NOTE: Questions are written on both sides of the sheets of paper making up this exam booklet!

Transcription

1 Biology 1010 Section A Midterm 1 January 30, 2008 (print): ANSWER KEY Name (signature): Student I.D. #: Time: 50 minutes Read the following instructions: 1. Do not open the examination until you are instructed to do so. 2. In addition to supplying the requested information on the front of the exam booklet, print your name at the top of pages 6 and 7 (one bonus mark). 3. Print your name in the space provided on the multiple choice answer sheet. You must also shade in the appropriate circles so that the computer can record your name. 4. This exam consists of two parts: PART I - 4 written answer questions (32 MARKS) PART II - 15 multiple-choice questions (15 MARKS) 5. Mark your multiple-choice answers on the multiple-choice answer sheet. 6. Respond to the written answer questions on the exam paper in the space provided. 7. Your exam booklet contains 5 sheets of paper. The test questions are printed on both sides of the exam booklet sheets of paper. 8. Hand in the entire exam booklet and the multiple choice answer sheet. 9. Carefully read and answer the questions being asked. NOTE: Questions are written on both sides of the sheets of paper making up this exam booklet!

2 PART I. - Written Answer Questions. Answer in the space provided. Question 1. Fill in the blanks with the best possible answer. (10 Marks - 1/2 mark per blank) a) Charles Darwin Researcher credited with developing the evolutionary theory b) Escherichia coli, Salmonella, Scientific name of a Gram-negative bacterium or other correct names c) Bacillus, Clostridium, or Scientific name of a Gram-positive bacterium or other correct names d) Transformation Uptake of naked DNA from the environment e) Matthais Schleiden Researchers credited with developing the cell theory Theodor Schwann f) Nucleic acids The four types of macromolecules found in cells Proteins Polysaccharides Lipids g) 18S rrna A type of rrna found in the small subunit of an eukaryotic ribosome h) 16S rrna A type of rrna found in the small subunit of a prokaryotic ribosome i) Peptidoglycan The major component of bacterial cells walls j) Archaea The three domains of life Bacteria Eukarya k) Roots The three basic plant organs Stems Leaves l) Connective tissue The name of the animal tissue that functions mainly to bind and support other tissues. 2

3 Question 2. Explain the meaning of the phrase Structure and function are correlated. In your answer use the various cytoskeletal elements to illustrate this concept. (7 Marks) In the answer there must be an explanation of the phrase Structure and function are correlated. The structure and function are correlated concept implies that knowing the structure of something provides one with insight into its function and vice versa. (1.5 Mark) The remaining marks as awarded for using the various cytoskeletal elements to illustrate the Structure and function are correlated concdept. The cytoskeleton is composed of three proteinaceous fibres of different sizes and composition and structures (1 Mark). Fibrous materials are often involved in structural roles such as mechanical support to the cell and maintenance of shape (1.5 Mark). Two of the cytoskeletal components (i.e., microtubules and microfilaments) can be rapidly assembled and disassembled where needed in the cell (1.5 Mark). This feature is consistent with their structure. Globular protein subunits (tubulin microtubules; actin microfilaments) make up fibres that lengthen or shorten through addition or removal of subunits from the fibre ends (1.5 Mark). In contrast, intermediate filaments are more permanent structures that may persist for long periods of time (1 Mark). These structures are composed of a number of fibrous keratin subunits that are woven together like a rope (1.5 Mark). 3

4 Question 3 You have been given a sample that contains microscopic particles. How would you determine if these particles are actually cells? In the space provided below briefly describe the best two different approaches you could use to address this question. (6 Marks) It is important to note in passing that any one of these approaches may not provide enough evidence to conclude that the particles are actually cells. One may have to perform a number of tests before a convincing argument is established. Approach 1 Cells are the basic unit of life and as such should be exhibit a number of emergent properties. Perhaps the easiest one to test is reproduction. The particles could be tested for the ability to reproduce or grow in numbers by putting them in or on a variety of nutrient media. One would examine the potential cultures for growth. Approach 2 All cells have membranes and DNA. So one could also examine the particles for their presence. Various types of microscopy (Light and Electron Microscope) could be used to look for the presence of membranes, subcellular organelles and other structures found in cells (flagella, cilia ). The cells could also be examined for movement. The particles could also be examined for the presence of DNA as well as the other macromolecules that are found in cells (e.g., proteins, RNA, lipids, polysaccharides) Any other reasonable approach will be accepted for a total of 3 marks/approach. The Perhaps one could examine the 4

5 Question 4 a) Draw and label a typical prokaryotic cell. (4 Marks) 0.5 Marks per label cytoplasm/cytosol plasma membrane cell wall capsule nucleoid region pilus ribosome flagellum b) Describe the similarities between a Gram-positive prokaryotic cell and a bacteriophage. (2 Marks) (1 Mark demonstrated knowledge of a bacteriophage) A bacteriophage is a virus of bacteria. Bacteriophage are acellular and composed of a protein coat or capsid and a nucleic acid genome (composed of RNA or DNA) Gram-positive bacteria and bacteriophage are both composed of proteins and nucleic acids (1 Mark) Gram-positive bacteria and bacteriophage both carry genomes containing genetic information (1 Mark) 5

6 c) What is the most significant difference between a prokaryotic cell and a virus? Provide support for your answer. (3 Marks) The most significant difference between a prokaryotic cell and a virus is the fact that a prokaryotic cell is a cell and a virus is acellular (1 Mark). In other words, the prokaryotic cell is living (a cell is the fundamental unit of life) and capable of carrying out all of the emergent properties characteristic of life whereas a virus is not living and does not show the emergent properties characteristic of life. (2 Marks for a reasonable statement of support) Written Answer Total (Max = 32) Multiple Choice (Max = 15) Examination Total (Max = 47) 6