Cytoplasm Flashcards
Describe the cytoplasm.
The cytoplasm is the material held within the PM, which contains the cells internal structures and organelles, like ribosomes, plasmids, inclusions and the nucleoid (Willey, et al., 2011, pp.65-73).
References: Willey, J.M., Sherwood, L.M., Woolverton, C.J. (2011) Prescott’s Microbiology. 8th edn. New York: McGraw-Hill.
What is the importance of bacterial cytoskeletal proteins?
Bacterial cytoskeletal proteins are important as they have important functions (Willey, et al., 2011, pp.65-73).
For example, the protein FtsZ is needed for cell division as it forms the septum which divides the daughter cells (Willey, et al., 2011, pp.65-73).
MreB maintains the cell shape in rod-shaped bacteria, and it also segregates chromosomes and localises proteins (Willey, et al., 2011, pp.65-73).
CreS causes curvature in curved rods (Willey, et al., 2011, pp.65-73).
References: Willey, J.M., Sherwood, L.M., Woolverton, C.J. (2011) Prescott’s Microbiology. 8th edn. New York: McGraw-Hill.
What are inclusions?
Inclusions are granules of organic or inorganic substances that either lie free in the cytoplasm or are surrounded by a single-layered membrane composed of proteins or phospholipids (Willey, et al., 2011, pp.65-73).
References: Willey, J.M., Sherwood, L.M., Woolverton, C.J. (2011) Prescott’s Microbiology. 8th edn. New York: McGraw-Hill.
Describe storage inclusions and give some examples of them.
Storage inclusions are used to store nutrients that are in excess that will be needed by the cell later (Willey, et al., 2011, pp.65-73).
Common storage inclusions are: glycogen inclusions, which store carbon; polyhydroxyalkonate granules, which also store carbon; sulphur globules, which are formed by bacteria which use reduced-sulphur containing compounds as their electron source; and polyphosphate granules, that store phosphate (Willey, et al., 2011, pp.65-73).
Cyanophycin granules are found in cyanobacteria, and store nitrogen for the bacteria (Willey, et al., 2011, pp.65-73).
References: Willey, J.M., Sherwood, L.M., Woolverton, C.J. (2011) Prescott’s Microbiology. 8th edn. New York: McGraw-Hill.
Describe microcompartments and the function of carboxysomes.
Microcompartments are inclusions with additional functions other than storage (Willey, et al., 2011, pp.65-73).
For example, carboxysomes store carbon and are composed of a protein coat (Willey, et al., 2011, pp.65-73).
The protein coat contains carbonic anhydrase, which converts carbonic acid to carbon dioxide (Willey, et al., 2011, pp.65-73).
The carboxysome concentrates the carbon dioxide in its lumen (Willey, et al., 2011, pp.65-73).
The protein coat also contains Rubisco, which converts carbon dioxide into sugar in a process called carbon dioxide fixation (Willey, et al., 2011, pp.65-73).
References: Willey, J.M., Sherwood, L.M., Woolverton, C.J. (2011) Prescott’s Microbiology. 8th edn. New York: McGraw-Hill.
Describe ribosomes.
Ribosomes are made up of proteins and RNA molecules and are the site of protein synthesis (Willey, et al., 2011, pp.65-73).
Most ribosomes lie in the cytoplasm, which produce proteins which will stay within the cell, while some ribosomes are attached to the PM, which synthesise proteins that will either go to the cell envelope or be transported outside the cell (Willey, et al., 2011, pp.65-73).
References: Willey, J.M., Sherwood, L.M., Woolverton, C.J. (2011) Prescott’s Microbiology. 8th edn. New York: McGraw-Hill.
Describe the nucleoid.
The nucleoid contains the cells chromosome and proteins (Willey, et al., 2011, pp.65-73).
In bacterial cells, the nucleoid isn’t covered by a membrane (Willey, et al., 2011, pp.65-73).
References: Willey, J.M., Sherwood, L.M., Woolverton, C.J. (2011) Prescott’s Microbiology. 8th edn. New York: McGraw-Hill.
Describe the cytoskeleton.
The eukaryotic cytoskeleton is composed of microfilaments, intermediate filaments and microtubules (Willey, et al., 2011, pp.65-73).
The bacterial cytoskeleton has proteins similar to the eukaryotic cytoskeletal proteins (Willey, et al., 2011, pp.65-73).
They also have similar functions, for example determining cell shape, taking part in cell division and localising certain proteins to certain sites in the cell (Willey, et al., 2011, pp.65-73).
References: Willey, J.M., Sherwood, L.M., Woolverton, C.J. (2011) Prescott’s Microbiology. 8th edn. New York: McGraw-Hill.
Describe the structure and function of a gas vacuole.
Gas vacuoles are aggregates of gas vesicles, which are hollow cylindrical structures (Willey, et al., 2011, pp.65-73).
The walls of the gas vesicle consist of protein subunits which form a rigid cylinder (Willey, et al., 2011, pp.65-73).
The cylinder is impermeable to water but permeable to atmospheric gases (Willey, et al., 2011, pp.65-73).
Gas vacuoles allow some aquatic bacteria to float by giving them buoyancy (Willey, et al., 2011, pp.65-73).
References: Willey, J.M., Sherwood, L.M., Woolverton, C.J. (2011) Prescott’s Microbiology. 8th edn. New York: McGraw-Hill.
