bio 4.pdf

8 Pages
Unlock Document

University of Arizona
Ecology & Evolutionary Biology

Biology 181R Sections 3, 4H Dr. Ramin Yadegari Hour Exam #4 December 1, 2011 (Version 1 KEY) LAST NAME: _____________________ FIRST NAME:__________________________ UA NET ID: ___________________ Instructions: Before starting this exam, read the Instructions! Fill inyour name and NetID on both the exam booklet and the bubble sheet. Circle your answer on the exam copy AND use a #2 pencil to mark the corresponding answer on the bubble sheet. If you must change an answer, be certain that your first choice is erased completely. The bubble sheet is your “official” answer sheet! Read each question carefully and choose THE BEST answer. If you are unclear regarding what the question is asking, raise your hand and ask for clarification. When you have finished the exam, turn in both the bubble sheet and the exam book to the instructor at the front of the room. There are multiple versions of this exam. DO NOTLET YOUR EYES WANDER FROM YOUR EXAM! If you violate the code of academic integrity, you will be subject to sanctions such as loss of credit for this exam and possibly being assigned a failing grade for the course. 1. The predominant mechanism driving cellular differentiation is the difference in gene _____. a) *expression b) sequences c) order d) replication e) copy 2. Which observation below provides evidence that differentiated cells retain all the genes of developing cells? a) Developing cells have many mRNA transcripts in common with mRNAs produced in mature cells. b) Differentiated cells generally synthesize a specific group of proteins. c) *Nuclei from mature cells can direct the development of an entire individual. d) Not all mature cells are capable of differentiation. e) None of the above. 3. Gene expression in developing organisms is regulated on several different levels. In many developing animals, regulation of gene expression is influenced by the action of Hox genes. Which of the following gene products is encoded by Hox genes? a) *transcription factors b) cell-surface molecules for cell-cell interactions c) signal-transduction factors such as protein kinases d) mRNA-processing factors e) Protein-degradation factors 1 4. Bicoid mutations produce “two-tailed’ Drosophila embryos. The protein encoded by the bicoid gene in Drosophila determines the _____ of the embryo. a) *anterior-posterior axis b) anterior-lateral axis c) posterior-dorsal axis d) posterior-ventral axis e) dorsal-ventral axis 5. Suppose you purified the protein encoded by the bicoid gene and injected it into the tail end of an early Drosophila embryo before formation of the head or tail structures. What might be the result of such an experiment after you allow further development to occur? a) The embryo would show no development of ventral regions. b) The embryo would show no development of anterior regions. c) The embryo would show a head and a tail as normal. d) The embryo would show two tails. e) *The embryo would show two heads. 6. All of the following are true of embryonic stem cells except _____. a) they can be found in human blastocysts b) they retain the potential to become different types of cells c) they continue to undergo mitosis when most cells have stopped dividing d) *they are terminally differentiated 7. What does the ABC model of flower development attempt to explain? a) *how different combinations of transcription-factor proteins trigger the formation of different floral organs b) why petals are colorful whereas the sepals are green c) why the four types of floral organs occur in whorls d) why apical meristems are converted to floral meristems in response to specific cell-to-cell signaling 8. Which of the following statements about stem cells is true? a) Embryonic stem cells can be harvested from human embryos produced during in vitro fertilization. b) The only known pluripotent animal stem cells are derived from embryos. c) The manner in which embryonic stem cells differentiate can be channeled by the appropriate signals. d) Both a and b e) *Both a and c 9. Induced pluripotent stem cells a) are obtained via activation of several genes required for the pluripotent character of the stem cells. b) may be produced from differentiated cells in culture . c) can be induced to form many different tissues. d) *All of the above e) None of the above. 