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Questions and Answers
What are the two main types of cells?
Prokaryotes and Eukaryotes
What is the size range of prokaryotic cells in diameter?
1-10 um
Prokaryotic cells contain a membrane-bound nucleus.
False
What are the two groups organisms can be divided into based on cellular organization?
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What distinguishes Gram-positive bacteria from Gram-negative bacteria?
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Which classification includes ancient bacteria that live in extreme conditions?
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What is the function of ribosomes in prokaryotic cells?
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Cells must __________ and respond to changes in their environments.
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Which of the following is NOT a characteristic of living organisms?
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Study Notes
Organization Within an Organism
- Atoms are organized into molecules.
- Multicellular organisms organize cells into tissues, organs, and organ systems.
- All organisms are made up of at least one cell.
- Life emerges at the cellular level.
Levels of Organization
- The levels of organization in biology are: atom, molecule, organelle, cell, tissue, organ, organ system, organism, population, community, ecosystem, and biosphere.
Key Concepts: Levels of Organization
- Studying life involves examining various levels of organization from atoms and molecules to the entire biosphere.
- Life arises at the cellular level.
Ecosystem
- Organisms require energy and materials for survival and activity.
Overview of Life’s Unity
- Organisms grow and reproduce.
- Genetic information is encoded in DNA.
- DNA is passed down through generations during reproduction.
- Development transforms a single cell into an adult organism.
Key Concepts
- All organisms share key characteristics:
- Made up of one or more cells
- Require energy and raw materials
- Respond to changes in their environments
- Contain DNA
Cells as the Smallest Unit of Life
- The cell is the smallest unit capable of performing life processes.
- Cells fulfill the criteria of living organisms:
- Reproduction: Cell replication
- Nutrition: Nutrition
- Respiration: Respiration
- Excretion: Excretion
- Irritability/Respond: Respond to the environment
- Movement: Movement within and externally
- Growth: Increase in size and number
Genus and Species
- A species describes one type of organism.
- Species have a two-part scientific name:
- Genus name
- Specific epithet (second part that designates the specific species within the genus)
Domains
- Current classification systems organize all species into three domains:
- Bacteria (single-celled prokaryotes)
- Archaea (single-celled prokaryotes)
- Eukarya (protists, plants, fungi, and animals)
Bacteria and Archaea
-
Bacteria:
- Most common bacteria found in diverse environments
-
Archaea:
- Ancient bacteria adapted to extreme living conditions
Eukarya
- Includes protists, plants, fungi, and animals.
Two Main Types of Cells
- Prokaryotes: Lack a membrane-bound nucleus and organelles.
- Eukaryotes: Possess membrane-bound nucleus and organelles.
Age of Cell Types
- Prokaryotes: Older, existing 3.8 billion years ago
- Eukaryotes: Younger, appearing 2.7 billion years ago
The Six Kingdoms
-
Prokaryotic Kingdoms:
- Eubacteria
- Archaebacteria
-
Eukaryotic Kingdoms:
- Animals
- Plants
- Fungi
- Protists
Organisms Classified by Cell Structure and Number of Cells
-
Single-celled:
- Prokaryotes: Bacteria
- Eukaryotes: Fungi, Protozoa, Algae
-
Multicellular:
- Eukaryotes: Fungi, Algae, Plants, Animals
Prokaryotes
- Simple cell structure with limited types of cell parts.
- Two main prokaryotic kingdoms:
- Eubacteria: Common bacteria found everywhere.
- Archaebacteria (arche=ancient or old): Ancient bacteria adapted to extreme environments.
Prokaryotic Cells
- 1-10 um in diameter, visible with light microscopes.
- Lack a membrane-bound nucleus and organelles.
- Genetic material is located in the cytoplasm.
- Ribosomes are the only organelle present.
Cell Wall
-
Bacterial cell wall:
- Rigid and surrounds the cytoplasmic membrane.
- Determines the shape of bacteria.
- Prevents cell bursting.
- Has a unique chemical structure used to differentiate Gram-positive and Gram-negative bacteria.
Plasma Membrane
- A phospholipid and protein layer that separates the cytoplasm from the external environment.
- Regulates the flow of materials in and out of the cell.
Ribosomes
- Translate the genetic code into proteins.
- Found free-floating in the cytoplasm.
- Composed of large (50S) and small (30S) subunits.
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Description
Explore the various levels of organization in biology, from atoms and molecules to ecosystems. This quiz will cover essential concepts that illustrate how life is structured and the unity of living organisms. Understand how life emerges at the cellular level and the significance of genetic information.
