Unit 1 Short Answer Questions 1. Cell Ultratrsucture 1. 2. 3.
What is a prokaryotic and a eukaryotic cell? How is DNA arranged in a prokaryotic cell You should be able to identify and state the function of the following structures in a prokaryotic cell: nucleoid, ribosome, cell wall, capsule, pili, flagella. 4. What is the cell wall in a prokaryotic cell made of? 5. How is the DNA arranged in the chromosomes of eukaryotic cells? 6. What is the cell wall in a eukaryotic cell made of? 7. You should be able to identify and state the function of the following structures in a eukaryotic cell: cell wall, cell membrane, nucleus, nucleolus, nuclear membrane, SER, RER, ribosome, Golgi apparatus, mitochondria, lysosome, chloroplast, vacuole, centriole, vesicle, plasmodesmata, middle lamella, nucleosome, microvilli. Endomembranes, peroxisomes, cytoskeleton. 8. For the features listed in Q8, you should be able to identify those which are found only in plant cells, animal cells, and which are common to both. 9. Describe the internal structure of the mitochondria. 10. describe the internal structure of the chloroplast. 2. Cell Growth, Cycle, and Differentiation 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27.
What are the 2 stages of the cell cycle? What are the 3 stages of interphase, and what is happening during each? What process is happening during the M phase? Name and describe the 4 stages of mitosis. What are spindle fibres composed of? What is the function of the spindle fibres? What is cytokinesis? Describe what happens during cytokinesis in plant and animal cells. What is a mitotic index? How do you calculate a mitotic index? Where are the 3 checkpoints during the cell cycle, and what happens at each? What happens during G0? What are the molecular signals which indicate that cells can progress to the next phase of the cycle? Which molecules activate these signals? What is MPF, and which checkpoint does it allow cells to pass? What does MPF make happen in the cell? How does MPF switch itself off? What are cancer cells? What are the 2 classes of tumour, and which is cancerous? Which genes stimulate cell division in normal cells? Which dominant mutated genes cause excessive cell growth? Which recessive mutated genes also cause excessive cell growth? Describe how the genes you answered for Q21 and 22 result in excessive growth. What is differentiation? Which type of cells are specialised cells differentiated from? What causes differentiation? Describe the Jacob Monod hypothesis of gene regulation.
3. Cell and Tissue Culture 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19.
What are cell and tissue cultures? What factors are needed by all cell cultures? What are microbial cultures used for? What nutrients must be included in animal cell cultures? Why is it also useful to include antibiotics and universal indicator in the growth medium for animal cells? Which chemical is essential for animal cell proliferation? Describe the 2 types of animal cell culture. Why do animal cells need a solid surface to grow on? How do animal cells grow, and when do they stop? What is a cloned cell? What are animal cell cultures used for? Why can plant cells be described a nuclear totipotent? What are explants? What are protoplasts? What is a callus? Which chemicals need to be present to promote plant cell differentiation? What is a hybrid? Name the process where protoplasts from different plant species are fused. Why are plant cell cultures useful?
4. Structure and Function of Cell Molecules Carbohydrates 1. 2. 3. 4. 5. 6. 7.
What are the differences between D and L glucose. Which is more abundant? How does linear glucose form a ring? How can you distinguish between Îą and Î˛ ring forms of glucose? Describe/draw how a glycosidic linkage is formed between 2 monosaccharides to form sucrose, maltose, and cellobiose. Describe the structure of cellulose, glycogen, and starch (amylopectin and amylose). Why are polysaccharides ideal storage compounds? Why is branching beneficial to starch and glycogen?
Lipids 1. 2. 3. 4. 5. 6. 7. 8. 9. 10.
What roles do lipids play? What are the structural components of triglycerides? Describe how the components of a triglyceride are bonded together. What is the difference between a saturated, unsaturated, and polyunsaturated fatty acid? Why is the formation of an ester bond known as a dehydration process? What is hydrolysis, and what would happen if a triglyceride was hydrolysed? What is the difference between a triglyceride and a phospholipid? Why do phospholipids naturally form a bilayer? Describe the structure of steroids. Why is cholesterol important?
Nucleic acids 1. 2. 3. 4. 5.
