Chapter 5

Question 1

what is the first law of thermodynamics?

Answer 1

energy cannot be created nor destroyed

Question 2

what is the second law of thermodynamics?

Answer 2

entropy increases spontaneously and energy transfer is never completely efficient

Question 3

what is entropy?

Answer 3

the measure of disorder of a system

Question 4

why do cells need energy?

Answer 4

to do work

Question 5

what is the ultimate source of energy for living organisms?

Answer 5

the sun

Question 6

energy from the sun flows in what direction through the food chain?

Answer 6

sun > producers > consumers

Question 7

in what form does energy escape with each energy transfer?

Answer 7

heat (dispersed heat is not a useful form of energy)

Question 8

what does a metabolic reaction involve?

Answer 8

reactants, intermediates, products

Question 9

what are the molecules involved with metabolism?

Answer 9

enzymes, energy carriers, cofactors, transport proteins

Question 10

which reactions require energy/ATP?

Answer 10

endergonic

Question 11

which reactions release energy/ATP?

Answer 11

exergonic

Question 12

when is energy released?

Answer 12

when ATP gives up a phosphate group

Question 13

when ATP gives up a phosphate group, it becomes ____

Answer 13

ADP (which has less potential energy than ATP)

Question 14

what is phosphorylation?

Answer 14

the transfer of energy when a phosphate group is transferred to another molecule

Question 15

a cell requires ____ to accumulate ATP by regenerating ADP

Answer 15

energy

Question 16

without ____, biochemical reactions would proceed very slowly

Answer 16

enzymes

Question 17

how do enzymes speed up reactions?

Answer 17

they lower the activation energy of reactions

Question 18

what are the features of enzymes?

Answer 18

• speed up reactions, DO NOT CAUSE reactions
• are not used up in reactions
• work for both forward and backward reactions
• easily recognize and bind to certain substances

Question 19

where do certain substrates bind to proceed with reactions?

Answer 19

active sites of enzymes (substrate-specific)

Question 20

what does enzyme activity depend on?

Answer 20

temperature, pH, salt, allosteric regulators, coenzymes, cofactors

Question 21

when do enzymes become denatures?

Answer 21

in extreme pH and heat

Question 22

what is an allosteric site?

Answer 22

a region of the enzyme other than the active site; alters the enzyme shape

Question 23

cofactors, or enzyme helpers, include ____ and ____

Answer 23

coenzymes, metal ions

Question 24

coenzymes include…

Answer 24

NAP+, NADPH+, NADPH, FAD

Question 25

what do coenzymes transport?

Answer 25

electrons and protons

Question 26

what is feedback inhibition?

Answer 26

where the end product in a series of enzymatic reactions inhibits the first enzyme in the series

Question 27

almost all ____ are coenzymes, or precursors of them

Answer 27

vitamins

Question 28

unlike enzymes, coenzymes can become ____ during use

Answer 28

altered

Question 29

what are the two types of metabolic pathways?

Answer 29

anabolic and catabolic

Question 30

which type of metabolic pathway builds up molecules (biosynthetic)?

Answer 30

anabolic

Question 31

what type of metabolic pathway breaks down molecules (degradive)?

Answer 31

catabolic

Question 32

redox reactions involving addition of electrons are ____ reactions

Answer 32

reduced

Question 33

redox reactions involving removal of electrons are ____ reactions

Answer 33

oxidized

Question 34

reduced and oxidized redox reactions are how the electron transport chain works in ____ and ____

Answer 34

cellular/aerobic respiration, photosynthesis

Question 35

cells must have a ____ to control what goes in and out of the cell

Answer 35

membrane layer

Question 36

____ are responsible for membrane activity

Answer 36

proteins

Question 37

describe the basic structure of all cell membranes

Answer 37

lipid bilayer with many embedded proteins

Question 38

in the lipid bilayer, the outer portion of phospholipids is ____

Answer 38

hydrophobic

Question 39

in the lipid bilayer, the inner portion of phospholipids is ____

Answer 39

hydrophilic

Question 40

the membrane is a mosaic of...

Answer 40

phospholipids, glycolipids, sterols, proteins

Question 41

what are the different types of membrane proteins?

Answer 41

active transport, passive transport, receptive, recognition

Question 42

when does transport require energy?

Answer 42

sometimes if the substance is moving against a concentration gradient

Question 43

____ is when ions or molecules move away from a concentration gradient

Answer 43

diffusion

Question 44

the cell membrane is not selective against the movement of...

Answer 44

oxygen, carbon dioxide, nonpolar small molecules, water

Question 45

the cell membrane is selective against the movement of...

Answer 45

large, organic molecules (such as glucose and ions such as H, Cl, Na, K, Ca)

Question 46

what do diffusion rates depend on?

Answer 46

temperature, size of concentration gradient, size of molecules

Question 47

diffusion is higher in ____ temperature, ____ concentration gradient, and ____ molecule size

Answer 47

increased, steeper, small

Question 48

moving passively from areas of high concentration to low concentration

Answer 48

osmosis

Question 49

a solution that has higher concentration of solutes than surrounding concentration

Answer 49

hypertonic

Question 50

a solution that has a lower concentration of solutes than surrounding concentration

Answer 50

hypotonic

Question 51

a solution that has the same amount of solutes than the surrounding concentration

Answer 51

isotonic

Question 52

pressure exerted by fluid on the walls of a cell

Answer 52

hydrostatic pressure

Question 53

cell contents exit the cell by ____

Answer 53

exocytosis

Question 54

cell contents enter the cell by ____

Answer 54

endocytosis

Question 55

name the three types of endocytosis

Answer 55

receptor-mediated, phagocytosis, bulk-phase

Question 56

type of endocytosis where a product binds to receptors on the plasma membrane, where a vesicle is formed

Answer 56

receptor-mediated

Question 57

type of endocytosis where microorganisms or cellular debris are engulfed

Answer 57

phagocytosis

Question 58

type of endocytosis where a vesicle forms around a small volume of extracellular fluid regardless of substance

Answer 58

bulk-phase