Essays Questions on General Biology - Examination 2 | BIOL 1001, Study notes of Biology

Download Essays Questions on General Biology - Examination 2 | BIOL 1001 and more Study notes Biology in PDF only on Docsity! Possible Essay Questions for Test #2 One of the following questions will be on your second test next Wednesday and will be worth 20 points. Each answer should be no more than 1/4 page (handwritten!) long. 1. Describe how bicarbonate buffers prevent large changes in pH in our blood. – A buffer is a compound that accepts or releases H+ in response to the addition of acid or base – If the blood becomes too acidic, bicarbonate accepts (and absorbs) H+ to make carbonic acid HCO3 – + H+  H2CO3 bicarbonate hydrogen ion carbonic acid – If the blood becomes too basic, carbonic acid releases hydrogen ions to combine with OH– to form water H2CO3 + OH –  HCO3 – + H2O carbonic acid hydroxide ion bicarbonate water 2. What are the biological consequences of the fact that ice floats? Lakes and rivers freeze from top to bottom, allowing fish to survive even when the surface of a lake has frozen over. If ice sank, the water would be displaced to the top and exposed to the colder temperature, forcing rivers and lakes to fill with ice and freeze solid, killing off possibly all life it held. 3. What are the differences between “dehydration synthesis” and “hydrolysis” reactions? – Monomers are joined together through dehydration synthesis, resulting in the loss of a water molecule (H2O) – Polymers are broken apart through hydrolysis (“water cutting”) – Water is broken into H and OH and is used to break the bond between monomers 4. Compare and contrast the structural polysaccharides cellulose and chitin. Both are polysaccharides derived from glucose monomers. However, chitin is a polymer of N-acetyl-D-glucosamine. Cellulose is a polymer of D-glucose. Both are used as structural components of living organisms. Chitin is only found in certain animals and fungi Cellulose is only found in plants. 5. Discuss the principal differences between eukaryotic and prokaryotic cells. Eukaryotic cells contain membrane-bound organelles, such as the nucleus, while prokaryotic cells do not. Differences in cellular structure of prokaryotes and eukaryotes include the presence of mitochondria and chloroplasts, the cell wall, and the structure of chromosomal DNA. 6. What special structures are found in plant cells but are not found in animal cells. Plant cells have a cell wall, chloroplasts and other specialized plastids, and a large central vacuole, whereas animal cells do not. 7. What are the three components of the cytoskeleton? Briefly describe the structure AND ONE function for each. 1. Microfilaments The smallest component of the cytoskeleton at about 7 nanometers in diameter. They are composed of G-actin protein and are wound in a helical shape.  Facilitate cytoplasmic division in animal cells 2. Intermediate filaments 8-12 nanometers in diameter and are twisted together in a cord shape. They are composed of keratin and keratin-like proteins.  Provide supporting framework within the cell 3. Microtubules Composed of alpha and beta tubulin that form long, hollow cylinders. These are fairly strong proteins and are the largest component of cytoskeleton at 25 nanometers.  Allow movement of chromosomes during cell division 8. Discuss the different types of lipids and their functions. 1) Wax Variable numbers of fatty acids bonded to a long-chain alcohol Waterproof covering on plants and animals Hydrophobic and water insoluble 2) Triglycerides Three fatty acids bonded to glycerol Energy storage in animals and some plants 3) Phospholipids Polar phosphate group and two fatty acids bonded to glycerol Component of cell membranes Hydrophobic (nonpolar fatty acid tail) and hydrophilic (polar functional group head) portions 4) Steroids Four fused rings of carbon atoms with functional groups attached Component of the membranes of eukaryotic cells Precursor for other steroids such as testosterone and bile salts 9. What are the components of the nucleus? Briefly describe the role played by each component. 1. Nuclear envelope – Nucleus is isolated from the rest of the cell 2. Nucleolus – Site of ribosome synthesis – consists of ribosomal RNA, proteins, ribosomes in various stages of synthesis, and DNA 3. Chromatin – consists of DNA and proteins – During cell division, chromatin becomes compacted into long strands called chromosomes