Understanding the Key Features and Levels of Living Things
Key Features of Living Things
- Complex Organization: Molecules interact in complex internal and external functions.
- Cellular Structure: Can be unicellular or multicellular.
- Feeding and Metabolism: Capture and use energy and matter for growth, development, and maintenance.
- Responsiveness: Detect external stimuli and respond appropriately.
- Reproduction: Ability to create new individuals, similar or different from themselves.
Levels of Biological Organization
Subatomic Level
Composed of neutral protons and
Read MoreCellular Organelles and Levels of Biotic Organization
Cellular Organelles
Cellular organelles comprise a supramolecular complex. Although they have their own characteristics, they cannot be considered living beings, as they do not meet the criteria for nutrition, relationships, and reproduction. Inside the cell, there are several cellular organelles such as mitochondria, peroxisomes, and the endoplasmic reticulum.
Viruses are macromolecular complexes consisting of two types of macromolecules: proteins and nucleic acids, and in some cases, lipids.
Levels
Read MoreCarbohydrates and Lipids: Monosaccharides to Polysaccharides
Carbohydrates and Lipids
Understandings: Monosaccharides and Polymers
Monosaccharide monomers are linked together by condensation reactions to form disaccharides and polysaccharide polymers.
| Monosaccharides | Glucose | Energy molecule used in aerobic respiration |
| Galactose | Nutritive sweetener in foods | |
| Fructose | Fruit sugar | |
| Disaccharides | Maltose | Malt sugar found in barley, consists of 2 glucose molecules |
| Lactose | Sugar found in milk | |
| Sucrose | Transport sugar found in plants because of its solubility | |
| Polysaccharides | Starch | Storage |
Health Hazards: Environmental, Chemical, and Biological Risks
Health Hazards: An Overview
Physical Environmental Insults: Ionizing radiation is a form of energy that can modify the structure of matter and cause changes in our cells. It can be natural or artificially produced by temperature variations. High temperatures with excessive humidity prevent the evaporation of sweat and can be lethal.
Chemical Hazards
Chemicals: Air pollution occurs when human activities alter the composition of the air by adding compounds that affect health. Water pollution, from domestic
Read MoreVascular Pathologies: Atherosclerosis and Congenital Anomalies
Consequences of Pathological Changes in Vessels
- Stenosis and obstruction of the vessel.
- Weakening of vessel walls.
- Production of thrombotic deposits.
Congenital Anomalies
- Abnormal blood vessels
- Strawberry aneurysm
- Arteriovenous fistulas (causing increased venous return and high risk of cardiac insufficiency)
Atherosclerosis
Atherosclerosis is a chronic inflammatory response of the arterial wall to some form of injury from the endothelial cells (EC). It commonly occurs in the abdominal aorta, coronary arteries,
Read MoreSickle Cell Anemia and Gene Transfer Explained
Sickle Cell Anemia: A Genetic Perspective
Sickle cell anemia is a genetic disease that affects the body’s red blood cells. It is caused by a mutation in the Hb gene, which codes for a polypeptide of 146 amino acids, a crucial component of haemoglobin. Haemoglobin is a vital protein in red blood cells responsible for oxygen transport.
In sickle cell anemia, the codon GAG found in the normal Hb gene is mutated to GTG. This is known as a base substitution mutation, where adenine (A) is replaced by thymine
Read More