Levels of Biological Organization: Bioelements & Biomolecules
Levels of Biological Organization
Subatomic Level: Includes subatomic particles that make up atoms (electrons, protons).
Atomic Level: Includes atoms that constitute our body. A bioelement is the set of atoms of the same type.
Molecular Level: Includes molecules and clusters of molecules, such as the cell membrane, composed of various types of cellular molecules.
Cellular Level: Includes cells and multicellular organelles.
Tissue Level: The level of organization of multicellular individuals, including
Read MoreUnderstanding the Digestive Process: Stages and Mechanisms
Understanding the Digestive Process
The digestive process encompasses all the steps involved in breaking down food within the digestive tract for assimilation.
Stages of Digestion
- Ingestion: This is the entry of food into the organism. Most animals have specialized structures in the mouth to facilitate the capture and ingestion of food.
- Digestion: This converts food into simpler molecules that cells can use. In most animals, food undergoes both mechanical and chemical transformation.
- Absorption: The
Cell Structure and Function: A Detailed Look
Cell Structure and Function
All living things are composed of cells, the fundamental units of life. Cells are the anatomical (structural), physiological (functional), and genetic (inheritance) units of living beings. They are capable of nutrition, interaction, and reproduction.
Cell Types
- Prokaryotes: Cells with no nucleus, DNA is spread throughout the cytoplasm. Example: Bacteria.
- Eukaryotes: Cells with a nucleus where DNA is contained. Examples: Animal and plant cells.
Cell Parts
- Plasma membrane: The
Cellular Organization: Structure, Function, and Interactions
The Cell: The Basic Unit of Life
The cell is the minimum reproductive unit and the hereditary basis of information that defines a species. It has the capacity for self-replication.
Plasma Membrane: Defining the Cell
The plasma membrane defines the cell and its interaction with the external environment. It facilitates cellular compartmentalization and interaction with the extracellular environment and other cells. The nuclear membrane differentiates “eukaryotic” from “prokaryotic” cells.
Organelles:
Read MoreNeo-Darwinism vs. Saltationism: Evolution Theories
Neo-Darwinism vs. Saltationism (Punctuated Equilibria)
Neo-Darwinism:
- The variability of populations is genetic and is due to two processes: mutation and genetic recombination.
- The gene pool is defined as the sum of all genes (each with their different alleles) present in all individuals of a population.
- Natural selection acts on genetic variability. Each individual in a population carries different alleles responsible for their phenotype.
- Natural selection leads to changes in the set of alleles of the
Nucleic Acids, DNA Replication, and Protein Synthesis
Nucleic Acids
DNA Functions: Stores genetic information, transmits information to other molecules and between generations. 10 base pairs per turn.
Nucleotides: Sugar and phosphate make the backbone; bases give chemical identity. Bases: Adenine + Thymine (2 H-bonds), Guanine + Cytosine (3 H-bonds). Has 1-3 phosphate groups attached. A, G = purines. T, C = pyrimidines.
Chargaff’s Base Pairing Rule: A-T, C-G (helped discover the helical shape of DNA). Pair because of base distance, H-bond pattern, and
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