Solutions and Test Bank For Lewin\'s Cells 3rd Edition By George Plopper PDF

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Test Bank; Solutions; eBook For Lewin's CELLS 3rd Edition By George Plopper, David Sharp, Eric Sikorski ; 9781284029390 , 9781284023558, 1284023559...

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For All Chapters : [email protected] Plopper/Cells 3E Chapter 1: What Is a Cell?

Multiple Choice

1. Which one of the following is least likely to be a constituent of a cell membrane? A) Enzymes B) Phospholipids C) Nucleic acids D) Channel proteins E) Transport proteins Answer: C

2. Which of the following is not one of the minimal features needed to make a cell? A) The ability to capture and utilize energy to build complex structures B) A cell wall C) A plasma membrane D) A genome, composed of DNA E) The ability to express information in the genetic code Answer: B

3. Which organelles are bounded by a double membrane? A) Mitochondria, Golgi apparatus, endoplasmic reticulum B) Nucleus, endoplasmic reticulum, lysosomes C) Mitochondria, nucleus, lysosomes D) Chloroplasts, Golgi apparatus, nucleus E) Nucleus, chloroplasts, mitochondria Answer: E

4. Which one of the following statements is false? A) Cytosolic proteins destined to be transported into mitochondria require a sorting signal.

For All Chapters : [email protected] B) Proteins imported into the peroxisome are unfolded by chaperone proteins prior to entering the peroxisome. C) Chaperone proteins assist in the import of proteins into mitochondria. D) Proteins with a mass greater than 40,000 daltons must pass through nuclear pore complexes to enter the nucleus. E) Proteins are routinely transported into the nucleus while RNA is normally transported out of the nucleus. Answer: B

5. Which one of the following statements supports the endosymbiont theory? A) In some instances, bacteria enter and live within the cytoplasm of a eukaryotic cell. B) The outer membrane of the nucleus is continuous with the endoplasmic reticulum. C) Plastids, which can synthesize their own ATP, are found only in plant cells. D) Mitochondrial DNA can be used to trace the maternal ancestry of a person. E) Yeast exposed to a low oxygen atmosphere can survive; humans cannot. Answer: A

6. Which one of the following statements about DNA repair is false? A) Repair proteins scan and detect damaged DNA. B) Exonuclease enzymes cut out damaged DNA. C) Damaged DNA is transported out of the nucleus. D) A new strand of DNA is synthesized to replace the damaged DNA. E) Errors in the DNA repair machinery result in mutations. Answer: C

7. Which statement best describes the phenomenon of epigenetic inheritance? A) Epigenetic inheritance is inheritance of mitochondrial DNA sequences. B) Cells that exhibit epigenetic inheritance have more mutations than other cells. C) Epigenetic inheritance only occurs in mammals. D) Two cells that have identical DNA sequences but different phenotypes exhibit epigenetic inheritance. E) Epigenetic inheritance refers to the fact that mitochondria have their own DNA. Answer: D

For All Chapters : [email protected] 8. Identify the mismatched organelle-function pair: A) Golgi apparatus: Energy handling B) Peroxisome: Oxidative processes C) Lysosome: Degradation of internalized proteins D) Endosome: Sorting of internalized proteins for transport to other compartments E) Nucleus: Gene expression proteins exported and imported Answer: A

9. Which statement best describes the relationship between receptors, signal transduction, and ligands? A) Signal transduction pathways link receptors to ligands. B) Ligands bind to signal transduction pathways, which then secrete receptors. C) Receptors on the outside of a cell communicate with ligands in the nucleus via signal transduction pathways. D) Ligands in one cell must bind to ligands on another cell to form receptors; the mechanism whereby this is done is called signal transduction. E) When ligands bind to receptors, the resulting change in the receptors stimulates a signal transduction pathway. Answer: E

10. Proteins that are secreted by a cell are synthesized by ribosomes found in the ________ and delivered to the plasma membrane via _____________. A) cytoplasm; exocytosis B) endoplasmic reticulum; exocytosis C) plasma membrane; exocytosis D) endoplasmic reticulum; endocytosis E) endoplasmic reticulum; channel proteins Answer: B

11. Which of the following in not a characteristic of microtubules? A) Composed of actin subunits B) Have a role in maintaining position and structure of organelles C) Make up the spindle in a dividing cell D) Are used as tracks by motor proteins to move material throughout the cell E) Are intrinsically unstable Answer: A

For All Chapters : [email protected]

Short Answer

12. A cellular membrane can accomplish two seemingly contradictory tasks: segregate cellular contents from the surrounding environment, and allow limited exchange with the environment. List two structural features of a cellular membrane that perform these tasks. Answer: The lipid bilayer is somewhat permeable to water but impermeable to ions, small charged molecules, and all large molecules. Proteins and protein complexes within the membrane allow for the specific and often regulated transport of molecules across the cell membrane.

13. What distinguishes a prokaryotic cell from a eukaryotic cell? Answer: A prokaryote has a single compartment that contains its genetic material, the apparatus for gene expression, and the products of gene expression. The compartment is bounded by a membrane, and there are no other compartments within it. A eukaryote has at least two compartments; the entire cell is contained within a surrounding plasma membrane; but the interior has a second compartment that contains the genetic material.

14. What is the function of the nuclear pore? Answer: Material with a greater mass than ~40,000 Daltons (corresponding to a small protein) can only enter or leave the nucleus if it is transported through nuclear pore complexes that are embedded in the (nuclear) envelope.

15. In mitochondria, hydrogen ions (protons) are translocated across the inner membrane, from the matrix into the intermembrane space, while electrons are transported along the membrane through a series of protein carriers. The result is to create a proton gradient across the membrane. The gradient drives the protons back across the membrane through a large protein complex that makes ATP. This process is called _____________. Answer: Chemiosmosis

For All Chapters : [email protected] 1. Explain what a “sorting signal” (or targeting signal) within a protein is used for. Answer: Sorting signals are short amino acid sequence used to target proteins to a specific organelle or location with a cell. The sorting signal is recognized by specific cellular machinery at one or more steps along the route to the protein’s final destination.

2. Describe how somatic cells differ from germ cells? Answer: Somatic cells are most of the cells of the organism that make up the body and organs.These cells are diploid and are usually specialized for a specific purpose. They do not contribute to the next generation. Germ cells are haploid and are usually sex specific (sperm in males, oocytes in females). Two germ cells fuse and the combined genetic material makes up the new diploid individual (zygote)....