Cereal Grains: Structure, Composition, and Dough Making
Grasses: Cereals are cultivated grasses, members of the monocotyledonous family Poaceae. Do not confuse them with pulses, which are legumes. The fruit (grain) develops after pollination. Pseudo-cereals include quinoa and amaranth.
Grain Structure
Embryo: 2 to 10% of the grain. It consists of the embryonic axis (EA) and scutellum (S). The EA contains primordial roots and shoots with leaf initials. The S is a secretory and absorptive organ that connects with the endosperm and releases hormones and enzymes
Read MoreCell Membrane Transport and Biological Molecules
Cell Membrane and Transport
The cell membrane, composed of a phospholipid bilayer, is selectively permeable, allowing certain molecules to pass while restricting others. Small non-polar molecules (O₂, CO₂) and small uncharged polar molecules (H₂O, glycerol) can pass freely, while ions (Na⁺, K⁺, Cl⁻) and large polar molecules (glucose, amino acids) require transport proteins. Membrane proteins serve various functions: structural support (desmosomes), enzymatic activity, signal transduction
Read MoreBiochemical Analysis: Lipids, Nucleic Acids
Isolation and Purification of Lecithin from Egg Yolk
Egg yolks are a rich and convenient source of lecithin. They contain water, fats, proteins, phospholipids, cholesterol, pigments, and vitamins. Using acetone extraction, most triacylglycerols, pigments, and vitamins can be removed, leaving mainly protein and phospholipid residue. Further extraction with chloroform-methanol solvents can remove the protein and provide a crude egg lecithin solution. Finally, lecithin can be separated from other contaminants
Read MoreAssisted Reproduction, Cloning, and Bioethics: An Overview
Assisted Reproductive Procedures
Assisted reproductive procedures include two main techniques:
- Artificial Insemination (AI): This involves introducing semen into the uterus through a cannula. The semen can be obtained from the male partner or from an anonymous donor through a sperm bank.
- In Vitro Fertilization (IVF): This involves achieving fertilization in a laboratory setting and then implanting the embryo into the mother’s uterus. Implementation consists of implanting the embryo in the wall of the
Lipids: Essential Biomolecules and Their Roles
Lipids: Structure and Classification
Lipids are a structurally diverse group of biomolecules. The only common characteristic is that a significant part, or all, of their molecule is insoluble in water and soluble in organic solvents (alcohol, acetone, ether, chloroform, etc.). Unlike proteins, nucleic acids, and polysaccharides, lipids do not form large polymers.
Classification of Lipids
Fatty Acids and Derivatives
Fatty acids are long-chain carboxylic acids. The hydrocarbon chain can be saturated or
Read MorePharmacodynamics: How Drugs Affect the Body
Pharmacodynamics
Pharmacodynamics is the study of how drugs affect the body. It explores drug interactions with biological systems and how these result in therapeutic or adverse effects. Understanding pharmacodynamics is crucial for comprehending both desired and undesired drug effects.
1. Mechanism of Drug Action
Drugs interact with specific molecules (often proteins like receptors, enzymes, or ion channels) to alter cellular functions, producing therapeutic or pharmacological effects.
Receptors
Receptors,
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