Biodiversity and Classification of Living Things
Biodiversity
What is Biodiversity?
It is the totality of species and ecosystems of a region, including the entire gene pool.
Morphological Adaptations
These are anatomical structures that ensure an organism’s harmonious relationship with its environment.
Physiological Adaptations and Types
These are changes in individual organ function, enabling better environmental adaptation. Types include body temperature regulation and fruit ripening.
Convergent Evolution
Different groups of animals or plants develop
Read MoreStem Cell Research and Cloning: Advancements and Applications
Stem Cells and Cloning
What are Totipotent Cells?
Totipotent cells have the remarkable ability to differentiate into any cell type, including embryonic tissues. Stem cells, on the other hand, can self-renew through mitotic divisions and differentiate into specific mature tissues. They vary in potency, ranging from totipotent to unipotent.
Embryo Formation
The journey begins when an egg leaves the ovary and travels to the fallopian tube. Fertilization creates a zygote, which divides into four cells within
Read MoreNervous and Endocrine Systems in Vertebrates
Nervous System
The nervous system collects various stimuli from both inside and outside the body through specialized neurons organized in receptors. External stimuli are detected by exteroceptors, while internal stimuli are detected by interoceptors. This information is transmitted to the central nervous system (CNS), which processes the information and generates a response. Organs that execute commands from the CNS are called effectors.
Invertebrate Nervous Systems
- Nerve Net: Found in primitive animals
Human Body Functions and Coordination
Interaction and Stimuli
The interaction function allows us to perceive internal and external changes (stimuli), interpret them, and generate coordinated responses for survival.
Stimuli and Receptors
A stimulus is a physical or chemical change that triggers a response. Specialized cells called receptors perceive stimuli and send information to coordination centers.
Types of Receptors
- Internal receptors: Perceive changes inside the body (e.g., blood sugar levels).
- External/Sensory receptors: Perceive external
Cellular Biology: From Nucleus to Apoptosis
The Nucleus
Structure
- Envelope: A double membrane with nuclear pores enabling communication between nucleus and cytoplasm.
- Nucleoplasm: The internal environment containing DNA, RNA, proteins, and the nucleolus.
- Cellular Matrix: A protein network organizing chromatin. The nuclear lamina, made of intermediate filaments, contacts the inner membrane.
- Nucleolus: Concentrates ribosomal genes encoding ribosomal RNA.
Chromatin and Chromosomes
During interphase, chromatin forms nucleosome filaments or 30 nm fibers.
Read MoreInfection Control and Prevention in Dental Practices
Infection Control in Dental Practices
Contamination and Infection
The mouth cavity can be contaminated by various germs. Infection occurs when the body is invaded by an external agent capable of causing disease.
Routes of Transmission
- Direct Contact: Occurs through contact with organic fluids (blood, saliva) that directly penetrate the body via oronasopharyngeal routes, skin wounds, conjunctiva, or other mucous membranes.
- Indirect Contact (Fomites): Occurs through contact with contaminated instruments