Photosynthesis: Light and Dark Reactions, Calvin Cycle
Photosystems
Photosystem I (PSI)
Able to absorb light of λ <700 nm.
Photosystem II (PSII)
Capable of absorbing light of λ <680 nm.
If a photon hits an electron in a photosynthetic pigment molecule, the electron captures the photon’s energy and jumps to a more distant orbit. It can be lost, ionizing the atom. The molecule, now oxidized, seeks electrons, which are supplied by the photolysis of water.
Absorption of light by the reaction center chlorophyll causes it to release an electron, which travels
Essential Nutrients and Balanced Diets for Optimal Health
Food and Nutrition
Food: Substances that provide energy to living beings, raw materials, and chemicals necessary for proper functioning and regulation of vital mechanisms.
Nutrition: The intake and subsequent use of energy and plastic materials necessary for life.
Types: Proteins, carbohydrates, fats, vitamins, water, mineral salts.
Macronutrients
The first three principles are immediate sources of energy.
Proteins
Proteins are complex nitrogenous substances of high molecular weight, containing amino acids
Read MoreCytosol, Cytoplasmic Inclusions, and Cell Cycle
Cytosol and Cytoplasmic Inclusions
Cytosol: The aqueous environment inside the cell, encompassing cytoplasmic organelles, a large number of enzymes, and structures such as inclusions. It is the site of protein synthesis, degradation, cytoskeleton processes, and most intermediary metabolism reactions.
Cytoplasmic Inclusions: Materials stored in the cell cytoplasm that are not membrane-bound. The most common are:
- Fat: The most important fuel store; most cells contain small droplets of water-insoluble
Animal Physiology: Nutrition, Digestion, Respiration, Circulation, and Excretion
Animal Physiology: Key Systems
Nutrition
The process by which living organisms obtain energy and matter for growth, development, and vital functions. Animals use energy from organic matter catabolism.
- Ingestion and digestion of food to release nutrients.
- Distribution of nutrients to body cells.
- Absorption of oxygen and transport to cells.
- Cell metabolism
- Waste removal from cells.
- Waste excretion.
Digestion
Macromolecule transformation into smaller, absorbable molecules.
- Physical/Mechanical: Fragmenting food,
Bacteria, Viruses, and the Immune System: A Deep Dive
Bacteria: Reproduction and Genetics
Asexual Reproduction
Bacteria, as primitive organisms, primarily reproduce asexually through fission (simple division or bipartition). The original cell divides, resulting in two identical daughter cells. This process lacks variability.
Sporulation
A more evolved form of asexual reproduction is sporulation. Under negative environmental conditions (changes in humidity, temperature, or nutrient scarcity), bacteria form spores—resistant structures that remain dormant.
Read MorePlant and Animal Nutrition
Plant Nutrition
Bryophyte Nutrition
Seedless plants are small and have a thallus organization. Although they have colonized the terrestrial environment, they lack true roots for water and mineral absorption, and vascular tissue for transport.
Cormophyte Nutrition Process
- Absorption of water and minerals by roots (root hairs are coated in a piliferous layer).
- Transportation of xylem sap.
- Gas exchange (carbon dioxide and oxygen).
- Transportation of phloem sap.
Xylem Transport
Water and mineral salts enter
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