Pdbio 120 Final

Front 1

Which of the following does not have a membrane?

Back 1

a. nucleus
b. ribosome
c. mitochondria
d. endoplasmic reticulum

Hint 1

b. A ribosome does not have a membrane.

Front 2

Which of the following best exemplifies the process aspect of cell theory?

Back 2

a. Archaea have a single, circular chromosome in the cytoplasm of a membrane-bound cell.
b. Saccharomyces cerevisiae, brewer’s yeast, reproduction involves budding, followed by
mitotic division and migration of the daughter nucleus to the “bud”, followed by pinching off
of the bud.
c. Most of the visible growth in a corn plant is through cell elongation by water uptake in internode
cells.
d. Human erythrocytes (red blood cells) are enucleate, meaning they lack a true nucleus.
e. None of the above.

Hint 2

b. Saccharomyces cerevisiae, brewer’s yeast, reproduction involves budding, followed by
mitotic division and migration of the daughter nucleus to the “bud”, followed by pinching off
of the bud.

Front 3

What is the significance of the phosphate group in a phospholipid?

Back 3

A) It is highly hydrophilic.
B) It lowers the molecule's potential energy.
C) It gives the molecule a bend or "kink."
D) It phosphorylates the molecule, changing its conformation.

Hint 3

A. It is highly hydrophilic

Front 4

What do phospholipids and triglycerides have in common?

Back 4

A) They both contain serine or some other organic compound.
B) They both have a phosphate.
C) They both have a glycerol backbone.
D) They both have three fatty acids.

Hint 4

C) They both have a glycerol backbone.

Front 5

DNA is described as being far less capable of catalytic activity than RNA or protein. This can be attributed to which of the following reasons?

Back 5

A. Lack of the –OH group on each #2 carbon of the deoxyribose sugar decreases its
reactivity.
B. The double-strand nature of the molecule increases its stability.
C. The hydrophobic interior of DNA is difficult to disrupt due to "hydrophobic
bonding" between the nonpolar nitrogenous bases that orient toward the center.
D. All of the above.
E. None of the above.

Hint 5

All of the freaking above.

Front 6

What is the difference between a ribonucleotide and a deoxyribonucleotide?

Back 6

A) ribonucleotides have a hydrogen atom on the 1' carbon of their sugar subunit.
B) ribonucleotides contain a sugar with five carbon atoms.
C) ribonucleotides contain a phosphate group.
D) ribonucleotides have a hydroxyl group on the 2' carbon of their sugar subunit.

Hint 6

D) ribonucleotides have a hydroxyl group on the 2' carbon of their sugar subunit.

Front 7

The chemiosmotic hypothesis claims:

Back 7

a. that substrate-level phosphorylation occurs in the electron transport chain
b. that substrate-level phosphorylation occurs in glycolysis and the Krebs cycle
c. that the electron transport chain is located in the inner membrane of mitochondria
d. that electron transport chains generate ATP indirectly, by proton pumping and
creation of a proton-motive force.

Hint 7

d. that electron transport chains generate ATP indirectly, by proton pumping and
creation of a proton-motive force.

Front 8

The basic task of the fermentation pathway is:

Back 8

a. to generate NADH from NAD, so electrons can be donated to the electron transport
chain
b. to synthesize pyruvate from lactate
c. to generate NAD+ from NADH, so glycolysis can continue
d. to synthesize electron acceptors, so aerobic respiration can continue

Hint 8

c. to generate NAD from NADH, so glycolysis can continue

Front 9

What is a difference between chlorophyll a and chlorophyll b?

Back 9

A) Chlorophyll a is a pigment, and chlorophyll b is the enzyme that transfers excited
electrons from chlorophyll a to electron carriers of the thylakoid membrane.
B) Chlorophyll a absorbs yellow light, and chlorophyll b absorbs green.
C) Chlorophyll a contains Mg++ in a ring structure, whereas chlorophyll b contains iron.
D) Chlorophyll a and b absorb light energy at slightly different wavelengths.

Hint 9

D) Chlorophyll a and b absorb light energy at slightly different wavelengths.

