BIO105 Final Exam Review: Comprehensive Study Notes

Scientific Foundations

Hypothesis

A hypothesis is a testable statement or prediction about the natural world that can be supported or refuted through experimentation or observation.

• Key Point: Hypotheses are central to the scientific method and must be falsifiable.

• Example: "If plants receive more sunlight, then they will grow taller."

Cell Structure and Function

Cell Doctrine

The Cell Doctrine (Cell Theory) states that all living things are composed of cells, cells are the basic unit of life, and all cells arise from pre-existing cells.

• Key Point: This theory underpins modern biology and emphasizes the importance of cells in structure and function.

Organelles and Their Function

• Nucleus: Contains genetic material (DNA) and controls cell activities.

• Mitochondria: Site of cellular respiration and ATP production.

• Ribosomes: Synthesize proteins; can be free or attached to the endoplasmic reticulum.

• Endoplasmic Reticulum (ER): Rough ER synthesizes proteins; Smooth ER synthesizes lipids and detoxifies.

• Golgi Apparatus: Modifies, sorts, and packages proteins and lipids for secretion or use within the cell.

• Lysosomes: Contain digestive enzymes to break down waste.

• Plasma Membrane: Regulates entry and exit of substances.

Types of Transport

• Active Transport: Movement of substances against their concentration gradient, requiring energy (ATP).

• Passive Transport: Movement of substances down their concentration gradient, not requiring energy (e.g., diffusion, osmosis).

• Osmosis: Diffusion of water across a selectively permeable membrane.

• Example: Water moving into a cell placed in a hypotonic solution.

Macromolecules

• Carbohydrates: Energy source and structural support (e.g., glucose, starch).

• Lipids: Energy storage, insulation, and membrane structure (e.g., fats, phospholipids).

• Proteins: Enzymes, structural components, transport (e.g., hemoglobin, actin).

• Nucleic Acids: Store and transmit genetic information (DNA, RNA).

Hydrolysis Reactions

Hydrolysis is a chemical reaction in which water is used to break down polymers into monomers.

• Example: Digestion of proteins into amino acids.

Anabolism versus Catabolism

• Anabolism: Building up of complex molecules from simpler ones (requires energy).

• Catabolism: Breaking down of complex molecules into simpler ones (releases energy).

Genetics and Cell Division

DNA and RNA

• DNA (Deoxyribonucleic Acid): Double-stranded molecule storing genetic information.

• RNA (Ribonucleic Acid): Single-stranded; involved in protein synthesis (mRNA, tRNA, rRNA).

• Replication: Process by which DNA makes a copy of itself during cell division.

• Transcription: Synthesis of RNA from a DNA template.

• Translation: Process where ribosomes synthesize proteins using mRNA as a template.

Chromosome Number and Ploidy

• Haploid: Cells with one set of chromosomes (n), e.g., gametes.

• Diploid: Cells with two sets of chromosomes (2n), e.g., somatic cells.

Histones

Histones are proteins that package and order DNA into structural units called nucleosomes.

Mitosis and Meiosis

• Mitosis: Cell division resulting in two genetically identical diploid cells.

• Meiosis: Cell division producing four genetically unique haploid gametes.

Interphase

Interphase is the phase of the cell cycle where the cell grows, replicates its DNA, and prepares for division.

Cyclins

Cyclins are regulatory proteins that control progression through the cell cycle.

Punnett Squares and Inheritance Patterns

• Punnett Square: Diagram used to predict the outcome of genetic crosses.

• Monohybrid Cross: Involves one gene; typical ratio is 3:1 for dominant:recessive in F2 generation.

• Dihybrid Cross: Involves two genes; typical ratio is 9:3:3:1 in F2 generation.

• Polygenic Inheritance: Trait controlled by multiple genes (e.g., skin color).

• Sex-Influenced Inheritance: Traits where expression differs between sexes.

• X-linked Pedigree: Inheritance pattern for genes located on the X chromosome.

Trisomy X

Trisomy X is a chromosomal disorder where females have three X chromosomes (47,XXX).

Energy and Metabolism

ATP (Adenosine Triphosphate)

ATP is the primary energy carrier in cells.

• Key Point: Energy is released when ATP is hydrolyzed to ADP and inorganic phosphate.

