0 lu aehleve ful se are eomprehensive essay questions, not short answer question

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0 lu aehleve ful se are eomprehensive essay questions, not short answer questions. . Draw and explain Figure 11-14, which is about the lipid bilayer and lipid movement. 2. Define: protein, enzyme, nucleotide, DNA, RNA, unsaturated fatty acid, amino acid (draw one also),lipid bilayer, eukaryotic cell, hydrophilic, hydrophobic, intracellular, extracellular, cell cortex, cytosol, cytoplasm, plasma membrane, multipass transmembrane protein, and glycerol (also draw), hydrogen bond, ion, transcylosis, autophagy 3. Describe and explain in detail the sodium/potassium pump. Include how it functions, what energy is consumed, what the the related potassium leak channels, and what is actually going on with the sodium and potassium levels in the cells. resulting gradient is used for, how quickly it works... Be sure to include the effect on membrane associated electric charge. 4. Describe and explain osmosis. Give examples such as what would happenif What does it mean when I (Charlic) say that cells are like capacitors? What does it mean when I say they are like batteries? (Be sure to clearly define both of these terms and then relate them to cells. Iaclude how cefls get their charge.) 6. Explain the process of "sugaring" of lipids and proteins. Additionally, include where it occurs and how it is that it appears on the outside surface of the cells 7 Describe and explain in detail electrochemical gradients including ex.amples of the movernent of ions. Contrast this with uncharged molecules. Include what such gradients are used for S. Describe and esplain the ATPADP transport across the mitochondrial inner membrane as covered in class and found in the energy-harvesting chapler. Include what powers it. It is found on page Figure 14-18. (antiporv/electrogenic) 9. Both comprehensively and in detail, explain intracellular vesicular traffic and membrane distribution/redistribution within the endomembrane system of eukaryotic cells 10. How do proteins, encoded by genes located in the sucleus, get made. processed, delivered, and transported across the membranes of mitochondria? What determines or directs these prot teins to the mitochondria? Also include all additional relevant information learned from the chapter How, when and where do the transmembrane proteins of the plasma membrane get imbedded into the membrane, and how do they gel to the plasma membrane (their path) 12 What determines if a protein is trafficked to the nucleus? Why do proteins of the same type sometimes get trafficked and ystem including what powers it. Include the information other times simply reside in the cylosol? Descrite the transport s found in figures 15-09 and 15-10 Describe and explained the complete details of the LDL transport system as shown in Figure 15-33 and explained in the sext. Include whatever other information that was discussed in class. What is the constitutive exocytosis pathway? Describe the secretory or regulated exoeytosis pathway, also including the regulation and control of molecular vesicles. Figure 15-35 is one on lysosomes. Draw and describe the anatomy and physiology of a lysosome. Describe and explain the formation, specific packaging, movement and fusion of vesicles

Explanation / Answer

Answer to QUE 5:

Capacitor is a electrical component which can store a defined amount of electrical charge. Capacitors have series of conductors (conductors of electricity) which are separated from each other with the help of insulators (which do not conduct electricity)

Battery: A battery is a device which transforms the chemical energy into electrical energy. Battery has cells in which chemical reactions occur that generate flow of electrons (electricity)

Analogy of batteries and capacitors with the Cell:

Biological cells have definite electrochemical gradient which is infered by the cations or ions present in the environment. For example the net charge inside of the cell is Negative due to the presence of negatively charged molecules like Phosphates, Sulphates, proteins etc

The extracellular fluid present outside the cell is rich in positively charged species like Sodium ions, Calcium ions.

The intracellular and extracellular compartments are separated from each other with the help of plasma membrane which made up of bilayer of phospholipids that serve as insulators and selectively regulate the flow of ions in and out of the cell. Thus, in a resting state, cell can be compared to a capacitor in electricals which is capable of storing energy.

Since cells also store charges, they can be compared to that of capacitors. or HOW CELLS GET THEIR CHARGE.

Cells get their charge due to the predominant anion or cations present in the environment. As seen from the above table there are both anions and cations in both ICF and ECF, but the net charge is dependent upon the higher amount of anions or cations present. Hence ICF is negatively charged while ECF has net positive charge.

When a cell is excited, the electochemical and concentration gradients drive the sodium into the cell and potassium out of the cell. The resting membrane potential is -70mV. It is brought to 35-40 mV during action potential or when the cell is depolarized. This is similar to a circuit where battery induces flow of electrons. The ions in and outside of the cell moves until different transport mechanisms brings the charge to normal.

So, during action potential or when the cell is depolarized it can be compared to a Battery.

Answer to QUE 6:

Sugaring of lipids and proteins refers to the Glycosylation. Glycosylation is the addition of a carbohydrate/ saccharide (sugar) to the proteins, lipids and other organic molecules with the help of enzymes and occurs during or after protein synthesis (protein translation).

Where it occurs? It occurs in the rough endoplasmic reticulum along with translation. It also occurs in cytoplasm and nucleus (o-GlcNAc modification)

How do they appear outside the cell membrane? When proteins are glycosylated, it results in formation of Glycoproteins (O-linked glycosylation-Ser, Thr; N linked glycosylation-Asn). These serve as membrane proteins and secreted proteins.

Membrane proteins appear branched and appear like tails or threads on the outside of the cell membrane. They exhibit Hydrophilicity which plays an important role in absorption of polar solutes, serves as label for cell recognition, important role in recognition and communication, protein folding etc

Purpose of glycosylation: Helps in proper folding of proteins making them stable, promotes cell adhesion, used by pathogens as evasion shield against immune responses.

Types: N linked glycosylation occures in eukaryotes in the lumen of endoplasmic reticulum

O linked glycosylation occurs in eukaryotes in golgi apparatus. It is also seen in archae, bacteria

Phosphoserine glycosylation seen in D. discoideum, Leishmania mexican, T.cruzi

C-mannosylation where mannose is added to the tryptophan residue

Glypiation which results in the formation of GPI (Glycosylphosphatidylinositol) anchor through glycan chain.

Intracellular fluid comprises of (major composition) Extracellular fluid comprises of (major composition) Potassium ions, Magnesium, Phosphate, sulphates, proteins Sodium, Bicarbonate, Chloride, organic acids Net charge is NEGATIVE Net charge is POSITIVE

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