Front 10

If pigments from a particular species of plant are extracted and subjected to paper
chromatography, which of the following is the most believable result?

Back 10

A) Paper chromatography for the plant would isolate a single band of pigment that is
characteristic of the particular plant.
B) Paper chromatography would separate the pigments from a particular plant into
several bands.
C) The single band of pigment that is isolated is always some shade of green.
D) Paper chromatography isolates only the pigments that reflect green light.

Hint 10

B) Paper chromatography would separate the pigments from a particular plant into
several bands.

Front 11

The absorption spectrum of a plant shows what wavelengths of light the plant
absorbs. The absorption spectrum depends on ________.

Back 11

A) the wavelengths of light that hit the plant.
B) wavelengths of light that are transmitted by the plant.
C) wavelengths of light to which the plant's pigments respond.
D) the thickness of the plant's leaves.

Hint 11

C) wavelengths of light to which the plant's pigments respond.

Front 12

In autumn, the leaves of deciduous trees change colors. This is because the
chlorophyll is degraded, and ________.

Back 12

A) the carotenoids and other pigments are still present in the leaves.
B) degraded chlorophyll becomes a pigment with different colors.
C) water supply to the leaves has been reduced.
D) the cells of the leaves begin to die.

Hint 12

A) the carotenoids and other pigments are still present in the leaves.

Front 13

As electrons are passed through the system of electron carriers associated with
photosystem II, they lose energy. What happens to this energy?

Back 13

A) It excites electrons of the reaction center of photosystem I.
B) It is lost as heat.
C) It is used to establish and maintain a proton gradient.
D) It is used to phosphorylate NAD+ to NADPH, the molecule that accepts electrons
from photosystem I.

Hint 13

C) It is used to establish and maintain a proton gradient.

Front 14

Plastoquinone (PQ), an electron carrier of small molecular weight, is found in the
electron transport chain associated with photosystem II. If PQ is not directly anchored to
other membrane or cytoplasmic structures, it is probably ________.

Back 14

A) mobile in the thylakoid membrane.
B) lipid soluble.
C) a molecule that serves as a shuttle between the electron transport chain and ATP
synthase.
D) Both A and B are correct.

Hint 14

D) Both A and B are correct.

Front 15

The electrons of photosystem II are excited and transferred to electron carriers. From
which molecule or structure do the photosystem II replacement electrons come?

Back 15

A) the electron carrier, plastocyanin
B) photosystem I
C) water
D) oxygen

Hint 15

C) water

Front 16

Data suggest that rubisco (ribulose-1,5-bisphosphate carboxylase) makes up 10% of
the total protein found in spinach leaves. Relatively speaking, that is a huge amount of
rubisco per total protein in the leaves. However, research elucidating the structure of
rubisco shows that it has four active sites. Why, with four active sites, might there be
such a large concentration of rubisco in plant matter?

Back 16

A) All heterotrophic organisms depend on plants, either directly or indirectly, for their
food supply.
B) Rubisco is a very slow enzyme; what it lacks in speed, it makes up in numbers.
C) Rubisco catalyzes four of the six reactions found in the Calvin cycle.
D) Three of the four active sites bind carbon dioxide; only one binds ribulose-1,5-
bisphosphate.

Hint 16

B) Rubisco is a very slow enzyme; what it lacks in speed, it makes up in numbers.

Front 17

When does crossing over occur?

Back 17

A) interphase
B) prophase I
C) metaphase I
D) prophase II
E) metaphase II

Hint 17

B) prophase I

Front 18

Which of the following is not a purpose of meiosis?

Back 18

A) to produce gametes
B) to reduce chromosome number
C) to prepare cells for fertilization
D) to produce daughter cells identical to the original

Hint 18

D) to produce daughter cells identical to the original

Front 19

A tetrad consists of

Back 19

A) four non-homologous chromosomes.
B) four non-homologous chromatids.
C) two homologous chromosomes, each with a sister chromatid.
D) four homologous pairs of chromosomes.

Hint 19

C) two homologous chromosomes, each with a sister chromatid.