UMBC UNIT II: Biology 141 | 72 Questions And Answers Already Graded A+

Chapter 7: What components are found in both prokaryotic and eukaryotic cells? What are the functions of these components? - Every cell has a cell membrane, cytoplasm, chromosomes, and ribosomes. Chapter 7: What are the major differences between prokaryotic and eukaryotic cells? - A prokaryotic cell has no membrane bound organelle while eukaryotic cells do. Chapter 7: What components are found only in prokaryotic and eukaryotic cells? - A prokaryotic cell has a nucleiuod region and while a eukaryotic cell has membrane bound organelles like a nucleus, mitochondria, chloroplasts, lysosomes, endosomes, vesicles, Golgi apparatus, smooth and rough endoplasmic reticulum. Chapter 7: What are the advantages of compartmentalization in organelles? - Compartmentalization in eukaryotic cells allows for the reduction of volume of the cytosol which prevents a low surface area to volume ratio. Substrates for reactions can be maintained at high concentrations within an organelle. Enzymes working on the same process are clustered which reduces extraneous enzymes working for no reason. Anabolic and catabolic reactions are kept separate so the cell isn't harmed. Chapter 7: Describe three types of cytoskeletal filaments. What functions do they serve in the cell? What is a motor proteins? Name two motor proteins, and give examples of their cellular roles. - Microfilaments/actin filaments, intermediate filaments, and microtubules are the three types of filaments. Actin filaments is made up of actin monomers that come together and wrap together. There's polarity in the two ends: the minus end grows slower than the plus end which means actin filaments have faster growth at the plus end. Not only do actin filaments provide the cell with shape but they also helps with movement/mobility. The motor proteins that are associated with actin are myosin. Myosin walks along actin filaments towards the minus end which allows the energy of ATP to cause motion. This is what causes cytosolic movement and cytokinesis in mitosis/meiosis. Microtubules also have polarity which grows at the plus end; but the minus end are anchored in the microtubules organizing center (centrosomes). They are composed of alpha tubular that come together to form a hollow tubes. They help form mitotic spindles and serve as tracks for kinesin and dynes which walk opposite direction. Kinesin walks along microtubules powered by the hydrolysis of ATP. Cilia and flagella are composed of microtubules which generate a wave length pattern that cause the cell to move. Intermediate filaments do not contain motor proteins because they are anchored and aren't polar. They provide the cell with strength.Chapter 7: How does the nuclear envelope differ from the plasma membrane? How do molecules move between the cytoplasm and the nucleus? - The plasma membrane surrounds the entire cell while the nuclear envelope surrounds just the nucleus. Also, the nuclear membrane has two phospholipid bilayers faced back to back while the plasma membrane only has one. Small non-polar molecules can pass through both membranes but certain signals like nuclear localization signals can bring a molecule straight through as well. In the nuclear envelope there are nuclear pores where molecules like ribosomes can enter and mRNA can exit.