Ch 4, 5, 8 homework - Name...

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Unformatted text preview: Name ____________________________ Ch 4, 5 & 8 homework- 1 point each Due 7/8/2010 Ch 4.  1. There are 3 types of cellular junctions. What are they and what is their role? 2. Imaging you discovered a new type of cell unknown to science. What features would you  look for to determine if the cell was prokaryotic or eukaryotic?  3. How do fibers in the cytoskeleton differ from one another? 4. What are the limits on which cell size depends? a. the number of organelles b. surface area-to-volume ratio c. number of surrounding cells d. amount of DNA in the nucleus e. thickness of the cell membrane 5. Bacterial cells are prokaryotic; unlike a typical eukaryotic cell, they _____.  a. lack a nucleus b. have a smaller nucleus c. lack a plasma membrane d. have more internal membranous compartments e. have a greater variety of organelles 6. Which of the following statements regarding the endomembrane system is  false?  a. The endomembrane system is involved in the synthesis, storage, and export of important  molecules.  b. The endomembrane system includes the rough and smooth endoplasmic reticulum.  c. The endomembrane system includes the nuclear envelope.  d. The endomembrane system is a system of interrelated membranes that are all physically  connected.  e. The endomembrane system divides the cell into compartments.  7. The endosymbiosis hypothesis proposes that  a. two cells were juxtaposed and one benefited from the other.  b. c. d. e. one cell was dependent on the other for survival.  a small cell lived inside a larger cell to the benefit of both cells.  a large cell engulfed and digested a smaller cell, exposing its enzymes for use by the  larger cell.  two cells merged into one cell, improving the enzyme function of the new cell.  8. Briefly describe the function of the following: (1pts) a. Golgi Apparatus b. Ribosome c. Smooth Endoplasmic Reticulum d. Mitochondria e. Lysosome 9. Match the following A) B) C) D) E) Golgi Apparatus         F) Mitochondria Smooth ER                 Rough ER                 Ribosomes Lysosomes 1. __________ synthesizes lipids, detoxifies, and stores calcium 2. __________ makes proteins and membrane phospholipids 3. __________ finished, sorts and ships cell products 4. __________ makes most of the cell’s ATP 5. __________ breaks down damaged organelles 10. Label each organelle (1pt) Ch 5  1. Describe the action of enzymes (how they work to catalyze a reaction). How do they  affect Ea? Be sure to include active site and induced fit (1). **Hint: drawing a picture is  sometimes easier 2. Define hypotonic, hypertonic and isotonic. What happens to an animal cell placed in a  hypertonic solution? A hypotonic solution? A plant cell in an isotonic solution? 3. A cell uses 3 types of inhibition. _______________ inhibition is when an inhibitor  physically  blocks the active site of an enzyme, preventing it from binding. _________________  inhibition is  when an inhibitor binds to someplace on the enzyme other than the active site and  changes it  shape preventing it from functioning. _________________ inhibition is when the product  from a  reaction builds up and acts as an inhibitor.  4. The sodium concentration is ten times less than the concentration in the surrounding  fluid. What mechanism would a cell use to move sodium out of the cell? 5. Plasma membranes are selectively permeable. This means that  a. anything can pass into or out of a cell as long as the membrane is intact and the cell is  healthy.  b. the plasma membrane allows some substances to enter or leave a cell more easily than  others.  c. glucose cannot enter the cell.  d. cholesterol cannot enter the cell.  e. plasma membranes must be very thick.  6. Small, nonpolar, hydrophobic molecules such as fatty acids  a. easily pass through a membrane's lipid bilayer.  b. very slowly diffuse through a membrane's lipid bilayer.  c. require transport proteins to pass through a membrane's lipid bilayer.  d. are actively transported across cell membranes.  e. usually enter the cell via endocytosis.  7. When two aqueous solutions that differ in solute concentration are placed on either side of a  semipermeable membrane and osmosis is allowed to take place, the water will  a. exhibit a net movement to the side with lower water concentration.  b. exhibit a net movement to the side with higher water concentration.  c. exhibit a net movement to the side with lower solute concentration.  d. exhibit an equal movement in both directions across the membrane.  e. not cross the membrane.  8. Facilitated diffusion across a biological membrane requires ________ and moves a substance  ________ its concentration gradient.  a. energy and transport proteins . . . down  b. energy . . . down  c. transport proteins . . . down  d. energy and transport proteins . . . against  e. transport proteins . . . against  9. Certain cells that line the stomach synthesize a digestive enzyme and secrete it into the stomach.  This enzyme is a protein. Which of the following processes could be responsible for its secretion?  a. endocytosis  b. exocytosis  c. diffusion  d. pinocytosis  e. passive transport  10. Heating inactivates enzymes by  a. breaking the covalent bonds that hold the molecule together.  b. removing phosphate groups from the enzyme.  c. causing enzyme molecules to stick together.  d. changing the enzyme's three-dimensional shape.  e. inducing the addition of amino acids.  Ch 8 1. Describe what happens in each phase of mitosis (3) ***Pictures may help, but DO NOT  copy and paste pictures, draw your own) a. Interphase b. Prophase  c. Metaphase  d. Anaphase  e. Telophase  f. Cytokenesis 2. Describe how cytokinesis differs in plants and animals 3. With the exception of identical twins, siblings who have the same two biological parents are  likely to look similar, but not identical, to each other because they have  a. identical chromosomes, but different genes.  b. identical genes but different chromosomes.  c. the same combination of traits, but different genes.  d. only a 20% chance of sharing the same combination of genes.  e. a similar but not identical combination of genes.  4. When animal cells are grown in a petri dish, they typically stop dividing once they have formed a  single, unbroken layer on the bottom of the dish. This arrest of division is an example of  a. cancer.  b. cell constraint.  density-dependent inhibition.  c. cell division repression.  d. growth factor desensitization.  5. Homologous chromosomes are…..   a. Identical chromosomes present in twins b. Two chromosomes carrying the genes for the same characteristic at the same loci c. Two chromosomes carrying the same gene for the same characteristic at different  loci d. Two sex chromosomes found in the same place at the same time 6. The process in which members of a chromosome pair fail to separate is known as  _______________.  7. a chromosome fragment breaks off and then reattaches to the original chromosome, but in the  reverse direction, the resulting chromosomal abnormality is called a(n) ____________________ 8. Which of the following statements regarding the differences between mitosis and meiosis is  false?  a. In meiosis four daughter cells are produced, whereas in mitosis two daughter cells are  produced.  b. Cells produced by mitosis are diploid, whereas cells produced by meiosis are haploid.  c. In mitosis cytokinesis occurs once, whereas in meiosis cytokinesis occurs twice.  d. Crossing over is a phenomenon that creates genetic diversity during mitosis.  e. Mitosis, but not meiosis, occurs in somatic cells.  9. Independent orientation of chromosomes at metaphase I results in an increase in the number of  a. gametes.  b. homologous chromosomes.  c. possible combinations of characteristics.  d. sex chromosomes.  e. points of crossing over.  10. Which of the following must occur for a plant or animal to grow and develop normally?  a. The organism must receive a supply of the appropriate hormones from its parents.  b. The organism must be able to control the timing and rate of cell division in different parts  of its body.  c. Sufficient light must be available to stimulate cell division.  d. Sufficient oxygen must be available to stimulate cell division.  e. Dividing cells must be freed from attachment sites.  ...
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This note was uploaded on 04/03/2012 for the course CHEMISTRY 251 taught by Professor N/a during the Spring '12 term at MD University College.

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