Download SI Practice exam 2

SI Practice exam 2
Part 1: Fill in the blank with the best term for the following definitions
1. _______________ are the types of bonds that maintain the secondary structure of a protein.
2. The process of assembling the proper amino acids into a protein, using the information in a
molecule of mRNA is called _________________.
3. A(n) _________________ is a section of DNA containing directions to build one polypeptide or
RNA molecule.
4. _________________ are the fundamental units of life.
5. Phagocytosis is a method by which the cell membrane can pinch off a vesicle to bring outside
material into the cell; this is a process called ____________________.
6. If chemical agents or high temperature disrupt interactions or bonds that stabilize the folded
shape, a protein is _____________________ and unable to function normally.
7. The covalent bonds that are formed between the R-groups of two cysteine amino acids is known
as ______________________.
8. ________________________ can function as both ana acid and a base.
Part 2: Multiple choice
1. Bacterial cells are prokaryotic. Unlike a typical eukaryotic cell, the bacterial cell does not have
a. DNA
b. A plasma membrane
c. Membrane delimited organelles in the cytoplasm
d. Ribosomes
e. Chromatin
2. Circle any of the following that are true.
a. The tertiary structure of a protein is assembled with covalent bonds, called peptide
bonds.
b. The secondary structure of proteins is typically a function of hydrogen bonding
between hydrogens on the alpha carbon and carboxylic double bonded oxygen.
c. The secondary structure of proteins is a function of hydrogen bonds being
established between amino hydrogens and carboxylic double bonded oxygen.
d. The quaternary structure of proteins is established when at least four polypeptides
are bonded into a biologically active unit.
3. Which nitrogenous bases are purines?
a. cytosine, uracil and thymine
b. adenine and guanine
c. adenine, uracil and thymine
d. guanine and cytosine
4. What is the fundamental difference between prokaryotic and eukaryotic cells?
a. prokaryotic cell don not have a plasma membrane
b. prokaryotic cells do not have a nucleus
5.
6.
7.
8.
c. prokaryotic cells do not have ribsomes
d. eukaryotic cells never have a cell wall
When a protein is denatured what kinds of bonds are the least likely to be broken?
a. hydrogen bonds
b. ionic bonds
c. peptide bonds
d. disulfide bonds
Each nucleotide has one nitrogenous base; either a purine with a double ring or a pyrmidine
with a single ring. Which statement is true regarding complimentary base pairing?
a. Purines always pair with purines, and pyrimidines always pair with other pyrimidines
b. The purine base cytosine always pairs with the purine base guanine
c. In RNA, the purine base adenine always pairs with the pyrimidine base uracil
d. Rosalind Franklin discovered complimentary base pairing
The condensation reaction joining two nucleotides together forms a _________
a. Phosphodiester linkage
b. Peptide bond
c. Double helix
d. pyrimidine
Botulism is a type of food poisoning caused by bacteria. The bacteria get canned in food and
produce a protein, which is extremely toxic. The bacteria themselves do not cause the disease.
It’s the protein they excrete that is so dangerous. But not all foods are equally risky. Which of
the following contaminated foods would be most dangerous regarding botulism?
a. Canned tomatoes (pH of approximately 2)
b. Canned soup (served hot)
c. Canned cherries (used to bake a cherry pie)
d. Canned olives (used in a salad)
9. Which of the following statements regarding proteins is correct?
a.
Alpha helices and beta sheets are forms of a polypeptide' s tertiary structure.
b. Nucleotides join via condensation reactions to form polypeptides.
c.
The words polypeptide and protein have identical meaning.
d. Protein structure is correlated with protein function.
10. How does compartmentalization into organelles help eukaryotes solve a problem associated
with the large size of eukaryotic cells?
a. Compartmentalization reduces diffusion distance and concentrates molecules needed for specific
reactions.
b. Compartmentalization makes it possible for eukaryotes to eat bacterial cells.
c. Compartmentalization lets eukaryotes become muiticellular.
d. Compartmentalization allows eukaryotes to perform chemical reactions like
photosynthesis that are not present in bacteria.
11. The following represents the N-base sequence of a double-stranded DNA containing a single
structural gene.
5'ATGTTTAAAAGGTGGTGA3'
3'TAG AAATTT TCC ACC ACT5'
Assume this DNA is replicated and the process proceeds on both template strands but is terminated after
only 6 bases of compliment are synthesized. Which choice below represents the base sequences of the two
compliment strands?
a.
3'TAG AAA 5' 5'ATG TTT 3'
b. 5'ATG TTT 3' 3'ACC ACT 5'
.
