TD-1 Cell Biology Tutorial PDF 2023-2024

Socle Commun L1 / USDB-1 (2023-2024) / Tutorial cell biology / Tut - 1 Prokaryotes: Prokaryotes are divided into two major taxonomic groups: Archaebacteria & Eubacteria Eubacteria = (True bacteria): Eubacteria are the most common and frequent forms of bacteria Archaebacteria = (Primitive ba...

Socle Commun L1 / USDB-1 (2023-2024) / Tutorial cell biology / Tut - 1 Prokaryotes: Prokaryotes are divided into two major taxonomic groups: Archaebacteria & Eubacteria Eubacteria = (True bacteria): Eubacteria are the most common and frequent forms of bacteria Archaebacteria = (Primitive bacteria): Typically found in extreme environments (also called: Extremophiles): thermal springs (~100C°), at the bottom of the ocean, in salt-saturated waters and other environments not thought to be favorable for life. They can metabolize specific substances like sulfur, and Gaseous hydrogen. Comparaison between Prokaryotic and Eukaryotic Cells Characteristic Prokaryotes Eucaryotes Size of cell Smaller size : Typically 1 -10 µm in Larger size : Typically 10 - 100 µm diameter in diameter Genetic material Nucleus No nuclear membrane or nucleoli: True nucleus consisting of nuclear no true nucleus = nucleoid. membrane and nucleoli Naked DNA, free in the (double membrane= nuclear cytoplasm envelope) Chromosome Single circular chromosome; lacks Multiple lineare Chromosomes with histones histones (Nbr > 1) Nucleolus Absent Present Genes Genes without introns the presence of introns Genetic Exchange The unidirectional transfer the fusion of gametes Reproduction Scissiparity (binary fission) Mitosis, meiosis Metabolic activities Synthesis of energy Photosynthesis, Respiration, Photosynthesis, Respiration, Fermentation Fermentation Proteins synthesis In the cytoplasm RNA synthesis (transcription) : in the nucleus Proteins synthesis (translation) :In the cell cytoplasm Cellular structures and organelles Endoplasmic reticulum Absent Present Golgi apparatus Absent Present Lysosome Absent Present Mitochondria Absent Present Chloroplast Absent Present in plants The peptidoglycan cell wall Present Absent Ribosomes Smaller size (70S), dispersed in the Larger size (80S) , dispersed in the cytoplasm cytoplasm or linked to the Endoplasmic Reticulum 1  Socle Commun L1 / USDB-1 (2023-2024) / Tutorial cell biology / Tut - 1 Akaryotes - The term Akaryote is used in biology to designate organisms lacking nuclei (plural of nucleus), organelles and metabolism. They do, however, have genetic information, in the form of DNA or RNA and reverse transcriptases) allowing parasitization of a cell. (Akaryote = non-cellular). In cell biology, the acellular characteristic is found in viruses. - Viruses require a host cell for their reproduction; according to the latter we note Eukaryotic viruses and Prokaryotic viruses or bacteriophages - Viruses can reproduce only in host cell by two alternative mechanisms: The lytic cycle, and the lysogenic cycle. Figure 1. Viral reproduction: Lytic cycle and Lysogenic cycle Size scale of living beings: (figure 2) -Compare the size of the following cells by giving the increasing order of cells size? Red blood cell, Plant cell, Yeast, Animal cell, Amoeba, Protozoa, Bacteria. 2 Socle Commun L1 / USDB-1 (2023-2024) / Tutorial cell biology / Tut - 1 Figure 2: Size scale of living beings 3