Lymphatic System: Parts, Function, and Immunity
What is the Lymphatic System?
Your lymphatic (lim-FA-tik) system not only helps the body defend itself against disease but also maintains homeostasis by keeping body fluids at a constant level. Body cells are constantly bathed in fluid. This tissue fluid is composed of water and dissolved substances that diffuse from the blood into the spaces between the cells that make up the surrounding tissues. This tissue fluid collects in open-ended lymph capillaries. Once the tissue fluid enters the lymph vessels,
DNA and Genetics: Understanding Heredity and Molecular Biology
The Genetic Revolution
The discovery of DNA’s molecular structure marked the beginning of a revolution in the field of genetics and reproduction.
Genetics: Understanding Biological Inheritance
Genetics is the study of everything related to biological inheritance, genes, and their expression in organisms. Born at the beginning of the 20th century with Mendel’s experiments in plant hybridization, it investigates how hereditary characteristics are transmitted across generations. Mendel established a pattern
Read MoreBiotic and Abiotic Organization, Human Cells, and Body Systems
Biotic and Abiotic Levels of Organization
- Atom Level: Consists of atoms of the chemical elements from which living matter is formed: carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur.
- Molecule Level: Formed by the joining of two or more atoms.
- Macromolecule Level: Formed when molecules join together.
- Organelle Level: When macromolecules join together, they form organelles.
- Cellular Level (Biotic): Organelles can be considered the organs of cells. They come together to form cells, which are the
Understanding Biological Evolution and Population Genetics
Species: Organisms capable of interbreeding with each other naturally, but do not cross with members of another species. (If crosses occur, the offspring are infertile).
Population: A group of individuals of the same species found in the same place and time, and are interbreeding.
Gene pool: All alleles of all genes found in all individuals of a population. (The sum of the genotypes in a population).
Population genetics: The study of the frequency, distribution, and inheritance of alleles in a population.
Read MoreProtein Synthesis: From mRNA to Polypeptide Chain
Ribosome Binding Sites
In the ribosome, there are three different attachment sites for tRNA: the P site, where the polypeptide chain is formed; the A site, into which the amino acid (AA) is going to join the protein chain; and the E site, where the tRNA is located before leaving the ribosome.
Transfer RNA (tRNA)
Transfer RNA molecules are responsible for transporting amino acids to the ribosome and incorporating them into the growing protein chain according to the sequence indicated by the messenger
Read MoreEcological Terms and Ecosystem Dynamics
Key Definitions in Ecology
Definitions:
- Aphotic: Total darkness area from 500m.
- Biocenosis: The set of populations living in a determined area.
- Biotope: Place or physical environment occupied by a community.
- Ectotherm: The main source of body heat depends on external sources.
- Endotherms: Control body temperature through the production of heat inside the body.
- Stenosis: Short interval of tolerance.
- Density: A factor that determines the size of the population.
- Euphotic: Area that receives sufficient light