Bi 112: Cell Biology for Health Occupations

Course Overview and Instructor Information

• Course Title: Bi 112: Cell Biology for Health Occupations.

• Instructor: Shannon Kelsey.

• Copyright Details: The course materials include content copyrighted by $\text{Pearson Prentice Hall, Inc. (2005)}$ and $\text{Pearson Education, Inc. (2014)}$.

Survival Tips for Bi 112

• Participation and Attendance: Students are expected to consistently attend Zoom sessions, participate actively, and engage with the material.

• Note-Taking Requirement: Students must take their own detailed notes; the provided PowerPoints do not contain the full content of the course.

• Resource Utilization:

  • Read assigned chapters alongside the PowerPoints.

  • Utilize available online resources.

  • Take advantage of any available tutoring services.

• Personal Responsibility: Students must be willing to put in the work and seek help when needed. The instructor is available during office hours for assistance.

Required Course Materials

• Textbook: Biology in Focus by Campbell.

  • Authors: Urry, Cain, Wasserman, Minorsky, Reece, and Campbell.

  • Edition: Custom Edition specifically for Portland Community College Cascade.

• Online Course Identifer: $\text{BI112RKS2018}$.

• Lab Manual: Required for the laboratory portion of the course.

Characteristics of Life

• Definition Difficulty: "Life" is difficult to define concisely in just a few words.

• Defining Traits of Living Things:

  • Cellular Composition: Consist of cells.

  • Growth and Development: Capacity to grow, develop, and reproduce.

  • Metabolism: Require energy inputs for biological processes.

  • Responsiveness: Ability to respond to environmental stimuli.

  • Homeostasis: Capability to regulate internal environments.

  • Genetic Framework: Possess a genetic system based on $\text{DNA}$ ($\text{deoxyribonucleic acid}$) that can change and adapt over time.

Genetic Material and Basic Structure

• DNA Composition: $\text{DNA}$ is structured as a double helix consisting of two single strands.

• Nucleotides: The basic building blocks of $\text{DNA}$ are represented by the following chemical bases:

  • $\text{A}$ (Adenine)

  • $\text{C}$ (Cytosine)

  • $\text{G}$ (Guanine)

  • $\text{T}$ (Thymine)

Energy Flow and Chemical Cycling in Ecosystems

• Energy Input: Light energy arrives from the sun.

• Primary Production: Plants convert light energy into chemical energy.

• Chemical Intake: Plants take up chemicals from the soil and the air.

• Consumption: Chemical energy is passed to organisms that eat the plants.

• Decomposition: Decomposers return chemicals to the soil.

• Energy Loss: Energy is lost to the environment as heat.

Biological Hierarchy and Emergent Properties

• Levels of Biological Organization:

  1. Biosphere

  2. Ecosystems

  3. Communities

  4. Populations

  5. Organisms

  6. Organs and Organ Systems

  7. Tissues

  8. Cells

  9. Organelles

  10. Molecules

• Emergent Properties: These are properties that emerge at each level of the hierarchy that were not present at the preceding level.

  • They result from the interaction of components.

  • They cannot be deduced simply by looking at the individual parts themselves.

  • "Life" itself is considered an emergent property arising at the level of the cell.

Prokaryotic vs. Eukaryotic Cells

• Prokaryotic Organisms:

  • Composed of single cells.

  • Lack a nucleus and membrane-bound organelles (with some minor exceptions).

  • Possess small ribosomes.

  • Most have a cell wall composed of peptidoglycan.

  • Cells are generally smaller and less complex than eukaryotes.

• Eukaryotic Organisms:

  • Can be single-celled or multi-celled.

  • Contain a nucleus and various specialized organelles.

  • Possess ribosomes that are larger and denser than those in prokaryotes.

  • Some types possess cell walls, though the composition varies.

  • Cells are larger and more complex.

