General Terminology

Key Biological Terms

This section covers essential terminology and concepts fundamental to General Biology. Understanding these terms is crucial for mastering the course material and succeeding on the final exam.

• Cell Cycle: The series of events that cells go through as they grow and divide. Includes interphase (G1, S, G2) and mitotic phase (mitosis and cytokinesis).

• Hydrolysis: A chemical reaction in which water is used to break down a compound; important in digestion and breakdown of macromolecules.

• Citric Acid Cycle (Krebs Cycle): A key metabolic pathway that generates energy through the oxidation of acetyl-CoA.

• Oxidative Phosphorylation: The process in mitochondria that produces ATP using energy released by electrons transferred to oxygen.

• Glycolysis: The breakdown of glucose into pyruvate, producing ATP and NADH.

• Cellular Respiration: The process by which cells extract energy from glucose, involving glycolysis, the citric acid cycle, and oxidative phosphorylation.

• Histones: Proteins that package and order DNA into structural units called nucleosomes.

• DNA Replication: The process of copying DNA prior to cell division.

• DNA Polymerase: The enzyme responsible for synthesizing new DNA strands.

• ATP Synthase: The enzyme that synthesizes ATP from ADP and inorganic phosphate during oxidative phosphorylation.

• RNA Polymerase: The enzyme that synthesizes RNA from a DNA template.

• mRNA, tRNA, rRNA: Types of RNA involved in protein synthesis; messenger, transfer, and ribosomal RNA, respectively.

• Dominant/Recessive Alleles: Dominant alleles mask the effect of recessive alleles in heterozygotes.

• Homozygous/Heterozygous: Homozygous individuals have two identical alleles; heterozygous have two different alleles.

• Non-disjunction: Failure of chromosomes to separate properly during cell division, leading to chromosomal abnormalities.

• Genetic Drift: Random changes in allele frequencies in a population.

• Natural Selection: The process by which organisms better adapted to their environment tend to survive and reproduce.

• Bottleneck Effect/Founder Effect: Types of genetic drift resulting from population size reduction or establishment of a new population.

• Biotic Potential: The maximum reproductive capacity of an organism under optimal environmental conditions.

• Ecosystem, Community, Population: Levels of ecological organization; populations are groups of the same species, communities are multiple populations, ecosystems include abiotic factors.

• Sensory Neurons/Motor Neurons: Sensory neurons transmit signals to the CNS; motor neurons transmit signals from the CNS to muscles.

• Diploid/Haploid Cells: Diploid cells have two sets of chromosomes; haploid cells have one set.

• Cyclins: Proteins that regulate the cell cycle.

• Catabolism/Anabolism: Catabolism breaks down molecules; anabolism builds up molecules.

• Exponential/Theoretical Growth: Population growth without environmental resistance.

• Carrying Capacity: The maximum population size an environment can sustain.

• Environmental Resistance: Factors that limit population growth.

Key Concepts

Characteristics of Life

Biologists define life using seven key characteristics. Understanding these is foundational for all biological study.

• Cellular Organization

• Homeostasis

• Metabolism

• Growth and Development

• Reproduction

• Response to Stimuli

• Adaptation through Evolution

Classification of Life: Life is organized into three domains (Bacteria, Archaea, Eukarya) and further into kingdoms.

The Scientific Method

The scientific method is a systematic approach to inquiry in biology.

• Observation

• Hypothesis Formation

• Experimentation

• Data Collection

• Analysis

• Conclusion

Macromolecules

Hydrolysis Reactions

Macromolecules are broken down by hydrolysis, which adds water to split bonds.

• Carbohydrates: Monosaccharides, disaccharides, polysaccharides

• Proteins: Amino acids joined by peptide bonds

• Lipids: Fatty acids and glycerol

• Nucleic Acids: Nucleotides

Example: Hydrolysis of sucrose yields glucose and fructose.

Cell Structures

Cell Theory (Cell Doctrine)

Cell theory is a fundamental principle in biology.

• All living things are composed of cells.

• Cells are the basic unit of life.

• All cells arise from pre-existing cells.

Advantages for Cells to Stay Small

• Higher surface area-to-volume ratio for efficient transport.

• Faster communication and metabolic processes.

Structure & Functions of Organelles in Eukaryotic Cells

• Nucleus: Contains genetic material.

