Enzymes and Vitamins: Essential Roles in Metabolism
Enzymes: Biological Catalysts
Enzymes are biological catalysts crucial for metabolic reactions and sustaining life in living creatures. They are usually proteins, although ribonucleoprotein enzymes, known as ribozymes, also exist. The region of the enzyme where the substrate fits is called the active site. The bond between the enzyme and substrate involves steric recognition. Enzymes are highly specific for each substrate and each biochemical reaction.
Key Features of Enzymes:
- Decrease the activation
Taxonomy and Biological Classification of Living Organisms
Unranked Systems
The advancement of knowledge led scientists to a conclusion: a series of common features are found in individuals of each group. These tri-fold categories are homogeneous. One of the group’s advantages is that it is able to include living beings until the moment they are unknown. A classification is good if it refers to characteristics that do not vary in people. According to the criterion, we get one or the other, and it is important that the classification criterion is objective
Read MoreHuman Reproduction: From Puberty to Parenthood
The Reproduction of Human Beings
Humans reproduce sexually. Women produce ovules, and men produce sperm. These two cells unite to form a zygote. Fertilization is internal, so we are viviparous. Reproduction includes:
- Production of gametes (in specialized organs)
- Fertilization (the union of gametes within the female reproductive system)
- Development of the zygote (within the female reproductive system. The zygote becomes an embryo and then a fetus)
- Labor and birth (of a fully formed baby)
- Child Development
Interphase Nuclei: Structure and Function in Detail
Interphase Nuclei: Concept and Structure
Concept
A separate structure from the cytoplasm by a membrane envelope that acts as the cell’s genetic memory.
Basic Structure
The basic structure enables us to distinguish the nuclear envelope, chromatin, nucleolus, and nucleoplasm.
1. Nuclear Envelope
Formed by two membranes separated by a perinuclear space, crossed by pores, the outer membrane has ribosomes on its outer surface. The nuclear envelope has, on the nucleoplasm side, a dense inner membrane called
Read MorePlant Cell Wall Structure, Function, and Phloem Transport
**Item 1: Membership of the Physical Cell Wall**
Regarding the composition, a physical wall is formed by different layers that vary in thickness, chemical composition, and direction of microfibrils. Starting from the outside of the plasma membrane, we find the middle lamella, an intercellular space of the plant cell, the primary wall, and finally, the secondary wall.
- Middle Lamella: Formed principally by pectins without cellulose. The soft tissue is not lignified.
- Primary Wall: It is a flexible structure
Bacterial Cell Structure, Metabolism, and Nutrition
Peptidoglycan: Chemical Composition
The repeating unit is:
- N-acetylglucosamine (NAG)
- N-acetylmuramic (NAM)
These are joined together by β (1→4) bonds. The various disaccharide units are joined together by β (1→4) bonds. This link may be broken by lysozyme. The tetrapeptide chain running from the -COOH group of each NAM lactyl often contains:
- L-alanine
- D-glutamic acid
- m-DAP
- D-alanine
The Peptidoglycan of Gram-Negative Bacteria
- Usually, peptidoglycan (PG) has one layer.
- The chains are joined by peptide