Introduction to Biology: Branches, Levels, and Characteristics of Living Things
Introduction to Biology
Biology is the science dedicated to the study of living things and phenomena related to life in all its aspects. Aristotle was the creator of biology. The theory of spontaneous generation explains asexual reproduction, and he studied and described more than 500 species of animals. Michael Christoph Hanov was the first person who used the term biology for the first time.
Branches of Biology
- Bacteriology: studies of bacteria
- Zoology: studies animals
- Botany: studies plants
- Mycology:
RNAi and ER Stress: Molecular Mechanisms and Biological Implications
(RNAi)highly evolutionally conserved process of post-transcriptional
gene silencing by which double stranded RNA (dsRNA), when introduced into a cell, causes sequence-specific degradation of homogolous mRNA sequences.
causes sequence-specific degradation of homogolous mRNA sequences.
Dicer: RNAse III enzyme
siRNA: 21-23 nt short interfering RNA
RISC: RNA-inducing silencing complex
Argonaute(Ago) protein is one of the main components in RISC. Ago cleaves and discards the passenger (sense) strand of the
Read MoreEukaryotic Cells: Structure, Organelles, and Cell Division
Eukaryotic Cells
Originated after prokaryotic cells. They are more complex and with some advantages over prokaryotic cells. Cytoplasm with organelles: structures that perform different functions. Genetic material is in the nucleus, where it is protected and provides better stability for cells. They have a cytoskeleton: a microscopic network of protein filaments and microtubules. Maintain the cell’s shape and internal organization. Helps cells move.
Organelles
Are membranous structures found in the
Read MoreEvolution and Ecology: Understanding the Dynamics of Organisms and Populations
Evolution
Change over time in the proportions of individual organisms that differ genetically.
Microevolution
Change over time in gene frequency within a population.
Macroevolution
Change over time in the proportions of species that determines the diversity of a taxonomic group.
New Organism Types
Micro-Mutation & Macro-Speciation
Alteration of Proportions of Different Organism Types
Micro-genetic drift, Natural Selection & Macro Adaptive Radiation
Natural Selection = not random, leads to evolution
Read MoreFrom DNA to Protein: Transcription and Translation
From DNA to RNA
From DNA to RNA: DNA does not synthesize proteins on its own. First, segments of the DNA called genes are copied into RNA. These RNA copies are used to direct the synthesis of protein. Many identical copies of RNA can be made from the same gene, enabling cells to rapidly synthesize protein.
Differences Between RNA and DNA
The nucleotides in RNA contain ribose sugar; DNA contains the base uracil instead of thymine. RNA is single-stranded and can fold into a variety of shapes and carry
Read MoreIntegumentary, Muscular, and Skeletal Systems: Functions and Disorders
Integumentary System
Functions
- Protection
- Regulation of temperature
- Sensory perception
- Regulate water loss
- Chemical synthesis
Physical barriers
- Waterproofing keratinized skin
- Certain waterproofs & protects
Biological barriers
- Langerhan’s cells
- Macrophages
- DNA
Temperature Regulation
- Sweat
- Constriction when cold
Cutaneous sensations
- Messiner’s corpuscles: light touch
- Merkel discs: light touch
- Pascinian receptors: pressure ducts
- Hair root plexus: sensations from movement of hairs
- Hair follicle receptors: movement across