Cell Structure and Function: Microscopy, Organelles, and Cellular Processes
Optical Microscope
The optical microscope has a resolving power of roughly 1000x. Resolving power is the minimum distance between two points that may be seen as different. The human eye has a resolving power of 0.2 mm.
Cell Theory
It was not until the mid-nineteenth century that the cell theory was developed. The cell theory states that:
- All living beings are composed of cells.
- The cell is the anatomical or structural unit of all living beings.
- The cell is the physiological unit of all living beings.
- Every
Understanding Genes, Genotype, Phenotype, and Heredity
Genes are fragments of DNA that encode the synthesis of specific proteins. A gene is the unit of genetic information, composed of a unique sequence of nucleotides.
Genotype is the genetic makeup of an organism for a specific trait, determined by two genes, one from each homologous chromosome.
Phenotype is the observable manifestation of the genotype, the traits we see in an organism due to its genetic information.
Karyotype is a visual representation of all pairs of chromosomes, numbered, classified,
Read MoreCellular Respiration and Photosynthesis Processes
New Ways to Share
Now you can send files to Slack or present them with Zoom without leaving Dropbox.
New Ways to Share
Now you can send files to Slack or present them with Zoom without leaving Dropbox.
Cellular Respiration
Process in which heterotrophic organisms obtain their energy at a cellular level, starting from a molecule of glucose.
- Cellular Respiration starts with Glycolysis.
- Most of the time, oxygen is available in the cell, and the Krebs Cycle follows glycolysis.
- After the Krebs cycle, the Electron
Flooded Evaporators & HVAC Components: Function & Selection
Flooded Evaporator: Function and Operation
A flooded evaporator maintains a reservoir of liquid refrigerant on the coil. This is regulated by a float valve. As the refrigerant evaporates, it is absorbed by the compressor. The liquid level in the evaporator drops, causing the float valve ball to lower. The ball is attached to a moving pivot that opens the valve, allowing more liquid refrigerant to enter. The float valve thus controls the liquid refrigerant level, closing when the desired level is
Read MoreOvarian and Menstrual Cycles: Puberty, Fertilization, and Fetal Development
The Ovarian Cycle
Ovarian follicles are large cells that form inside cavities in the ovaries, each containing an immature egg. Approximately every 28 days, an egg matures. Future eggs are already present in the fetus. At birth, a girl has approximately 400,000 future eggs, of which only about 400 will mature from puberty (menarche) onwards. After about 50 years, the maturation of eggs completes with menopause. The ovaries also produce the female hormones estrogen and progesterone.
Sexual reproduction,
Read MoreMicrobes and Viruses: Understanding Their Structure and Life Cycles
Microbes: The Microscopic World
Microbes are a diverse group of living organisms. They are so small that they can only be seen with a microscope. Microbes exist in two main forms:
- Acellular forms: Viruses, viroids, and prions.
- Cellular forms: Bacteria, protozoa, algae, and fungi.
Microbes share several key features:
- Small volume of cytoplasm.
- Accelerated metabolic reactions that occur very quickly.
Viruses: Obligate Intracellular Parasites
Viruses are microscopic acellular entities composed of a nucleic
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