BIO 160 Chapter 5

Question 1

What is energy?

Answer 1

The capacity to cause change

Question 2

kinetic energy

Answer 2

energy in motion

Question 3

potential energy

Answer 3

stored energy

Question 4

Conservation of Energy

Answer 4

1. energy cannot be created or destroyed

2. energy can be converted from one form to another

Question 5

entropy

Answer 5

measure of disorder or randomness in a system

Question 6

heat

Answer 6

is a type of kinetic energy and product of all energy conversions

Question 7

chemical energy

Answer 7

• arises from the arrangement of atoms and

* can be released by a chemical reaction.

Question 8

cellular respiration

Answer 8

• the energy-releasing chemical breakdown of fuel
molecules (ie glucose)
• the storage of that energy in a form the cell can use to
perform work (ie ATP)

Question 9

energy used by humans

Answer 9

• ~34% to do work

* ~66% as heat

Question 10

calorie

Answer 10

– A calorie is the amount of energy that can raise
the temperature of one gram of water by 1 ⁰C.
• Food Calories are kilocalories, equal to 1,000 calories.
• The energy of calories in food is burned off by many
activities.

Question 11

ATP

Answer 11

• acts like an energy shuttle
• stores energy obtained from food
• releases it later as needed
• consists of an organic molecule called adenosine plus a
tail of three phosphate groups and
• is broken down to ADP and a phosphate group, releasing
energy.

Question 12

phosphate transfer

Answer 12

– ATP energizes other molecules by transferring 
phosphate groups.
– This energy helps cells perform
• mechanical work,
• transport work, and
• chemical work.

Question 13

ATP cycle

Answer 13

– Cellular work spends ATP continuously.
– ATP is recycled from ADP and a phosphate group
through cellular respiration.
– A working muscle cell spends and recycles up to
10 million ATP molecules per second.

Question 14

metabolism

Answer 14

total of all chemical reactions in an organism

Question 15

activation energy

Answer 15

– Activation energy activates the reactants and
• triggers a chemical reaction.
– Enzymes reduce the amount of activation energy
required to break bonds of reactant molecules.
– Enzymes can function over and over again.
– Many enzymes are named for their substrates, but
with an –ase ending

Question 16

induced fit

Answer 16

– An enzyme is very selective in the reaction it
catalyzes.
– Each enzyme recognizes a substrate, a specific
reactant molecule.
• The active site fits to the substrate, and the enzyme
changes shape slightly.
• This interaction is called induced because the entry of
the substrate induces the enzyme to change shape
slightly

Question 17

feedback regulation

Answer 17

– Some products of a reaction may inhibit the
enzyme required for its production.
• This is called feedback regulation.
• It prevents the cell from wasting resources.

Question 18

enzyme inhibitors

Answer 18

• Penicillin blocks the active site of an enzyme that bacteria
use in making cell walls.
• Ibuprofen inhibits an enzyme involved in pain signaling.
• Many cancer drugs inhibit enzymes that promote cell
division.

Question 19

transport proteins

Answer 19

• are located in membranes and

* help move substances across a cell membrane

Question 20

passive transports

Answer 20

• Diffusion
• Osmosis
• Facilitated diffusion

Question 21

active transports

Answer 21

• ATPases (ie pumps)

Question 22

concentration gradient

Answer 22

a region in which the substance’s density

changes.

Question 23

diffusion

Answer 23

is the movement of molecules so that they spread

out evenly into the available space

Question 24

osmosis

Answer 24

diffusion of water across a selectively permeable

membrane

Question 25

facilitated diffusion

Answer 25

movement of molecules so using

a transport protein but does not require energy

Question 26

hypertonic solution

Answer 26

higher concentration of

solute

Question 27

hypotonic solution

Answer 27

lower concentration of solute

Question 28

isotonic solution

Answer 28

equal concentration of solute

Question 29

osmoregulation

Answer 29

is the control of water balance within a cell or

organism.

Question 30

plasmolysis

Answer 30

occurs when the cell membrane pulls away from

the cell wall, causing plant to shrivel

Question 31

turgid

Answer 31

normal

Question 32

active transport

Answer 32

requires that a cell expend
energy to move molecules across a membrane.
• Na+/K+ pump pumps 2 K+ into the cell and 3 Na+ out
of the cell

Question 33

exocytosis

Answer 33

the secretion of large molecules

within transport vesicles.

Question 34

endocytosis

Answer 34

imports material into the cell using

transport vesicles

Question 35

phagocytosis

Answer 35

(ie “cellular eating”) brings material
into the cell by engulfing food or other
substances within a vacoule or vesicle

Question 36

role of membranes in cell signaling

Answer 36

– The plasma membrane helps convey signals
• between cells and
• between cells and their environment.
– Receptors on a cell surface trigger signal
transduction pathways that
• relay the signal and
• convert it to chemical forms that can function within the
cell.

Question 37

phospholipids

Answer 37

• are key ingredients of membranes,
• were probably among the first organic compounds that
formed from chemical reactions on early Earth, and
• self-assemble into simple membranes

Question 38

explain relationship between heat and entrophy

Answer 38

all energy conversions generate heat, everytime energy is converted, entrophy increases

Question 39

compare the processes by which a car and a human use “fuel” to perfom work

Answer 39

car -octane+oxygen => combustion =heat energy, kinetic energy of movement => carbon dioxide, water.. HUMAN - Glucose +oxygen=>cellular respiration.. heat energy, ATPs=> carbon dioxide

Question 40

compare the amout of energy in a calorie, kilocalorie, Calorie

Answer 40

kilocalorie = Calorie, 1000 calories = 1 kilocalorie

Question 41

explain how ATP powers cellular work

Answer 41

transfer of phospate from triphosphate tail provides energy for cellular work, motor transport, or chemical reaction

Question 42

explain how ATP is recycled

Answer 42

it is recycled in cellular respiration, ADP=>ATP

Question 43

explain why enzymes are needed in living organisms

Answer 43

countless chemical reactions constantly change organisms molecular makeup

Question 44

explain how enzymes are able to speed up chemical reactions

Answer 44

w/ enzymes activation energy is lessened

Question 45

explain how inhibitor and poison can affect enzyme activity

Answer 45

stop enzymes from creating products

Question 46

diffusion vs osmosis

Answer 46

diffusion - the movement of molecules spreading out evenly into the available space, osmosis - diffusion of water through a selectivley permeable membrane

Question 47

passive vs active transport

Answer 47

passive transport - cells don’t expend energy for it to happen, active transport -expends energy to move molecules across a membrane

Question 48

hypertonic vs hypotonic

Answer 48

hypertonic - higher concentration of solute, hypotonic - lower concentration of solute

Question 49

endocytosis vs exocytosis

Answer 49

exocytosis - spilling the contents outside the cell, endocytosis- cell takes material in

Question 50

phagocytosis vs pinocytosis

Answer 50

phagocytosis - cellular eating, pinocytosis - cellular drinking

Question 51

explain how signal transduction pathways permit environmental stimuli to impact the activities inside cell

Answer 51

enzymes catalyze chemical reactions, receptors tell cell “adrenaline is here” certain things happen in the cell with the intorduction of adrenaline, CELL NEEDS MORE ENERGY

Question 52

explain why phospholipids were probably some of the first organic compounds to form as life emerged on Earth

Answer 52

all cells have a plasma membrane, when a mixture of phospholipids and water is shaken, phospholipids organize into bilayers