• Equation:

$\mathrm{ATP} + \mathrm{H}_2\mathrm{O} \rightarrow \mathrm{ADP} + \mathrm{P_i} + \text{energy}$

Citric Acid Cycle

The Citric Acid Cycle (Krebs Cycle) is a series of chemical reactions used by all aerobic organisms to generate energy through the oxidation of acetyl-CoA.

• Key Point: Produces NADH, FADH2, and ATP, releasing CO2 as a waste product.

Tissues and Organ Systems

Muscle Tissue and Types

• Skeletal Muscle: Voluntary, striated, attached to bones.

• Cardiac Muscle: Involuntary, striated, found in the heart.

• Smooth Muscle: Involuntary, non-striated, found in walls of organs.

Nervous Tissue

Nervous tissue is specialized for communication via electrical and chemical signals.

• Axons: Transmit impulses away from the cell body.

• Dendrites: Receive signals and transmit them toward the cell body.

Epithelial Tissues

• Shapes: Squamous (flat), cuboidal (cube-shaped), columnar (tall).

• Locations: Skin, lining of digestive tract, glands, etc.

• Basement Membrane: Thin layer anchoring epithelium to underlying tissue.

• Goblet Cells: Specialized epithelial cells that secrete mucus.

Types of Junctions

• Tight Junctions: Prevent leakage between cells.

• Desmosomes: Provide mechanical strength.

• Gap Junctions: Allow communication between cells.

Kingdoms and Evolution

Kingdoms

Biological classification divides life into several kingdoms, such as Animalia, Plantae, Fungi, Protista, Archaea, and Bacteria.

Homologous versus Analogous Structures

• Homologous Structures: Similar in structure due to shared ancestry (e.g., human arm and bat wing).

• Analogous Structures: Similar in function but not ancestry (e.g., bird wing and insect wing).

Evolutionary Tree

An evolutionary tree (phylogenetic tree) shows relationships among species based on evolutionary history.

"Homo" Species

The genus Homo includes modern humans (Homo sapiens) and extinct relatives (e.g., Homo neanderthalensis).

Pangea

Pangea was a supercontinent that existed during the late Paleozoic and early Mesozoic eras.

Population Genetics and Evolution

Genetic Drift

Genetic drift is a change in allele frequencies due to random events, especially in small populations.

• Bottleneck Effect: Sharp reduction in population size leads to reduced genetic diversity.

• Founder Effect: New population started by a small group, leading to different allele frequencies.

Gene Flow

Gene flow is the transfer of alleles from one population to another, increasing genetic diversity.

Antigenic Shift

Antigenic shift is a major change in the surface proteins of viruses, often leading to new strains.

Population Dynamics and Ecology

Population Growth Curves

• Exponential Growth: Population increases rapidly under ideal conditions.

• Logistic Growth: Population growth slows as it approaches carrying capacity.

Carrying Capacity

Carrying capacity is the maximum population size an environment can sustain.

Limiting Factors

Limiting factors are environmental factors that restrict population growth (e.g., food, space, disease).

Biotic Potential

Biotic potential is the maximum reproductive capacity of a population under optimal conditions.

Rule of 72 and Growth Rate Formula

• Rule of 72: Estimates the time required for a population to double. Divide 72 by the annual growth rate (%).

• Formula:

$\text{Doubling Time} = \frac{72}{\text{Growth Rate (\%)}}$

• Population Growth Rate Formula:

$\text{Growth Rate} = \frac{\text{Births} - \text{Deaths}}{\text{Total Population}} \times 100$

Summary Table: Types of Muscle Tissue

Type	Location	Control	Striations
Skeletal	Attached to bones	Voluntary	Yes
Cardiac	Heart	Involuntary	Yes
Smooth	Walls of organs	Involuntary	No

Summary Table: Types of Epithelial Tissue Shapes

Shape	Description	Example Location
Squamous	Flat, thin	Alveoli of lungs
Cuboidal	Cube-shaped	Kidney tubules
Columnar	Tall, column-like	Lining of intestine

Additional info:

• Some terms (e.g., tRNA, ribosomal subunits) are components of the translation process in protein synthesis.

• Population dynamics, gene flow, and genetic drift are key concepts in evolutionary biology and ecology.