Details of Testbank for Biology 2nd Edition from OpenStax College ISBN 9781947172517Chapter 1 1 Figure 1.6 1: C; 2: F; 3: A; 4: B; 5: D; 6: E. The
... [Show More] original hypothesis is incorrect, as the coffeemaker works when plugged into the outlet. Alternative hypotheses include that the toaster might be broken or that the toaster wasn't turned on. 3 Figure 1.16 Communities exist within populations which exist within ecosystems. 4 B 6 D 8 C 10 C 12 B 14 D 16 Answers will vary, but should apply the steps of the scientific method. One possibility could be a car which doesn’t start. The hypothesis could be that the car doesn’t start because the battery is dead. The experiment would be to change the battery or to charge the battery and then check whether the car starts or not. If it starts, the problem was due to the battery, and the hypothesis is accepted. 18 Answers will vary. Topics that fall inside the area of biological study include how diseases affect human bodies, how pollution impacts a species’ habitat, and how plants respond to their environments. Topics that fall outside of biology (the “study of life”) include how metamorphic rock is formed and how planetary orbits function. 20 Answers will vary. Layers of sedimentary rock have order but are not alive. Technology is capable of regulation but is not, of itself, alive. 22 During your walk, you may begin to perspire, which cools your body and helps your body to maintain a constant internal temperature. You might also become thirsty and pause long enough for a cool drink, which will help to restore the water lost during perspiration. Chapter 2
2 | P a g e1 Figure 2.3 Carbon-12 has six neutrons. Carbon-13 has seven neutrons.
3. Figure 2.24 C
3 A
6 C
8 D
10C
12
D
14 Ionic bonds are created between ions. The electrons are not shared between the
atoms, but rather are associated more with one ion than the other. Ionic bonds are strong
bonds, but are weaker than covalent bonds, meaning it takes less energy to break an ionic
bond compared with a covalent one.
16 Buffers absorb the free hydrogen ions and hydroxide ions that result from chemical
reactions. Because they can bond these ions, they prevent increases or decreases in pH.
An example of a buffer system is the bicarbonate system in the human body. This system
is able to absorb hydrogen and hydroxide ions to prevent changes in pH and keep cells
functioning properly.
18 Carbon is unique and found in all living things because it can form up to four covalent
bonds between atoms or molecules. These can be nonpolar or polar covalent bonds,
and they allow for the formation of long chains ofcarbon molecules that combine to form
proteins and DNA.
Chapter 3
1 Figure 3.5 Glucose and galactose are aldoses. Fructose is a ketose.
3 Figure 3.33 Adenine is larger than cytosine and will not be able to base pair properly
with the guanine on the opposing strand. This will cause the DNA to bulge. DNA repair
enzymes may recognize the bulge and replace the incorrect nucleotide.
4 C
6 A
8 D
10 B
12 D
14 C
3 | P a g e16 B
18 C
20 C
21 Biological macromolecules are organic because they contain carbon.
23 Amino acids can be linked into long chains through condensation reactions. One of the
hydrogen atoms bonded to the nitrogen atom of an amino acid reacts with the –OH group
attached to the terminal carbon on another amino acid. Since both ends of the molecule
can participate in condensation reactions, peptide bonds can be made in both
directions to create a long amino acid chain.
25 The β 1-4 glycosidic linkage in cellulose cannot be broken down by human digestive
enzymes. Herbivores such as cows, koalas, and buffalos are able to digest grass that is
rich in cellulose and use it as a food source because bacteria and protists in their
digestive systems, especially in the rumen, secrete the enzyme cellulase. Cellulases can
break down cellulose into glucose monomers that can be used as an energy source by
the animal.
27 Fat serves as a valuable way for animals to store energy. It can also provide insulation.
Waxes can protect plant leaves and mammalian fur from getting wet. Phospholipids and
steroids are important components of animal cell membranes, as well as plant, fungal,
and bacterial membranes.
29 Fats have a higher energy density than carbohydrates (averaging 9kcal/gram versus
4.3kcal/gram respectively). Thus, on a per gram basis, more energy can be stored in fats
than can be stored in carbohydrates. Additionally, fats are packaged into spherical
globules to minimize interactions with the water-based plasma membrane, while
glycogen is a large branched carbohydrate that cannot be compacted for storage.
31 A change in gene sequence can lead to a different amino acid being added to a
polypeptide chain instead of the normal one. This causes a change in protein structure
and function. For example, in sickle cell anemia, the hemoglobin β chain has a single
amino acid substitution—the amino acid glutamic acid in position six is substituted by
valine. Because of this change, hemoglobin molecules form aggregates, and the disc-
shaped red blood cellsassume a crescent shape, which results in serious health problems.
33 The protein must form a channel in the plasma membrane that allows water into the
cell since water cannot cross the plasma membrane by itself. Since aquaporins are
embedded in the plasma membrane and connect with both the intracellular and
extracellular spaces, it must be amphipathic like the plasma membrane. The top and
bottom of the protein must contain charged or polar amino acids (hydrophilic) to interact
with the aqueous environments. The exterior transmembrane region must contain non-
polar amino acids (hydrophobic) that can interact with the phospholipid tail. However,
the inside of this channel must contain hydrophilic amino acids since they will interact
with the traveling water molecules.