• Mitochondria: Site of cellular respiration.

• Ribosomes: Protein synthesis.

• Endoplasmic Reticulum: Protein and lipid synthesis.

• Golgi Apparatus: Modifies and packages proteins.

• Lysosome: Digestion of cellular waste.

• Peroxisome: Breakdown of fatty acids and detoxification.

Process of Creating and Secreting Proteins

• Transcription in nucleus

• Translation at ribosome

• Modification in ER and Golgi

• Secretion via vesicles

Plasma Membrane

Types of Transport Across Membranes

• Passive Transport: Diffusion, osmosis, facilitated diffusion

• Active Transport: Requires energy (ATP)

• Endocytosis/Exocytosis: Bulk transport

Metabolic Respiration

Steps of Cellular Respiration & ATP Production

Cellular respiration consists of glycolysis, the citric acid cycle, and oxidative phosphorylation.

• Glycolysis: 2 ATP, 2 NADH

• Citric Acid Cycle: 2 ATP, 6 NADH, 2 FADH2

• Oxidative Phosphorylation: ~34 ATP

Total ATP: Approximately 36-38 ATP per glucose molecule.

The Cell Cycle

Steps of the Cell Cycle

• Interphase: G1 (growth), S (DNA synthesis), G2 (preparation)

• Mitotic Phase: Mitosis and cytokinesis

DNA Replication

Steps of DNA Replication and Repair

• Initiation at origins of replication

• Elongation by DNA polymerase

• Proofreading and repair mechanisms

Protein Synthesis

Steps of Translation

• Initiation: Ribosome assembles on mRNA

• Elongation: tRNA brings amino acids, peptide bonds form

• Termination: Stop codon signals release

Mitosis/Meiosis

Phases of Mitosis

• Prophase

• Metaphase

• Anaphase

• Telophase

• Cytokinesis

Genetics

Types of Inheritance Patterns

• Complete Dominance: One allele masks another

• Incomplete Dominance: Heterozygote shows intermediate phenotype

• Co-dominance: Both alleles are expressed

• Polygenic Inheritance: Multiple genes affect a trait

• Sex-linked/X-linked: Traits associated with sex chromosomes

Example: Blood type (co-dominance), color blindness (X-linked)

Chromosome Abnormalities

• Nondisjunction: Failure to separate chromosomes

• Deletion: Loss of chromosome segment

• Translocation: Segment moves to another chromosome

Punnett Squares

Punnett squares are used to predict genotypes and phenotypes in crosses.

• Monohybrid Cross: One trait

• Dihybrid Cross: Two traits

Evolution

Evidence for Evolution

• Fossil record

• Anatomical structures

• Molecular evidence

Anatomical Structures

• Homologous: Similar due to shared ancestry

• Analogous: Similar due to convergent evolution

• Vestigial: Reduced or unused structures

Classification of Primates

• Hominoids: Apes and humans

• Hominids: Great apes and humans

• Hominins: Humans and their ancestors

Evolutionary Trees

Phylogenetic trees show evolutionary relationships.

Population Dynamics

Population Growth Curves

• Exponential Growth:

• Logistic Growth:

Population Dynamic Calculations

• Growth Rate:

• Doubling Time (Rule of 72):

Tissue

Classification and Types of Epithelial Tissue

• Simple: One layer

• Stratified: Multiple layers

• Squamous: Flat cells

• Cuboidal: Cube-shaped

• Columnar: Tall cells

Types of Junctions in Epithelial Tissue

• Adhesion Junctions: Hold cells together

• Tight Junctions: Prevent leakage

• Gap Junctions: Allow communication

Classification and Types of Connective Tissue

• Fibrous Connective Tissue: Dense, supports organs

• Special Connective Tissue: Includes cartilage, bone, blood

Types of Muscle Tissue

• Cardiac Muscle: Involuntary, heart

• Smooth Muscle: Involuntary, organs

• Skeletal Muscle: Voluntary, attached to bones

Types of Neurons

• Sensory Neurons: Carry signals to CNS

• Motor Neurons: Carry signals from CNS

Summary Table: Types of Tissue and Junctions

Additional info: This guide expands on brief review points to provide context and explanations suitable for exam preparation. All key terms and concepts are covered, with examples and formulas where relevant.