Mendelian Inheritance and Genetic Processes
Mendelian Inheritance
Inheritance is transmitted by hereditary factors stored in gametes. These factors are of maternal and paternal origin and join in the new individual without mixing, separating again when these individuals form reproductive cells.
Mendel’s Laws are the primary rules that govern the inheritance of characteristics from one generation to another.
Mendel’s First Law: The Law of Uniformity
Based on pure breeds, all individuals of the first generation are equal. All hybrids for the character
Read MoreHuman Nutrition, Diet, Food Safety, and Digestion
Human Nutrition
Understanding Nutrients
Nutrition is the set of processes by which the body receives, transforms, and incorporates the necessary nutrients for its cells. Nutrients are chemical compounds in foods that cells need to live.
Features of Nutrients:
- Energy Efficiency: Supplying energy for the functioning of cells.
- Plastic or Repair: Providing components for growth and renewal of cells that are destroyed.
- Regulatory: Supplying chemical substances that control the reactions of the cells.
Types
Read MoreScabies: Symptoms, Causes, Treatment, and Prevention
What is Scabies?
Scabies is a skin infestation caused by the mite Sarcoptes scabiei var hominis of the Sarcoptidae family.
Morphologic Classification
- Arthropoda: Non-segmented, small body size, with 4 pairs of legs, dorsoventrally flattened, no eyes or trachea.
- Females: 300-500 microns long by 230-420 microns wide.
- Males: 213-285 microns long by 162-210 microns wide.
- Eggs: 160 microns in length.
Etiology and Life Cycle
- Parasitism Level: Obligate, living all or a phase of their life cycle inside or on the
Understanding Hypersensitivity, HIV Infection, and Transplant Rejection
Hypersensitivity
Hypersensitivity is an exaggerated immune response that, instead of protecting the body, causes multiple alterations.
Immediate Hypersensitivity Type I: Allergy
Known as allergy, this is a very quick response that appears 15 to 20 minutes after contact with the antigen (allergen). Pollen allergens can be an example. The allergic reaction takes place in three phases:
- Awareness Phase: When the body first comes into contact with the allergen, macrophages may engulf it and display its fragments
Evolutionary Theories: Lamarck, Darwin, Neo-Darwinism, and Hominization
Lamarck’s Theory of Evolution
Lamarck proposed an evolutionary theory, albeit incorrect in its explanation of how evolution occurs. He focused on the use and disuse of organs. His main points were:
- Species are not invariable; they evolve from one another.
- The use or disuse of organs causes their development or atrophy.
- These acquired characteristics through use or disuse are inherited, leading to degeneration and eventual disappearance over generations.
Darwin’s Theory of Evolution
Darwin provided the
Read MoreSexual vs Asexual Reproduction: Genetic Diversity
There are two types of reproduction: sexual and asexual. In sexual reproduction, descendants are genetically different. For example, humans reproduce through the union of gametes. Individual differences are the norm in sexual reproduction because special haploid cells, the sexual reproductive cells (meiospores and gametes), are formed by meiosis. Meiosis is the division of cells. In asexual reproduction, descendants are genetically identical. For example, roses reproduce through cuttings, where
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