Photosynthesis: Light and Dark Reactions
Fundamentals of Photosynthesis
In photosynthesis, light is captured by pigments. When a photon is absorbed by an electron, a photosynthetic pigment is excited. The pigment electron will be provided again if there is a primary donor of electrons. The liberated electrons pass to a primary electron acceptor and then to an electron transport chain. Reactions that occur in this chain are exothermic. The energy is used to create a proton gradient through the thylakoid membrane. Subsequently, the passage
Read MoreTransposons and RNA: Key Aspects and Functions
Transposons
Transposons are segments of DNA that can move or “jump” from one chromosomal location (donor site) to another, either within the same chromosome or to a different one (target site). The insertion of a transposon into an essential gene could be lethal to the cell, so this movement is closely regulated and usually infrequent. Transposons are molecular parasites that passively replicate within the host cell’s chromosome. In some cases, transposons carry genes that are useful to the host
Read MoreHormones, Nervous System Functions, and Endocrine Disorders
Hormones and Glandular Functions
Main Glands and Hormones:
- Hypothalamus: Releasing factors and inhibitors act on the pituitary, enabling hormone production.
- Pituitary:
- Oxytocin: Stimulates uterine contractions during childbirth and milk production in the breast.
- Growth Hormone: Stimulates bone growth.
- Thyroid:
- Thyroid Hormone: Regulates metabolism.
- Calcitonin: Decreases blood calcium levels by promoting bone deposition.
- Adrenal Glands/Pancreas:
- Adrenaline: Prepares the body for intense muscle activity and
Understanding Cancer and Evolution: Key Concepts
Homologous and Analogous Traits
Homologous traits are traits shared by two or more different species that share a common ancestor.
Analogous traits do not share a common origin but have a similar function.
Phylogenetic Tree
A phylogenetic tree is a reconstruction of hypothesized evolutionary relationships among organisms based on genetics, physical characteristics, and behavior.
Transitional Forms
Transitional forms record both the gain and loss of prominent characteristics over time.
Anthropocene
Anthropocene
Read MoreCell Structure and Function: A Comprehensive Look
The Cell: Vital Unit of All Life
The cell is the vital unit, anatomical, functional, and breeding unit of all life.
Basic Components
- Atom: Small particle made up of electrons.
- Molecule: Formed by the interaction of several atoms.
Bioelements
Elements found in living beings:
- Main: Present in greater proportion in the cell.
- Secondary: Present in smaller proportion in the cell.
- Trace elements: Present in very small proportion in the cell.
Biomolecules
Molecules formed in living beings:
- Carbohydrates: Molecules
Understanding the Causes of Congenital Malformations
Etiology of Malformations
Etiologic factors responsible for malformations differ according to whether they intervene before, during, or after fertilization. Before fertilization, these are genetic abnormalities, which are transmitted by the laws of inheritance.
Hereditary Factors
Simple Transmission of Inherited Malformations
A single gene is abnormal. The modes of transmission are differentiated by character: dominant, recessive, or sex-linked.
- Autosomal Dominant (e.g., achondroplastic dwarfism). If