BIO 240 Exam 2

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1

A small membrane vesicle containing a transmembrane protein is shown in FIgure 1. ASsume that this membrane vesicle is in the cytoplasm of a cell. When the vesicle fuses with the plasma membrane, what do you expect to happen?

The N-terminus of the protein will be intracellular

2

Ion channels are classified as membrane transport proteins. Channels discriminate by size and charge. In addition to Na+, which one of the following ions would you expect to be able to freely diffuse through the Na+ channel?

H+

3

Which type of gated ion channel open and closes using mechanical force?

stressed-gated

4

Pumps are transporters that eare able to harness energy provided by other components in the cells to drive the movement of solutes across membranes, against their concentration gradient. This type of transport is called ____.

active transport

5

An experiment plasma membrane structure/function used two different cells with fluorescently labeled integral membrane proteins is shown in Fig 2. What is the eventual outcome of the experiment 1 hour following the putting these two cells in the same petri dish?

The two cells fuse and the proteins migrate around the membrane until the proteins are evenly distributed around the cell

6

A molecule moves down its concentration gradient by ______ transport, but requires ______ transport to move up its concentration gradient. Transporter proteins and ion channels function in membrane transport by providing a _______ pathway through the membrane for specific polar solutes or inorganic ions. _________ function by binding the transported solute at a specific ligand binding site and changing conformation to transport the solute across the membrane.

Passive, active, hydrophillic, transporter proteins

7

Which of the following protein families are not involved in directing transport vesicles to the target membrane?

adaptins

8

After isolating the rough endoplasmic recticulum from the rest of the cytoplasm, you purify the RNA's attached to it. Which of the following proteins do you expect the RNA from the rough endoplasmic rectriculum to encode?

d. all
ER membrane proteins, plasma membrane proteins, soluble secreted proteins

9

What is the role of the nuclear localization sequence in a nuclear protein?

It is bound by cytoplasmic proteins that direct the nuclear protein through the nuclear pore.

10

Plasma membrane proteins are inserted into the membrane in the _____. The address information for protein sorting in a eukaryotic cell is contained in the _________ of the proteins. Proteins enter the nucleus in their _________ form. Proteins that remain in the cytosol do not contain a ________. Proteins are transported into the Golgi app via _______. The proteins transported into the endoplasmic rec by ______ are in their _______ form.

ER, N-term, fold, Signal Sequence, transport vesicles, translators, unfolded

11

Which enzyme of the citric acid cycle involved in another cycle of cellular metabolism

succinate dehydrogenase

12

When elemental sodium is adde to water, the sodium atoms ionize spontaneously. Uncharged Na becomes Na+. This means that the Na atom have been _____.

oxidized

13

During respiration, energy is retrieved from the high-energy bonds found in certain organic molecules. Which of the following, in addition to energy, are the ultimate products of respiration?

CO2, H2O

14

Oxidation is the process by which oxygen atoms are added to a target molecule. Generally, the atom that is oxidized will experience which of the following with respect to the electrons in its outer shell?

a net loss

15

Chemical reactions that lead to a release of free energy are referred to as "energetically favorable" Another common way in which thee reactions are described is _________

spontaneous

16

change G indicates the change in the standard free energy as a reactant is converted to product. Given what you know these values, which reaction below is likely the non-reversible reaction?

glucose-> Co2+H2O change G= -686 kcal/mole

17

Glycolysis is an anaerobic process see to catabolize glucose. What does it mean for this process to be anaerobic?

No oxygen is required

18

Which of the following stages in the breakdown of the piece of toast you had for breakfast generates the most ATP?

the citric acid cycle

19

The advantage to the cell of the gradual oxidation of glucose during cellular respiration compared with the combustion to CO2 and H2O in a single step is that ________

energy can be extracted in usable amounts

20

Glycolysis generates more stored energy than it expends. What is the net number of activated carrier molecules produced in this process (number and type of molecules produced mien the number of those molecules used as input)?

2 ATP, 2 NADH

21

Which of the following processes does not take place in the mitochondria?

glycogen breakdown

22

Which reaction does the enzyme phosphoglucose isomerase catalyze?

glucose 6-phosphate-> fructose 6-phosphate

23

In anaerobic conditions, brewer's yeast produces ____.

ethanol and CO2

24

What purpose does the phosphorylation of glusoce 6-phosphate by the enzyme hexokinase serve as the first step in glycol's?

It generates a high energy phosphate bond.

25

Which of the following cells rely exclusively on glycolysis to supply them with ATP?

anaerobic growing Lactoballus (yogurt bacterium)

26

Fatty acids can easily be used to generate energy for the cell. Which of the folwing fatty acids will yield the least numbers of ATP

CH3-CH2-CH2-CH2-CH2-CH2-COOH (smallest)

27

Oxidative phosphorylation is a process that occurs in the ______ of the _____. It requires an electron-transport chain that operates on the high-energy electrons taken form the activated carrier molecules. _______ that are produced by glycolysis. These electrons are transferred through a series of molecules, and the energy released during these transfers is used to generate a gradient of _______. Because their concentration is much _______ in the inter membrane space than in the mitochondrial matrix, the flow down the concentration gradient is energetically favorable and can thus be coupled to the production of ______ from ________.

Inner membrane, mitochondria, NAHD, H+, higher, ATP, ADP

28

Which of the following statements is false?
a. Electrons donated by NADH to the NADH dehydrogenase complex can pump more protons than electrons donated by FADH2 attached to succinated dehydrogenase
b. the ph in the mitochondrial membrane space is higher than in the matrix
c. e- being passed along the mitochondria inner membrane represents a series if redox reactions
d. the difference in proton concentration across the inner mitochondrial membrane represents a chemical and electrical potential that can be used perform work.

the ph in the mitochondrial membrane space is higher than in the matrix

29

The pathway for contents to move from the extracellular save to inside the cell is the ______ pathway.

endocytic

30

In which cellular location would you expect to find ribosomes translating mRNAs that encode ribosomal proteins? oi

in the cytosol

31

Stage 1 of oxidative phosphorylation requires the movement of e- along the e- transport chain. What is the final result of these e- transfers?

O2 is reduced to H2O

32

The proteins embedded in the outer membrane of the mitochondria are smaller in structure and function to those along the bacterial plasma membrane
a. true
b. flase

False

33

Where are proteins in the chlorplast synthesized?

in both the cytosol and the chloroplast

34

Most proteins destined to enter the endoplasmic reticulum

begin to cross the membrane while still being synthesized