Cell Theory & Types - BIOL0011 Lecture 1

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Questions and Answers

Who proposed the first two tenets of cell theory?

Rudolf Virchow

Theodor Schwann (correct)

Anton Van Leeuwenhoek

Matthias Schleiden (correct)

What is the smallest unit that can give rise to new life?

Tissue

Cell (correct)

Organism

Organ

Which scientist proposed that all cells arise from pre-existing cells?

Anton Van Leeuwenhoek

Theodor Schwann

Matthias Schleiden

Rudolf Virchow (correct)

What is NOT a feature of living organisms?

Ability to move Signup and view all the answers

Which of the following components is NOT typically found in a cell?

Muscle fibers Signup and view all the answers

How did Anton Van Leeuwenhoek contribute to microbiology?

Observed organisms in pond water Signup and view all the answers

What is the primary function of ribosomes within cells?

Protein synthesis Signup and view all the answers

Which level of organization is directly composed of cells?

Tissue Signup and view all the answers

What is the primary function of the plasma membrane in cells?

To allow the exchange of materials with the environment Signup and view all the answers

Which of the following processes is NOT performed by cells?

Erosion Signup and view all the answers

How do cells adapt to environmental changes?

By undergoing structural and physiological changes Signup and view all the answers

In the context of life processes, which of the following is an example of a response to stimuli?

A plant bending toward light Signup and view all the answers

What does it mean for cells to maintain homeostasis?

To regulate their internal processes and conditions Signup and view all the answers

Which level of organization is the most complex?

Organ system Signup and view all the answers

What is a key characteristic of cells regarding reproduction?

Cells can reproduce both sexually and asexually Signup and view all the answers

What does the term 'metabolic processes' refer to?

Chemical reactions that maintain cell function Signup and view all the answers

What is one of the tenets of Cell Theory?

All organisms are composed of one or more cells. Signup and view all the answers

Which of the following statements correctly distinguishes a prokaryotic cell from a eukaryotic cell?

Prokaryotic cells lack membrane-bound organelles. Signup and view all the answers

Who was the first to observe cells and what did he name them?

Robert Hooke, named them cellulae. Signup and view all the answers

During which century was the microscope invented, leading to the discovery of cells?

17th century Signup and view all the answers

Which of the following is NOT a characteristic of a prokaryotic cell?

Has membrane-bound organelles. Signup and view all the answers

Which statement correctly identifies a feature exclusive to eukaryotic cells?

Organized into complex structures and contain organelles. Signup and view all the answers

Which cellular structure is primarily absent in animal cells but present in plant cells?

Chloroplasts Signup and view all the answers

What is the primary significance of the invention of the microscope in biology?

It enabled the discovery of organisms invisible to the naked eye. Signup and view all the answers

What type of ribosomes are found in prokaryotic cells?

70S ribosomes Signup and view all the answers

Which of the following organelles is absent in prokaryotic cells?

Golgi body Signup and view all the answers

What is a characteristic of eukaryotic cells in terms of genetic material?

Genetic material housed within a well-developed nucleus Signup and view all the answers

How do eukaryotic cells typically undergo cytokinesis?

Forming a cell plate Signup and view all the answers

Which of the following statements about eukaryotic cells is correct?

Eukaryotic cells may contain membrane-bound organelles Signup and view all the answers

What is the primary nutritional mode of prokaryotic cells compared to eukaryotic cells?

Autotrophic in prokaryotic and heterotrophic in eukaryotic Signup and view all the answers

Which of the following characteristics is true for ribosomes in eukaryotic cells?

They are larger than those in prokaryotic cells Signup and view all the answers

Which of the following processes are vital for maintaining life in a cell?

Respire and reproduce Signup and view all the answers

What distinguishes prokaryotic cells from eukaryotic cells?

Complex organelles Signup and view all the answers

What is the primary function of ribosomes in a cell?

Site of protein synthesis Signup and view all the answers

Which cellular component is described as the aqueous site of metabolic reactions?

Cytoplasm Signup and view all the answers

How do specialized cells contribute to the function of living organisms?

They are assigned particular tasks based on structure Signup and view all the answers

What role does osmoregulation play in cells?

It maintains water balance Signup and view all the answers

Which characteristic is primarily responsible for the variation in cell size and shape?

Function and specialization Signup and view all the answers

What is the primary structural difference between the cytoplasm and cytosol?

Cytoplasm contains organelles; cytosol does not Signup and view all the answers

Study Notes

Cell Theory

Cell theory is a fundamental concept in biology, outlining the properties of cells.
All organisms consist of one or more cells.
Cells are the basic structural and functional units of life.
New cells arise only from pre-existing cells through division.

Key Contributors to Cell Theory

Robert Hooke (1665) discovered and named cells (cellulae) while examining cork.
Anton Van Leeuwenhoek (1667) was the first to observe living cells in pond water.
Matthias Schleiden and Theodor Schwann (1800s) concluded that all plants and animals are composed of cells.
Rudolf Virchow (1855) proposed that all cells come from pre-existing cells.

Characteristics of Living Organisms

Composed of cells containing membranes, cytoplasm, genetic material, ribosomes, and various organelles.
Exhibit growth and development, either in size and biomass or by increasing cell number.
Self-regulate metabolic processes and maintain homeostasis through respiration for energy production.
Respond to environmental stimuli (light, temperature, sound, etc.) with movement.
Capable of reproduction, both sexually and asexually.
Adapt structurally, physiologically, and behaviorally to environmental changes (evolution).
Organized into levels: chemical, cellular, tissue, organ, and organ systems.

Components of Cells

All cells possess a plasma membrane that encases the cytoplasm, separating it from the environment.
Genetic material is vital for cell reproduction and the continuation of life.
Cytoplasm is the medium for metabolic processes, consisting of cytosol and organelles.
Ribosomes serve as the site for protein production.

Prokaryotic vs. Eukaryotic Cells

Prokaryotic Cells:
- Simplest cellular organization, lacking membrane-bound organelles.
- Have no organized nucleus; genetic material is freely located in the cell.
- Utilize 70S ribosomes and typically exhibit a rigid, rectangular shape.
Eukaryotic Cells:
- More complex with membrane-bound organelles (e.g., mitochondria, Golgi apparatus).
- Possess a well-defined nucleus that holds the genetic material.
- Use 80S ribosomes and can vary in shape, typically flexible and round.

Special Features

Eukaryotic cells may contain lysosomes and centrioles, whereas prokaryotes do not.
Cytokinesis varies: prokaryotes form a cell plate, while eukaryotes utilize a contractile ring mechanism.
Nutrition methods differ: prokaryotes often autotrophic; eukaryotes are mainly heterotrophic.
Storage materials are distinct: starch in plants, glycogen in animals.

Distinguishing Plant and Animal Cells

Plant cells typically have rigid structures while animal cells are more flexible.
Storage forms: plants store starch; animals store glycogen.
Plant cells usually lack centrioles, which are present in animal cells.

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Description

Explore the fundamental concepts of Cell Theory and the different types of cells in this quiz from BIOL0011 Lecture 1. Understand the principles that govern cellular biology and the classification of cells. Test your knowledge and reinforce your learning!