Seed Plants: An In-Depth Look at Spermatophytes
Spermatophytes: The Seed-Bearing Lineage
Spermatophytes are a monophyletic group encompassing all vascular plants that produce seeds. The term originates from the Greek words “sperma” (seed) and “phyton” (plant), translating to “seed plants.” This group aligns precisely with the traditional classification of flowering plants, as the pollen grain in seed plants generates a pollen tube to reach the ovum, facilitating fertilization.
Gymnosperms: Vascular Plants with Naked Seeds
Gymnosperms are vascular
Read MoreAnimal Physiology: Key Mechanisms and Systems
Osmoregulation and Excretion
Osmosis and Water Balance
Osmosis is the movement of water across a semipermeable membrane from an area of low solute concentration to an area of high solute concentration. Excretion is the process of removing metabolic wastes and toxins from the body. Animals employ different strategies to maintain water balance:
- Osmoconformers: These animals, like jellyfish, maintain an internal osmolarity similar to their environment.
- Osmoregulators: These animals, like humans, actively
Organ Transplantation and Assisted Reproduction
Transplantation
Transplanting: Replacement of a diseased organ or tissue that endangers a person’s life. Donor: Usually a deceased person (brain dead) or a living person. Spanish Legislation: 1. Defines brain death as a scientific, legal, and ethical concept. 2. Respects the deceased’s will regarding donation. 3. Death diagnosis is made by an independent medical team. 4. Ensures altruism and non-commercialization. 5. Guarantees donor anonymity. 6. Applies medical criteria for organ distribution.
Types
Read MoreCell Biology Fundamentals: Proteins, Lipids, and Nucleic Acids
1. Peptide bond links amino acids together to form proteins.
2. Triglycerides are composed of one molecule of glycerol and three fatty acids.
3. The primary structure of a protein is the unique sequence of amino acids.
4. DNA and RNA are types of nucleic acids.
5. Matthias Schleiden and Theodor Schwann are known for articulating the cell theory.
6. The mitochondrion is an organelle that functions as the site of energy production in eukaryotic cells.
7. A nucleotide is made up of a sugar, a phosphate group,
Read MoreFundamentals of Genetics: DNA, Proteins, and Applications
What is Genetics?
The unit of inheritance is called a gene. Genes are transmitted according to defined rules or laws. They are located on chromosomes, structures composed of a substance in the cell nucleus. Sex is determined by genes or chromosomes in most living organisms.
Key Genetic Terms:
- Genotype: Genetic constitution of an individual character or a whole set of genes.
- Phenotype: The external expression characteristic of the individual.
- Alleles: Each variant of a gene. For each gene, an individual
Cell Structure: From Theory to Chromosomes
1.1. The Cell Theory
Thanks to Schleiden and Schwann, the development of cell theory began:
• The cell is the structural unit of all living things.
• It is the functional unit that performs all life processes.
• Every cell comes from an existing one.
• It represents the genetic unity of all living things, containing the hereditary material passed to daughter cells.
3.1. Prokaryotic Cell Structure
• Cell wall: a rigid casing formed by polysaccharides and proteins that give shape to bacteria.
Read More