Cell Membrane Structure: Lipids, Proteins, and Fluidity
Cell Membrane Structure
The plasma membrane, a thin layer of lipids and proteins, separates a cell from its surrounding. To maintain their internal environment, the cells of all organisms must constantly exchange molecules and ions with the fluid environment that surrounds them. Transport proteins move particular ions and molecules, including water, in a directed way across the membrane.
Lipids in Biological Membranes
Biological membranes consist of lipids. Phospholipids and sterols (such as cholesterol)
Read MoreMicroalgae: Characteristics, Cultivation, and Applications
Microalga, in its narrowest sense, is a photoautotrophic, unicellular eukaryote which uses CO2 and gains energy from light.
In eukaryotic algae, the donor DNA is integrated into the genomic or chloroplast DNA. Only Chlamydomonas reinhardtii (single-cell green alga with 2 flagella) has a history of stable genetic modifications and subsequent cultivation of the GM-strains. Vegetative cells of C. reinhardtii are haploid. Under stress conditions, e.g., nitrogen starvation, haploid gametes develop. There
Read MoreHuman Genome and Genetic Engineering: Advances and Implications
The Human Genome
The human genome is the complete set of genes within a human being. It contains all the information necessary for basic human development. In the human species, the genome is packaged into 46 chromosomes: 23 from the father and 23 from the mother. These 46 chromosomes are grouped in pairs. 22 pairs are autosomes, which do not carry information about sex characteristics, and one pair are sex chromosomes. Females have two identical X chromosomes (XX), while males have one X and one
Read MoreDNA, Protein Domains, Huntington’s Disease, and Replication
Hypothesis on DNA Melting Temperature (Tm) and GC Content
It was hypothesized that DNA with a higher GC content and normal high salt concentrations (Na+/K+) would have a higher Tm. To prove or disprove this hypothesis, researchers took different kinds of animal DNA (stripped of proteins) with varying GC content. The GC content was measured using biochemical methods. The Tm is the temperature at which half of the DNA is single-stranded and the other half is double-stranded. Heat was added to the various
Read MorePreservative Effectiveness and Cell Culture Applications
Preservatives
Preservatives are substances added to products to prevent or inhibit the growth of microorganisms, such as bacteria, yeast, mold, and fungi. They help extend the shelf life, maintain quality, and ensure safety.
Types of Preservatives
- Chemical Preservatives:
- Parabens (e.g., methylparaben, propylparaben)
- Formaldehyde-releasing agents (e.g., DMDM hydantoin)
- Isothiazolinones (e.g., methylisothiazolinone)
- Phenoxyethanol
- Natural Preservatives:
- Essential oils (e.g., tea tree oil, lavender oil)
- Plant
Biotechnology and Genetic Engineering: Applications and Techniques
Biotechnology vs. Traditional Genetic Engineering
Traditional genetic engineering is slow, requiring many generations to achieve desired traits. It involves recombining genetic material of the same species without directly manipulating the DNA sequence of genes.
Biotechnology, on the other hand, allows for rapid genetic changes in a single generation. It enables the recombination of DNA from different species and the production of new genes.
Key Concepts
- Recombinant DNA Technology: A procedure involving