Cell Biology and Genetics Overview

Cell Theory:
- All living organisms are composed of cells.
- The cell is the basic unit of life.
- All cells arise from pre-existing cells.
Types of Cells:
- Prokaryotic: No nucleus, smaller, simpler (e.g., bacteria).
- Eukaryotic: Has a nucleus, larger, more complex (e.g., plants, animals).
Cell Organelles:
- Nucleus: Contains DNA and controls cell activities.
- Mitochondria: Powerhouse of the cell, produces ATP.
- Ribosomes: Site of protein synthesis.
- Endoplasmic Reticulum (ER):
  - Rough ER: Studded with ribosomes, involved in protein synthesis.
  - Smooth ER: Lacks ribosomes, synthesizes lipids.
- Golgi Apparatus: Modifies, sorts, and packages proteins and lipids.

DNA Structure: Double helix made of nucleotides (adenine, thymine, cytosine, guanine).
Gene: A segment of DNA that codes for a protein.
Alleles: Different versions of a gene (dominant and recessive).
Mendelian Genetics: Laws of segregation and independent assortment governing inheritance.

Natural Selection: Process where organisms better adapted to their environment tend to survive and produce more offspring.
Speciation: Formation of new and distinct species through evolutionary processes.
Common Descent: All species share a common ancestor.

Ecosystem: A community of living organisms interacting with their physical environment.
Biomes: Large ecological areas with distinct climates and ecosystems (e.g., rainforest, desert).
Energy Flow:
- Producers (autotrophs) convert sunlight into energy.
- Consumers (heterotrophs) consume producers or other consumers.

Organ Systems:
- Circulatory: Transports blood, nutrients, gases.
- Respiratory: Exchanges gases (oxygen and carbon dioxide).
- Digestive: Breaks down food, absorbs nutrients.
- Nervous: Controls body functions via signals.
Homeostasis: Maintaining stable internal conditions despite external changes.

Bacteria: Single-celled prokaryotes, can be beneficial or pathogenic.
Viruses: Non-living entities that require a host to replicate.
Fungi: Eukaryotic organisms, important for decomposition and nutrient cycling.

Photosynthesis: Process by which plants convert light energy into chemical energy (glucose).
Plant Structures:
- Roots: Absorb water and nutrients.
- Stems: Support and transport.
- Leaves: Site of photosynthesis.

Animal Classification:
- Vertebrates: Have a backbone (e.g., mammals, birds, reptiles).
- Invertebrates: No backbone (e.g., insects, mollusks).
Animal Behavior: Study of how animals interact with each other and their environment.

Macromolecules:
- Carbohydrates: Energy storage and structure.
- Proteins: Catalysts (enzymes), structure, transport.
- Lipids: Energy storage, cell membranes.
- Nucleic Acids: DNA and RNA, genetic information.

Applications: Genetic engineering, cloning, CRISPR technology, biopharmaceuticals.
Ethical Considerations: Concerns regarding genetic modification, cloning, and ecological impacts.

Cell Theory states that all living organisms are made up of cells, which are the basic units of life, and cells originate from pre-existing cells.
Prokaryotic cells lack a nucleus, are generally smaller, and simpler, while eukaryotic cells contain a nucleus, are larger, and more complex.
Key organelles include:
- Nucleus: Houses DNA and regulates cell functions.
- Mitochondria: Known as the cell's powerhouse, generating ATP for energy.
- Ribosomes: Crucial for protein synthesis.
- Endoplasmic Reticulum (ER):
  - Rough ER: Contains ribosomes, important for protein production.
  - Smooth ER: Lacks ribosomes; involved in lipid synthesis.
- Golgi Apparatus: Modifies, sorts, and packages proteins and lipids.

DNA is structured as a double helix made of nucleotides: adenine, thymine, cytosine, and guanine.
A gene is a DNA segment that encodes a protein, with variations known as alleles (dominant and recessive).
Mendelian genetics introduces key principles like laws of segregation and independent assortment, which dictate inheritance patterns.

Natural selection leads to the survival and reproduction of organisms best suited to their environment.
Speciation refers to the process through which new species arise from evolutionary changes.
Common descent suggests that all species are derived from a shared ancestor.

An ecosystem consists of interacting communities of living organisms and their physical surroundings.
Biomes are large ecological areas characterized by specific climates and ecosystems, such as rainforests and deserts.
Energy flow within ecosystems starts with producers (autotrophs) that convert sunlight into energy, absorbed by consumers (heterotrophs).

The body comprises various organ systems, including:
- Circulatory System: Responsible for transporting blood, nutrients, and gases.
- Respiratory System: Facilitates gas exchange (oxygen and carbon dioxide).
- Digestive System: Breaks down food and absorbs nutrients.
- Nervous System: Controls bodily functions through signaling.
Homeostasis refers to the ability to maintain stable internal conditions amidst external fluctuations.

Bacteria are single-celled prokaryotic organisms that can be either beneficial or harmful.
Viruses are non-living entities that depend on host cells for replication.
Fungi are eukaryotic organisms that play a vital role in decomposition and nutrient cycling.

Photosynthesis allows plants to convert light energy into chemical energy stored as glucose.
Key plant structures include:
- Roots: Absorb water and necessary minerals.
- Stems: Provide structural support and transport materials.
- Leaves: Main site for photosynthesis.

Animal classification divides creatures into vertebrates (with backbones, e.g., mammals, birds) and invertebrates (without backbones, e.g., insects, mollusks).
Animal behavior explores interactions among animals and their environments.

Macromolecules serve essential functions:
- Carbohydrates: Provide energy storage and structural support.
- Proteins: Function as enzymes, structural elements, and transport molecules.
- Lipids: Serve as energy storage and form cell membranes.
- Nucleic Acids: DNA and RNA encode genetic information.

Applications include genetic engineering, cloning, CRISPR technology, and the production of biopharmaceuticals.
Ethical considerations surround issues related to genetic modifications, cloning practices, and ecological impacts.