells.

Question 2

What are the non-cellular components of the body?

Answer 2

Water
Macronutrients(carbohydrates, proteins, lipids)
Micronutrients(vitamins, minerals)
Electrolytes

Note: All of them together are called protoplasm.

Question 3

Organelles

Answer 3

Organelles are specialized structures with characteristic shapes that have specific functions.

Question 4

Organelles are suspended in what?

Answer 4

Cytoplasm

Question 5

What is cell membrane?

Answer 5

It is the outer border (coating) of a cell.

Question 6

Which organelle controls all activities of a cell?

Answer 6

Nucleus

Question 7

How many chromosomes does the nucleus contain?

Answer 7

23 pair of chromosomes

Question 8

Which structure of a cell is responsible for metabolism and oxygenation?

Answer 8

Mitochondria

Question 9

How are tissues formed?

Answer 9

When similar cells that have a common function are grouped together.

Question 10

What are the four basic tissue types in the human body?

Answer 10

Epithelial tissue
Connective tissue
Muscular tissue
Nervous tissue

Question 11

Organic molecules that make up cell membrane

Answer 11

Phospholipids
Cholesterol
Protein

Question 12

Function of plasma membrane

Answer 12

• Physical barrier: Encloses the cell, separating the cytoplasm from the extracellular fluid.
• Selective permeability: Determines which substances enter or exit the cell.
• Communication: Plasma membrane proteins interact with specific chemical messengers and relay messages to the cell interior.
• Cell recognition: Cell surface carbohydrates allow cells to recognize each other.

Question 13

Function of cytoplasm

Answer 13

• The cytoplasm is responsible for holding the components of the cell and protects them from damage.
• It acts as a medium for chemical reactions.

Question 14

Function of nucleus

Answer 14

It is the control center of a cell as it contains chromosomes.

Question 15

Function of Mitochondria

Answer 15

Site of aerobic cell respiration—ATP production.

Question 16

Function of Lysosomes

Answer 16

Contain enzymes to digest ingested material or damaged tissue.

Question 17

Function of Golgi Apparatus

Answer 17

• Synthesis of carbohydrates.

- Packaging of materials for secretion from the cell.

Question 18

Function of Ribosomes

Answer 18

Site of protein synthesis.

Question 19

Function of Endoplasmic Reticulum

Answer 19

• Passageway for transport of materials within the cell.

- Synthesis of lipids.

Question 20

Function of phospholipids in plasma membrane

Answer 20

The phospholipids forms a bilayer which makes up most of the membrane. Phospholipids permit lipid-soluble materials to easily enter or leave the cell by diffusion through the cell membrane.

Question 21

Diffusion

Answer 21

Diffusion is the movement of molecules from an region of higher concentration to a region of lower concentration.

Question 22

Osmosis

Answer 22

It is the diffusion of a solvent such as water through a selectively permeable membrane from a region of low concentration to a region of high concentration.

Question 23

Substances that can diffuse through the lipid bilayer

Answer 23

Oxygen, carbon dioxide, and steroids.

Question 24

Substances that cannot diffuse through the lipid bilayer

Answer 24

Ions and uncharged molecules(glucose).

Question 25

Osmotic pressure

Answer 25

It is the tendency of water to move into the cell by osmosis.

Question 26

Chromatin

Answer 26

A substance made up of DNA, protein and RNA.

Question 27

Importance of mitosis in the body

Answer 27

It is necessary for the growth of an organism and for repair of tissues.