Biochem Test 3

Front 1

D-Glyceraldehyde

Back 1

Front 2

D-Ribose

Back 2

Front 3

D-Glucose

Back 3

Front 4

D-Mannose

Back 4

Front 5

D-Galactose

Back 5

Front 6

D-Fructose

Back 6

Front 7

β anomer of D-glucopyranose

Back 7

Front 8

β anomer of D-fructofuranose

Back 8

Front 9

α anomer of D-glucopyranose

Back 9

Front 10

α anomer of D-fructofuranose

Back 10

Front 11

How many steroisomers are possible for a ketopentose such as a ribulose?

Back 11

4

Front 12

Which structure(s) shown in the figure above represent reducing sugars?

Back 12

Front 13

Which structure shown in the figure above is a ketohexose?

Back 13

Front 14

The structures shown in the figure above are represented a:

Back 14

Fischer projections

Front 15

Alcohols react with aldehydes to form:

Back 15

hemiacetals

Front 16

At equilibrium in solution, D-glucose consists of a mixture of its anomers. Which statement mostaccurately describes this solution?

Back 16

The Beta-anomer predominates over the alpha-anomer by a ratio of approximately 2:1.

Front 17

The transformation of a monosaccharide into its ______ occurs easily and does not require theassistance of a catalyst.

Back 17

anomer

Front 18

Back 18

Front 19

The figure below shows structures of several types of sugars. Which one is an alditol?

Back 19

Front 20

The bonding of alcohols to the anomeric center of a carbohydrate results in the formation of a(n) __________ bond.

Back 20

glycosidic

Front 21

Which of these polysaccharides is a branched polymer?

Back 21

amylopectin

Front 22

Chitin differs from cellulose due to

Back 22

replacement of the C2 OH group by an acetamido group.

Front 23

Which polysaccharide is found in a helically coiled conformation?

Back 23

α-amylose

Front 24

Starch is a mixture of

Back 24

alpha-amylose and amylopectin.

Front 25

Bacterial cell walls are composed of _____.

Back 25

peptidoglycans

Front 26

Which statement about N-linked glycosylation is correct?

Back 26

N-linked sugars are attached to proteins as a 14 residue oligosaccharide during translation in theendoplasmic reticulum.

Front 27

O-linked oligosaccharides are commonly attached to the —OH group of _____.

Back 27

threonine

Front 28

Glycoproteins

Back 28

exhibit microheterogeneity.

Front 29

Which of the following statements are true regarding fatty acids?

Back 29

IV. In higher plants and animals, C16 and C18 species predominate.

II. Synthesis of fatty acids occurs in 2 carbon units.

Front 30

Rank the melting points of the following fatty acids from highest to lowest: (1) cis-oleic(18:1) (2) trans-oleic (18:1) (3) linoleic (18:2) (4) steraic (18:0) (5) palmitic (16:0)

Back 30

4 > 5 > 2 > 1 > 3

Front 31

Which of the following is true about membrane proteins embedded within the lipid bilayer?

Back 31

As the temperature decreases, lateral diffusion of the membrane protein is restricted in bilayers withlipids which have longer chain fatty acids and fewer double bonds.

Front 32

The protein that forms a transmembrane pore that allows growing polypeptides to pass through theRER membrane is called the ______.

Back 32

translocon

Front 33

Unsaturated fatty acids:

Back 33

A) are commonly found in plants and animalsB) usually contain a double bond with cis stereochemistryC) sometimes contain multiple double bondsD) have lower melting points than the analogous saturated fatty acids.

Front 34

Adipocytes

Back 34

Are specialized cells for the synthesis of triglycerides.

Front 35

While fatty acids are most often formed by the condensation of __-carbon units, isoprenoids areassembled from __-carbon units.

Back 35

2, 5

Front 36

Which of the following amino acids from an integral membrane protein would likely contact themembrane?

Back 36

Ala

Front 37

Transmembrane proteins

Back 37

I. are predominantly constructed of a single hydrophobic α-helix.

III. are sometimes constructed from β-barrels with hydrophobic interiors and exteriors.

IV. may have transmembrane helices identified by the free energy of transfer to water.

Front 38

The _________ model describes the cell membrane as an assortment of integral proteins suspendedfreely in a lipid bilayer.

Back 38

fluid mosaic

Front 39

The _________, which is found embedded in the endoplasmic reticulum, is a _______ protein.

Back 39

translocon...transmembrane pore

Front 40

Glycosphingolipids with several attached carbohydrates (including at least one sialic acid) are called

Back 40

gangliosides

Front 41

Which of the following structures correctly represents a glycerophospholipid?

Back 41

Front 42

Back 42

Location A

Front 43

Back 43

Exchange for a lipid in position A for a lipid in position B.

Front 44

Which of the following is an example of nonmediated transport?

Back 44

simple diffusion

Front 45

Which statement does not describe the transport of ions by valinomycin?

Back 45

Transport may be active or passive.

Front 46

Which of the following channels open in response to an extracellular stimulus such as a neurotransmitter?

Back 46

ligand-gated channels

Front 47

Which of the following is not an example of a passive-mediated transporter?

Back 47

lactose permease

Front 48

Which statement about aquaporins is false?

Back 48

They transport water and hydronium ions efficiently.

Front 49

Which of the following correctly rank the steps in erythrocyte glucose transport by GLUT1? I. Glucose binding results in a conformational change, opening the binding site on theof the membrane II. Glucose binds to the transporter on one side of the membraneIII. The transporter reverts to initial conformationIV. The glucose disassociates opposite side

Back 49

II, I, IV, III

Front 50

Lactose permease uses a ___________ gradient generated ______ to cotransport lactose across the cellmembrane.

Back 50

proton; via oxidative metabolism

Front 51

The Kv channel is transiently closed by ___________.

Back 51

a spherical globular segment on the N-terminus

Front 52

In the intestinal epithelium, glucose enters the cell in symport with ______, which is subsequently ejectedby ________.

Back 52

Na+; the Na+/K+ pump

Front 53

A pore that simultaneously transports two different molecules in different directions is called

Back 53

an antiport.

Front 54

The greater the magnitude of the concentration gradient:

Back 54

the more rapid the rate of diffusion.

Front 55

The E. coli maltoporin utilizes what has been termed the greasy slide. Which of the following statementsbest describe the function of the greasy slide?

Back 55

Hydroxyl groups on glucose hydrogen bond with polar and charged side chains lining the channel, thusresulting in a series of interactions mimicking a screw-like pathway.

Front 56

What type of gradient is required for efficient lactose transport in E. coli?

Back 56

proton