Key Concepts in Biology

Key Concepts in Biology

1. Cell Theory

• All living organisms are composed of cells.
• The cell is the basic unit of life.
• All cells arise from pre-existing cells.

2. Structure of Cells

• Prokaryotic Cells:
  • Lack a nucleus and membrane-bound organelles.
  • Examples: Bacteria and Archaea.
• Eukaryotic Cells:
  • Have a nucleus and membrane-bound organelles.
  • Examples: Plants, animals, fungi, and protists.

3. Genetics

• DNA Structure: Double helix made of nucleotides (A, T, C, G).
• Genes: Segments of DNA that code for proteins.
• Alleles: Different forms of a gene.

4. Evolution

• Natural Selection: Mechanism of evolution where organisms better adapted to their environment tend to survive and reproduce.
• Common Descent: All species share a common ancestor.

5. Ecology

• Ecosystems: Communities of living organisms interacting with their environment.
• Biodiversity: Variety of life in a particular habitat or ecosystem.

6. Photosynthesis

• Process by which plants, algae, and some bacteria convert light energy into chemical energy (glucose).
• Formula: 6CO₂ + 6H₂O + light → C₆H₁₂O₆ + 6O₂.

7. Cellular Respiration

• Process by which organisms convert glucose into energy (ATP).
• Formula: C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + ATP.

8. Homeostasis

• The ability of an organism to maintain stable internal conditions despite changes in the external environment.
• Mechanisms include temperature regulation, pH balance, and osmotic balance.

9. Classification of Living Organisms

• Taxonomy: Science of classifying organisms.
  • Domains: Archaea, Bacteria, Eukarya.
  • Kingdoms: Animalia, Plantae, Fungi, Protista, Archaea, Bacteria.

10. Human Body Systems

• Circulatory System: Transports blood, nutrients, gases, and waste.
• Respiratory System: Facilitates gas exchange (oxygen and carbon dioxide).
• Nervous System: Controls body functions through electrical signals.
• Digestive System: Breaks down food and absorbs nutrients.

11. Microbiology

• Study of microorganisms (bacteria, viruses, fungi, and protozoa).
• Importance in health, disease, and biotechnology.

12. Molecular Biology

• Focus on the molecular mechanisms of biological processes.
• Techniques include DNA sequencing, polymerase chain reaction (PCR), and gene cloning.

13. Biochemistry

• Study of chemical processes within and related to living organisms.
• Includes metabolic pathways and the structure and function of biomolecules (proteins, carbohydrates, lipids, nucleic acids).

These notes provide a foundational overview of significant concepts within biology, useful for further study or quick review.

Cell Theory

• All living organisms are composed of cells.
• Cells are the fundamental building blocks of life.
• New cells are created from pre-existing cells through cell division.

Structure of Cells

• Prokaryotic Cells:
  • Lack a membrane-bound nucleus and organelles.
  • Examples include bacteria and archaea.
• Eukaryotic Cells:
  • Possess a nucleus and membrane-bound organelles.
  • Examples include plants, animals, fungi, and protists.

Genetics

• DNA Structure:
  • DNA is a double helix composed of nucleotides.
  • Nucleotides are comprised of a sugar, phosphate, and a nitrogenous base: adenine (A), thymine (T), cytosine (C), and guanine (G).
• Genes:
  • Genes are segments of DNA that contain the instructions for building proteins.
• Alleles:
  • Alleles are different versions of the same gene and contribute to variations in traits.

Evolution

• Natural Selection:
  • Natural selection is the process where organisms with traits better suited to their environment survive and reproduce at higher rates.
• Common Descent:
  • All living organisms share a common ancestor.

Ecology

• Ecosystems:
  • Ecosystems consist of living organisms (biotic) interacting with their non-living environment (abiotic).
• Biodiversity:
  • Biodiversity refers to the variety of life within a habitat or ecosystem.

Photosynthesis

• The process by which plants, algae, and some bacteria convert light energy into chemical energy (glucose).
• Formula: 6CO₂ + 6H₂O + light → C₆H₁₂O₆ + 6O₂.

Cellular Respiration

• The process in which organisms convert glucose into usable energy (ATP).
• Formula: C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + ATP.

Homeostasis

• The ability of an organism to maintain stable internal conditions despite changes in the external environment.
• Mechanisms include temperature regulation, pH balance, and osmotic balance.

Classification of Living Organisms

• Taxonomy:
  • Taxonomy is the science of classifying organisms.
• Domains:
  • Domains are the broadest taxonomic categories: Archaea, Bacteria, and Eukarya.
• Kingdoms:
  • Kingdoms are further subcategories within domains: Animalia, Plantae, Fungi, Protista, Archaea, and Bacteria.

Human Body Systems

• Circulatory System:
  • Transports blood, nutrients, gases, and waste throughout the body.
• Respiratory System:
  • Facilitates gas exchange (oxygen and carbon dioxide).
• Nervous System:
  • Controls body functions through electrical signals.
• Digestive System:
  • Breaks down food and absorbs nutrients.

Microbiology

• The study of microorganisms, including bacteria, viruses, fungi, and protozoa.
• Microorganisms play important roles in health, disease, and biotechnology.

Molecular Biology

• Focuses on the molecular mechanisms underlying biological processes.
• Techniques include DNA sequencing, Polymerase Chain Reaction (PCR), and gene cloning.

Biochemistry

• The study of chemical processes within and related to living organisms.
• Biochemistry encompasses metabolic pathways and the structure and function of biomolecules (proteins, carbohydrates, lipids, and nucleic acids).

Test your knowledge on fundamental concepts in biology, including cell theory, cell structure, genetics, evolution, and ecology. This quiz will cover essential principles that form the foundation of biological sciences. Ideal for students and enthusiasts looking to solidify their understanding of living organisms.