Key Concepts in Biology

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, simpler structure (e.g., bacteria).
- Eukaryotic: Nucleus present, complex structure (e.g., plant and animal cells).
Cell Organelles:
- Nucleus: Contains genetic material (DNA).
- Mitochondria: Powerhouse of the cell, energy production.
- Ribosomes: Protein synthesis.
- Endoplasmic Reticulum: Synthesis and transport of proteins and lipids.

DNA Structure: Double helix made of nucleotides (adenine, thymine, cytosine, guanine).
Genes: Segments of DNA that code for proteins.
Alleles: Different forms of a gene.
Mendelian Genetics: Principles of inheritance (dominant/recessive traits).

Natural Selection: Survival of the fittest; organisms better adapted to their environment tend to survive and reproduce.
Speciation: Formation of new species through evolutionary processes.
Common Ancestry: All life shares a common ancestor.

Ecosystems: Community of living organisms interacting with their environment.
Biomes: Large geographical areas with similar climate and ecosystems (e.g., deserts, forests).
Food Chains/Webs: Energy flow through trophic levels (producers, consumers, decomposers).

Homeostasis: Regulation of internal conditions (temperature, pH, etc.).
Organ Systems:
- Respiratory: Gas exchange (lungs).
- Circulatory: Blood transport (heart, blood vessels).
- Nervous: Signal transmission (brain, nerves).

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

Bacteria: Single-celled organisms, some beneficial (gut flora), some pathogenic (disease-causing).
Viruses: Non-cellular entities that require a host to replicate.

Genetic Engineering: Manipulation of organisms' DNA for practical purposes (e.g., CRISPR technology).
Biopharmaceuticals: Use of biological processes for drug development.

All living organisms are made up of cells, which serve as the fundamental unit of life.
Cell Theory states that all cells arise from pre-existing cells.
Prokaryotic cells lack a nucleus and have a simpler structure, exemplified by bacteria.
Eukaryotic cells contain a nucleus and are more complex, represented by plant and animal cells.
Key cell organelles include:
- Nucleus: Stores and manages genetic material (DNA).
- Mitochondria: Known as the powerhouse of the cell, responsible for energy production.
- Ribosomes: Sites for protein synthesis.
- Endoplasmic Reticulum: Involved in the synthesis and transport of proteins and lipids.

DNA is structured as a double helix composed of nucleotides: adenine, thymine, cytosine, and guanine.
Genes are specific segments of DNA that encode proteins essential for various functions.
Alleles are the different versions of a gene that can lead to variations in traits.
Mendelian Genetics explains the inheritance of traits through dominant and recessive patterns.

Natural Selection is the mechanism through which "survival of the fittest" occurs, favoring organisms that are better adapted to their environments.
Speciation refers to the evolutionary process resulting in the formation of new species.
All life forms share a common ancestor, emphasizing the interconnectedness of species.

Ecosystems consist of communities of living organisms that interact with one another and their physical environment.
Biomes are large regions characterized by similar climates and ecosystems, such as deserts and forests.
Food Chains and Food Webs illustrate the flow of energy through different trophic levels: producers, consumers, and decomposers.

Homeostasis is the process by which living organisms regulate their internal conditions, such as temperature and pH levels.
Major organ systems include:
- Respiratory System: Facilitates gas exchange through the lungs.
- Circulatory System: Transports blood via the heart and blood vessels.
- Nervous System: Responsible for signal transmission through the brain and nerves.

Photosynthesis is the method by which plants convert light energy into chemical energy, primarily in the form of glucose.
Key plant structures include:
- Roots: Absorb water and nutrients from the soil.
- Stems: Provide support and facilitate transport within the plant.
- Leaves: Serve as the primary site for photosynthesis.

Bacteria are single-celled organisms; some are beneficial, like gut flora, while others can cause diseases.
Viruses are non-cellular entities that must infect a host cell to reproduce.

Genetic Engineering involves altering the DNA of organisms for various applications, including techniques like CRISPR.
Biopharmaceuticals utilize biological processes in the development of drugs, merging biology with therapeutic innovation.

Prioritize understanding core concepts over rote memorization of facts.
Use diagrams and models to clarify complex biological processes.
Engage in active recall and practice questions to enhance retention and learning.