Biology Chapter on Spontaneous Generation and Cell Theory

Questions and Answers

What did Anton van Leeuwenhoek observe using a single lens microscope?

Plant cells in a leaf

Live cells in pond water (correct)

Bacterial colonies on agar

Fungi growing on bread

Which statement is part of modern cell theory?

Only multicellular organisms consist of cells.

All organisms are made of multiple tissues.

Cells can spontaneously generate from non-living matter.

All living cells arise from pre-existing cells. (correct)

Which type of cells do not have membrane-bound organelles?

Eukaryotic cells

Prokaryotic cells (correct)

Plant cells

Animal cells

What is the primary function of the nucleus in a cell?

To direct cell activities and contain genetic material Signup and view all the answers

What does the cell membrane primarily control?

The movement of substances in and out of the cell Signup and view all the answers

What is the role of ribosomes found in eukaryotic cells?

To synthesize proteins Signup and view all the answers

Which component provides structural support to plant cells?

Cell wall Signup and view all the answers

What is the term used for the gel-like substance found within a cell?

Cytoplasm Signup and view all the answers

Which statement accurately summarizes the findings of Francisco Redi regarding spontaneous generation?

Macroorganisms do not spontaneously generate, as proven by his experiments. Signup and view all the answers

What was the purpose of the long, twisted necks of Pasteur's swan-neck flasks?

To trap airborne microorganisms while allowing air to enter. Signup and view all the answers

Which of the following is NOT one of the main tenets of the Cell Theory?

Cells arise from nonliving matter. Signup and view all the answers

Who is credited with coining the term 'cell' and in which year?

Robert Hooke in 1665. Signup and view all the answers

How long did it take for the Cell Theory to be formulated?

173 years. Signup and view all the answers

Which of the following best describes the main outcome of Pasteur's experimentation with swan-neck flasks?

Microorganisms, not spontaneous generation, cause microbial growth. Signup and view all the answers

Which contributor to the Cell Theory invented the first compound microscope?

Janssen. Signup and view all the answers

What did Pasteur's predictions about the sterility of boiled broth involve?

Intact necks would keep the broth sterile. Signup and view all the answers

Study Notes

Spontaneous Generation

Francisco Redi's experiment with three jars (open, gauze-covered, sealed) demonstrated that macroorganisms do not spontaneously generate.
Pasteur's work with swan-neck flasks proved microorganisms don't arise from spontaneous generation; the broth remained sterile unless the necks were broken, allowing contamination.
Pasteur established that microbial growth results from microorganisms rather than a "life force."

Cell Theory

Formulated by Theodor Schwann and Matthias Schleiden, consisting of three fundamental principles:
- All organisms are composed of cells.
- All existing cells arise from pre-existing living cells, eliminating spontaneous generation.
- Cells are the basic unit of life.
The development of the microscope played a crucial role in establishing the Cell Theory, taking over 173 years to formulate (1665-1838).

Contributors to Cell Theory

Janssen: Inventor of the first compound microscope.
Robert Hooke (1665): Observed cork and named "cells" from Latin ‘cellula’.
Anton van Leeuwenhoek: Used a single lens microscope for live cell observation, introducing "animacules."
Matthias Schleiden: Proposed that plants are made of cells.
Theodor Schwann: Concluded that all animals consist of cells and published the first statement of the Cell Theory.
Rudolf Virchow: Added that all cells come from pre-existing cells.

Modern Cell Theory

Modern principles include:
- All living things consist of one or more cells.
- Living cells arise from pre-existing cells by division.
- Cells are fundamental units of structure and function.
- The activity of an organism depends on independent cell activities.
- Metabolism occurs within cells.
- Cells contain DNA in chromosomes and RNA in the nucleus/cytoplasm.
- Chemical composition of similar species' cells is consistent.
- Hereditary information (DNA) is transferred between cells.
- All cells share basic chemical composition.

Types of Cells

Cells are the smallest units capable of performing life functions, categorized into two types:
- Prokaryotic: Lack membrane-bound organelles, simpler internal structure, primarily unicellular organisms like bacteria.
- Eukaryotic: Contain membrane-bound organelles and are primarily multicellular organisms.

Parts of the Cell (Organelles)

Organelles are specialized structures within a cell.
Cell Membrane: Outer layer, regulates movement in/out of the cell; composed of a phospholipid bilayer.
Cell Wall: Found in plant cells and bacteria, providing support and protection.
Nucleus: Directs cellular activities, surrounded by a nuclear membrane, containing DNA.
Nuclear Membrane: Two layers with openings to allow material exchange with the cytoplasm.
Chromosomes: Structures made of DNA within the nucleus, carrying genetic information.
Nucleolus: Located inside the nucleus, responsible for RNA production for protein synthesis.
Cytoplasm: Gel-like substance within the cell, housing organelles and hereditary material.

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Description

Explore the foundational concepts of spontaneous generation and cell theory in this quiz. Learn about the critical experiments of Francisco Redi and Louis Pasteur, as well as the key principles established by Theodor Schwann and Matthias Schleiden. Test your understanding of the historical development and contributions to the science of biology.