Cell Biology: Cell Theory and Organelles

Cell Theory:
- All living orAll living organisms, from the simplest single-celled bacteria to complex multicellular organisms such as plants and animals, are fundamentally composed of cells. These essential building blocks serve as the foundation for structure and function in all forms of life..
- The cell is the basic unit of life.
- All cells arise from pre-existing cells.
Prokaryotic vs. Eukaryotic Cells:
- Prokaryotic: No nucleus, smaller, simpler (e.g., bacteria).
- Eukaryotic: Nucleus present, larger, complex (e.g., plants, animals).
Cell Organelles:
- Nucleus: Contains genetic material (DNA).
- Mitochondria: Powerhouse of the cell, ATP production.
- Ribosomes: Protein synthesis.
- Endoplasmic Reticulum: Protein and lipid synthesis (rough and smooth).
- Golgi Apparatus: Modifies, sorts, and packages proteins.
- Lysosomes: Digestion and waste removal.

DNA Structure:
- Double helix composed of nucleotides (A, T, C, G).
- A-T and C-G base pairing.
Gene Expression:
- Transcription: DNA to RNA.
- Translation: RNA to protein.
Mendelian Genetics:
- Law of Segregation: Alleles separate during gamete formation.
- Law of Independent Assortment: Genes for different traits segregate independently.

Natural Selection:
- Mechanism of evolution where organisms better adapted to their environment tend to survive and produce more offspring.
Evolutionary Evidence:
- Fossil records, comparative anatomy, molecular biology, and biogeography.

Ecosystems:
- Biotic (living) and abiotic (non-living) components interacting.
Food Chains/Webs:
- Energy flow from producers (plants) to consumers (herbivores, carnivores) to decomposers.
Biodiversity:
- Variety of life in a particular habitat or ecosystem.
- Important for ecosystem resilience and function.

Body Systems:
- Circulatory: Transports nutrients and oxygen.
- Respiratory: Gas exchange (oxygen and carbon dioxide).
- Digestive: Breaks down food for nutrients.
- Nervous: Controls body activities through signals.
Homeostasis:
- Maintenance of stable internal conditions despite external changes.

Types of Microorganisms:
- Bacteria, viruses, fungi, and protozoa.
Importance:
- Decomposition, fermentation, human health (gut microbiota), and biotechnology applications.

Photosynthesis:
- Conversion of light energy into chemical energy (glucose) in chloroplasts.
Plant Structure:
- Roots (absorption), stems (support), leaves (photosynthesis), flowers (reproduction).

Innate vs. Learned Behavior:
- Innate: Instinctual (e.g., reflexes).
- Learned: Acquired through experience (e.g., conditioning).
Social Behavior:
- Communication, mating rituals, group dynamics, and territoriality.

Macromolecules:
- Proteins, carbohydrates, lipids, and nucleic acids.
Enzymes:
- Biological catalysts that speed up chemical reactions without being consumed.

Homeostasis: Maintaining stable internal conditions.
Adaptation: Changes in organisms that enhance survival and reproduction.
Symbiosis: Close interactions between species (mutualism, commensalism, parasitism).

Cell Theory: Fundamental principles stating all organisms are made of cells, which are the basic units of life, and all cells originate from existing cells.
Prokaryotic Cells: Feature no nucleus, smaller and simpler, exemplified by bacteria.
Eukaryotic Cells: Contain a nucleus, larger and more complex; include animals and plants.
Nucleus: Houses genetic material (DNA), critical for cell function and heredity.
Mitochondria: Known as the powerhouse of the cell, it produces ATP, the primary energy currency.
Ribosomes: Sites of protein synthesis, crucial for cellular functions.
Endoplasmic Reticulum: Divided into rough (with ribosomes for protein synthesis) and smooth (lipid synthesis).
Golgi Apparatus: Responsible for modifying, sorting, and packaging proteins for secretion or delivery to other organelles.
Lysosomes: Contain enzymes for digestion and removal of cellular waste.

DNA Structure: Composed of a double helix with nucleotides adenine (A), thymine (T), cytosine (C), and guanine (G); A pairs with T, and C pairs with G.
Gene Expression Process: Involves two key steps; transcription, which converts DNA to RNA, followed by translation, converting RNA to protein.
Law of Segregation: Explains how alleles separate during gamete formation, ensuring genetic diversity.
Law of Independent Assortment: States that genes for different traits are inherited independently of each other.

Natural Selection: The process where organisms better adapted to environments survive and reproduce, influencing the evolution of species.
Evolutionary Evidence: Supported by fossil records, comparative anatomy, molecular biology, and patterns in biogeography.

Ecosystems: Composed of biotic and abiotic elements that function together within a habitat.
Food Chains/Webs: Illustrates energy flow and nutrient cycling from producers to various consumer levels and decomposers.
Biodiversity: Refers to the variety of life in an ecosystem, important for maintaining resilience and ecological stability.

Body Systems: Comprised of various systems; circulatory (nutrient and oxygen transport), respiratory (gas exchange), digestive (nutrient breakdown), and nervous (signals and control).
Homeostasis: The ability of an organism to maintain stable internal conditions despite external environmental changes.

Types of Microorganisms: Includes bacteria, viruses, fungi, and protozoa, each playing various roles in ecosystems and health.
Importance of Microorganisms: Essential for decomposition, fermentation, maintaining gut health, and various biotechnological applications.

Photosynthesis: Process by which plants convert light energy into chemical energy to produce glucose in chloroplasts.
Plant Structure: Organized into roots (water and nutrient absorption), stems (support), leaves (photosynthesis), and flowers (reproduction).

Innate vs. Learned Behavior: Innate behaviors are instinctual (e.g., reflexes), while learned behaviors are acquired through experience (e.g., conditioning).
Social Behavior: Involves communication, mating rituals, group dynamics, and territorial behaviors among species.

Macromolecules: The four main types are proteins, carbohydrates, lipids, and nucleic acids, which perform vital biological functions.
Enzymes: Serve as biological catalysts, speeding up chemical reactions without being consumed in the process.

Homeostasis: The process of maintaining stable internal conditions.
Adaptation: Involves alterations in organisms that improve their chances of survival and reproduction.
Symbiosis: Describes close ecological interactions among species, including mutualism, commensalism, and parasitism.