Download Mid-Term Exam 1a - Buffalo State College Faculty and Staff Web

STATE UNIVERSITY COLLEGE AT BUFFALO
Department of Biology
Biology 100
Principles of Biology
Fall 2004
Dr. Wadsworth
Mid-Term Exam 1a
Biomolecules, Membranes and Cells
Cover Sheet
Name: ____________________________________________________
(Print)
Instructions.
1. Print your name in the space designated on this cover sheet.
2. Be sure that your exam has 8 pages including this cover sheet.
3. Read each question carefully and answer in the space provide
4. At the end of the exam there are 6 short answer questions. Answer only 5 of
these 6 questions. Answering all six questions may reduce your grade.
Under the question you choose not to answer, please write the word "Skip".
Failure to write "SKIP" under the one question you choose not to answer will
reduce your grade.
Multiple Choice
Choose the best answer for the question or the best ending for each statement. Write the letter (A-E) which
corresponds to the best answer on the line before the question. (2 pts each)
_____ 1. Which of the following might describe the subatomic composition of a positively charged
nitrogen ion?
A.
B.
C.
D.
E.
7 protons, 6 neutrons, 7 electrons
7 protons, 7 neutrons, 6 electrons
8 protons, 7 neutrons, 7 electrons
8 protons, 6 neutrons, 7 electrons
8 protons, 7 neutrons, 6 electrons
_____2. What are the four most abundant elements found in biological molecules?
A.
B.
C.
D.
E.
Hydrogen, Sulfur, Nitrogen, and Oxygen
Carbon, Oxygen, Hydrogen, and Nitrogen
Phosphorus, Hydrogen, Carbon, and Oxygen
Carbon, Oxygen, Nitrogen, and Sulfur
Carbon, Hydrogen, Sulfur and Phosphorus
_____3. Which of the following would convert a neutrally charged hydrogen atom into a hydrogen ion?
A.
B.
C.
D.
E.
Addition of a charged proton.
Addition of two positively charged protons
Loss of an electon
Any change in the subatomic structure
Loss of a proton
_____ 4. How does an atom with a valence number of 1 differ from an atom with a valence number of 2?
A. The atom with the valence number of 2 has twice the electrons as the atom with the
valence number of 1.
B. The atom with the valence number of 2 can form twice as many covalent bonds as the
atom with the valence number of 1.
C. The atom with the valence number of 2 is more electronegative than the atom with the
valence number of 1.
D. The atom with the valence number of 2 is twice as large as the atom with the valence
number of 1.
E. The atom with the valence number of 2 has one more electron than the atom with a
valence number of 1.
_____ 5. The protein that causes mad cow disease is a prion. Which of the following best explains why it
is a prion?
A.
B.
C.
D.
E.
It forms plaques in the brain that result in a loss of memory.
It assembles into long rods in red blood cells causing them to take a sickle shape.
It produces fever and fatigue.
It induces the misfolding of proteins in individuals that ingest it.
It leads to the substitution of hydrophobic amino acids for hydrophilic amino acids.
_____ 6. Polymers are broken down to form monomers by an hydrolysis reaction. Which of the following
best describes why this reaction is called a hydrolysis reaction?
A. A water molecule is split to restore the hydroxyl and hydrogen on the monomers
B. The energy stored in the molecule is released during splitting and temporarily stored in
water.
C. A water molecule needs to be divided into an hydroxyl and a hydrogen to release energy
to split the polymers.
D. A hydroxyl and hydrogen are split from the polymer to form a new water molecule.
E. The chemical bonds within a polymer are much like those found in water.
_____7. When a protein is in its native state, where would you expect to find the amino acids with
hydrophilic side groups?
A. Covalently linked to one another to form the peptide bonds
B. Covalently linked to hydrophobic amino acids to form peptide bonds
C. Buried in the interior of the protein, bound to water
D. Linked to one another through hydrophilic interactions
E. Near the surface of the protein
_____ 8. Nucleotides are made of which of the following sets of components?
A. Nitrogenous base, Carboxyl Group, Sugar
B. Amino acid, Fatty Acid, Sugar
C. Hydroxyl, Phosphate, Carboxyl
D. Amino acid, Nitrogenous base, Sugar
E. Sugar, Phosphate, Nitrogenous base
_______ 9. Which of the following classes of molecules consist of four interlocking carbon rings modified
with various functional groups?
A. Steroids
B. Fatty Acids
C. Triglyceride
D. Polypeptides
E. Cellulose
_____ 10. Glucose is an example of which of the following classes of biomolecules?
A. Proteins
B. Amino Acids
C. Nucleotides
D. Monosaccharides
E. Triglycerides
_____ 11. Which of the following classes of biomolecules can serve as a hormone in humans?
A.
B.
C.
D.
E.
RNA and DNA
Proteins and Nucleic Acids
Proteins and Steroids
Proteins and Polysaccharides
Polysaccharides and Steroids
_____ 12. The phrase "Primacy of Proteins" is used to emphasize:
A.
B.
C.
D.
