If there are “CUES” listed within the question, please USE them and UNDERLINE them in your answer!
Chapter 6
1) Explain how prokaryotes carry out specific cellular functions without the use of cellular organelles. (CUES: enzymes,
proteins, plasma membrane, embedded)
2) Using Figure 6.9, compare & contrast animal & plant cells. (CUES: lysosomes, plasmodesmata, cell wall, centrioles,
chloroplasts, mitochondria, central vacuole)
3) Briefly describe the structure, function & location of the following cell parts:
a. Nucleus (including chromatin & nucleolus)
b. Ribosomes
c. ER (smooth AND rough)
d. Golgi apparatus
e. Lysosome
f. Peroxisome
g. Vacuoles
h. Mitochondria
i. Chloroplasts
j. Cytoskeleton (microtubules & microfilaments)
4) Use Figure 6.16 to help you answer the following: In I-cell disease, an enzyme in the endomembrane system that normally
adds sugar groups to proteins is lacking, resulting in the proteins not being targeted to the lysosomes as they would be in normal
cells. The “I” stands for “inclusion bodies” that appear in the cells. What do you think these inclusions are, and why do they
accumulate?
5) Microtubules are composed of tubulin protein and are thought to be essential during mitosis and meiosis II, as sister
chromatids are separated and moved to opposite ends of the cell. Experimentally, how could you use a repressor protein to
show that microtubules are, in fact, essential for the separation of sister chromatids? (CUES: RNA polymerase, transcription,
translation, gene, promoter)
6) Males afflicted with Kartagener’s syndrome are sterile, and they tend to suffer from lung infections. This disorder affects
cellular components. Suggest what the underlying defect might be. [HINT: What do cells that line the respiratory tract &
sperm cells have in common?] (CUES: cilia, flagella, microtubules, cytoskeleton)
7) An enzyme called salivary amylase is manufactured in the cells of your salivary glands and secreted as part of saliva. Explain
how salivary amylase is produced and secreted, starting at the DNA level. (CUES: gene, transport vesicles, transcription,
translation, mRNA, ribosome, nucleus, rough ER, plasma membrane, Golgi apparatus)
8) Use Figures 6.30 and 6.31 to compare & contrast the 3 different intercellular junctions in animal tissues. Also, explain how
plant cells are connected.
9) The polypeptide chain that makes up a tight junction weaves back & forth through the membrane 4 times, with 2 extracellular loops, and 1 loop plus short C-terminal and N-terminal tails in the cytoplasm. Looking at Figure 5.17, what would you
predict about the amino acid sequence of each region named above in the tight junction protein? (CUES: R-groups, polar,
nonpolar, aqueous, hydrophilic, hydrophobic, alpha helix)
Chapter 7
1) The molecules listed below are often moved into or out of cells during biological processes. Classify each molecule as “ionic”,
“polar”, or “nonpolar” AND as “large” or “small”. Using your classification, decide whether or not they would be able to cross the
plasma membrane freely without the help of a membrane protein.
a. N2
b. H3O+ c. tyrosine (see p. 79) d. cholesterol (see p. 77) e. CO2 f. glucose
2) Use Figure 7.13 to describe the flow of water in hypertonic, hypotonic & isotonic solutions. How is this different in an animal
& plant cell? (CUES: turgid, flaccid, plasmolyzed, lysis)
3) After celery is stored in an open, dry container in the refrigerator for two days, it is wilted. However, immersing the cut
stalk in water for a few hours restores the integrity of the celery. Explain. (CUES: turgid, osmosis)
4) Aquaporins exclude passage of hydronium ions (H3O+). Recent research on fat metabolism has shown that some aquaporins
allow passage of glycerol, a three-carbon alcohol, as well as H2O. Since H3O+ is much closer in size to water than is glycerol,
what do you suppose is the basis of this selectivity? (CUES: amino acids, R-groups, polar, ionic)
5) The current model of the plasma membrane is referred to as the fluid mosaic model. Provide evidence that the membrane is
“fluid” and describe the “mosaic” of this model. In your answer, describe at least one physical factor and one chemical factor
that influence membrane fluidity. (CUES: unsaturated, saturated, ECM, glycoprotein, carbohydrate, cholesterol, integral
protein, phospholipid, temperature)
6) Briefly explain how each of the three factors below can impact the diffusion of solutes across cell membranes:
a. size of the diffusion molecule (CUES: integral protein, facilitated diffusion)
b. temperature (CUES: molecular energy)
c. concentration gradient (CUES: low solute concentration, high solute concentration, passive transport, active
transport, energy)
7) Use Figure 7.17 to describe the movement of molecules in active & passive transport across a selectively permeable
membrane. USE EACH CUE IN YOUR DESCRIPTION OF BOTH ACTIVE & PASSIVE TRANSPORT. (CUES: ATP,
concentration gradient, integral protein, hydrophilic, hydrophobic, polar, non-polar)
Chapter 8
1) Discuss the forms of energy found in an apple as it grows on a tree, then falls, then is digested by someone who eats it.
