Human Digestive Enzymes
Human digestive enzymes are mainly synthesized in the salivary glands and in the pancreas As we’ve discussed, enzymes are made up of amino acids found in proteins so a ready supply of these building blocks is required to ensure there are optimal levels of digestive enzymes at all times. Digestive enzymes are mixed in the saliva and pancreatic juices and are released into the mouth and small intestines, respectively, to support digestion of proteins, fats, and carbohydrates. Their synthesis and release occur via carefully orchestrated and tightly controlled hormone systems that are activated not just when food hits our taste buds but also by the sight, smell and sound of…
Q & A on Cell Structure
Q: What is cell theory? Cell theory asserts that the cell is the constituent unit of living beings. Before the discovery of the cell, it was not recognized that living beings were made of building blocks like cells. The cell theory is one of the basic theories of Biology. Q: Are there living beings without cells? Viruses are considered the only living beings that do not have cells. Viruses are constituted by genetic material (DNA or RNA) enwrapped by a protein capsule. They do not have membranes and cell organelles nor do they have self-metabolism. Q: In 1665 Robert Hooke, an English scientist, published his book Micrographia, in which he…
What is the function of Golgi body?
The Golgi body is actually a pile or stack of membranous structures called cisternae. The numbers of cisternae in a single stack vary between 6-8. In some protists, however, the number could extend up to 60. The Golgi bodies are found in both plant & animal cells. The cisternae of Golgi body have four structural components i.e., cis-Golgi, endo-Golgi, medial-Golgi and trans-Golgi. The vesicles extending from endoplasmic reticulum fuse with the network. These vesicles then enter the stacks of Golgi body and finally reach the trans-Golgi. The different regions of Golgi apparatus contain different types of enzymes. These enzymes have certain specific tasks assigned to them. Vesicles leave the Golgi…
Animal Cell
All animal cells are multicellular. They are eukaryotic cells. Animal cells are surrounded by a plasma membrane and it contains the nucleus and organelles that are membrane-bound. Unlike the eukaryotic cells of plants and fungi, animal cells do not have a cell wall. This feature was lost in the distant past by the single-celled organisms that gave rise to the kingdom Animalia. Animal cells are of various sizes and have irregular shapes. Most of the cells size range between 1 and 100 micrometers and are visible only with the microscope. Trillions of cells are found in the human body. There are many different types of cells, approximately 210 distinct cell types…
Microscopy
Of all the techniques used in biology, microscopy is probably the most important. The vast majority of living organisms are too small to be seen in any detail with the human eye and cells and their organelles can only be seen with the aid of a microscope. Cells were first seen in 1665 by Robert Hooke (who named them after monks’ cells in a monastery) and were studied in more detail by Leeuwenhoek using a primitive microscope. Units of measurement: Metre (m) = 1 m Millimetre mm = 10-3 m Micrometre µm = 10-6 m Nanometre nm = 10-9 m Magnification and Resolution By using more lenses microscopes can achieve…
INFLORESCENCE
The arrangement of flower on the floral axis is called inflorescence. Racemose In this type of inflorescence, the main axis continues to grow and does not terminate in a flower and give off flower laterally in an acropetal manner where old flowers are arranged toward the base and young flowers are at the tip. When peduncle is broad then flowers are centripetally arranged. This is of following different types : Raceme – When peduncle (main axis) is elongated and flowers are pedicellate. eg. Radish, a characteristic feature of Cruciferae family When peduncle is branched and each branch bear pedicellated flowers like racemose and are arranged in acropetal manner known as compound…
