Biology Chapter 1: Cell Structures and Functions

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Questions and Answers

Who invented the microscope with a maximum of 30x magnification?

Zacharias and Hans Janssen (correct)

Ernst Ruska

Anton van Leeuwenhoek

Robert Hooke

Which scientist is known for observing cork and coining the term 'cells'?

Anton van Leeuwenhoek

Zacharias Janssen

Ernst Ruska

Robert Hooke (correct)

What significant contribution did Anton van Leeuwenhoek make to microscopy?

Invented the first microscope

Observed protozoa and bacteria (correct)

Formulated the cell theory

Developed the electron microscope

What does the term 'animalcules' refer to?

Single-celled organisms observed by Leeuwenhoek Signup and view all the answers

What year was the first prototype of the electron microscope built?

1931 Signup and view all the answers

Which part of the microscope is responsible for holding the objectives?

Revolving nosepiece Signup and view all the answers

What feature allows modern electron microscopes to magnify objects up to 500,000 times?

Resolution capabilities Signup and view all the answers

Which of the following is NOT a part of the mechanical parts of a microscope?

Condenser Signup and view all the answers

What is the function of the iris diaphragm in a microscope?

Regulates the amount of light reaching the specimen Signup and view all the answers

Which component of the microscope is used to tilt it for better viewing angles?

Inclination joint Signup and view all the answers

The total magnification of a microscope is calculated by multiplying which two elements?

Ocular lens and objective lens Signup and view all the answers

What was Matthias Schleiden's contribution to the cell theory?

All plants are made of cells Signup and view all the answers

Which type of objective lens typically has a magnification of 40x?

High Power Signup and view all the answers

According to Rudolf Virchow, what is a key statement about cells?

All existing cells come from preexisting cells Signup and view all the answers

What does the condenser do in a microscope?

Concentrates light onto the specimen Signup and view all the answers

Which component directly allows the observer to view the specimen under a microscope?

Eyepiece or ocular Signup and view all the answers

What is the size of the smallest cell in humans?

5 µm Signup and view all the answers

Which cell is the largest in humans?

Ovum cell Signup and view all the answers

What shape do human red blood cells primarily have?

Circular biconcave Signup and view all the answers

Which of the following cells can change shape to engulf microorganisms?

White blood cells Signup and view all the answers

What is the length of the longest cell in humans?

1 m Signup and view all the answers

Which cell type is primarily branched to conduct impulses?

Nerve cells Signup and view all the answers

What is the primary reason for shape variation among different cells?

Function of the cell Signup and view all the answers

What is a feature of Euglena and Amoeba regarding cell shape?

Ability to change shape Signup and view all the answers

What is the primary function of cells in living organisms?

Cells are the smallest functional unit of life. Signup and view all the answers

Who is credited with the observation of living cells, termed 'animalcules'?

Anton van Leeuwenhoek Signup and view all the answers

Which statement is NOT one of the main tenets of the cell theory?

Cells are capable of photosynthesis. Signup and view all the answers

What did Rudolf Virchow contribute to the modern cell theory?

All cells come from pre-existing cells. Signup and view all the answers

What unit is used to measure the size of a cell?

Micrometer Signup and view all the answers

Which of the following scientists projected that plant cells are made of cells?

Matthias Schleiden Signup and view all the answers

Which of the following describes the size of the smallest cell?

It measures 0.1 µm. Signup and view all the answers

How do cells relate in terms of chemical composition and metabolic activity?

All cells exhibit relatively similar chemical compositions and metabolic activity. Signup and view all the answers

Study Notes

Development of the Microscope

In 1597, Zacharias and Hans Janssen invented the first microscope with a maximum magnification of 30x.
Robert Hooke, through his microscope, discovered that cork consists of small, hollow compartments, naming them "cells" after the rooms in monasteries.
Anton van Leeuwenhoek improved lens polishing techniques, resulting in higher magnifications, leading to the discovery of protozoa and bacteria, coining the term "animalcules" for single-celled organisms he observed.

Electron Microscopy

Ernst Ruska and Max Knoll developed the first prototype of the electron microscope in 1931.
Modern electron microscopes can magnify objects up to 500,000 times their actual size, enhancing resolution and detail.

Parts of the Microscope

Mechanical Parts: Include body tube, revolving nosepiece, arm, stage, stage clips, base, and inclination joint; provide support and structure.
Illuminating Parts: Comprise the mirror, condenser, and iris diaphragm; manage light direction and intensity on the specimen.
Magnifying Parts: Eyepiece (ocular) and objectives; eyepiece magnifies the specimen, with various objective lenses (scanner 4x, low power 10x, high power 40x, oil immersion 100x) contributing to total magnification.

Cell Theory

Formulated through the contributions of several scientists:
- Matthias Schleiden determined all plant parts are made of cells.
- Theodor Schwann stated that all animals are composed of cells, marking the first statement of cell theory: all living things are made of cells.
- Rudolf Virchow established that all cells arise from preexisting cells, completing the second statement of cell theory.

Tenets of the Modern Cell Theory

All living organisms consist of one or more cells.
Cells are the smallest functional unit of life.
Cells arise only from preexisting cells.
Cells transmit hereditary information during cell division.
All cells share similar chemical compositions and metabolic activities.

Size and Shape of Cells

Cells vary in size and shape; mycoplasma is the smallest cell at 0.1 µm, while the ostrich egg is the largest at 18 cm.
In humans: sperm cell (5 µm) is the smallest, ovum cell (120 µm) is the largest, and nerve cell (1 m) is the longest.
Cell shape is often specialized for function:
- Human red blood cells are circular and biconcave for easy movement through capillaries.
- Nerve cells are branched to transmit impulses effectively.
- Some cells, like white blood cells, can alter their shape to engulf microorganisms.

Contributors to Cell Theory

Robert Hooke: Coined the term "cells" from his cork observations.
Anton van Leeuwenhoek: First to observe living cells (animalcules).
Matthias Schleiden: Identified cells as the building blocks of plants.
Theodor Schwann: Expanded the theory to animals.
Rudolf Virchow: Proposed that new cells come from existing cells.

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Description

This quiz covers the key concepts of Chapter 1 in Biology, focusing on structures and functions of the cell. You will explore the discovery of the cell through microscopy and learn about the contributions to cell theory. Test your knowledge of historical figures and the fundamental principles that define cellular biology.