Human Digestion, Circulation, and Nutrition
Diet and Nutrition
Diet varies according to individuals, regions, days, and seasons of the year. A balanced diet allows the individual, according to their age and situation, to maintain good health. To create a balanced diet, we must take into account:
- A diet needs to provide the necessary calories and essential nutrients.
- Calories should come from carbohydrates, fats, and proteins.
- Animal proteins should not exceed 40% of the total protein intake.
- Intake of vegetable fats and bluefish should be more
Evolutionary Evidence: Fossils to DNA Analysis
Paleontological Evidence
- Fossils: Mineralized remains of organisms found in sedimentary rocks. They reveal past life forms and their evolutionary relationships to current species.
- Some fossils, like *Archaeopteryx* (a primitive bird with feathers and teeth), represent intermediate forms between major groups, linking birds and reptiles.
- Modern geological dating techniques determine the age of fossils.
Embryological Evidence
Embryology, the study of early organism development, reveals that embryos of different
Read MoreAnimal Nervous Systems: Evolution, Structure, and Function
Evolutionary Features of the Nervous System
As animals evolve, their nervous systems become increasingly complex, exhibiting several key characteristics:
- Increased number of nerve cells.
- Concentration of nerve cells, particularly at the anterior (head) end.
- Increased number of interconnections between nerve cells.
- Specialization of nerve cells to perform different functions.
Nervous Systems in Invertebrates
The complexity of an animal’s nervous system is closely related to its activity and lifestyle. Several
Read MoreMuscle Contraction, Agonists, and Antagonists
Agonists, Antagonists, and Synergists
Agonists: These are the main muscles responsible for movement. They produce most of the force required for a particular action.
Antagonists: These muscles oppose the primary mover (agonist). They play a protective role and help control the movement of the agonist.
Synergists: These muscles assist the primary movers.
Muscle Contraction
Muscle contraction occurs when tension is applied to the bones via the tendons, resulting in torque on a joint.
Types of Muscle Actions
- Isometric:
Cell Biology: Regulation, Organelles, Division, and Photosynthesis
Cellular Regulation and Maintenance
Regulation of pH is essential for maintaining life. It requires that cellular and organic fluids stay within certain limits. Otherwise, structural changes in biomolecules and alterations in chemical reactions may occur. In aqueous solutions, living beings use weak acid-base buffer systems and their conjugates. Types include:
- Inorganic bicarbonate: HCO3– + H+ ⇌ H2CO3 ⇌ CO2 + H2O
- Phosphate: HPO42- + H+ ⇌ H2PO4–
Cellular Organelles and Their Functions
Ribosomes:
Read MoreDNA Replication: Mechanisms, Enzymes, and E. Coli Process
DNA Replication Fundamentals
The organism has the ability to create exact copies of itself, based on a template. This was discovered when it was clear that DNA somehow acts to serve as a template in replication and transcription of genetic information. Each of the two strands are complementary to each other, following these rules:
- DNA replication is semiconservative: Each DNA strand is the template for the synthesis of a new chain. The result is two new DNA molecules, each with a new chain and an