Biology Chapter 4: Introduction to the Cell

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Questions and Answers

What significant evolutionary milestone occurred about 1 billion years ago?

Origin of multicellular organisms

Emergence of eukaryotes (correct)

Arising of prokaryotes

Development of photosynthesis

Which of the following groups are considered examples of eukaryotes?

Bacteria and Archaea

Archaea and Viruses

Viruses and Algae

Fungi and Protists (correct)

Which cellular structure is unique to eukaryotic cells?

Cytoplasm

Ribosomes

Nucleus (correct)

Cell membrane

What does the endosymbiotic theory explain?

How prokaryotes evolved to become eukaryotes (C) Signup and view all the answers

What type of cells lack nuclei and organelles?

Prokaryotic cells (A) Signup and view all the answers

Which of the following statements is true regarding common features of prokaryotes and eukaryotes?

Both have DNA (B) Signup and view all the answers

What is the meaning of the term 'organelle'?

A structure acting as a specialized organ within a cell (B) Signup and view all the answers

What key difference distinguishes prokaryotic cells from eukaryotic cells?

Eukaryotic cells contain organelles (B) Signup and view all the answers

What was Robert Hooke's significant contribution to cell biology?

He coined the term 'cells' after observing cork. (D) Signup and view all the answers

Which scientist is known as the 'Father of Microbiology'?

Leeuwenhoek (C) Signup and view all the answers

What was a key finding of Matthias Schleiden in 1838?

All plants are made of cells. (A) Signup and view all the answers

What advancement did Leeuwenhoek introduce to microscopy?

He improved lens design for better magnification. (B) Signup and view all the answers

According to the cell theory, what does Rudolph Virchow's conclusion entail?

All new cells arise from preexisting cells. (B) Signup and view all the answers

What is the primary focus of the study of cells?

The smallest unit of life. (D) Signup and view all the answers

Which statement represents a characteristic of all eukaryotic cells?

They contain membrane-bound organelles. (B) Signup and view all the answers

What evidence contributed to the development of the cell theory?

Cells are the basic building blocks of all living organisms. (A) Signup and view all the answers

What is the basic unit of structure and function in living things?

Cells (D) Signup and view all the answers

Which statement is a tenant of the Modern Cell Theory?

Energy flow occurs within cells. (C) Signup and view all the answers

How do prokaryotic cells primarily differ from eukaryotic cells?

Prokaryotic cells are smaller and do not have a nucleus. (D) Signup and view all the answers

What is the composition of cells generally recognized to be?

Similar within species but varied across different species. (D) Signup and view all the answers

Which of the following is NOT true about prokaryotic cells?

They contain a true nucleus. (B) Signup and view all the answers

What measurement unit is equivalent to one micrometer (µm)?

1 millionth of a meter. (C) Signup and view all the answers

What characteristic is common to both prokaryotic and eukaryotic cells?

Surrounded by a cell membrane. (A) Signup and view all the answers

Which option describes eukaryotic cells?

Are larger and contain a nucleus. (D) Signup and view all the answers

Study Notes

Introduction to the Cell

Cell theory is foundational in biology, explaining the essence of living organisms.
The microscope played a crucial role in the discovery and understanding of cells.

Historical Contributions

Robert Hooke (1665) observed cork slices, coining the term "cells."
Anton van Leeuwenhoek (1674) vastly improved microscope design, achieving 300x magnification; observed microscopic life, earning the title "Father of Microbiology."
Matthias Schleiden (1838) concluded that all plants consist of cells.
Theodor Schwann (1839) determined that all animals are made of cells.
Rudolph Virchow (1855) proposed that all new cells arise from preexisting cells, further advancing cell theory.

Cell Theory

Traditional Cell Theory:
- Living beings are composed of one or more cells; all cells arise from existing cells.
- Cells are the fundamental unit of structure and function in living organisms.
- Cells possess specialized structures for essential life functions.
Modern Cell Theory:
- Energy flow (metabolism) occurs within cells.
- Cells contain hereditary information (DNA) transferred during cell division.
- Cells of similar species exhibit chemical composition uniformity.

Cell Size

Cells are on the micrometer scale; 1 µm equals 1/1,000,000th of a meter.
Organelles are smaller, measured in nanometers.

Types of Cells

Cells are categorized as prokaryotic or eukaryotic.
All cells possess a cell membrane and DNA.

Prokaryotic Cells

Smaller, simpler, and more primitive; evolved before eukaryotic cells.
Lack a nucleus and membrane-bound organelles.
Examples include bacteria such as Staphylococcus and Escherichia coli.

Eukaryotic Cells

Larger and more advanced than prokaryotes; contain a nucleus.
Have specialized functions and numerous internal membranes around organelles.
Include all cells in multicellular organisms and some unicellular organisms.
Evolved from prokaryotic cells approximately 1 billion years ago.
Examples include protists, fungi, animals, and plants.

Origin of Eukaryotic Cells

The Endosymbiotic Theory suggests eukaryotic cells evolved from prokaryotic communities.
Mitochondria and chloroplasts are thought to have originated from engulfed prokaryotes.

Common Features of Prokaryotes and Eukaryotes

Both types of cells have a cell membrane, cytoplasm, DNA, and ribosomes.
They perform all essential life activities.

Organelles

Organelles function like specialized organs within a cell.
The nucleus, a prominent organelle, houses the cell's genetic material (DNA).

Key Differences

Prokaryotic Cells: Do not have a nucleus or organelles; primarily bacteria.
Eukaryotic Cells: Possess a nucleus and organelles; includes plants, animals, fungi, and protists.

Useful Mnemonic

"Eu Do" signifies that Eukaryotes have a nucleus, while "Pro No" indicates that Prokaryotes do not.

Review Topics

Key events leading to the development of cell theory.

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Description

This quiz covers key events in the development of cell theory and the role of the microscope in cell discovery. You'll be tasked with restating the traditional and modern cell theories, as well as comparing prokaryotic and eukaryotic cells. Prepare to dive into the fundamental concepts that shape our understanding of biology!