Biological Foundations: From Bioelements to Biodiversity
Essential Bioelements and Biomolecules
Primary Bioelements: Carbon (C), Oxygen (O), Hydrogen (H), Nitrogen (N), Phosphorus (P), and Sulfur (S). These are highly abundant, making up 98% of living matter. Carbon is the most characteristic, as it forms the long chains that serve as the basic structure of living things.
Secondary Bioelements: Calcium (Ca), Sodium (Na), Potassium (K), Magnesium (Mg), and Chlorine (Cl).
Trace Elements: Also known as vestigial elements, these make up less than 0.1% of the
Read MoreWheat Stem Borer and Red Pumpkin Beetle Pest Management
Wheat Stem Borer (S. inferens)
Systematic Position
- Class: Insecta
- Order: Lepidoptera
- Family: Noctuidae
Habits
The wheat stem borer is a nocturnal insect, living for 10–15 days. Eggs are laid on the inner surface of the host plant’s leaf sheath. Caterpillars bore into the stems of the wheat plant to feed. The caterpillar prefers moist weather to infest new shoots.
Damage
The caterpillars attack and destroy young shoots of the wheat crop, causing uneven growth. The central shoot is damaged completely, resulting
Read MoreCell Biology Fundamentals: Cycle, Control, and Structure
Cell Cycle: Growth, Replication, and Division
The cell cycle is an ordered sequence of events enabling a cell to grow, replicate its DNA, and divide into two genetically identical daughter cells, ensuring accurate genetic transmission. It comprises interphase (G1, S, G2 phases) and the mitotic (M) phase (mitosis and cytokinesis).
- G1 Phase: The cell grows metabolically, synthesizing proteins and organelles while assessing environmental conditions at the restriction point before committing to division.
Mechanisms of Biological Gas Exchange
Gas Exchange Fundamentals
Gas exchange is the process where an organism takes in oxygen and eliminates carbon dioxide. Oxygen is essential for respiration and must reach every cell. Carbon dioxide is a waste product of respiration that must be removed from the body. Gas exchange occurs via diffusion across a gas exchange surface. Oxygen diffuses from air or water, either into the blood for transport to the cells or directly into the cells. Carbon dioxide diffuses from the cells or the blood back
Read MoreCell Biology: Theory, Transport, and Structures
Cell Theory and Microscope Technology
1. Can cells appear spontaneously without genetic material from a previous cell?
No, cells do not appear spontaneously; they pass copies of their genetic material on to their daughter cells.
2. Compare and contrast a TEM and SEM.
In a TEM (Transmission Electron Microscope), electrons are transmitted through a specimen to a fluorescent screen. An SEM (Scanning Electron Microscope) is a modification that directs electrons over the surface of the specimen, producing
Read MoreEssential Principles of Cell Biology and Biochemistry
Biological Molecules: Lipids and Their Functions
Lipids are organic molecules that are insoluble in water, with an oily, waxy, or fatty consistency. Their functions are to store energy, to participate in muscle contraction, to act as insulators, and to make up part of the cell membranes. There are three kinds of lipids:
- Fatty acids and waxes: These are only made up of carbon, hydrogen, and oxygen.
- Phospholipids: These also contain phosphorus and nitrogen. They are made up of a polar head with a phosphate