Biochemistry Lecture 1 PDF

Biochemistry Lecture 1 EBA1300 Dr /Sherine Farouk  Cell biology (also cellular biology or cytology) is a branch of biology that studies the structure, function, and behavior of cells. principles of cell theory All living organisms are composed of one or more cells. A cell is the ba...

Biochemistry Lecture 1 EBA1300 Dr /Sherine Farouk  Cell biology (also cellular biology or cytology) is a branch of biology that studies the structure, function, and behavior of cells. principles of cell theory All living organisms are composed of one or more cells. A cell is the basic structural and functional unit of living organisms. All cells arise from pre-existing cells by cell division. The living organisms may be 1-Unicellular organisms: made up of only one cell. carries out all of the functions needed by the organism, e.g bacteria and yeast 2-Multicellular organisms : composed of more than one cell, with groups of cells differentiating to take on specialized functions. e.g humans and plants First Cells Seen in Cork The cell was first discovered and named by Robert Hooke in 1665. He remarked that it looked strangely similar to cellula or small rooms which monks inhabited, thus deriving the name. However what Hooke actually saw was the dead cell walls of plant cells (cork)  How do microscopes work and assist in the cell theory? Because most cells are too small to be seen by the naked eye, the study of cells has depended heavily on the use of microscopes. A light microscope: sends a beam of light through a specimen, or the object you are studying. Low magnification up to1500X An electron microscope: a more powerful microscope, passes a beam of electrons through the specimen. Sending electrons through a cell allows us to see its smallest parts, even the parts inside the cell High magnification of up to 1,000,000x  Based on cellular structure, there are two types of cells: 1- Prokaryotic "prokaryote" means "before the nucleus " Cell anatomy 2-Eukaryotic: comes from a Latin word Eucaryotes which means 'one that possesses a true nucleus. cells share four common components: 1) a plasma membrane, an outer covering that separates the cell's interior from its surrounding environment; 2) cytoplasm, consisting of a jelly-like region within the cell in which other cellular components are found; 3) DNA, the genetic material of the cell; and 4) ribosomes,  prokaryotes and eukaryotes examples Examples of prokaryotes Bacteria and archaea are the two types of prokaryotes. Examples of eukaryotes Animals, plants, fungi, algae and protozoans  Archaea We don’t observe archaea as frequently as bacteria and eukaryotes. This is because they are only found in the harshest environments. For example: THERMOPHILES: Thermophiles live in extreme temperatures. HALOFILES: Halofiles reside in salty environments. METHANOGENES: Methanogenes produce methane gas. As for their anatomy, Archaea resembles features of both eukarya and bacteria. For example, halophiles Feauters in common with bacteria they are single-cell, have no nucleus, and look like bacteria for structure. Hence their close relation to bacteria. Features in common with eukarya. they don’t have peptidoglycan developed in their cell envelope. On top of that, they are resistant to antibiotics like eukarya. Whereas, antibiotics would destroy bacteria. Features of prokaryotic cell No nucleus No membrane bound organelles(no mitochondria ,no endoplasmic reticulum(ER) and no Golgi apparatus. Genetic material in the form of circular DNA. Have scattered smaller ribosomes. Peptidoglycan is in the cell wall of bacteria. This is an essential component of the cell envelope. This feature can only be found in bacteria. Finally, if you’ve ever taken antibiotics, then you’d know that bacteria are sensitive to this type of medicine. It’s been specifically designed to destroy or slow down the growth of bacteria. Shapes of prokaryotic cells Prokaryotes come in various shapes, but many fall into three categories: cocci (spherical), bacilli (rod-shaped), and spirilli (spiral-shaped)  Eukaryotic cell features Even though single-cell eukarya exist, eukaryotes are mostly multicellular. For example, the plant and animal kingdoms are mostly multicellular. On the other hand, the protozoa, fungi, and algae kingdoms have unicellular eukarya. 1. a membrane-bound nucleus 2. Genetic material enclosed inside the nucleus 3. Larger ribosomes 4. numerous membrane-bound organelles including the endoplasmic reticulum, Golgi apparatus, chloroplasts, mitochondria Peroxisomes Lysosomes Eukarya are resistant to traditional antibiotics. And finally, eukarya allay doesn’t have peptidoglycan which exists in bacteria. This protects their envelope and maintains its shape. Differences between eukaryote and prokaryotic cells