Key Concepts in Biology: Cell and Genetics

Cell Theory:
- All living organisms are composed of cells.
- The cell is the basic unit of life.
- All cells arise from pre-existing cells.
Cell Types:
- Prokaryotic: No nucleus, simpler structure (e.g., bacteria).
- Eukaryotic: Contains a nucleus and organelles (e.g., plants, animals).
Cell Organelles:
- Nucleus: Contains genetic material (DNA).
- Mitochondria: Powerhouse of the cell, produces ATP.
- Ribosomes: Sites of protein synthesis.
- Endoplasmic Reticulum (ER): Rough (with ribosomes) and smooth (without ribosomes), involved in protein and lipid synthesis.
- Golgi Apparatus: Modifies, sorts, and packages proteins.

DNA Structure:
- Double helix made of nucleotides (adenine, thymine, cytosine, guanine).
Genes:
- Segments of DNA that code for proteins.
- Each individual has two alleles for each gene (one from each parent).
Mendelian Genetics:
- Law of Segregation: Alleles separate during gamete formation.
- Law of Independent Assortment: Genes for different traits can segregate independently.
Chromosomes:
- Humans have 23 pairs (46 total); one set from each parent.

Natural Selection:
- Mechanism of evolution where organisms better adapted to their environment tend to survive and reproduce.
Common Descent:
- All living organisms share a common ancestor.
Speciation:
- The formation of new and distinct species through evolutionary processes.

Ecosystems:
- Composed of living (biotic) factors and non-living (abiotic) factors.
Biomes:
- Large ecological areas with specific climates (e.g., desert, rainforest).
Food Chains & Webs:
- Energy flow in an ecosystem, starting from producers to various levels of consumers.

Homeostasis:
- The maintenance of stable internal conditions (e.g., temperature regulation).
Systems of the Body:
- Circulatory, respiratory, digestive, nervous, and immune systems, each with specific functions.

Taxonomy:
- The science of categorizing organisms; includes domains (Archaea, Bacteria, Eukarya) and kingdoms.
Binomial Nomenclature:
- Two-part naming system for species (genus and species).

Macromolecules:
- Proteins (amino acids), carbohydrates (sugars), lipids (fatty acids), nucleic acids (DNA/RNA).
Metabolism:
- Sum of all chemical reactions in an organism; includes anabolism (building up) and catabolism (breaking down).

Photosynthesis:
- Conversion of light energy into chemical energy by plants.
Cell Respiration:
- Process of converting glucose and oxygen into energy (ATP), carbon dioxide, and water.

Genetic Engineering:
- Direct manipulation of an organism's genes using biotechnology (e.g., CRISPR).
Cloning:
- Creating a genetically identical copy of an organism.

Hypothesis Testing:
- Scientific method involving observation, hypothesis formulation, experimentation, and conclusion.
Theory of Emergence:
- Complex systems and patterns arise from simpler interactions.

This summary captures essential topics within biology, providing a foundation for further study and detail.

All living organisms are composed of cells.
The cell is the basic unit of life.
All cells arise from pre-existing cells.
Prokaryotic Cells: Lack a nucleus and have simpler structures. Examples include bacteria.
Eukaryotic Cells: Contain a nucleus and other membrane-bound organelles. Examples include plants and animals.
Nucleus: The control center of the cell, containing DNA.
Mitochondria: Powerhouses of the cell, responsible for producing ATP (energy).
Ribosomes: Sites of protein synthesis.
Endoplasmic Reticulum (ER): Network of membranes involved in protein and lipid synthesis.
- Rough ER: Contains ribosomes and is involved in protein synthesis and modification.
- Smooth ER: Lacks ribosomes and is involved in lipid synthesis and detoxification.
Golgi Apparatus: Modifies, sorts, and packages proteins for transport.

DNA: A double helix composed of nucleotides (adenine, thymine, cytosine, guanine).
Genes: Specific segments of DNA that code for proteins.
Each individual inherits two alleles for each gene, one from each parent.
Mendelian Genetics:
- Law of Segregation: Alleles for a trait separate during gamete (sperm and egg) formation, so each gamete receives only one allele.
- Law of Independent Assortment: Genes for different traits segregate independently of each other during gamete formation.
Chromosomes: Humans have 23 pairs (46 total) chromosomes; one set from each parent.

Natural Selection: Organisms with traits better suited to their environment are more likely to survive and reproduce, passing on those advantageous traits to their offspring.
Common Descent: All living organisms share a common ancestor.
Speciation: The formation of new species through evolutionary processes.

Ecosystems: Made up of living (biotic) factors (plants, animals, microorganisms) and non-living (abiotic) factors (temperature, water, sunlight).
Biomes: Large ecological areas characterized by specific climates and dominant plant and animal communities (e.g., desert, rainforest).
Food Chains & Webs: Illustrate energy flow in an ecosystem, with producers (plants) at the base, followed by consumers (herbivores, carnivores) and decomposers.

Homeostasis: The maintenance of stable internal conditions in an organism, despite external changes (e.g., temperature regulation).
Systems of the Body: Different organ systems work together to maintain homeostasis, including the circulatory, respiratory, digestive, nervous, and immune systems.

Taxonomy: The science of classifying organisms into hierarchical categories based on shared characteristics, including domains (Archaea, Bacteria, Eukarya) and kingdoms.
Binomial Nomenclature: A two-part naming system for species, consisting of the genus and species name (e.g., Homo sapiens).

Macromolecules: Large molecules essential for life, including:
- Proteins: Made up of amino acids, play a wide range of roles (enzymes, structural components, hormones).
- Carbohydrates: Composed of sugars, provide energy and structural support (e.g., starch, cellulose).
- Lipids: Fats and oils, important for energy storage, insulation, and cell membranes.
- Nucleic Acids: DNA and RNA, responsible for storing and transmitting genetic information.
Metabolism: The sum of all chemical reactions in an organism.
- Anabolism: Building up of complex molecules from simpler ones (e.g., protein synthesis).
- Catabolism: Breaking down of complex molecules into simpler ones (e.g., digestion).

Photosynthesis: The process by which plants use light energy to convert carbon dioxide and water into glucose (sugar) and oxygen.
Cell Respiration: The process of converting glucose and oxygen into ATP (energy), carbon dioxide, and water.

Genetic Engineering: The direct manipulation of an organism's genes using biotechnology, such as CRISPR.
Cloning: Creates a genetically identical copy of an organism.

Hypothesis Testing: The scientific method involves making observations, forming hypotheses, designing experiments, analyzing data, and drawing conclusions.
Theory of Emergence: Complex systems and patterns arise from the interactions of simpler components.