Cell

Question 1

Define Cell

Answer 1

Cell is the basic structural and functional unit of life.

Question 2

Cell was first discovered by…

[ Who? When? How? and What cell? ]

Answer 2

• Robert Hooke
• 1665
• Self-made Microscope
• Cork Cell of Bark

Question 3

Cell is a Latin word for…

[ Meaning in Latin ]

Answer 3

A Little room

Question 4

Who first observed the living cell?

[ Who? When? How? and What cell? ]

Answer 4

• Leeuwenhoek
• 1674
• Improved Microscope
• Free living pond cells

Question 5

Who discovered the Nucleus?

Answer 5

Robert Brown (1831) discovered the nucleus.

Question 6

Who coined the term Protoplasm?

Answer 6

Purkinje (1839) coined the term protoplasm.

Question 7

The Cell Theory

[ Authors and State the Theory ]

Answer 7

Schleiden and Schwann proposed the cell theory. They stated that,

• All plants and animals are composed of cells.
• Cell is the basic unit of life.

It was further expanded by Virchow by suggesting that all cells arise from pre-existing cells.

Question 8

Cells have different shapes and size.

[ Why? ]

Answer 8

The shape and size of cells are related to the specific function they perform.

Question 9

Cell Membrane

Answer 9

• Made of - Lipids and Proteins.
• Selectively Permeable Membrane.
• Outermost covering of the cell that separates the contents of cell from external environment.
• Regulates the entry and exit of materials in and out of cell.
• Prevents the entry of certain substances.

Question 10

Diffusion

Answer 10

The net movement of particles from a region of higher concentration to a region of lower concentration.

Question 11

Osmosis

Answer 11

The net movement of water from a region of higher concentration to a region of lower concentration
[OR]
from a region of lower solute concentration to a region of higher solute concentration through a selectively permeable membrane.

[ MUST - Selectively Permeable Membrane & SOLUTE CONCENTRATION ]

Question 12

Hypotonic Solution

[ Hypo-potamus ]

Answer 12

• Outside solution has higher water concentration than inside the cell.
• Cell will swell.

Question 13

Hypertonic Solution

Answer 13

• Outside solution has lower water concentration than inside the cell.
• Cell will shrink by water loss.

Question 14

Isotonic Solution

[ Iso ]

Answer 14

• Medium has exactly the same water concentration as the cell.
• Cell will stay the same.

Question 15

Examples of Osmosis

[ Any 2 from book ]

Answer 15

• Unicellular freshwater organisms and most plant cells gain water through osmosis.
• Absorption of water by plant root.

Question 16

Endocytosis

Answer 16

• Flexibility of the cell membrane enables the cell to engulf food and other materials from external environment.
• Done in Amoeba

Question 17

Cell Wall

Answer 17

• Plant cells.
• Rigid outer covering.
• Cellulose in plants - Structural strength.
• Help plants, fungi and bacteria to withstand very dilute (hypotonic) solutions without bursting.
• As cell swells, pressure is built-up against the cell wall. The wall exerts equal pressure against the swollen cell.

Question 18

What is the plant cell wall made up of?

Answer 18

Cellulose

Question 19

What is the fungal cell wall made up of?

Answer 19

Chitin

Question 20

What is the bacterial cell wall made up of?

Answer 20

Peptidoglycan

Question 21

Plasmolysis

HINT [ Plasmo - Plasma , Lysis - Breakdown ]

Answer 21

When a cell loses water through osmosis there is shrinkage or contraction of the contents of the cell away from the cell wall.

Question 22

Nucleus

[ Structure & Parts ]

Answer 22

• Nuclear Membrane
• Nuclear Pore
• Chromatin material ( pre division )

Question 23

Nuclear Membrane

Answer 23

• Double layered covering of nucleus.
• Has pores which regulate movement of substances between the nucleus and the cytoplasm.

Question 24

Chromatin Material or Chromosomes

Answer 24

• Rod shaped structures.
• Contains genetic information in the form of DNA.
• Chromosomes are in the form of entangled threads called chromatin before cell division.

Question 25

**Functional segment of DNA**

Answer 25

**Gene**

Question 26

**Function of Nucleus**

Answer 26

* **Cellular Division.** * **Regulates life processes** of cell by **directing chemical activities.**

Question 27

**Genetic Material of Prokaryotes** | [ Region called? ]

Answer 27

* **Prokaryotes** **lack well-defined nuclear region.** * **Nucleic acid** is randomly **scattered**. * This **region** is called **Nucleoid**.

Question 28

Prokaryotes lack...

Answer 28

* Well defined nuclear region. * Double membrane bound organelles

Question 29

**Chlorophyll of photosynthetic prokaryotes** is associated with _ _ _ _ _ _ _.

Answer 29

**Membranous vesicles**

Question 30

**Prokaryotes - Eukaroytes** | [ Differentiate Points ]

Answer 30

1. Size 2. Nuclear Region 3. Chromosome Number 4. Membrane-bound Organelles

Question 31

Cytoplasm

Answer 31

* The fluid content inside the plasma membrane.

Question 32

Name **all cell organelles** | [ Give one word to describe function ]

Answer 32

* Endoplasmic Reticulum - Internal transport system * Golgi Apparatus - Secretory / Packing Centre * Lysosomes - Suicidal bag * Mitochondria - Power house * Plastids - Color * Vacuoles - Storage * Ribosomes

Question 33

**Endoplasmic Reticulm** | [ Internal Transport System ]

Answer 33

**i. Structure** * Membrane-bound tubes or sheets * Stacks of them **ii. RER** * **Protein** manufacture * has **ribosomes** **iii. SER** * **Lipid** manufacture * Liver cells ( vertebrated) - **Drug detox** **Proteins and Lipids synthesised** are **used** as, * **Membrane bio genesis** * **Enzyme / Hormone**

Question 34

**Golgi Apparatus** | [ Secretory and Packing Centre ]

Answer 34

**i. Structure** * Membrane bound sacs arranged in stacks (cisterns) * Hav connection with the ER. **ii. Function** * Storage, modification, packing of products * Simple to Complex sugars * Formation of Lysosomes

Question 35

The **enzymes of Lysosomes** are from...

Answer 35

the **Rough Endoplasmic Reticulm (RER)**.

Question 36

**Simple from complex** substances

Answer 36

Lysosomes

Question 37

**Two membranes** of **Mitochondria**

Answer 37

* Inner Membrane - Deeply folded to increase area of ATP generation. * Outer Membrane - Porous

Question 38

What is **ATP?**

Answer 38

* **Adenosine triphosphate** is the **energy currency** of the cell. * The body uses **energy stored in ATP** to **make chemical compounds** and to **do work.**

Question 39

**Similarities** of **Mitochondria** and **Plastid**.

Answer 39

* Both have their **own DNA and ribosomes** to make **own proteins**

Question 40

Types of Plastids | [ State and write functions ]

Answer 40

* Chromoplast (coloured) * Leucoplast (colourless or white) - storage of proteins, fats and starch.

Question 41

**Structure** of **Plastids**

Answer 41

Numerous membrane layers embedded in a material called stroma.