(CUES: chemical, potential, kinetic)
2) How does ATP usually transfer energy from exergonic to endergonic reactions? (CUES: dehydration synthesis, hydrolysis,
coupled)
3) Use Figure 8.19 & 8.20 to explain how the following factors influence enzyme activity. Please consider both an increase &
decrease in activity with your discussion.
a. Temperature
b. pH
c. co-factors
d. competitive inhibitors
e. allosteric inhibitors
f. allosteric activators
4) DNA polymerase from T. aquaticus (Taq) is used in PCR (polymerase chain reaction). PCR is a technique where millions of
copies of DNA can be made from one original copy. In this method, the target DNA molecule being copied is subjected to
temperatures over 95 oC to make the double-stranded DNA separate. The temperature is then lowered slightly to allow primers
to anneal before the Taq polymerase catalyzes the reactions to incorporate new nucleotides into the complementary strands.
The cycle is then repeated over and over until there are millions of copies of the target DNA.
 Predict why this bacterial polymerase is used instead of a human polymerase. (CUES: adaptation, denature, tertiary
structure, function)
5) a. Explain how the structure of an enzyme makes that enzyme substrate-specific. (CUES: shape, function, bonds,
R-groups)
b. If an enzyme binds to a polar substrate, what specific amino acids may be found within the active site of the
enzyme? (Use p. 79.)
6) What is activation energy? Explain at least two things that an enzyme does to lower the activation energy needed to start a
reaction. (CUES: transition state, strain, orientation, substrate)
7) Most enzyme-catalyzed chemical reactions in humans occur most readily around body temperature, 37 oC. Why do these
reactions slow down at lower temperatures? Why do they slow down at higher temperatures?
8) A farm worker accidentally was splashed with a powerful insecticide. A few minutes later he went into convulsions, stopped
breathing, and died. The insecticide acted as a competitive inhibitor of an enzyme important in the function of the nervous
system. Describe the structural relationship between the enzyme, its substrate, and the insecticide. (CUES: tertiary
structure, binding, active site, substrate)
9) Imagine you are a pharmacological researcher who wants to design a drug that inhibits a particular enzyme. Upon reading the
scientific literature, you find that the enzyme’s active site is similar to that of several other enzymes whose activity must
remain unchanged. What might be a good approach to developing your inhibitor drug so that it only inhibits the specific enzyme
of interest? (CUES: competititive inhibitor, noncompetitive inhibitor, active site, allosteric site)
Chapter 11
1) Use Figure 11.4 to explain 2 ways cells communicate over short distances & 1 way that they communicate over long distances.
(CUES: diffusion, secretory vesicle, paracrine, synapse, neurotransmitter, endocrine, bloodstream, endocrine cell, target cell)
2) How is a ligand binding to a receptor similar to the process of allosteric regulation? (CUES: tertiary structure, function,
complementary, extracellular, cytoplasmic)
3) Compare “first messengers” (e.g. ligands, hormones) with “second messengers” (e.g. cAMP) with regard to their chemical
nature, where they are found, and their activity. (CUES: steroids, ions, small molecules, proteins, bloodstream, within cells)
4) Use Figure 11.13 to answer the following: How can a target cell’s response to a single hormone result in a response that
affects millions of other molecules?
5) If a cell has no proteins in its membrane, will it be able to respond to any environmental stimuli? Explain your answer.
(CUES: polar, nonpolar, protein hormone, steroid hormone, phospholipid bilayer, intracellular receptor)
6) Use Figure 11.8 to discuss how signal transduction can be terminated. Also, why is it important that signal transduction is
terminated quickly within a cell? (CUES: kinase, phosphatase, over-expression, under-expression )
7) Estrogens are a group of steroid hormones that stimulate growth in many of their target cells. Propose the reasons for
testing whether or not a breast cancer tumor in a human mammary gland expresses the gene for the estrogen receptor. If the
tumor cells do express the gene for the estrogen receptor, what therapeutic option is logical?
8) Some hormones, such as anti-diuretic hormone (ADH), act on very specific targets (for ADH, the kidney). Other hormones,
such as insulin, are able to affect every cell in the body. Based on what you have learned about how ligands exert their effects
on target cells, speculate as to how some hormones can affect many targets, while other hormones affect only one. (CUES:
receptor, response, signal transduction pathway, shape)
9) A chemical called dioxin, or TCDD, is produced as a contaminant during some chemical manufacturing processes. Trace
amounts of this substance were present in Agent Orange, a defoliant sprayed on vegetation during the Vietnam War, causing
leaves to fall off. There has been a continuing controversy over its effects on soldiers exposed to it during the war. Animal
tests have shown that dioxin can be lethal and can cause birth defects, cancer, liver and thymus damage, and immune system
suppression. But its effects on humans are unclear, and even animal tests are uneven; a hamster is not affected by a dose that
can kill a guinea pig. Researchers have discovered that dioxin exerts its effects like a steroid hormone. How might this
mechanism help explain the variety of effects of dioxin on different body systems and in different animals? (CUES: receptor,
cell types, genes, transcription factors, gene expression)