Cell Biology and Genetics Overview

Cell Structure: Basic unit of life; includes prokaryotic (no nucleus) and eukaryotic (nucleus present) cells.
Organelles:
- Nucleus: Contains DNA, controls cell activities.
- Mitochondria: Powerhouse of the cell, energy production (ATP).
- Ribosomes: Protein synthesis.
- Endoplasmic Reticulum (ER): Rough ER (with ribosomes) synthesizes proteins; Smooth ER synthesizes lipids.
- Golgi Apparatus: Modifies, sorts, and packages proteins.
- Lysosomes: Digestive enzymes for waste breakdown.

DNA Structure: Double helix composed of nucleotides (adenine, thymine, cytosine, guanine).
Gene Expression: Process from DNA to RNA (transcription) and RNA to protein (translation).
Mendelian Genetics: Law of Segregation, Law of Independent Assortment; dominant and recessive traits.
Chromosomes: Humans have 23 pairs; sex chromosomes determine gender (XX or XY).

Natural Selection: Mechanism of evolution; organisms better adapted to their environment tend to survive and produce offspring.
Speciation: Formation of new species through isolation, genetic drift, and adaptation.
Evidence of Evolution: Fossil records, comparative anatomy, molecular biology.

Ecosystems: Community of living organisms and their physical environment interacting as a system.
Biomes: Large ecological areas (e.g., forests, deserts) characterized by specific climate and vegetation.
Food Chains and Webs: Energy flow through producers (plants), consumers (animals), and decomposers (fungi/bacteria).
Population Dynamics: Study of populations, including growth rates, carrying capacity, and factors affecting population size.

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

Macromolecules:
- Proteins: Made of amino acids, perform various functions (enzymes, structure).
- Carbohydrates: Sugars and starches, energy sources.
- Lipids: Fats and oils, energy storage and cell membranes.
- Nucleic Acids: DNA and RNA, genetic information storage and transfer.

Bacteria: Prokaryotic microorganisms; roles in decomposition, fermentation, and disease.
Viruses: Non-cellular entities that require a host to replicate.
Fungi: Eukaryotic organisms; decomposers and some are pathogenic.

Photosynthesis: Process by which plants convert light energy into chemical energy (glucose).
Plant Structure: Roots (absorb water/nutrients), stems (support), leaves (photosynthesis).

Innate vs. Learned Behaviors: Innate behaviors are genetic; learned behaviors are acquired through experience.
Social Structures: Group dynamics in species (e.g., packs, herds).
Communication: Methods animals use to convey information (vocalizations, body language).

Cells are the basic unit of life, categorized into prokaryotic (lack nucleus) and eukaryotic (contain nucleus) types.
The nucleus houses DNA and regulates cellular activities.
Mitochondria generate ATP, serving as the cell's energy currency.
Ribosomes are essential for synthesizing proteins.
The endoplasmic reticulum has two forms: Rough ER, which is ribosome-studded and synthesizes proteins, and Smooth ER, which synthesizes lipids.
The Golgi apparatus modifies, sorts, and packages proteins for transport.
Lysosomes contain digestive enzymes important for breaking down waste materials.

DNA is structured as a double helix composed of nucleotides: adenine, thymine, cytosine, and guanine.
Gene expression involves transcription (DNA to RNA) and translation (RNA to protein).
Mendelian genetics focuses on inheritance patterns, including the Law of Segregation and the Law of Independent Assortment; it distinguishes between dominant and recessive traits.
Humans possess 23 pairs of chromosomes, with sex chromosomes (XX for females, XY for males) determining gender.

Natural selection is a fundamental mechanism of evolution, whereby organisms best suited to their environment are more likely to survive and reproduce.
Speciation occurs when new species emerge due to factors like isolation, genetic drift, and adaptation to different environments.
Evidence supporting evolution can be found in fossil records, comparative anatomical structures, and advancements in molecular biology.

Ecosystems comprise communities of living organisms along with their physical environments, functioning interactively.
Biomes are large ecological regions, such as forests and deserts, identified by their climate and predominant vegetation types.
Food chains and webs illustrate energy transfer, starting with producers (plants), through consumers (animals), and ending with decomposers (fungi and bacteria).
Population dynamics examines changes in population sizes, growth rates, and carrying capacities influenced by various environmental factors.

Homeostasis is the process through which organisms maintain stable internal conditions, such as temperature and pH levels.
Major organ systems include:
- Circulatory: Responsible for blood and nutrient transport.
- Respiratory: Facilitates gas exchange of oxygen and carbon dioxide.
- Digestive: Breaks down food for nutrient absorption.
- Nervous: Coordinates body functions through signaling.

Macromolecules consist of:
- Proteins: Composed of amino acids, performing diverse roles including enzymatic and structural functions.
- Carbohydrates: Sugars and starches that serve as primary energy sources.
- Lipids: Include fats and oils for energy storage and forming cell membranes.
- Nucleic acids: DNA and RNA, responsible for the storage and transfer of genetic information.

Bacteria are prokaryotic microorganisms contributing to decomposition, fermentation, and occasionally disease.
Viruses are non-cellular entities that must infect a host to replicate.
Fungi are eukaryotic organisms that act as decomposers, with some species being pathogenic.

Photosynthesis enables plants to convert light energy into chemical energy stored as glucose.
Plant structures include:
- Roots: Function in water and nutrient absorption.
- Stems: Provide structural support.
- Leaves: Main site of photosynthesis.

Innate behaviors are genetically inherited, while learned behaviors develop through experience.
Social structures determine group dynamics within species, as seen in packs or herds.
Communication in animals involves vocalizations and body language to convey information.