4 | P a g e35 The four types of RNA are messenger RNA, ribosomal RNA, transfer RNA, and
microRNA. Messenger RNA carries the information from the DNA that controls all cellular
activities. The mRNA binds to the ribosomes that are constructed of proteins and rRNA,
and tRNA transfers the correct amino acid to the site of protein synthesis. microRNA
regulates the availability of mRNA for translation.
Chapter 4
1 Figure 4.7 Substances can diffuse more quickly through small cells. Small cells have no
need for organelles and therefore do not need to expend energy getting substances across
organelle membranes. Large cells have organelles that can separate cellular processes,
enabling them to build molecules that are more complex.
3 Figure 4.18 It would end up on the outside. After the vesicle passes through the Golgi
apparatus and fuses with the plasma membrane, it turns inside out.
4 C
6 D
8 D
10 B
12 D
14 A
16 C
18 D
20 D
22 C
24 D
25 A light microscope would be ideal when viewing a small living organism, especially
when the cell has been stained to reveal details.
27 A transmission electron microscope would be ideal for viewing the cell’s internal
structures, because many of the internal structures have membranes that are not visible
by the light microscope.
29 The cell theory states: All living things are made of cells.;Cells are the most basic unit
of life.;New cells arise from existing cells. All humans are multicellular organisms whose
smallest building blocks are cells. Adult humans begin with the fusion of a male gamete
cell with a female gamete cell to form a fertilized egg (single cell). That cell then divides
into two cells, which each divides into two more cells, and so forth until all the cells of a
human embryo are made. As the embryo passes through all the developmental stages to
make an adult human,the cells that are added arise from division of existing cells.
5 | P a g e31 Some microbes are beneficial. For instance, E. coli bacteria populate the human
gut and help break down fiber in the diet. Some foods such as yogurt are formed by
bacteria.
33 Both are similar in that they are enveloped in a double membrane, both have an
intermembrane space, and both make ATP. Both mitochondria and chloroplasts have
DNA, and mitochondria have inner folds called cristae and a matrix, while chloroplasts
have chlorophyll and accessorypigments in the thylakoids that form stacks (grana) and a
stroma.
35 “Form follows function” refers to the idea that the function of a body part dictates the
form of that body part. As an example, compare your arm to a bat’s wing. While the
bones of the two
correspond, the parts serve different functions in each organism and their forms have
adapted to follow that function.
37 Centrioles and flagella are alike in that they are made up of microtubules. In
centrioles, two rings of nine microtubule “triplets” are arranged at right angles to one
another. This arrangementdoes not occur in flagella.
39 A macrophage engulfs a pathogen by rearranging its actin microfilaments to bend the
plasma membrane around the pathogen. Once the pathogen is sealed in an endosome
inside the macrophage, the vesicle is walked along microtubules until it combines with a
lysosome todigest the pathogen.
41 They differ because plant cell walls are rigid. Plasmodesmata, which a plant cell needs
for transportation and communication, are able to allow movement of really large
molecules. Gap junctions are necessary in animal cells for transportation and
communication.
43 E. coli infections generally cause food poisoning, meaning that the invading bacteria
cross from the lumen of the gut into the rest of the body. Tight junctions hold the
epithelial layer that lines the digestive tract together so that the material that crosses into
the body is tightly regulated. One way E. coli can avoid this regulation is to destroy the
tight junctions so that it can enter the body between the epithelial cells, rather than
having to go through the cells.
Chapter 5
1 Figure 5.12 No, it must have been hypotonic as a hypotonic solution would cause
water toenter the cells, thereby
making them burst.
3 Figure 5.19 A decrease in pH means an increase in positively charged H+ ions, and an
increase in the electrical gradient across the membrane. The transport of amino acids into
the cell will increase.
4 A
6 | P a g e6 A
8 C
10 A
12 D
14 D
16 B
18 C
20 B
21 The fluid characteristic of the cell membrane allows greater flexibility to
the cell than it would if the membrane were rigid. It also allows the motion of membrane
components, required for some types of membrane transport.
23 Peripheral proteins can bind to other molecules in the extracellular space. However,
they cannot directly transmit a signal to the inside of the cell since they do not have a
transmembrane domain (region that goes through the plasma membrane to the inside of
the cell). They must associate with integral membrane proteins in order to pass the signal
to the inside of the cell.
25 Water moves through a membrane in osmosis because there is a concentration
gradient across the membrane of solute and solvent. The solute cannot effectively move
to balance the concentration on both sides of the membrane, so water moves to achieve
this balance.
27 Decreasing temperature will decrease the kinetic energy in the system. A lower
temperature means less energy in the molecules, so they will move at a slower speed.
Lowering temperature also decreases the kinetic energy of the molecules in the plasma
membrane, compressing them together. This increases the density of the plasma
membrane, which slows diffusion into the cell.