12. The base sequence of the molecule produced by transcription of the above gene would be
a.
5'AUGUUUAAAAGGUGGUGA 3'
b. 5'UACAAAUUUUCCACCACU 3'
c.
5'TAG AAAATT TCC ACC ACT 3'
d.
3' TAG AAA TTT TCCACCACT5'
13. Which of the following is true of DNA in bacterial cells?
a. All bacterial DNA is part of a chromosome in the cell's nucleoid region.
b. Bacterial DNA usually forms linear chromosomes.
c.
B acterial DNA does not contain genes.
d. Bacterial DNA is supercoiled; full-length uncoiled bacterial DNA cannot fit in the cell.
14. Which of the following is not true about the Cell Theory?
a. It was proposed by Schwann and Schleider around 1840.
b. All cells are derived from preexisting cells.
c. The cell is the basic structural and functional unit of life.
d. All living things are composed of multiple cells.
15. Chargaff s rules state that in DNA, the
a. # purines = # pyrimidines, the #A's = #G's and the #T’s = #U' s.
b. # purines = # pyrimidines, the #T's = #A's and the #C's = #G's.
c. sugar-phosphate backbone is formed by phosphodiester linkages and is helical in
structure.
d. two strands are antiparallel and have complementary base pairing.
16. Which of the following side-chain interactions are important in determining tertiary
structure?
a. covalent bonds
b. ionic bonds
c. hydrogen bonds and van der Waals interactions
d. all of the above
e. all of the above
f.
a and c
g. b and c
17. Franklin's x-ray crystallography of DNA showed that
a. it was held together by hydrogen bonds.
b. that there is an equal number of T's and A's.
c. it was a helical structure.
d. there were antiparallel strands.
18. You inspect two nucleic acids taken from a cell. One is DNA and one is mRNA. How could
you tell the difference? They are both complete molecules.
a. The DNA only would contain uracil.
b. The mRNA would contain fewer nucleotides.c. Only the DNA would be acidic.
d. Only the RNA would contain the sugar deoxyribose.
e. Onlv the DNA would have a 5' and a 3' end.
19. Which of the following pairs matches the name of a membrane transport process with the
primary function of that process?
a. Exocytosis—the movement of macromolecules into the cell by vesicle fusion with the
plasma membrane.
b. Pinocytosis—the uptake of water and solutes into the cell by formation of vesicles at
the plasma membrane.
c. Osmosis—passive diffusion of small solutes across a membrane.
d. Phagocytosis—secretion of large particles from the cell by fusion of vesicles with the
plasma membrane.
20. In the following protein, which of the labeled regions (a, b, or c) is most likely to have a large
number of cysteine amino acids?
a
21. The experiments that supported the hypothesis that proteins could be incorporated into the
phospholipid bilayer, and even extend through it, involved freeze fracture techniques. What
kind of imaging system allowed researchers to visualize the particles inside the fractured eel]
membrane?
a. light choreography
b. light interference microscopy
c.
electron microscopy
d. phase contrast light microscopy
22. A certain cell has mitochondria, ribosomes, and smooth ER. Based on this, it could not be
a. a cell from a grasshopper.
b. a yeast cell.
c.
a cell from a plant.
d. E. coli.
Part 3: Short Answer. Please write and/or draw whatever you think is necessary to answer the
question completely.
1. A given strand of DNA contains 16% cytosine. Provide the percentage made of each of the other three
nucleotides in the double-stranded DNA molecule.
2. On Grey's Anatomy, it has been discovered that a patient has been contaminated with mycosplasma
pneumoniae. One of Izzie's interns has decided that the best way to treat this is by giving the patient
antibiotics. Do you agree or disagree with the new intern's reasoning? Why or why not?
3. Please explain why as cell size increases the metabolic efficiency decreases.
4. Mitochrondria are assumed to have become a part of today's cells through the process of endocytosis.
What are the reasons why we have reached this conclusion?
Part 4: Listed below are some amino acids.
(Note: There may be no correct answers, 1 correct answer, or more than one correct answer for each
of the following.)
A-Valine
B-Cystein
C-Lysine
D-Glutamic acid
1. Which is the most non-polar?______________________________
2. Which is most likely to be buried deep as possible in the center of a protein's 3-D structure
when in an aqueous solution? _____________________________
3. Which one(s) would be likely to act as a base? ________________________________
\. Which one(s) is/are likely to form strong covalent bonds with other amino acids of the same
type to help stabilize tertiary structure? _____________________________
5. Which one(s) is/are most likely found to help support the a-helical structure in the secondary
structure of a protein? ___________________________