Cell Structures: Golgi, Lysosomes, Vacuoles, Ribosomes, Mitochondria
Golgi Apparatus
The Golgi apparatus is composed of flattened, sac-like units (cisternae) formed by smooth membranes. These cisternae are typically clustered in groups of 5 to 8, forming a stack called a dictyosome. At the edges of the cisternae, vesicles bud off, containing various cellular products. Dictyosomes have two faces: a forming face (cis) and a maturing face (trans), which leads to the corresponding vesicles.
Lysosomes
Lysosomes are characteristic of animal cells. They are membrane-bound,
Read MoreCharacteristics of Fish, Amphibians, Reptiles, Birds, and Mammals
Fish
Body Features
- Fusiform body.
- Fish limbs are fins. Most fish have: 2 pectoral fins, 2 pelvic fins, one caudal fin, one anal fin, and one or more dorsal fins. However, there are exceptions.
- Their body is covered with scales, which are overlapped. Sharks and rays have small denticles instead of flat scales.
- They have a sensory organ, the lateral line, which detects water vibrations.
- Most fish have a natatory bladder, an
Pulmonary and Plant Respiration, Animal and Plant Excretion
Pulmonary Respiration
In pulmonary respiration, gas exchange is performed in the lungs. The lungs are connected to the outside through the mouth and nostrils, and continue via the pharynx, larynx, trachea, and bronchi. This type of respiration occurs in vertebrates: amphibians, reptiles, birds, and mammals.
Evolution of the Pulmonary Respiratory System
- Increasing the area of gas exchange (e.g., amphibians).
- Acquisition of ventilation mechanisms. In reptiles, birds, and mammals, the process of air entering
Male Reproductive System: Structure, Function, and Evolution
Male Reproductive System: Structure and Function
Male Reproductive System
The male reproductive system has two main parts: the reproductive organs and accessory glands. The main organ, or male gonad, is the testis, which is located in the scrotum.
- Scrotum: The scrotum is a pouch of pigmented skin arising from the lower abdominal wall. It protects the testes and acts as a thermoregulator.
- Testes: Testes are the primary sex organs and are extra-abdominal in position. Each testis contains about
Workplace Hazards and Control Measures
Contaminants can act on the source, the media, and the recipient. Elimination should address all three points.
Factors Affecting Hearing Damage:
- Intensity
- Frequency
- Type of noise
- Exposure Duration
Noise Levels and Effects:
- 10-20 dB(A): Barely audible.
- 40-50 dB(A): Comfortable sound.
- 60-65 dB(A): Normal city noise.
- 85 dB(A): Warning!
- 100-200 dB(A): Noise nuisance. Difficult to talk.
- 120-130 dB(A): Threshold of pain.
- 140 dB(A) or more: One exposure may cause permanent hearing loss.
Levels without Personal Protective
Read MoreCellular Respiration: Energy in Living Things
Living things need a constant power consumption; the cells use it in the form of chemical energy. Cellular respiration, the process used by most animal and plant cells, is the degradation of biomolecules (glucose, lipids, proteins) to produce the necessary energy release, so the organism can fulfill its vital functions. By degradation of glucose (glycolysis), pyruvic acid is formed. This acid is split into carbon dioxide and water, generating 36 ATP molecules.
Cellular respiration is a part of metabolism,
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