Chapter 6

Question 1

5 major classes of proteins:

Answer 1

Metabolic enzymes

Structural proteins

Transport proteins

Cell signaling proteins

Genomic caretaker proteins

Question 2

metabolic enzymes:

Answer 2

catalyze chemical reactions involved in energy conversion in cells

Question 3

structural proteins:

Answer 3

provide an intracellular and extracellular network of protein cables and scaffolds

Question 4

transport proteins:

Answer 4

passively or actively move small molecules across otherwise impermeable cellular membranes

Question 5

cell signaling proteins:

Answer 5

transmit extracellular signals into the cell and between cells

Question 6

genomic caretaker proteins:

Answer 6

maintain and regulate genetic information in cells.

Question 7

Enzymes do the following:

Answer 7

Lower activation energy

Increase rate of product formation

Does not alter equilibrium concentration of
products and reactants

Question 8

_______ are responsible for synthesis and degradation of macromolecules

Answer 8

Metabolic enzymes

Question 9

the most abundant proteins in living

organisms

Answer 9

Structural proteins

Question 10

Structural protein ex:

Answer 10

Actin

Tubulin

Collagen

Question 11

Two basic classes of transporter protein:

Answer 11

Passive

Active

Question 12

Passive Transporter Proteins

Answer 12

Porins
Transport small molecules such as water and glycerol

Ion channels
Transport charged ions

Question 13

Active Transport Proteins energy comes from:

Answer 13

ATP hydrolysis

Ionic gradient

Question 14

Cell Signaling Proteins ex:

Answer 14

Membrane receptors

Nuclear receptors

Intracellular signaling proteins

Question 15

Membrane receptor examples:

Answer 15

G-protein coupled receptors (GPCR)

Receptor tyrosine kinases

Question 16

Genomic Caretaker Proteins Includes proteins involved in:

Answer 16

DNA replication, repair, and recombination and gene expression

Question 17

DNA polymerase

Answer 17

uses DNA template to guide synthesis of nascent DNA strands

Question 18

DNA ligase

Answer 18

seals newly formed DNA

Question 19

Topoisomerase

Answer 19

unwinds DNA

Question 20

DNA primase

Answer 20

assist DNA polymerase by preparing the DNA template for replication

Question 21

Photolyase

Answer 21

repairs thymine dimers that are formed as a result of UV radiation

Question 22

Enzyme aiding in gene expression

Answer 22

RNA Polymerase

Question 23

Myoglobin

Answer 23

Concentrated in muscle

Storage depot for O2

Question 24

Hemoglobin

Answer 24

Major protein in blood cells

35% of dry weight of red blood cells

Transports O2 from lungs and tissues through the
circulatory system

Question 25

Myoglobin structure:

Answer 25

Single polypeptide chain with one heme group

Question 26

Hemoglobin structure:

Answer 26

Four polypeptides with two alpha and two beta subunits

Question 27

Only about _____ of the residues are identical, but have similar tertiary structures

Answer 27

18%

Myoglobin and hemoglobin

Question 28

Myoglobin and hemoglobin both ______ bind to _____

Answer 28

reversibly

O2