ch 6

Question 1

organisms that capture energy from sunlight are called

Answer 1

phototrophs (plants are most common example)

Question 2

plants use the energy of sunlight to convert carbon dioxide and water into __ and __

Answer 2

sugar and oxygen

Question 3

organisms that obtain energy by breaking down organic compounds acquired from ingesting other organisms into carbon dioxide and water

Answer 3

chemotrophs (animals)

Question 4

organisms that are able to convert carbon dioxide into glucose are called

Answer 4

autotrophs (or “self feeders”)

Question 5

organisms that obtain their carbon by eating other organisms or molecules derived from other organisms are called

Answer 5

heterotrophs (or “other feeders”)

Question 6

plants are phototrophs and autotrophs, making them

Answer 6

photoautotrophs

Question 7

animals are both chemotrophs and heterotrophs, making them

Answer 7

chemoheterotrophs

Question 8

microorganisms that gain energy from sunlight but obtain their carbon from preformed organic molecules are called

Answer 8

photoheterotrophs

Question 9

microorganisms that extract energy from inorganic sources but build their own organic molecules are called

Answer 9

chemoautotrophs

Question 10

The building and breaking down of carbon sources to harness or release energy

Answer 10

metabolism

Question 11

catabolism:

Answer 11

the set of chemical reactions that break down molecules into smaller units and produce ATP

Question 12

anabolism:

Answer 12

the building of molecules from smaller units, requiring an input of energy (ATP)

Question 13

the energy of a system is:

Answer 13

the system’s capacity to do work

Question 14

kinetic energy:

Answer 14

the energy of motion

ex: a ball bouncing down a set of stairs posses kinetic energy

Question 15

potential energy:

Answer 15

stored energy
ex: the potential energy of a ball at the top of a flight of stairs is higher than it’s potential energy at the bottom of the stairs

Question 16

chemical energy is a form of __ energy

Answer 16

potential

Question 17

ATP is composed of:

Answer 17

adenosine- base adenine & 5 carbon sugar ribose attached to triphosphate (3 phosphate groups)

Question 18

the chemical energy of ATP is held in the ____

Answer 18

bonds connecting the phosphate groups

Question 19

the chemical bonds connecting the phosphate groups in ATP store ___ energy that is released when the bonds are broken. In turn, the released energy can power the __ of a cell.

Answer 19

potential; work

Question 20

the first law of thermodynamics:

Answer 20

(law of conservation of energy) the universe contains a constant amount of energy. energy is neither created nor destroyed, it just changes from one form to another

Question 21

when energy changes form, the total amount of energy remains __. But in going from one form of energy to another, the energy available to do work __.

Answer 21

constant; decreases

Question 22

second law of thermodynamics:

Answer 22

the transformation of energy is associated with an increase of disorder in the universe

Question 23

the degree of disorder in the universe is called

Answer 23

entropy (S)

Question 24

__ __ is a form of kinetic energy corresponding to the random motion of molecules, and results in a given temperature.

Answer 24

thermal energy

Question 25

in chemical reactions, most of the entropy increase occurs through the transformation of various forms of energy into ___, which we experience as heat

Answer 25

thermal energy

Question 26

in living organisms, catabolic reactions result in an __ of entropy as a single ordered biomolecule is broken down into several smaller ones with more freedom to move around

Answer 26

increase

Question 27

anabolic reactions seem to __ entropy bc they use individual building blocks to synthesize more ordered biomolecules such as proteins or nucleic acids

Answer 27

decrease

Question 28

the amount of energy available to do work is called

Answer 28

Gibbs Free Energy (G)

Question 29

reactions with a negative deltaG that release energy and proceed spontaneously are called

Answer 29

exergonic

Question 30

reactions with a positive deltaG that require an input of energy and are not spontaneous are called

Answer 30

endergonic

Question 31

a chemical reaction in which a water molecule is split into a proton (H+) and a hydroxyl group (OH-)

Answer 31

ATP + H2O –> ADP + P

Question 32

the reaction of ATP with water is an __ reaction that releases energy

Answer 32

exergonic

Question 33

__ is an energy acceptor and __ is an energy provider.

Answer 33

ADP; ATP

Question 34

proteins that act as catalysts in most chemical reactions are

Answer 34

enzymes

Question 35

the energy input necessary to reach the transition state is called the

Answer 35

activation energy

Question 36

enzymes reduce activation energy by:

Answer 36

stabilizing the transition state and decreasing its free energy

Question 37

enzymes are folded into 3D shapes that bring particular amino acids into proximity to form an __

Answer 37

active site
(this explains why enzymes are so big, so they can move as they need to in order to bring together the amino acids to form the active site)

Question 38

the __ of an enzyme is the portion of the enzyme that binds substrate and converts it into product

Answer 38

active site

Question 39

irreversible inhibitors:

Answer 39

usually form covalent bonds with enzymes and irreversibly inactivate them

Question 40

reversible inhibitors:

Answer 40

form weak bonds with enzymes and easily dissociate from them

Question 41

competitive inhibitors:

Answer 41

bind to the active site of the enzyme and prevent the binding of a substrate (compete with substrate by being structurally similar)
> can be overcome by increasing the concentration of the substrate

Question 42

non competitive inhibitors:

Answer 42

usually have a structure very different from the substrate and bind to the enzyme at a place different from the active site, so enzyme can still bind to substrate but it slows down the enzymes ability to catalyze by changing the shape of the enzyme and reducing its activity

Question 43

negative feedback:

Answer 43

the final product inhibits the first step of the reaction

Question 44

allosteric enzyme:

Answer 44

an enzyme that is activated or inhibited when binding to another molecule changes its shape.

Question 45

Chemical energy:

Answer 45

possible due to the position of electrons around the nucleus of an atom. The farther away the electron is from the nucleus, the larger the amount of potential energy present

Question 46

the total energy available

Answer 46

enthalpy (H)

Question 47

Catabolic reactions have a __ ΔG and release energy, often in the form of ATP.

Answer 47

negative

Question 48

Anabolic reactions have a __ ΔG and require an energy input, often in the form of ATP

Answer 48

positive