29 The cell harvests energy from ATP produced by its own metabolism to power active
transportprocesses, such as the activity of pumps.
31 Intestinal epithelial cells use active transport to fulfill their specific role as the cells that
transfer
glucose from the digested food to the bloodstream. Intestinal cells are exposed to an
environment with fluctuating glucose levels. Immediately after eating, glucose in the gut
lumen will be high, and could accumulate in intestinal cells by diffusion. However, when
the gut lumen is empty, glucose levels are higher in the intestinal cells. If glucose moved
by facilitated diffusion, this would cause glucose to flow back out of the intestinal cells
and into the gut. Active transport proteins ensure that glucose moves into the intestinal
cells, and cannot move back into the gut. It also ensures that glucose transport continues
to occur even if high levels of glucose are already present in the intestinal cells. This
7 | P a g emaximizes the amount of energy the body can harvest from food.
33 The proteins allow a cell to select what compound will be transported, meeting the
needs of the cell and not bringing in anything else.
Chapter 6
1 Figure 6.8 A compost pile decomposing is an exergonic process; enthalpy increases
(energy is released) and entropy increases (large molecules are broken down into
smaller ones). A baby developing from a fertilized egg is an endergonic process; enthalpy
decreases (energy is absorbed) and entropy decreases. Sand art being destroyed is an
exergonic process; there is no change in enthalpy, but entropy increases. A ball rolling
downhill is an exergonic process; enthalpy decreases (energy is released), but there is no
change in entropy.
3 Figure 6.14 Three sodium ions could be moved by the hydrolysis of one ATP molecule.
The
∆G of the coupled reaction must be negative. Movement of three sodium ions across the
membrane will take 6.3 kcal of energy (2.1 kcal × 3 Na+ ions = 6.3 kcal). Hydrolysis of
ATP provides 7.3 kcal of energy, more than enough to power this reaction. Movement of
four sodium ions across the membrane, however, would require 8.4 kcal of energy, more
than one ATP molecule can provide.
4 C
6 C
8 B
10A
12 A
14 C
16 Physical exercise involves both anabolic and catabolic processes. Body cells break
down sugars to provide ATP to do the work necessary for exercise, such as muscle
contractions. This is catabolism. Muscle cells also must repair muscle tissue damaged by
exercise by building newmuscle. This is anabolism.
18 A spontaneous reaction is one that has a negative ∆G and thus releases energy.
However, a spontaneous reaction need not occur quickly or suddenly like an
instantaneous reaction. It may occur over long periods due to a large energy of activation,
which prevents the reaction from occurring quickly.
20 The ant farm had lower entropy before the earthquake because it was a highly
ordered system. After the earthquake, the system became much more disordered and had
higher entropy.
22 The activation energy for hydrolysis is very low. Not only is ATP hydrolysis an
8 | P a g eexergonic process with a large −∆G, but ATP is also a very unstable molecule that rapidly
breaks down into ADP + Pi if not utilized quickly. Thissuggests a very low EA since it
hydrolyzes so quickly.
24 Feedback inhibition allows cells to control the amounts of metabolic products
produced. If there is too much of a particular product relative to the cell’s needs, feedback
inhibition effectively causes the cell to decrease production of that particular product. In
general, this reduces the production of superfluous products and conserves energy,
maximizing energy efficiency.
Chapter 7
1 Figure 7.11 After DNP poisoning, the electron transport chain can no longer form a
proton gradient, and ATP synthase can no longer make ATP. DNP is an effective diet drug
because it uncouples ATP synthesis; in other words, after taking it, a person obtains less
energy out of the food he or she eats. Interestingly, one of the worst side effects of this
drug is hyperthermia, or overheating of the body. Since ATP cannot be formed, the energy
from electron transport is lost as heat.
3 Figure 7.14 The illness is caused by lactate accumulation. Lactate levels rise after
exercise, making the symptoms worse. Milk sickness is rare today but was common in the
midwestern United States in the early1800s.
4 A
6 C
8 B
10 C
12 C
14 A
16 A
18 ATP provides the cell with a way to handle energy in an efficient manner. The
molecule can be charged, stored, and used as needed. Moreover, the energy from
hydrolyzing ATP is delivered as a consistent amount. Harvesting energy from the bonds
of several different compounds would result in energy deliveries of different quantities.
20 All cells must consume energy to carry out basic functions, such as pumping ions
across membranes. A red blood cell would lose its membrane potential if glycolysis were
blocked, andit would eventually die.
22 Q and cytochrome c are transport molecules. Their function does not result directly in
ATP synthesis in that they are not pumps. Moreover, Q is the only component of the
electron transport chain that is not a protein. Ubiquinone and cytochrome c are small,
mobile electron carriers, whereas the other components of the electron transport chain
are large complexes anchored in the inner mitochondrial membrane.
9 | P a g e24 Fermentation uses glycolysis only. Anaerobic respiration uses all three parts of cellular respiration, including the parts in the mitochondria like the citric acid cycle and electron transport;it also uses a different final [Show Less]