Biology Class 9: Fundamental Unit of Life

Questions and Answers

Which of the following statements about prokaryotic and eukaryotic cells is true?

Eukaryotic cells are always larger than prokaryotic cells.

Prokaryotic cells contain membrane-bound organelles.

Both cell types contain DNA. (correct)

Prokaryotic cells have a nucleus while eukaryotic cells do not.

What is the primary function of the cell membrane?

To provide structural support to the cell

To store genetic information

To facilitate protein synthesis

To control the movement of substances in and out of the cell (correct)

What is the role of ribosomes within a cell?

To break down waste materials

To synthesize lipids

To produce proteins (correct)

To store energy

Which of the following correctly describes the function of the cytoplasm?

It provides a medium for biochemical reactions Signup and view all the answers

Which cellular structure is primarily involved in energy production?

Mitochondria Signup and view all the answers

What is the primary distinguishing feature of prokaryotic cells compared to eukaryotic cells?

Prokaryotic cells do not have membrane-bound organelles. Signup and view all the answers

Which component is primarily responsible for controlling the movement of substances in and out of the cell?

Cell membrane Signup and view all the answers

Which of the following best describes the role of mitochondria in eukaryotic cells?

Production of ATP through cellular respiration Signup and view all the answers

What is the function of the lysosomes in a eukaryotic cell?

Digestion of biomolecules Signup and view all the answers

Which structure within the cell is responsible for packaging and processing proteins before they are sent to their destination?

Golgi apparatus Signup and view all the answers

Study Notes

Primary Function of the Cell Membrane

The cell membrane regulates the entry and exit of substances, maintaining homeostasis.
It provides a barrier that separates the internal environment of the cell from the external environment.
The membrane is selectively permeable, allowing specific ions and molecules to pass while blocking others.

Prokaryotic vs Eukaryotic Cells

Prokaryotic cells lack a nucleus and organelles, while eukaryotic cells possess both.
Prokaryotes are typically smaller and simpler in structure compared to eukaryotes.
Both types of cells have DNA, ribosomes, and a plasma membrane, but their organization and complexity differ significantly.

Role of Ribosomes

Ribosomes are essential for protein synthesis, translating messenger RNA (mRNA) into polypeptide chains.
They can be found either free-floating in the cytoplasm or attached to the endoplasmic reticulum, forming rough ER.
Ribosomes are composed of ribosomal RNA (rRNA) and proteins, playing a crucial role in the cell's overall function.

Cellular Structure for Energy Production

Mitochondria are the organelles primarily involved in energy production through a process called cellular respiration.
They convert glucose and oxygen into adenosine triphosphate (ATP), the energy currency of the cell.
Mitochondria possess their own DNA and double membrane, indicating an evolutionary relationship to prokaryotic cells.

Function of the Cytoplasm

The cytoplasm is the gel-like substance within the cell membrane, facilitating the movement of materials and organelles.
It provides a site for biochemical reactions, including metabolic processes crucial for cell survival.
The cytoplasm contains cytosol, organelles, and various molecules, contributing to the cell's structural integrity and functionality.

Description

Test your knowledge on the fundamental unit of life in this quiz for biology class 9. Explore questions about cell membrane functions, differences between prokaryotic and eukaryotic cells, and the roles of ribosomes and other cellular structures. Perfect for CBSE syllabus preparation.