BIO 204 week 1 Plant Cell Organelles and Their Functions

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Plant Cell Organelles and Their Functions Worksheet

View the Cell Diagram.

Write a 50- to 75-word response for each question.

Include your references and in-text citations. APA formatted references should go at the end of this document and each response should have an in-text citation.

Question Student response
What is the interdependent relationship between mitochondria and other organelles? The mitochondria are the power house of the cell or he key players (Raghvendra & Padmasree. 2003) in other words. They provide energy (ATP) to all other organelles. There would be no protein synthesis without this ATP and the active transport across the cell membrane would also stop. The other organelles help in maintaining the functionality and integrity of mitochondria. for instance, the nucleus supplies proteins to the Mitochondria.
What are the similarities and differences between the Golgi apparatus and the endoplasmic reticulum? The similarities between the Golgi apparatus and the endoplasmic reticulum are that both are critical for a cell and both are packaging organelle (Teasdale & Jackson. 1996). sometimes the Golgi look similar to the rough ER. The differences are that Golgi is an arrangement of a few fluid-filled dishes while the ER is a network of tubules and vesicles.
What is the function of the central vacuole? Why does a plant require this function? The central vacuoles play the role of providing support to the cell and also maintain its structures. they are able to do so by maintaining turgor pressure. it is this fluid pressure that keeps the cell rigid. they also help store nutrients, waste products, pigments and minerals. Plants require this function in order to be able to maintain their structural integrity or else the plant would always stay wilted and will not get the needed nutrients as well.
Describe the structure and function of chloroplasts. Include the terms inner membrane, outer membrane, stroma, thylakoid membranes, and grana. Include the functions of stroma and grana. Chloroplasts are important organelles in plant cells. The chloroplasts have three membranes; the outer membrane, the inner membrane and the thylakoid system. Stroma is a semi gel like fluid stored between the inner and the outer membrane. Stroma helps in the synthesis of organic molecules from water and carbon dioxide. These are also known as the dark reactions. The thylakoids are arranged in stacks (Anderson, J.M. 1981) known as Grana. the Grana help in increasing the surface area of the thylakoids so that more light can be absorbed. The chloroplasts help make food through photosynthesis and also contain the key organelles for pathogen defense.
Explain the function of the smooth endoplasmic reticulum and the rough endoplasmic reticulum. How are their functions similar to those of the nucleus? How are they different? The smooth endoplasmic reticulum does the function of production and metabolism of fats and steroid hormones while the rough endoplasmic reticulum is useful in protein production and protein folding. The nucleus acts as the brain of the cell while the ERs function as the manufacturing and packaging system. The similarity lies in the protein synthesis (Voeltz, etal. 2002) which starts from the nucleus and moved to the ribosomes on the rough ER. The rough ER also sends signals to the nucleus when problems occur.
For covalent, ionic, and hydrogen bonds, describe a) each type of bond, b) which is the strongest and weakest and why, and c) which disassociate in water and why. The covalent bonds are the ones in which two atoms are connected to each other by the sharing of two or more electrons. Ionic bonds are formed when two atoms have a large difference in electronegativity. Hydrogen bonds only form between hydrogen and oxygen (O), nitrogen (N) or fluorine (F). The covalent bond is the strongest because the electrons are shared between two atoms while the Hydrogen bond is the weakest because the interaction is only attractive in nature. The Ionic bonds dissociate in water because water has the capacity to separate the cations and the anions and form new products. But this is just a physical change.
Compare exergonic and endergonic reactions. Provide an example of each. Exergonic reactions are the ones in which the energy is released to the surroundings while the endergonic reactions are the ones in which the energy is absorbed from the surroundings. In both types of reactions the chemicals bonds are broken and this takes in energy and when the new chemical bonds are formed, energy is given out.An example of an exergonic reaction is the decomposition of Hydrogen peroxide into water and oxygen. While that of an endergonic reaction is photosynthesis.
Discuss the similarities and differences between osmosis and diffusion. What are the driving forces behind each process? Why are membranes selectively permeable? How do they control what crosses them? The differences between the two are that diffusion can take place in any kind of medium while osmosis takes place only in liquid medium. also, diffusion doesn’t require a semi-permeable membrane while osmosis does. it is the free energy or chemical potential that drives the two forces. some membranes (Dainty, J. 1976) are selectively permeable because they only allow some molecules to pass through them. they control what crosses them through the phospholipids and the proteins.
What role does solute concentration play in osmosis? How does water’s chemical potential influence osmosis? The solute concentration helps in the movement of water from high concentration to low concentration. Low concentration of solute means a high concentration of solvent and this leads to a high chemical potential of water. it is this variation in chemical potential that makes it necessary for osmosis to take place and if there is a balance, no movement happens.
Distinguish between osmotic pressure and potential. What organelle is related to osmotic potential? What organelle is related to osmotic pressure? Osmotic pressure is the applied by a solution to prevent the inward flow of water while potential is the movement of water molecules from a hypotonic (Low concentration) to a more hypertonic solution (high concentration). The central vacuole is related to the osmotic pressure while the cell membrane is relate to the potential.
What role do aquaporins play in cell membrane permeability? The tetramers in cell membranes which are formed by aquaporins help in the transportation of water across the membrane. they can discontinue the flow of water if their 3-dimensional structure gets altered through the alteration of the gating. They have a narrow pore that prevents any large molecule from entering

References

Anderson, J.M. 1981. Distribution of the cytochromes of spinach chloroplasts between the appressed membranes of grana stacks and stroma-exposed thylakoid regions. FEBS Letters. Volume 138, Issue 1.February 08, 1982 . Pages 62–66

Dainty, J. 1976. Water Relations of Plant Cells. Springer Berlin Heidelberg. 10.1007/978-3-642-66227-0_2

Raghvendra & Padmasree. 2003. Beneficial interactions of mitochondrial metabolism with photosynthetic carbon assimilation Trends in Plant Science , Volume 8 , Issue 11 , 546 – 553. DOI: http://dx.doi.org/10.1016/j.tplants.2003.09.015

Teasdale & Jackson. 1996. Signal-mediated sorting of membrane proteins between the endoplasmic reticulum and the golgi apparatus. Annual Review of Cell and Developmental Biology Vol. 12: 27-54.DOI: 10.1146/annurev.cellbio.12.1.27

Voeltz, etal. 2002. Structural organization of the endoplasmic reticulum EMBO Rep. 2002 Oct; 3(10): 944–950.

doi:  10.1093/embo-reports/kvf202




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