Cell Theory, Biology, and Human Body Processes
Key Figures and Discoveries in Biology
Schleiden and Schwann authored the cell theory. Jansen is associated with the microscope, while Knoll and Ruska developed the electron microscope. The scientific method is based on facts, logic, and order. Carolus Linnaeus developed Systema Naturae and is a key figure in taxonomy.
Branches of Biology
- Anatomy: The study of the structure of living things.
- Physiology: Studies the functioning of organisms.
- Genetics: Deals with the study of the transmission of hereditary characteristics.
- Evolution: Studies the evolutionary development of organisms.
- Embryology: Explains the development of an organism from the egg cell to a multicellular organism.
- Cytology: Studies cell structures.
- Histology: Studies tissues.
- Ecology: Studies the relationships between organisms and their environment.
- Microbiology: Studies microorganisms.
- Morphology: Studies the form of living beings.
Important Contributions
Thomas Morgan proposed the chromosome theory. Aristotle posed the theory of spontaneous generation. Galen is considered the father of anatomy. H. Z. Jansen observed the first organisms. Pasteur investigated the relationship between germs and diseases. Hooke introduced the word “cell.” Linnaeus is known as the father of taxonomy. Mendel is the father of genetics. Darwin’s seminal work is “On the Origin of Species.” Leeuwenhoek invented the microscope. Knoll and Ruska invented the electron microscope. Schleiden and Schwann are the authors of the cell theory. Oparin hypothesized biochemical evolution for the origin of life.
Scientific Method
Experimental tests are performed to test a hypothesis. Observation involves observing the fact. A universally accepted theory is a hypothesis tested by practice. A hypothesis is a guess or possible response to a problem. Coacervates are a proposed model by Oparin to explain the origin of cells. A scenario establishes cause-and-effect relationships.
Essential Nutrients
- Carbohydrates: The main source of energy for the body.
- Lipids: Highly concentrated sources of energy due to a larger amount of hydrogen atoms in their molecular chains.
- Proteins: Nutrients composed of units called amino acids.
- Vitamins: A class of nutrients found in foods of plant origin.
- Water: The essential nutrient in the diet.
The Human Digestive Process
The digestive process in humans involves the digestive system, which consists of digestive components. Ingestion or capture involves the passage of food through the mouth. Digestion involves breaking down food into large, soluble substances. Oral digestion involves the trituration of food. Chemical digestion involves viscous liquid saliva. Saliva contains mucin, a substance that softens the food in the mouth.
Cell Division: Mitosis
Mitosis is a process of cell division in which the two resulting cells obtain exactly the same genetic information as the parent cell.
- Interphase: The state in which the cell is when it is not in the process of division.
- Prophase: The first phase of mitosis. During this phase, the centriole of the cell doubles, and each one goes to one pole of the cell. The nuclear membrane disintegrates.
- Metaphase: The second stage of mitosis. During this phase, chromosomes are directed toward the equatorial plane of the cell. The cytoplasmic spindle appears.
- Anaphase: The third stage of mitosis. The chromatids are divided and directed towards the spindle poles by the cytoplasm.
- Telophase: The last stage of mitosis. Chromosomes reach the poles. A nuclear membrane forms around the chromosomes.
Meiosis and Genetic Material
Meiosis consists of two cell divisions. Gametogenesis occurs in male and female cells. A gene is a unit of hereditary material, consisting of deoxyribonucleic acid (DNA).
Chemical Compounds
Chemical compounds include inorganic substances like water, minerals, and organic salts, as well as organic compounds like carbohydrates, lipids, proteins, and nucleic acids.
Carbohydrates
Carbohydrates are complex molecules made up of simple molecules (monosaccharides). Examples include:
- Monosaccharides: Glucose, fructose, galactose
- Disaccharides: Maltose, sucrose, lactose
- Polysaccharides: Starch (vegetable), glycogen (animal), cellulose (plant cell walls)
Lipids
Salts help maintain water balance. Lipids or fats are composed of fatty acids and can be classified by solubility, and as saturated or unsaturated.