Unit 2

Question 1

The most abundant molecules in a cell are…

Answer 1

Water

Question 2

Water is an ideal solvent in cells because it…

Answer 2

Is a polar molecule that can form hydrogen bonds with itself and other polar molecules

Question 3

In polysaccharides, sugars are linked together by means of … bonds.

Answer 3

Glycosidic

Question 4

Sugars can cyclize if they contain … or more carbons.

Answer 4

5

Question 5

A few sugars joined together are called a(n)…

Answer 5

Oligosaccaride

Question 6

The major bonds in glycogen are… glycosidic bonds.

Answer 6

a 1-4 glycosidic bonds

Question 7

Cell membranes are composed principally of…

Answer 7

Lipids

Question 8

Lipids play a major role in cells as…

Answer 8

1. A form of energy
2. Components of cell membranes
3. Part of the cell signalling function

Question 9

Fatty acids are stored in fat droplets in the form of…

Answer 9

Triacylglycerols

Question 10

Which of the following store the most chemical energy per unit weight?

Answer 10

Lipids

Question 11

Sphingomyelin contains two hydrocarbon chains linked to…

Answer 11

Serine

Question 12

An amphipathic molecule is…

Answer 12

Part water soluble and part water insoluble

Question 13

Steroid hormones are derivatives of…

Answer 13

Cholesterol

Question 14

RNA in cells can serve as a…

Answer 14

1. regulator of gene expression
2. carrier of information from the nucleus to the cytoplasm
3. catalysts or enzymes

Question 15

The pyrimidine bases in DNA are…

Answer 15

Cytosine and Thymidine

Question 16

Complementary base pairs form … bonds to direct replication of DNA.

Answer 16

Hydrogen

Question 17

DNA differs from RNA in all of the following ways except…

Answer 17

DNA can form hydrogen bonds with complementary sequences

Question 18

Nucleotides have an important function in cells as…

Answer 18

1. Building blocks for nucleic acids
2. carriers of chemical energy
3. intracellular signal molecules
4. carriers of reactive groups

Question 19

In DNA which bases pair with each other…

Answer 19

G pairs with C and A pairs with T

Question 20

Polymerisation of nucleotides to form nucleic acids involves the formation of… bonds?

Answer 20

Phosphodiester

Question 21

Serine, Threonine, Asparagine and Glutamine are all what type of amino acids?

Answer 21

Polar

Question 22

Which of the following is not a basic amino acid?

Answer 22

Glutamine

Question 23

Proteins are polymers of how many different amino acids?

Answer 23

20

Question 24

In the primary structure of a protein, amino acids are joined together by … bond?

Answer 24

Peptide

Question 25

The scientist who first determined the complete amino acid sequence of a protein (insulin) was?

Answer 25

Frederick Sanger

Question 26

Anfinsen's experiments on denatured ribonuclease showed that...

Answer 26

Proteins can renature and regain their enzymatic activity

Question 27

Which of the following is/are involved in forming the tertiary structures of proteins?

Answer 27

1. H bonds 2. Hydrophobic interactions 3. ionic bonds

Question 28

The interaction of the alpha and beta subunits to form a hemoglobin molecule is an example of ...structure

Answer 28

Quaternary

Question 29

The most common molecules in cellular membranes are the...

Answer 29

phospholipids

Question 30

The unique properties of different membranes are primarily a function of their...

Answer 30

proteins

Question 31

Fluidity of a membrane depends on the...

Answer 31

1. length of the phospholipid fatty acid chains 2. temperature 3. number of double bonds in the fatty acid chains 4. cholestrol content

Question 32

Cholesterol affects the fluidity of membranes by...

Answer 32

decreasing membrane fluidity at high temperatures and increasing membrane fluidity at low temperature

Question 33

What mole percent of cholesterol in found in the plasma membrane of E.Coli and related bacteria?

Answer 33

0%

Question 34

Phospholipids in a membrane commonly...

Answer 34

1. move laterally in the plane of the bilayer | 2. rotate within the bilayer

Question 35

The role of double bonds in the fatty acid tails of membrane phospholipids is to...

Answer 35

increase membrane fluidity

Question 36

The currently accepted model of membrane structure is called the .......model

Answer 36

fluid mosaic

Question 37

The fluid mosaic model of cell membranes was proposed by...

Answer 37

Singer and Nicolson

Question 38

Intergral membrane proteins are those that...

Answer 38

are directly associated with membrane lipids

Question 39

Transmembrane proteins that span the membrane are...

Answer 39

integral membrane proteins

Question 40

Transmembrane proteins can span the lipid bilayer as...

Answer 40

1. alpha helices | 2. ß-barrels

Question 41

Membrane proteins can be anchored to the cytosolic face of the plasma membrane by...

Answer 41

prenyl groups

Question 42

Lipid bilayers are permeable only to molecules that are .......... and ..........

Answer 42

small; uncharged

Question 43

Passive transport molecules....

Answer 43

carry small molecules across membranes

Question 44

Molecules that traverse a membrane against their concentration gradient do so by........ transport

Answer 44

active

Question 45

Channels form pores through which molecules of appropriate size and charge can cross a membrane. By contrast carrier proteins...

Answer 45

selectively bind the molecules to be transported, charge configuration, and release it on the other side

Question 46

Active transporter proteins can...

Answer 46

1. transport molecules against its concentration gradient 2. use the energy of ATP hydrolysis to undergo a configurational change 3. transport H' across a membrane against a pH gradient