The Diversity of Life and Taxonomy

• Taxonomic Categories: Organized from the broadest classification to the narrowest:

  1. Domain

  2. Kingdom

  3. Phylum

  4. Class

  5. Order

  6. Family

  7. Genus

  8. species

• The Three Domains:

  • Bacteria

  • Archaea

  • Eukarya

Detailed Breakdown of Biological Domains and Kingdoms

• Domain Bacteria:

  • Single-celled prokaryotes, often found in colonial forms.

  • Kingdom: Eubacteria.

  • Most are heterotrophic with various ecological roles.

  • Ubiquitous (found everywhere).

  • Scale reference: $\approx 2\,\mu\text{m}$.

• Domain Archaea:

  • Unicellular prokaryotes.

  • Kingdom: Archaebacteria.

  • Can be heterotrophic or autotrophic.

  • Biochemically more similar to Eukarya than Bacteria.

  • Commonly extremophiles, living in harsh environments like hydrothermal vents and hot springs.

  • Scale reference: $\approx 2\,\mu\text{m}$.

• Domain Eukarya:

  • Kingdom Protista: The simplest eukaryotes; very diverse; found everywhere; includes algae, protozoa, and slime molds; can be heterotrophic or autotrophic. Scale reference: $\approx 100\,\mu\text{m}$.

  • Kingdom Fungi: Mostly multicellular with walled cells; heterotrophic (decomposers); digest food externally; include yeast, mushrooms, mold, and Penicillium; many are symbionts.

  • Kingdom Plantae: Multicellular with walled cells; photosynthetic (autotrophic); diverse morphology and habitats; includes mosses, ferns, conifers, and flowering plants.

  • Kingdom Animalia: Multicellular; heterotrophic; digest food internally; move; most reproduce sexually; the vast majority are invertebrates.

Biological Nomenclature

• Origins: The naming system was devised by Carolus Linnaeus ($1707-1778$).

• Binomial System: Every organism is given a two-part name.

  • First Name: Genus (plural: genera).

  • Second Name: species (specific epithet within the genus).

• Formatting: Scientific names must be italicized.

• Example 1 (Homo sapiens): Genus is Homo, species is sapiens.

• Example 2 (American Black Bear):

  • Domain: Eukarya

  • Kingdom: Animalia

  • Phylum: Chordata

  • Class: Mammalia

  • Order: Carnivora

  • Family: Ursidae

  • Genus: Ursus

  • Species: Ursus americanus

• Common Name Discrepancies: Multiple different species can share the same common name (e.g., "Robin" refers to Turdus migratorius in North America and Erithacus rubecula in Europe).

Evolution and Natural Selection

• Charles Darwin: Credited with the theory of evolution by natural selection as an explanation for life's diversity.

• Definition of Evolution: A genetically based change in a line of descent of a population over a period of time.

• Key Distinction: Populations change over time, NOT individuals.

• Mutation as the Basis of Variation:

  • Mutation: A change in the structure of $\text{DNA}$.

  • Provides the raw material for evolution by creating heritable variations.

  • Most mutations are neutral, but they can also be harmful or beneficial.

• Adaptive Trait: A specific trait that provides an individual with an advantage in survival or reproduction under a specific set of environmental circumstances.

The Process of Natural Selection

• Natural Selection Steps:

  1. A population exists with varied inherited traits.

  2. Elimination of individuals with certain traits occurs (environmental pressure).

  3. Survivors reproduce.

  4. There is an increasing frequency of traits that enhance survival in the population.

• Example - Antibiotic Resistance:

  • Antibiotics are applied to kill bacteria.

  • Mutations for antibiotic resistance exist naturally or arise spontaneously.

  • Antibiotic-resistant bacteria survive and reproduce more successfully than non-resistant bacteria.

  • Over time, the proportion of resistant bacteria in the population increases.

• Artificial Selection:

  • Human breeders act as selective agents.

  • Individuals with favored traits are intentionally bred.

  • The favored traits become more common in the population over generations.

Supplemental Information

• Scientific Method: The formal process of science will be covered specifically in the Lab PowerPoint materials.