Genetic Engineering: Techniques and Applications
DNA Fragmentation
Fragmentation of DNA: Enzymes capable of breaking the DNA are called restriction endonucleases, restrictases, or restriction enzymes. They are able to recognize and cut at specific points in the sequence of nucleotides, which are called target sequences.
Use of a Vector
A vector is responsible for introducing a particular piece of DNA into other cells.
Plasmids
Bacteria possess a circular, double-stranded DNA molecule in which they carry most of their genetic information. But they also
Read MoreImmune System: Defenses, Responses, and Immunopathology
Concept of Immunity
Immunity is a set of mechanisms that an individual possesses to counter the invasion of any foreign body or to deal with tumors. This property is acquired before birth and matures and consolidates in the first years of life. In vertebrates, it implies that different agencies distinguish self from outside, i.e., recognize all cell types. The immune system is responsible for conferring immunity. This system, present even in invertebrates, reaches its greatest complexity in primates
Read MoreProtein Structures and Functions: From Amino Acids to Enzymes
Proteins: Structures and Functions
Proteins are organic biomolecules formed by carbon (C), hydrogen (H), oxygen (O), and nitrogen (N), often containing sulfur (S), iron (Fe), zinc (Zn), and copper (Cu). They account for 50% of the dry matter of a living being. Their molecular weight is quite high despite being composed of core building blocks (monomers) of low molecular mass. The monomer of proteins is called an alpha-amino acid. Proteins have a variety of functions to perform, and they are found
Read MorePhotosynthesis and Cellular Metabolism: An In-Depth Look
Anabolism
The path is constructive metabolism, the synthesis pathway from simple molecules to complex molecules. There are two stages:
- Heterotrophic Anabolism: Simple organic molecules to complex organic molecules such as starch, fat, or proteins. Its objective is the synthesis of macromolecules (energy reserves).
- Autotrophic Anabolism: The passage of inorganic molecules (H2O, CO2, NO3–) to simple molecules such as glucose or glycerin. These are beings that make their organized matter from inorganic
Squid: Anatomy, Behavior, and Classification
Squid: Anatomy and Behavior
Squid have two gills, and a circulatory system that consists of a systemic heart and two branchial hearts. Their tentacles are equipped with highly muscular suckers, and if lost, they cannot grow back. Squids can blend in with their surroundings with ease to avoid predators.
They also have cells called chromatophores in their skin that give squids the ability to change color if they feel threatened, a strategy that is combined with the expulsion of the ink they produce.
Read MoreCellular Respiration, Nutrition, and Human Body Systems
Cellular Respiration and Energy Production
Nutrients contribute to the fuel for cell energy. Cells use this energy to perform their functions. Cellular respiration occurs in the mitochondria. Glucose is the nutrient most commonly used. There are three phenomena in this process:
- Consumption of oxygen, whose presence is necessary for combustion
- Release of energy, used by cells
- Production of carbon dioxide and water
The useful energy contained in nutrients are chemical substances. This energy is called
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