General Biology Lesson 1: Cell Theory

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Questions and Answers

Who invented the very first microscope?

Zacharias Janssen

What term did Robert Hooke use to describe the box-shaped structures he saw in cork?

cells

What did Anton Van Leeuwenhoek observe in pond water?

animalcules

Who stated that plants are made up of cells?

Matthias Schleiden Signup and view all the answers

What did Theodor Schwann state about animals?

Animals are made up of cells. Signup and view all the answers

What did Rudolf Virchow state about cells?

Cells come from pre-existing cells through cell division. Signup and view all the answers

Which of the following is NOT one of the original postulates of cell theory?

Cells can create energy from nonliving matter Signup and view all the answers

What type of structures are organelles often referred to as?

little organs Signup and view all the answers

What is the primary function of the cell membrane?

Separates and regulates passage between the cell's inner contents and the environment. Signup and view all the answers

What is the cell wall made up of?

cellulose Signup and view all the answers

What is the function of the nucleus?

Store DNA and control cell activities. Signup and view all the answers

Where are ribosomes synthesized?

In the nucleolus. Signup and view all the answers

What is the function of mitochondria?

Produces chemical energy in the form of ATP. Signup and view all the answers

What does the rough endoplasmic reticulum have attached to its surface?

Ribosomes Signup and view all the answers

What is the primary function of the Golgi body?

Sorts, labels, packages, and distributes lipids and proteins. Signup and view all the answers

What is the primary role of lysosomes?

Digest cellular nutrients and aid in apoptosis. Signup and view all the answers

What process occurs in chloroplasts?

Photosynthesis Signup and view all the answers

What do vacuoles primarily store?

Nutrients and waste products. Signup and view all the answers

What is the cytoskeleton's primary function?

Provides structure and shape and facilitates cell movement. Signup and view all the answers

Study Notes

Historical Development of Cell Theory

1590s: Zacharias Janssen invented the first microscope.
1665: Robert Hooke observed cork and termed the structures as "cells."
1674: Anton Van Leeuwenhoek discovered "animalcules" in pond water, founding microbiology.
1838: Matthias Schleiden identified that plants consist of cells.
1839: Theodor Schwann concluded that animals are made of cells.
1855: Rudolf Virchow proclaimed that cells arise from pre-existing cells, establishing a fundamental principle of cell theory.

Cell Theory

First Postulate: All living organisms are composed of cells.
Second Postulate: Cells are the basic structural and functional units of life.
Third Postulate: New cells arise from existing cells ("Omnis cellula e cellula").
Modern Additions:
- Cells contain genetic material passed during cell division.
- All cells share the same structural and chemical makeup.
- Energy flow occurs within cells through biochemical processes.

Organelles: Structures and Functions

Definition: Organelles are specialized structures performing essential functions in cellular life.

Cell Membrane

Structure: Composed of thin, double layers of proteins and fats.
Function: Encloses cell contents; regulates material exchange with the environment.

Cell Wall

Structure: Rigid membrane made of cellulose.
Function: Offers protection, support, and structure; exclusive to plant cells.

Nucleus

Structure: Membrane-bound spherical body, identified by Robert Brown in 1831.
Function: Houses DNA; oversees cell activities and protein synthesis.

Nucleolus

Structure: Spherical body within the nucleus.
Function: Manufactures and assembles ribosomes.

Ribosome

Structure: Complex of proteins and RNA.
Function: Primary site for protein synthesis.

Mitochondria

Structure: Double-membraned, rod-shaped with independent DNA.
Function: Produces ATP, the cell's energy currency.

Endoplasmic Reticulum (ER)

Structure: Network of membranous sacs and tubules with two types:
- Rough ER: Ribosome-studded surface.
  - Function: Modifies proteins from ribosomes; synthesizes phospholipids.
- Smooth ER: Lacks ribosomes.
  - Function: Synthesizes carbohydrates, lipids, and steroids; stores calcium ions.

Golgi Body

Structure: Series of flat, stacked sacs resembling pancakes.
Function: Modifies, sorts, packages, and distributes lipids and proteins.

Lysosome

Structure: Spherical bodies that produce enzymes, found only in animal cells.
Function: Digests cellular nutrients, facilitates apoptosis, breaks down pathogens, and recycles damaged cells.

Chloroplast

Structure: Disc-shaped organelle exclusive to plant cells.
Function: Conducts photosynthesis; contains chlorophyll for capturing light energy.

Vacuole

Structure: Large, membrane-enclosed fluid-filled space, primarily in plant cells.
Function: Stores nutrients and waste; maintains water balance and cell shape.

Cytoskeleton/Cytoplasm

Structure: Network of protein filaments, including microfilaments, microtubules, and intermediate filaments.
Function: Provides structural support, enables cellular movement, and assists in spindle formation during cell division.

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Description

This quiz covers the fundamental concepts of cell theory, exploring the contributions of key figures in the history of microscopy, like Janssen, Hooke, and Leeuwenhoek. Delve into the basic structure of cells and understand the significance of these developments in biology. Test your knowledge on how the study of cells revolutionized our understanding of life.