E.
that proteins are the largest of the biomolecules
that proteins contain "information"
that proteins are hydrophobic
that proteins are highly hydrophilic that
proteins perform most cellular functions
_____ 13. Which of the following molecules would have the most atoms.
A.
B.
C.
D.
E.
Saturated triglyceride
Saturated fatty acid
Unsaturated fatty acid
Polyunsaturated fatty acid
Polyunsaturated triglyceride
_____ 14. Which of the following are functions of carbohydrates in cells?
A.
B.
C.
D.
E.
Storage of energy and hormones
Motion and membranes
Membranes and cell walls
Storage of energy and structural
Hormones and structural
_____ 15. Which of the following parts of the cell is larger?
A.
B.
C.
D.
E.
Cytoplasm
Ribosome
Nucleus
Mitochondria
Chromatin
_____ 16. Which of the following organelles would you find in plant cells but not animal cells?
A. Nucleus
B. Cytoskeleton
C. Central Vacuole
D. Mitochondria
E. Vesicles
_____ 17. What organelle is most responsible for assembling membranes?
A. Endoplasmic Reticulum
B. Plasma Membrane
C. Choloroplasts
D. Mitochondria
E. Cytoskeleton
_____ 18. Which of the following is found in both eukaryotic and prokaryotic cells?
A. Endoplasmic Reticulum
B. Nucleus
C. Mitochondria
D. Ribosomes
E. Golgi
_____ 19. Which of the following does not increase the fluidity of membranes?
A.
B.
C.
D.
E.
Increasing temperature
Double bonds in the fatty acid chains
Cholesterol
Unsaturated fatty acids
Saturated fatty acids
_____ 20. Which of the following best describes a difference between facilitated transport and active
transport.
A. Active transport requires energy facilitate diffusion doesn’t
B. Active transport moves molecules from areas of high concentration to areas of low
concentration, and facilitated diffusion moves molecules from areas of low concentration
to high concentration.
C. Active transport uses a membrane protein facilitated diffusion doesn’t.
D. Active transport moves macromolecules across the membrane, while facilitate diffusion
moves ions across membranes
E. Active transport is specific to a limited set of molecules, while facilitated diffusion can
transport any small uncharged molecule.
_____ 21. Which of the following best describes the arrangement of intergral membrane proteins in a
membrane?
A.
B.
C.
D.
E.
The proteins are sandwiched between layers of phospholipid bilayer
The proteins coat the outside of the phospholipid bilayer
The proteins pierce the phospholipid bilayer
The proteins clump on the surface of the phospholipid bilayer
The proteins only interact with the hydrophobic tails of the phospholipids
_____ 22. The glycine pump that transports the amino acid glycine across the membrane can not transport
the amino acid alanine across the membrane. What explain why the glycine pump cannot
transport alanine?
A.
B.
C.
D.
E.
Alanine can not be easily hydrolized
Alanine is a triglyceride and, therefore, is too hydrophobic to move across the membrane
Alanine does not have a shape complementary to the binding site of the glycine pump
Alanine is only found outside of cells
Alanine is an ion and ions are never transported across the membrane by active transport.
_____ 23. During endocytosis:
A. materials stored in the cytoplasmic vesicles are transported to the plasma membrane and
ejected.
B. Solutes containing necessary materials pass directly into the cell through the plasma
membrane.
C. Carrier proteins ferry large molecules through the membrane.
D. Pumps concentrate large molecules inside of cells.
E. Materials are enclosed in invaginations of the plasma membrane, which subsequently
pinch off, forming cytoplasmic vesicles.
_____ 24. Which of the following molecules uses simple diffusion to move across the plasma membrane:
A.
B.
C.
D.
E.
LDL particles
Very small ions
Small uncharged particles
Proteins
Large bulky particles
_____ 25. Biological membranes are called selectively premeable membranes because:
A. They are composed of about 50% protein and 50% lipids
B. Charge molecules can not pass through the membrane
C. Active transport requires energy
D. Active transport requires a carrier protein
E. Only some molecules pass through the membrane
Short Answer Questions
Answer only five of the following six questions in the space below each question. Under the one question
you choose not to answer, write the word "SKIP".
26. Milk proteins remain dissolved in solution when in their native state but clump together to form curds
in their denatured state. What explains this difference in the way native and denatured proteins behave?
27. Draw the structure of glucose.
28. Describe three differences between plant and animal cells.
29. Plants around the equator often have saturated fats in their membranes, while plants near the arctic
often have unsaturated fatty acids in their membranes. What advantage is it to the arctic plants to have
unsaturated fatty acids in their membranes?
30. Biological membranes are described as being semipermeable. An example of this is that some
monosaccharides such as glucose can cross the membrane, but other monosaccharides such as raffinose
cannot. What is the likely explanation for the difference in the permeability of these two equally sized
monosaccharides?
31. The structure of the amino acid phenylalanine is drawn below. Explain whether this molecule could be
described as amphipathic or not.
H
O
H
N
C
C
H
H
O
CH
H
C
H
H
H
C
C
C
CH
C
H