Key Concepts in Biology

Cell Theory:
- All living things are composed of cells.
- The cell is the basic unit of life.
- All cells arise from pre-existing cells.
Types of Cells:
- Prokaryotic: Simple, no nucleus (e.g., bacteria).
- Eukaryotic: Complex, with a nucleus (e.g., plant and animal cells).
Cell Organelles:
- Nucleus: Contains genetic material.
- Mitochondria: Powerhouse of the cell; energy production.
- Ribosomes: Protein synthesis.
- Endoplasmic Reticulum: Protein and lipid synthesis.
- Golgi Apparatus: Modifies and packages proteins.

DNA Structure: Double helix, composed of nucleotides (adenine, thymine, cytosine, guanine).
Gene: Segment of DNA that encodes for a protein.
Chromosomes: Structures made of DNA that carry genetic information.
Mendelian Genetics: Patterns of inheritance governed by dominant and recessive alleles.
Punnett Square: Tool for predicting genetic outcomes.

Theory of Evolution:
- Proposed by Charles Darwin; explains the diversity of life through natural selection.
- Natural Selection: Process by which favorable traits increase an organism's chances of survival and reproduction.
Speciation: Formation of new and distinct species in the course of evolution.

Ecosystem Dynamics: Interactions among organisms and their environment.
Food Chains and Webs:
- Producers (plants), consumers (herbivores, carnivores), and decomposers (fungi, bacteria).
Biomes: Large ecological areas with distinct climates and ecosystems (e.g., tundra, rainforest).

Organ Systems:
- Circulatory, respiratory, digestive, nervous, and muscular systems.
Homeostasis: Maintaining stable internal conditions (e.g., temperature, pH).
Immune System: Body's defense against pathogens.

Genetic Engineering: Manipulation of an organism's DNA to achieve desired traits.
CRISPR: A tool for precise editing of genes.

Photosynthesis: Conversion of light energy into chemical energy by plants.
Cellular Respiration: Process by which cells convert glucose and oxygen into energy, carbon dioxide, and water.

These notes provide a foundational understanding of biological concepts and principles.

Atoms are the basic units of matter.
Molecules, such as DNA and proteins, consist of combinations of atoms.
Cells are the fundamental unit of life and can be prokaryotic (simple, no nucleus) or eukaryotic (complex, with a nucleus).
Tissues are groups of similar cells that work together to perform a specific function.
Organs are composed of different tissues that cooperate to carry out complex tasks.
Organ systems are ensembles of organs that collectively perform complex biological functions.
An organism refers to any individual living entity.
Populations consist of groups of the same species inhabiting a defined area.
A community is formed by different populations living together in a specific environment.
Ecosystems include the community along with its physical surroundings.
The biosphere represents the global ecological system integrating all living beings.

Cell Theory posits that all living organisms are made of cells, which are the basic units of life, and that all cells originate from pre-existing cells.
Prokaryotic cells are simpler in structure, lacking a nucleus, and include organisms like bacteria.
Eukaryotic cells are more complex, containing a nucleus, and examples include plant and animal cells.
Key cell organelles include the nucleus (holds genetic material), mitochondria (energy production), ribosomes (protein synthesis), endoplasmic reticulum (synthesis of proteins and lipids), and Golgi apparatus (modifies and packages proteins).

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 and dictates various traits.
Chromosomes are DNA structures that carry genetic information.
Mendelian Genetics studies inheritance patterns based on dominant and recessive alleles.
Punnett Squares are utilized to predict potential genetic outcomes during reproduction.

The Theory of Evolution, introduced by Charles Darwin, accounts for life's diversity through the mechanism of natural selection.
Natural Selection favors advantageous traits, enhancing an organism's survival and reproductive success.
Speciation refers to the process by which new and distinct species arise during evolutionary change.

Ecosystem Dynamics involves the intricate interactions between organisms and their environments.
Food Chains and Webs illustrate energy flow through producers (plants), consumers (herbivores, carnivores), and decomposers (like fungi and bacteria).
Biomes are large ecological regions characterized by specific climates and ecosystems, such as tundras and rainforests.

Key Organ Systems include the circulatory, respiratory, digestive, nervous, and muscular systems, each with distinct functions.
Homeostasis refers to the process of maintaining stable internal conditions, such as temperature and pH levels.
The Immune System serves as the body’s defense mechanism against pathogens.

Genetic Engineering involves altering an organism's DNA to develop specific traits.
CRISPR is a revolutionary technology used for precise editing of genes.

Photosynthesis is the process by which plants convert light energy into chemical energy.
Cellular Respiration describes how cells transform glucose and oxygen into energy, carbon dioxide, and water, essential for metabolism.

These notes encapsulate essential biological concepts and principles critical for understanding the subject.