Class 9 Science Chapter 5 Quiz

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Questions and Answers

What is the process of water movement through a semipermeable membrane called?

Diffusion

Filtration

Capillarity

Osmosis (correct)

What happens to the water in potato cup B after adding sugar?

Water leaves the cup.

Water enters the hollowed section. (correct)

Water evaporates.

Water freezes.

Why is potato cup A important in the osmosis experiment?

To observe the effects of salt.

To serve as a control with no solute. (correct)

To provide additional nutrients.

To be a comparison for the other cups.

What prevents osmosis from occurring in potato cup A?

Lack of a liquid medium. Signup and view all the answers

What occurs in potato cup C after the addition of salt?

Water accumulates in the hollowed portion. Signup and view all the answers

What is a characteristic of prokaryotic cells?

Membrane-bound organelles are absent Signup and view all the answers

Which statement distinguishes plant cells from animal cells?

Plant cells contain plastids Signup and view all the answers

What is NOT a feature of eukaryotic cells?

Absence of nucleolus Signup and view all the answers

How do amoebas obtain their food?

By encircling food with pseudopodia Signup and view all the answers

Which difference is true regarding the size of prokaryotic and eukaryotic cells?

Eukaryotic cells are generally larger Signup and view all the answers

Which of the following is found in eukaryotic cells but absent in prokaryotic cells?

Nucleolus Signup and view all the answers

What is a common feature of animal cells?

Presence of centrosomes and centrioles Signup and view all the answers

What mechanism separates daughter cells in plant cell division?

Creation of a cell plate Signup and view all the answers

Which organelles contain their own genetic material?

Chloroplast and Mitochondria Signup and view all the answers

Why is the plasma membrane considered selectively permeable?

It lets only certain molecules enter or exit. Signup and view all the answers

Who was the scientist that first discovered cells?

Robert Hooke Signup and view all the answers

What occurs if the organization of a cell is severely damaged?

The cell will not survive. Signup and view all the answers

Why are lysosomes referred to as 'suicide bags'?

They contain enzymes that can digest the cell. Signup and view all the answers

What happens if the plasma membrane is ruptured?

The lysosomes may burst and digest the cell. Signup and view all the answers

What is the primary function of the Golgi apparatus in a cell?

Modification and packaging of proteins Signup and view all the answers

What role do ribosomes play in a cell?

They synthesize proteins. Signup and view all the answers

What is the primary function of the Golgi apparatus?

Storage, modification, and packaging of products Signup and view all the answers

Why are mitochondria referred to as the powerhouse of the cell?

They synthesize energy in the form of ATP during respiration Signup and view all the answers

Where are lipids that compose the cell membrane synthesized?

Smooth endoplasmic reticulum Signup and view all the answers

How do CO2 and O2 typically move in and out of cells?

By diffusion Signup and view all the answers

Which characteristic distinguishes prokaryotic cells from eukaryotic cells?

Well-defined nuclear membrane Signup and view all the answers

What type of endoplasmic reticulum is responsible for producing proteins for the cell membrane?

Rough endoplasmic reticulum Signup and view all the answers

What happens to the concentration of CO2 during respiration inside the cell?

It accumulates Signup and view all the answers

What do prokaryotic cells lack that eukaryotic cells possess?

Nucleus Signup and view all the answers

Study Notes

Fundamental Unit of Life: Key Concepts

Organelles with Genetic Material: Chloroplasts and mitochondria have their own DNA, distinguishing them from other organelles.
Site of Protein Synthesis: Proteins are synthesized in ribosomes, which can be found either free in the cytoplasm or attached to the rough endoplasmic reticulum.

Discovery of Cells

Robert Hooke: An English scientist who discovered cells in 1665 using a self-designed microscope to observe cork.

Celular Structure and Function

Cell as a Unit of Life: Cells are the foundational building blocks of all living organisms, responsible for all life processes.
Plasma Membrane: Characterized as selectively permeable, made of lipids and proteins, controlling the entry and exit of molecules.
Cell Death Mechanism: If a cell’s organization is disrupted, lysosomes can release digestive enzymes, leading to cellular self-digestion and death.
Lysosomes: Known as "suicide bags," they contain hydrolytic enzymes for digestion, which can also lead to cell destruction if released.

Importance of Golgi Apparatus

Role of Golgi Apparatus: Essential for the modification, packaging, and transport of cellular materials. Without it, cells cannot effectively manage biochemical substances.

Energy Production

Mitochondria: Known as the powerhouse of the cell, they generate ATP through respiration, crucial for cellular energy.

Membrane Components

Synthesis of Cell Membrane Components:
- Smooth Endoplasmic Reticulum (SER): Synthesizes lipids.
- Rough Endoplasmic Reticulum (RER): Contains ribosomes for protein synthesis.

Gas Exchange Mechanism

Diffusion of Gases: CO2 and O2 move across cell membranes through diffusion, with CO2 being produced in respiration and O2 consumed.

Prokaryotic vs. Eukaryotic Cells

Prokaryotic Cells: Typically smaller (1-10μm), have no defined nuclear membrane, single chromosome, and lack membrane-bound organelles.
Eukaryotic Cells: Generally larger (5-100μm), possess a well-defined nuclear membrane, multiple chromosomes, and contain membrane-bound organelles.

Plant Cells vs. Animal Cells

Structural Differences:
- Plant Cells: Have a cell wall, plastids, large vacuoles, and form daughter cells via cell plate.
- Animal Cells: Lack a cell wall, no plastids, smaller vacuoles, and form daughter cells by constriction.

Feeding Mechanism

Amoeba Feeding: Uses pseudopodia to envelop planktonic bacteria and forms a food vacuole for digestion.

Osmosis Explained

Definition of Osmosis: Movement of water through a semipermeable membrane from high to low water concentration, crucial for cellular processes.

Osmosis Experiment with Potatoes

Observation of Osmosis: Adding sugar or salt creates a hypertonic solution that draws water into the potato cups (B and C).
Control: Cup A serves as a control to demonstrate osmotic differences, while cup D (boiled potato) shows altered permeability but no osmotic effect.

Expectations from the Experiment

Water Accumulation Reasons: Occurs in cups containing sugar or salt due to the osmotic pressure.
No Water Accumulation: In cups A and D, due to lack of a solution to facilitate osmosis.

These notes capture the key elements and concepts from the Chapter on the Fundamental Unit of Life, essential for Class 9 Science students.

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Description

Test your understanding of Chapter 5 - The Fundamental Unit of Life from Class 9 Science. This quiz features very short answer and short answer questions that will challenge your knowledge on key concepts such as organelles and protein synthesis.