Microbiology chapter 3. Microbiology - Cell structure and Funtion Review for the
ID: 202063 • Letter: M
Question
Microbiology chapter 3. Microbiology - Cell structure and FuntionReview for the exam. Please type for me and explain the concept that I should prepare for the exam. who and what did they do Chapter 3 Chapter 3 CONCEPTS C3.2 Prokaryotic Cell Features C3.3 Function of Bacterial Cytoplasmic Membranes selectively permeable barrier ENERGY requirement-why? C3.4 Osmosis, the diffusion of water across a semipermeable membrane. C3.5 Effects of isotonic, hypertonic, and hypotonic solutions on cells. C3.6 what are Endospores? C3.7 what is the Endosymbiotic Theory ? X-
Explanation / Answer
C3.2
Prokaryotes lack an organized nucleus and other membrane-bound organelles. Prokaryotic DNA is found in a central part of the cell called the nucleoid. The cell wall of a prokaryote acts as an extra layer of protection, helps maintain cell shape, and prevents dehydration.
C3.3
Plasma membrane. The plasma membrane or bacterial cytoplasmic membrane is composed of a phospholipid bilayer and thus has all of the general functions of a cell membrane such as acting as a permeability barrier for most molecules and serving as the location for the transport of molecules into thecell.
C3.6
An endospore is an extremely resistant dormant cell structure produced by some bacterial species. If you break down the term endospore, 'endo-' means 'inside' and '-spore' refers to the 'dormant structure,' so the endospore is a structure formed inside the cell. There are many examples of endospore-forming bacteria.
C3.7
Endosymbiotic theory. noun. A theory stating that the eukaryotes evolved through a process whereby different types of free-living prokaryotes became incorporated inside larger prokaryotic cells and eventually developed into mitochondria, chloroplasts, and possibly other organelles.
F3.1
Prokaryotic cells have the following features:
1.The genetic material (DNA) is localized to a region called the nucleoid which has no surrounding membrane.
2.The cell contains large numbers of ribosomes that are used for protein synthesis.
3.At the periphery of the cell is the plasma membrane. In some prokaryotes the plasma membrane folds in to form structures called mesosomes, the function of which is not clearly understood.
4.Outside the plasma membrane of most prokaryotes is a fairly rigid wall which gives the organism its shape. The walls of bacteria consist of peptidoglycans. Sometimes there is also an outer capsule. Note that the cell wall of prokaryotes differs chemically from the eukaryotic cell wall of plant cells and of protists.
5.Some bacteria have flagella which are used for locomotion and/or pili, which may be used to pull two cells in close contact, and perhaps to facilitate the transfer of genetic material.
F3.3
The cell capsule is a very large structure of some prokaryotic cells, such as bacterial cells. It is a polysaccharide layer that lies outside the cell envelope of bacteria, and is thus deemed part of the outer envelope of a bacterial cell. Prokaryotic cells are those with undefined inner organelles.
F3.4
A slime layer in bacteria is an easily removable (e.g. by centrifugation), unorganized layer of extracellular material that surrounds bacteria cells. Specifically, this consists mostly of exopolysaccharides, glycoproteins, and glycolipids.
F3.5
The major component of the bacterial cell wall is peptidoglycan or murein. This rigid structure of peptidoglycan, specific only to prokaryotes, gives the cell shape and surrounds the cytoplasmic membrane.
F3.7
The 2 types of cell wall is Gram+ and Gram-
F3.10
In Gram-positive bacteria, the S-layer is attached to the peptidoglycan layer. Gram-negative bacteria's S-layer is attached directly to the outer membrane). Specific to Gram-positive bacteria is the presence of teichoic acids in the cell wall.
F3.13
yes
F3.14
The primary role of the flagellum is locomotion, but it also often has function as a sensory organelle, being sensitive to chemicals and temperatures outside the cell. Flagella are organelles defined by function rather than structure.
F3.17
Axial filaments in spirochetes bacteria that are anchored at the end of a cell causing rotation and movement of the cell.
Flagella are cell structures that allow for movement. The spirochetes have a type of flagella called endoflagella. These are bundled together to form an axial filament. The axial filaments wrap around the cell body, connect both ends of the cell, and embed in the outer membrane.