Fundamentals of Ecology: Ecosystems and Environmental Factors
Ecological Pyramids: Structure and Representation
The ecological pyramid is a form of representation used to show how various characteristics of trophic levels, such as production or biomass, change when moving from one level to another.
Each trophic level is represented by a rectangle. The rectangle forming the base of the pyramid represents the producers (manufacturers), whose resources are available to other trophic levels. The length of the base of each rectangle is proportional to the measured
Read MoreLactic Acid Bacteria: Biochemistry, Pathways, and Food Preservation
Lactic Acid Bacteria (LAB)
Gram-positive, non-motile, and non-spore forming bacteria that are strict fermenters.
They are catalase and oxidase negative and cannot synthesize cytochromes.
LAB can be either homofermentative or heterofermentative. The type of fermentation is determined by the enzymes produced by the organism.
Homofermentative: Converts glucose into two lactic acid molecules, with 85–95% of the glucose carbon ending up as lactate. This pathway uses the glycolytic (Embden-Meyerhof) pathway.
Cell Organelles: Structure, Function, and Energy Production
Essential Cellular Organelles: Structure and Function
Membrane-Bound Organelles
Golgi Apparatus
The Golgi apparatus consists of flattened sacs (cisternae) and independent vesicles surrounded by a membrane and assembled in groups called dictyosomes. Its function is the secretion of substances taken from the endoplasmic reticulum and destined for lysosomes.
Lysosomes
Lysosome Structure and Role: These are spherical vesicles surrounded by a membrane, which contain hydrolytic enzymes. They are responsible
Read MoreCore Concepts in Plant Biology and Animal Diversity
Plant Evolution and Life Cycles
- Land plants evolved from green algae (Charophytes).
- The gametophyte is haploid (n) and produces haploid gametes by mitosis.
- Fusion of gametes gives rise to the diploid (2n) sporophyte, which produces haploid spores by meiosis.
- Bryophytes lack specialized tissues for support and water conduction.
- Vascular plants have two types of vascular tissue: xylem and phloem.
- Xylem conducts most of the water and minerals.
- Phloem consists of living cells arranged into tubes, distributing
Human Nutrition: Process, Nutrients, and Infant Feeding
The Nutrition Process: Ingestion, Digestion, Absorption, and Expulsion
Ingestion
Ingestion involves the mechanical and chemical preparation of food before it enters the stomach:
- Chewing (Mastication): This is the crushing and fragmentation of food, carried out by the tongue and the teeth.
- Insalivation: This is the impregnation of food with saliva, secreted by the salivary glands, until it becomes a mass called the food bolus.
- Swallowing (Deglutition): The food bolus passes through the pharynx and esophagus
Anatomy and Function of Digestive & Respiratory Systems
The Human and Avian Digestive System Anatomy
Pharynx: Swallowing and Lymphocyte Maturation
The Pharynx is a muscular tube that leads into the next portions of the digestive tract: the esophagus and trachea. The tonsils are used for the maturation of lymphocytes. Below the cartilaginous fold belonging to the larynx is the epiglottis, which covers the glottis during swallowing to prevent food from passing into the trachea. The medulla controls swallowing, including closing the nostrils by raising the
Read More