Biology Overview: Cells, Genetics, Evolution

Cell Theory: All living organisms are composed of cells; cells are the basic unit of life; all cells arise from pre-existing cells.
Prokaryotic vs. Eukaryotic Cells:
- Prokaryotic: No nucleus, smaller, simpler structure (e.g., bacteria).
- Eukaryotic: Nucleus present, larger, more complex (e.g., plants, animals).

DNA Structure: Double helix formed by nucleotides (adenine, thymine, cytosine, guanine).
Gene Expression: Process of transcribing DNA to mRNA, then translating mRNA to protein.
Mendelian Genetics:
- Law of Segregation: Alleles segregate during gamete formation.
- Law of Independent Assortment: Genes on different chromosomes assort independently.

Natural Selection: Mechanism by which organisms better adapted to their environment tend to survive and produce more offspring.
Evidence of Evolution:
- Fossil record
- Comparative anatomy (homologous and analogous structures)
- Molecular biology (DNA and protein comparisons)

Ecosystems: Biotic (living) and abiotic (non-living) components interacting.
Food Webs: Represent interconnected food chains in an ecosystem; energy flow from producers to consumers.
Biomes: Major ecological communities defined by climate and vegetation (e.g., tundra, rainforest).

Organ Systems:
- Circulatory: Transports nutrients and oxygen.
- Respiratory: Gas exchange (oxygen and carbon dioxide).
- Digestive: Breaks down food and absorbs nutrients.
Homeostasis: Maintenance of stable internal conditions (e.g., temperature, pH).

Photosynthesis: Process by which plants convert light energy to chemical energy in glucose.
Plant Structures:
- Roots: Absorb water and nutrients.
- Stems: Support and transport.
- Leaves: Main site of photosynthesis.

Bacteria: Prokaryotic microorganisms, essential for nutrient cycling.
Viruses: Non-cellular pathogens that require a host to replicate.
Fungi: Eukaryotic organisms, decomposers, and can form symbiotic relationships.

Genetic Engineering: Modification of organisms' DNA (e.g., CRISPR technology).
Cloning: Producing identical copies of organisms or cells.
Bioremediation: Use of organisms to remove pollutants from the environment.

Cell Theory: Fundamental principle stating that all living organisms consist of cells, which serve as the basic life unit, and that all cells originate from existing cells.
Prokaryotic Cells: Characterized by the absence of a nucleus, these are smaller and simpler in structure, representing organisms like bacteria.
Eukaryotic Cells: Possess a nucleus, larger and more complex, found in organisms such as plants and animals.

DNA Structure: Comprised of a double helix formed by nucleotides, which include adenine (A), thymine (T), cytosine (C), and guanine (G).
Gene Expression: Involves transcribing DNA into messenger RNA (mRNA), followed by the translation of mRNA into proteins.
Mendelian Genetics:
- Law of Segregation: During gamete formation, alleles segregate from each other.
- Law of Independent Assortment: Genes located on different chromosomes sort independently during gamete formation.

Natural Selection: A process wherein organisms with traits better suited to their environment are more likely to survive and reproduce.
Evidence of Evolution:
- Fossil record showing changes over time.
- Comparative anatomy highlighting homologous (similar structure, different function) and analogous (different structure, similar function) structures.
- Molecular biology through comparisons of DNA and proteins across species.

Ecosystems: Comprised of both biotic (living) and abiotic (non-living) components that interact within a specific environment.
Food Webs: Illustrate the interconnected food chains within an ecosystem, demonstrating energy flow from producers to various consumers.
Biomes: Large ecological communities, characterized by distinct climate and vegetation types, such as tundra and rainforest.

Organ Systems:
- Circulatory System: Responsible for nutrient and oxygen transport throughout the body.
- Respiratory System: Facilitates the exchange of gases, namely oxygen intake and carbon dioxide expulsion.
- Digestive System: Breaks down food to enable nutrient absorption.
Homeostasis: The ability to maintain stable internal conditions, including temperature and pH balance.

Photosynthesis: The process wherein plants convert light energy into chemical energy, primarily in the form of glucose.
Plant Structures:
- Roots: Function to absorb water and essential nutrients from soil.
- Stems: Provide support while facilitating nutrient and water transport.
- Leaves: The primary site for photosynthesis, where light intake occurs.

Bacteria: Essential prokaryotic microorganisms that play crucial roles in nutrient cycling within ecosystems.
Viruses: Non-cellular entities that require a host organism to replicate and propagate.
Fungi: Eukaryotic organisms that serve as decomposers and can establish symbiotic relationships with other species.

Genetic Engineering: Involves altering an organism's DNA, utilizing techniques such as CRISPR for targeted modifications.
Cloning: The process of creating genetically identical copies of organisms or cells.
Bioremediation: The application of living organisms to eliminate pollutants from the environment, promoting ecological health.