Key Concepts in Biology

All living organisms are made of cells (Cell Theory).
Two main types of cells:
- Prokaryotic (no nucleus, small, e.g., bacteria)
- Eukaryotic (nucleus present, larger, e.g., plants and animals)
Organelles serve specific functions (e.g., mitochondria for energy, ribosomes for protein synthesis).

DNA: The hereditary material; structure is a double helix.
Genes: Segments of DNA that code for proteins.
Mendelian genetics: Principles of inheritance, including dominant and recessive traits.
Molecular genetics: Study of gene structure and function.

Theory of Natural Selection: Organisms better adapted to their environment tend to survive and reproduce.
Speciation: The formation of new and distinct species in the course of evolution.
Genetic drift and gene flow contribute to evolutionary changes.

Ecosystems: Community of living organisms interacting with their environment.
Biomes: Large ecological areas (e.g., forests, deserts).
Food chains/webs: Represent the flow of energy and nutrients between organisms.
Biodiversity: The variety of life in a given area; crucial for ecosystem resilience.

Homeostasis: The maintenance of stable internal conditions in an organism.
Major systems in animals:
- Circulatory (transport of nutrients and gases)
- Respiratory (gas exchange)
- Nervous (control and coordination)
- Digestive (breakdown and absorption of food)

Photosynthesis: Process by which plants convert sunlight into chemical energy.
Plant structures: Roots (absorption), stem (support), leaves (photosynthesis).
Reproductive strategies: Sexual (flowers, seeds) and asexual (cuttings, runners).

Study of microorganisms: Bacteria, viruses, fungi, and protozoa.
Importance in ecology (decomposers) and human health (pathogens and antibiotics).
Role in biotechnological applications (e.g., fermentation, genetic engineering).

Metabolism: Sum of all chemical reactions in a cell or organism (anabolic and catabolic pathways).
Cellular respiration: Process of converting glucose into ATP, involving glycolysis, Krebs cycle, and oxidative phosphorylation.
Photosynthesis: Light-dependent reactions and Calvin cycle in plants.

All living things are composed of cells, a fundamental principle known as the Cell Theory.
Cells are categorized into prokaryotes (lacking a nucleus and small, like bacteria) and eukaryotes (with a nucleus and larger, such as plants and animals).
Organelles are specialized structures within cells that perform specific functions, like mitochondria for energy production and ribosomes for protein synthesis.

DNA, structured as a double helix, holds the genetic information passed down from parents to offspring.
Sections of DNA called genes code for the production of proteins, which are crucial for various bodily functions.
The principles of inheritance, like dominant and recessive traits, are explained by Mendelian genetics.
Molecular genetics focuses on examining the structure, function, and organization of genes.

Natural Selection proposes that organisms with traits better suited to their environment are more likely to survive and reproduce, passing these advantageous traits to their offspring.
The formation of distinct new species is called speciation, a gradual process driven by evolution.
Genetic drift, random changes in gene frequencies within a population, and gene flow, the transfer of genes between populations, are two factors contributing to evolutionary change.

Ecosystems are interconnected communities of living organisms interacting with their physical environment.
Biomes are large-scale ecological areas characterized by distinct climate, vegetation, and animal life, such as forests or deserts.
Food chains and webs illustrate the flow of energy and nutrients between organisms within an ecosystem.
Biodiversity, the variety of life forms in a given area, is crucial for the health and resilience of ecosystems.

Homeostasis refers to the maintenance of a stable internal environment within an organism, crucial for its survival.
Major organ systems in animals include the circulatory system (transporting nutrients and gases), the respiratory system (gas exchange), the nervous system (control and coordination), and the digestive system (food breakdown and absorption).

Photosynthesis, the process of converting sunlight into chemical energy, is the primary source of energy for most ecosystems.
Plants have specialized structures: roots for absorption, stems for support, and leaves for photosynthesis.
Plants exhibit a variety of reproductive strategies, including sexual reproduction (using flowers and seeds) and asexual reproduction (using cuttings or runners).

The study of microorganisms, including bacteria, viruses, fungi, and protozoa, is called microbiology.
Microorganisms play essential roles in the environment as decomposers and are also important in human health, both as pathogens causing diseases and in the development of antibiotics.
They have significant applications in biotechnology, such as fermentation and genetic engineering.

Metabolism encompasses all chemical reactions occurring within a cell or organism, encompassing both anabolic (building up) and catabolic (breaking down) pathways.
Cellular respiration is the process by which glucose is converted into ATP, the energy currency of cells, involving glycolysis, the Krebs cycle, and oxidative phosphorylation.
Photosynthesis involves light-dependent reactions and the Calvin cycle in plants, converting light energy into chemical energy stored in glucose.

ATP (adenosine triphosphate) is the molecule that serves as the primary energy source for cellular processes.
Homeostasis refers to the maintenance of a stable internal environment in an organism.
Symbiosis describes interactions between different species, including mutualism (both benefit), commensalism (one benefits, other unaffected), and parasitism (one benefits at the expense of the other).

The scientific method is a systematic approach to acquiring knowledge, involving observation, formulating a hypothesis, experimentation, data analysis, and drawing conclusions.

Biology has wide-ranging applications in medicine, such as understanding diseases and developing treatments.
In agriculture, biology helps improve food production and develop crops resistant to pests and diseases.
Conservation efforts rely on biological knowledge to protect biodiversity and maintain healthy ecosystems.