Part 1 – Classwork Component of Test

Definition of Life

The definition of life is central to biology and involves understanding cellular organization and DNA. Living organisms share several key characteristics that distinguish them from non-living matter.

• Cellular Organization: All living things are composed of one or more cells, which are the basic units of life.

• DNA: Deoxyribonucleic acid is the hereditary material in almost all living organisms.

• Other Characteristics: Metabolism, growth, response to stimuli, reproduction, and homeostasis.

• Example: Bacteria are unicellular organisms with DNA, capable of metabolism and reproduction.

Cell Theory

Cell theory is a fundamental concept in biology, describing the properties of cells as the basic unit of life.

• Key Contributors: Robert Hooke (examined bark from an oak tree), Schleiden & Schwann (formulated the cell theory).

• Main Tenets:

  1. All living things are composed of cells.

  2. The cell is the basic unit of structure and function in living things.

  3. All cells arise from pre-existing cells.

• Example: Plant tissues observed under a microscope reveal many cells, supporting cell theory.

Biological Classification: Domains and Kingdoms

Biological classification organizes living organisms into hierarchical categories based on shared characteristics.

• Three Domains: Bacteria, Archaea, Eukarya.

• Six Kingdoms: Bacteria, Archaea, Protista, Fungi, Plantae, Animalia.

• Hierarchy: Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species.

• Mnemonic: "Dear King Philip Came Over For Good Soup" helps remember the order.

• Classification Table:

Additional info: The six kingdoms are sometimes grouped differently depending on the classification system.

Scientific Names and Classification

Scientific names use binomial nomenclature, consisting of genus and species, to uniquely identify organisms.

• Genus: The first part of the scientific name, capitalized.

• Species: The second part, lowercase.

• Example: Homo sapiens (human).

• Difference between Category and Taxon: A category is a rank in the hierarchy; a taxon is a group of organisms at any rank.

Levels of Biological Organization

Biology studies life at multiple levels, from molecules to biospheres.

• Molecules → Organelles → Cells → Tissues → Organs → Organ Systems → Organisms → Populations → Communities → Ecosystems → Biosphere

• Example: The human heart (organ) is made of muscle tissue (tissue), which consists of cells.

Prokaryotes vs. Eukaryotes

Cells are classified as prokaryotic or eukaryotic based on their structure.

5 Major Themes of Biology

Biology is unified by several major themes:

• Evolution

• Information Flow

• Structure & Function

• Energy & Matter

• Interactions

Key Terms

Important terms for classification and cell biology:

• Absorptive heterotroph: Organism that obtains nutrients by absorbing organic matter.

• Autotroph: Organism that produces its own food from inorganic substances.

• Binomial: Two-part scientific naming system.

• Colony: Group of cells or organisms living together.

• Emergent Properties: New properties that arise at each level of organization.

• Eukaryotic cell: Cell with a nucleus and organelles.

• Evolution: Change in populations over time.

• Heterotroph: Organism that obtains food by consuming other organisms.

• Hooke: Scientist who first described cells.

• Ingestive heterotroph: Organism that ingests food.

• Linnaeus: Developed the modern classification system.

• Multicellular: Composed of multiple cells.

• Nucleus: Organelle containing genetic material.

• Photosynthetic Autotroph: Organism that uses light to synthesize food.

• Prokaryotic cell: Cell without a nucleus.

• Schleiden: Co-founder of cell theory.

• Schwann: Co-founder of cell theory.

• Taxonomy: Science of classification.

• Unicellular: Composed of a single cell.

Part 2 – Lab Component of Test

Using a Dichotomous Key

A dichotomous key is a tool used to identify organisms based on a series of choices that lead to the correct name.

• Application: Used to identify unknown organisms by answering a sequence of questions about their characteristics.

• Example: Identifying a tree species by leaf shape and arrangement.

Tree Key Lab & Terms

Tree keys are specialized dichotomous keys for identifying tree species.

• Abbreviated Tree Key: Simplified version for quick identification.

• Example: Using leaf margin and type to distinguish between oak and maple.

Microscope Lab

Microscopes are essential tools in biology for observing cells and tissues.

• Types of Microscopes:

  • DS (Dissecting Scope or Stereomicroscope): Used for low magnification observation of larger specimens.

  • CLM (Compound Light Microscope): Used for higher magnification of thin specimens.

  • SEM (Scanning Electron Microscope): Produces detailed 3D images of specimen surfaces.

  • TEM (Transmission Electron Microscope): Provides high-resolution images of internal structures.

• Key Parts of CLM: Ocular lenses, objective lenses, stage, coarse focus, fine focus, nose piece, mechanical stage adjustment knobs.

• Magnification: Total magnification is calculated by multiplying the ocular lens magnification by the objective lens magnification.

• Formula:

• Example: Ocular lens (10x) and objective lens (40x) gives total magnification of 400x.

Classification Lab

Classification labs involve identifying organisms using keys and microscopes, and determining cell type.

• Photomicrograph/Electron Micrograph: Images used to identify cell structure and type.

• Prokaryote vs. Eukaryote: Identification based on presence or absence of nucleus and organelles.

• Example: Bacterial cells (prokaryotes) lack a nucleus; plant cells (eukaryotes) have a nucleus.

Microscope Types Table