Cell Biology Fundamentals

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the fundamental structural and functional unit of all living beings?

Cell (correct)

Organ system

Tissue

Organ

Who discovered the 'cell' while examining a thin slice of cork?

Antony van Leeuwenhoek

Robert Hooke (correct)

Matthias Schleiden

Theodor Schwann

Who added the concept that all cells arise from pre-existing cells to the cell theory?

Matthias Schleiden

Robert Hooke

Rudolf Virchow (correct)

Theodor Schwann

What is the size of the smallest cells, such as bacteria?

0.3-5.0 micrometre Signup and view all the answers

Which type of organism is made up of just one single cell?

Single-celled Signup and view all the answers

What is the main difference between a single-celled organism and a multi-celled organism?

The number of cells present Signup and view all the answers

Who developed the compound microscope?

Robert Hooke Signup and view all the answers

What is the name of the German botanist who discovered that every plant is made up of a large number of cells?

Matthias Schleiden Signup and view all the answers

What is the name given to lysosomes due to their role in cellular destruction?

Suicide bags Signup and view all the answers

In which type of cell is a centrosome found?

Animal cell Signup and view all the answers

What is the function of spindle fibres in cell division?

To separate chromosomes Signup and view all the answers

Which type of plastid is responsible for storing starch in plant cells?

Leucoplasts Signup and view all the answers

What is the name of the green-coloured pigment found in chloroplasts?

Chlorophyll Signup and view all the answers

What is the term for small particles in the cytoplasm that contain food materials?

Granules Signup and view all the answers

What is the term for cells that lack a nuclear membrane?

Prokaryotic cells Signup and view all the answers

What is the largest single cell in the living world today?

Ostrich egg Signup and view all the answers

What is the name of the thread-like structures found in the nucleoplasm?

Chromatin fibres Signup and view all the answers

Why do cells generally remain small in size?

To facilitate rapid communication between different regions and for greater diffusion of substances Signup and view all the answers

What is the shape of human red blood cells?

Circular and biconcave Signup and view all the answers

What is the main function of the cell membrane?

To regulate the entry and exit of substances through fine pores Signup and view all the answers

What is the composition of the cell membrane?

Lipoproteins Signup and view all the answers

What is the function of the cell wall in plant cells?

To provide shape and a certain degree of rigidity to the cell Signup and view all the answers

What is the characteristic of the cell wall?

Non-living and freely permeable Signup and view all the answers

What is the nature of cytoplasm?

Semi-liquid Signup and view all the answers

Study Notes

Cell: The Unit of Life

The cell is the fundamental structural and functional unit of all living beings.
A cell is the smallest part of an organism capable of independent existence and performing essential functions of life.

Discovery of Cells

Antony van Leeuwenhoek, a Dutch scientist, constructed the first microscope.
Robert Hooke, an English scientist, developed a compound microscope and observed "box-like" compartments in a cork slice, which he named "cells".

Cell Theory

Matthias Schleiden, a German botanist, discovered that every plant is made up of cells.
Theodor Schwann, a German zoologist, discovered that all animals and plants are composed of cells.
Rudolf Virchow added to the cell theory by stating that all cells arise from pre-existing cells.

Types of Cells

Single-celled organisms: made up of just one cell, e.g. bacteria, yeast, amoeba.
Few-celled organisms: made up of a few hundred or thousand cells, e.g. Spirogyra, Volvox.
Multi-celled organisms: made up of millions and billions of cells, e.g. human beings, mango trees.

Size of Cells

Cells are very small and can only be seen with a microscope.
Smallest cells: bacteria (0.3-5.0 micrometre).
Longest cells: nerve cells.
Largest cells: birds' eggs, e.g. ostrich egg is the largest single cell.

Importance of Cell Size

Small cell size allows for rapid communication between regions for effective functioning.
Small cell size provides a large surface area/volume ratio for greater diffusion of substances in and out of the cell.

Cell Shapes and Functions

Human red blood cells: circular and biconcave for passing through narrow capillaries and transporting oxygen.
White blood cells: amoeboid for squeezing out through capillary walls.
Nerve cells: long for conducting impulses from distant parts of the body to the brain and vice versa.
Muscle cells: long and contractile for pulling or squeezing parts.
Guard cells: bean-shaped for opening and closing stomatal pores in leaves.

Structure of a Cell

Three essential parts: cell membrane, nucleus, and cytoplasm.
Cell membrane (plasma membrane): a living membrane with fine pores, allowing selective permeability.
Cell wall (in plant cells): a non-living, permeable structure providing shape and rigidity.

Cell Organelles

Cytoplasm: a semi-liquid substance containing many damaged cells that can be rapidly destroyed by lysosomes.
Centrosome (in animal cells): containing two centrioles, which develop into spindle fibers during cell division.
Plastids (in plant cells): leucoplasts (colourless), chromoplasts (variously coloured), and chloroplasts (green-coloured).
Non-living substances or cell inclusions: granules, vacuoles.

Nucleus

A small, spherical mass located in the center of the cytoplasm.
Nucleoplasm contains chromatin fibers.
Prokaryotic cells: lack nuclear membrane, e.g. bacteria.
Eukaryotic cells: have a double nuclear membrane, e.g. all other organisms.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Learn about the basic building blocks of life, cells, and their functions in living organisms. Discover how the invention of the microscope led to the discovery of cells.