2 10.Mammalian adult stem cells are usually capable of dividing into a few cell types; they are therefore said to be _______. a) *multipotent b) totipotent c) terminally differentiated d) rearranged e) embryonic 11.To respond to a signal, a cell must have a(n) _______ molecule that can detect the signal. a) paracrine b) *receptor c) autocrine d) responder e) All of the above 12.The receptor of cortisol a) is an ion channel receptor. b) is a protein kinase receptor. c) exists within the plasma membrane and dimerizes. d) *can form a complex that binds to DNA. e) None of the above 13.Which of the following statements about the insulin receptor is false? a) It autophosphorylates (phosphorylation of its own select amino acid residues). b) It requires binding by two insulin molecules to be activated. c) It catalyzes the phosphorylation of insulin response substrates. d) *It is located entirely within the cytoplasm. e) None of the above 14.Viagra, used to treat erectile dysfunction, acts by means of the release of the second messenger a) cyclic AMP. b) calcium ion. c) *nitric oxide. d) calmodulin. e) acetylcholine. 15.The receptors for steroid hormones are located inside the cell, instead of on the membrane surface like most other signal receptors. Why is this not a problem for steroids? a) because the receptors can be readily stimulated to exit and relocate on the membrane surface b) because receptors located inside cells are less susceptible to blockage by inhibitors located on or near the cell surface, so it serves as a protective mechanism c) *because steroid hormones are lipid soluble so can readily diffuse through the lipid bilayer of the cell membrane d) because the receptors are repressible, meaning they are actively altering cell function unless the target hormone is present 3 16.Put the steps of the process of signal transduction in the order they occur: 1. A conformational change in the signal-receptor complex activates an enzyme. 2. Protein kinases are activated. 3. A signal molecule binds to a receptor. 4. Target proteins are phosphorylated. a) 1, 2, 3, 4 b) *3, 1, 2, 4 c) 3, 4, 1, 2 d) 3, 2, 1, 4 17.Plasmodesmata are cell-cell junctions that are found between ___________. a) individual cardiac cells in heart muscle tissue b) *adjacent plant cells c) adjacent animal cells in the same tissue type d) the plasma membrane of actively dividing prokaryotes e) None of the above. 18.Hormones are chemical substances produced in one organ that are released into the bloodstream and affect the function of a target organ. For the target organ to respond to a particular hormone, it must _____. a) modify its plasma membrane to alter hormone entering the cytoplasm b) be from the same cell type as the organ that produced the hormone c) experiencing an imbalance that disrupts its normal function d) *have receptors that recognize and bind the hormone molecule 19.What does it mean to say that a signal is transduced? a) The signal enters the cell directly and binds to a receptor inside. b) *The physical form of the signal changes between the outside of the cell and the inside. c) The signal is amplified, such than even a single molecule evokes a large response. d) The signal triggers a sequence of phosphorylation events inside the cell 20.A G-protein receptor with GTP bound to it _____. a) *is in its active state b) signals a protein to maintain its shape and conformation c) will use cGMP as a second messenger d) directly affects gene expression 21.Which of the following sequences (in a double-stranded form) is most likely to be cut by a restriction enzyme? a) 5’-AATCGT-3’ b) 5’-AATTCT-3’ c) *5’-AATATT-3’ d) 5’-AAAATT-3’ e) 5’-ACTACT-3’ 22.Which of the following is a correct difference between a gene library and a gene clone? a) *A gene library contains many different cloned DNA sequences; a gene clone contains one type of DNA sequence. b) A gene library contains one type of cloned DNA sequence; a gene clone contains many different DNA sequences. c) A gene library is a much longer piece of DNA sequence than a gene clone. d) A gene library is a much shorter piece of DNA sequence than a gene clone. e) A gene library is sequence information stored in a computerized database; a gene clone is an actual sequence of DNA. 4 23.Plasmids are used as cloning vectors in genetic engineering. This means that plasmids allow for _____. a) *carrying of DNA into a cell and DNA replication b) DNA to mutate within the gene of interest
More Less

Related notes for ECOL 182R

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.