Describe the structure of a nucleotide. How do nucleotides join together to form a strand? How can you distinguish between a DNA and RNA nucleotide? Why do DNA strands lie anti-parallel to each other? Describe the structure of purine and pyrimidine bases, What type of bases is adenine, thymine, cytosine, guanine, and uracil? 6. How many H-bonds hold G and C, and A and T/U together? 7. Describe the role of DNA polymerase, DNA ligase, and RNA polymerase? 8. In DNA replication, which is the lead strand, and how is it formed? 9. Why is there a lag strand, which is it, and how is it made? 10. What are the 3 types of RNA, and what are their roles? Proteins 1. 2. 3. 4. 5.
What is the general structure of an amino acid? How is a peptide formed? You should be able to classify amino acids as polar, non-polar, basic or acidic depending on their side groups. Practice will be found in Scholar or past papers. Describe primary, secondary, tertiary, and quaternary structure in proteins, including the bonding involved. Describe the role of proteins in the body.
5. Membranes and the Cytoskeleton 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11.
What are the components of the cell membrane? How are these components arranged? What is the term used to describe the arrangement of molecules in the cell membrane? What are intrinsic proteins? What are extrinsic proteins? What is the role of cholesterol in the cell membrane? What are the functions of the membrane proteins? What is facilitated diffusion? What are the 3 components of the cytoskeleton? Describe the structure and function of these components of the cytoskeleton. Describe the role of the cytoskeleton in mitosis and cytokinesis.
6. Catalysis and Cell Pumps 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18.
You should know all the work on enzymes covered at Standard Grade and Higher. You should be able to state the function of the following class of enzymes: protease, ATPase, phosphatase, nuclease, kinase, synthase, polymerase. How do cofactors and coenzymes help enzyme activity? (higher!) Describe the induced fit hypothesis. What is an allosteric enzyme? What are the effects of a positive and negative modulator on an allosteric enzyme? Describe how competitive and non-competitive inhibitors affect enzyme activity. What is covalent modification? What is the function of glycogen phosphorylase? How is glycogen phosphorylase activated and inactivated? How can glycogen phosphorylase be controlled allosterically? What is proteolytic cleavage? How are trypsinogen and chymotrypsinogen activated? How does end-product inhibition control metabolic pathways? Which type of control is end-product inhibition an example of? Why is the sodium/potassium pump important for cells? What is the effect of sodium ions on the pump, and what happens as a result? What is the effect of potassium ion on the pump, and what happens as a result?
7. Cell Signalling 1. 2. 3. 4. 5. 6. 7. 8. 9. 10.
Why is cell signaling important? How do plant cells communicate with each other? What is a ligand? What is the role of a ligand in cell signaling? What is transduction? What is a signal transduction pathway? Give 3 examples of ligands and the role they play. Define extracellular cell signaling and describe an example. What is extracellular hydrophilic cell signaling? Describe the effect of the 3 types of receptor protein in extracellular hydrophilic cell signaling.
8. The Human Genome Project 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16.
What is the aim of the human genome project? What is monohybrid inheritance? What is dihybrid inheritance? What is recombination, and how does it arise? What are linked genes? What does the recombination frequency indicate? You should be able to construct a genetic map based on recombination frequencies – questions in Scholar. What are restriction enzymes? Describe the role of restriction enzymes in physical mapping. Describe the process of gel electrophoresis. Based on the results from restriction enzymes you should be able to construct a physical map of DNA – past paper questions. Describe the steps involved in the ‘dideoxy chain termination method’ of DNA sequencing. What is a primer? What are ‘dd’ nucleotides? Describe the stages in PCR. Why is comparative genome analysis beneficial?
9. Human Therapeutics 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16.
Describe deletion, duplication, translocation, and inversion chromosome mutations. Describe insertion, deletion, substitution, and inversion gene mutations. State which of the gene mutations in Q2 are point and frameshift mutations. What causes cystic fibrosis? What effect does cystic fibrosis have on the body? What causes Duchenne’s muscular dystrophy? What effect does Duchenne’s muscular dystrophy have on the body? How are genetic disorders detected? How is a DNA probe made? Describe the process of hybridization. What is gene therapy? What conditions need to be met for gene therapy to be successful? What factors should be considered when finding s delivery methods for a gene> What is an intron? What is a variable number tandem repeat? How can a person be identified by DNA profiling?
10. Agriculture 1. 2. 3. 4.
Which plasmid is used to genetically modify plants, and which bacterium does it come from? Describe how plants are genetically modified using this plasmid. How are animals genetically modified? Describe the genetic modification of Flavr Savr tomatoes, and BST.