week five

Question 1

Define catalyst

Answer 1

substances that increase the rate of chemical reactions without themselves being consumed

Question 2

Define the rate of a chemical reaction

Answer 2

amount of product formed (or reactant consumed) per unit of time

Question 3

What are the functions of an enzyme?

Answer 3

-lower the activation energy for the reaction
-increase the rate of a specific reaction

Question 4

Glyphosate is the active ingredient in the herbicide called ROUND-UP. What common biological molecule does glyphosate resemble?

Answer 4

an amino acid

Question 5

Glyphosate affects plants because it…

Answer 5

binds to a biosynthetic enzyme and inhibits its activity

Question 6

Do catalyst affect the equilibrium state of the reaction? Why?

Answer 6

catalysts do not change the equilibrium state of the reaction because they affect both the forward and reverse reactions to the same extent

Question 7

Catalysts are usually proteins called _____

Answer 7

enzymes

Question 8

exergonic reactions ______ free energy and endergonic reactions _____ free energy

Answer 8

exergonic reactions release free energy and endergonic reactions require free energy

Question 9

For an exergonic reaction, the energy _____ is more than the initial input of energy, so there is a ______ of energy.

Answer 9

For an exergonic reaction, the energy released is more than the initial input of energy, so there is a net release of energy.

Question 10

This intermediate between reactants and products is called the ________

Answer 10

This intermediate between reactants and products is called the transition state

Question 11

Define the transition state, is it stable, does it require free energy?

Answer 11

intermediate between reactants and products is called the transition state, It is highly unstable and therefore has a large amount of free energy

Question 12

In all chemical reactions, reactants adopt at least ______ before their conversion into products

Answer 12

In all chemical reactions, reactants adopt at least one transition state before their conversion into products

Question 13

To reach the transition state what must happen to the reactant?

Answer 13

the reactant must absorb energy from its surroundings

Question 14

What is activation energy?

Answer 14

all chemical reactions, even spontaneous ones that release energy, require an input of energy that we can think of as an “energy barrier.” The energy input necessary to reach the transition state is called the activation energy

Question 15

There is an _____ correlation between the rate of a reaction and the height of the energy barrier: the ______ the energy barrier, the _____ the reaction and the ______ the barrier, the ______ the reaction

Answer 15

There is an inverse correlation between the rate of a reaction and the height of the energy barrier: the lower the energy barrier, the faster the reaction and the higher the barrier, the slower the reaction

Question 16

Although an enzyme ______ the activation energy, the difference in free energy between reactants and products ______

Answer 16

Although an enzyme reduces the activation energy, the difference in free energy between reactants and products does not change

Question 17

Are catalysts consumed in the chemical process?

Answer 17

no

Question 18

In a chemical reaction catalyzed by an enzyme, the reactant is often referred to as the ______

Answer 18

substrate

Question 19

What are the letters that represent substrate, enzyme, and product?

Answer 19

S
E
P

Question 20

To form an enzyme–substrate complex, enzymes bind substrates at a region of the enzyme called ______

Answer 20

the active site

Question 21

Many enzymes require additional nonprotein molecules, called ______

Answer 21

Many enzymes require additional nonprotein molecules, called cofactors

Question 22

Are cofactors organic?

Answer 22

Cofactors can be inorganic or organic

Question 23

The activity of enzymes is ______ to temperature

Answer 23

The activity of enzymes is also sensitive to temperature. Enzymes have an optimal temperature, which is the temperature at which the enzyme is most active

Question 24

What happens when an enzyme gets too hot?

Answer 24

At very high temperatures, enzymes unfold, or denature

Question 25

What happens when an enzyme gets too cold?

Answer 25

At low temperatures, enzyme activity is typically low, as molecules move slowly, or have lower kinetic energy, reducing the probability that the substrate and enzyme will come together and interact with each other

Question 26

What happens when the pH is too low with enzymes?

Answer 26

most enzymes would be denatured

Question 27

What is a inhibitor?

Answer 27

decrease the activity of enzymes

Question 28

What is an activator?

Answer 28

increase the activity of enzymes

Question 29

What are enzymes that bind at sites other than their active sites

Answer 29

allosteric enzymes

Question 30

they have a nucleus they are prokaryotic they store and follow instruction their structure is crucial for their function they interact with the enviorment

Answer 30

they are prokaryotic

Question 31

Answer 31

C

Question 32

Please select the properties of life that ALL living things harbor. Select all that apply. capable of self replication stores and follows instruction membrane delimited are spherical capable of evolution responds to the environment large enough to be seen with the naked eye stores and uses energy

Answer 32

capable of self replication stores and follows instruction membrane delimited capable of evolution responds to the environment stores and uses energy

Question 33

What trends do elements in the first 3 rows of the periodic table share? Match the statements. -Atoms in the same row have the same..... -Atoms in the same column have the same..... - number of electron shells - number of valence electrons

Answer 33

Question 34

An atom has 6 protons. Which if these is NOT true about the atom? In a neutral state it has 6 electrons It has 6 neutrons Its atomic number is 6 It forms 6 bonds

Answer 34

it forms 6 bonds

Question 35

Answer 35

Question 36

Answer 36

A C D

Question 37

True or False? Based on the information in the previous questions on caffeine, caffeine is a hydrophilic molecule.

Answer 37

true

Question 38

Answer 38

faces: A avoids: B

Question 39

The [H+] of a solution changes from .000001 to .000000001? Has the pH increased or decreased or stays the same?

Answer 39

increased

Question 40

You have a solution with a Hydrogen ion concentration of .00001. The pH of this solution is ______ . This solution is ______ .

Answer 40

You have a solution with a Hydrogen ion concentration of .00001. The pH of this solution is 5 . This solution is acidic .

Question 41

A solution of pH 5 contains ______________ H+ than the same amount of solution at pH 3. "Fold" is a synonym for "times" or multiplication.

Answer 41

100 fold less

Question 42

There are 20 different amino acids. What makes one amino acid different from another?

Answer 42

different side chains (R-groups) attached to an α carbon

Question 43

What element is found in both nucleic acids and all proteins?

Answer 43

nitrogen

Question 44

Which of the following includes all of the pyrimidines found in nucleic acids? cytosine, uracil, and thymine cytosine and thymine cytosine, uracil, and guanine cytosine and uracil adenine and guanine

Answer 44

cytosine, uracil, and thymine

Question 45

What critical feature of DNA structure allows it to replicate?

Answer 45

complementary bases connected by weak hydrogen bonds

Question 46

Plants such as the Venus flytrap produce chemical compounds that break down insects into substances that are usable by the plant. The chemical compounds that break down the insects are most likely lipids carbohydrates hydrocarbons proteins nucleic acids

Answer 46

proteins

Question 47

Sucrase is the enzyme that breaks down sucrose (table sugar) into glucose and fructose. Will sucrase also catalyze the breakdown of another disaccharide maltose? Yes, because enzymes are resuabale No, because enzymes are very specific for their substrates No, because enzymes are not recycled and reused Yes, because an enzyme that breaks one sugar can also break other sugars

Answer 47

No, because enzymes are very specific for their substrates