Biology Chapter 5: The Fundamental Unit of Life

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Questions and Answers

What did Robert Hooke observe when examining a thin slice of cork?

He observed that the cork resembled a honeycomb structure consisting of many little compartments.

In what year did Robert Hooke make his observation about cork?

1665

The word 'cell' is derived from a Latin word meaning 'a little room'.

True

What is the first step in preparing a slide of onion peel for observation under a microscope?

Peel off the skin (epidermis) from the concave side of the onion bulb. Signup and view all the answers

What is the purpose of using safranin solution on the onion peel?

To color the peel for better visibility Signup and view all the answers

What do we call organisms made up of a single cell?

Unicellular organisms Signup and view all the answers

Which of the following are examples of multicellular organisms?

Animals Signup and view all the answers

All cells visible under a microscope in onion bulbs are different from each other.

False Signup and view all the answers

What did Robert Hooke observe while examining a thin slice of cork?

He observed that it resembled a structure of a honeycomb consisting of many little compartments. Signup and view all the answers

The term 'cell' comes from the Latin word meaning ______.

a little room Signup and view all the answers

What is the purpose of using a cover slip when preparing a microscope slide?

To prevent air bubbles and to keep the specimen flat. Signup and view all the answers

What type of organisms are Chlamydomonas, Paramecium, and bacteria?

They are unicellular organisms. Signup and view all the answers

All multicellular organisms are made up of similar cells.

True Signup and view all the answers

What did Robert Hooke call the compartments he observed?

Cells Signup and view all the answers

What are some examples of multicellular organisms?

Fungi, plants, and animals. Signup and view all the answers

To prepare a temporary mount of onion peel, a drop of ______ solution is used.

safranin Signup and view all the answers

Study Notes

Robert Hooke and the Discovery of Cells

In 1665, Robert Hooke observed cork under a microscope and noted its resemblance to a honeycomb structure.
Hooke coined the term "cells," derived from the Latin word for 'a little room.'
This observation marked the first recognition of living things as composed of distinct units, leading to the foundational concept of cell theory in biology.

The Compound Microscope

Hooke designed his own microscope, which featured various components:
- Eyepiece
- Coarse adjustment
- Fine adjustment
- Body tube
- Arm
- Clips
- Objective lens
- Stage
- Swivel
- Condenser
- Mirror
The compound microscope allows for both low and high power observations of specimens.

Observing Onion Peel Cells

A practical activity involves peeling the epidermis from an onion and observing it under a microscope.
Safranin solution is used to stain the peel, enhancing visibility of cellular structures.
The processed sample exhibits numerous small compartments, reinforcing the concept of cells as fundamental units of life.

Unicellular vs. Multicellular Organisms

Unicellular organisms (including Chlamydomonas, Paramecium, and bacteria) consist of a single cell.
Multicellular organisms are composed of many cells that group together to form complex structures and perform various functions.
Examples of multicellular organisms include certain fungi, plants, and animals.
Onion bulbs display similarities in cellular structure across different sizes, indicating a shared organizational pattern among multicellular organisms.

Robert Hooke and the Discovery of Cells

In 1665, Robert Hooke observed cork under a microscope and noted its resemblance to a honeycomb structure.
Hooke coined the term "cells," derived from the Latin word for 'a little room.'
This observation marked the first recognition of living things as composed of distinct units, leading to the foundational concept of cell theory in biology.

The Compound Microscope

Hooke designed his own microscope, which featured various components:
- Eyepiece
- Coarse adjustment
- Fine adjustment
- Body tube
- Arm
- Clips
- Objective lens
- Stage
- Swivel
- Condenser
- Mirror
The compound microscope allows for both low and high power observations of specimens.

Observing Onion Peel Cells

A practical activity involves peeling the epidermis from an onion and observing it under a microscope.
Safranin solution is used to stain the peel, enhancing visibility of cellular structures.
The processed sample exhibits numerous small compartments, reinforcing the concept of cells as fundamental units of life.

Unicellular vs. Multicellular Organisms

Unicellular organisms (including Chlamydomonas, Paramecium, and bacteria) consist of a single cell.
Multicellular organisms are composed of many cells that group together to form complex structures and perform various functions.
Examples of multicellular organisms include certain fungi, plants, and animals.
Onion bulbs display similarities in cellular structure across different sizes, indicating a shared organizational pattern among multicellular organisms.

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Description

Explore the fundamental unit of life in Chapter 5 of Biology. This chapter focuses on Robert Hooke's observations of cork and similarities to honeycomb structures. Learn about cell theory and the importance of cells in living organisms.