Bio 1A Lab 2

Front 1

Starch will be hydrolyzed by ______ into ________, a dissaccharide

Back 1

alpha amylase (found in saliva), maltose

Front 2

how do we measure/determine amylase activity?

Back 2

by measuring the disappearance of starch or the appearance of maltose

Front 3

you will react starch w/ _____. after 5 minutes you will stop the reaction by adding ______.

Back 3

alpha amylase, DNS (dinitrosalicylate, ph>14)

Front 4

DNS solution has two functions:

Back 4

1. extreame alkalinity denatures amylase

2. and it allows you to measure the amount of maltose produced indirectly.

Front 5

At high temperature (T ≥ 95°C) DNS reacts with maltose to ___. What funtional group maltose does DNS react?

Back 5

*produce a brown soluble product.

*Aldehyde group

Front 6

what drive the reaction of DNS and maltose?

Back 6

**heat

maltose + DNS ---> brown compound

Front 7

What is in the Blank tube and the order we add them?

Back 7

1. O.5 ml of 100 ng amylase/ml

2. 1 ml DNS

3. 1 ml 4% starch

Front 8

What is in the reaction tube and the order we add them?

Back 8

1. 0.5 ml of amylase

2. 1 ml starch

3. after five minutes add 1 ml of DNS **DNS solution is close to pH 14; the alkalinity denatures amylase almost immediately at room temp.

Front 9

Why did we add DNS first and then starch?

Back 9

Because DNS denatures the amylase b/f the amylase can react with the starch

Front 10

Environmental effects on activity: what are we comparing

Back 10

A) substrate concentration B) pH C) temperature

Front 11

[Temperature and enzyme activity] in this experiment both substrate and enzyme must be at a given ______

Back 11

temperature (equilibration)

Front 12

[temp] what's in the blank?

Back 12

same as in part one

Amylase, DNS, starch
**A blank for each temperature

Front 13

The affinity of an enzyme for its substrate is inversely related to the _____

Back 13

Km (michaelis constant)

Front 14

Affinity=

Back 14

1/Km

**the Km value is equal to the amount of substrate at which the enzyme is operating at 1/2 Vmax

Front 15

[saliva experiment] what do you use for your blank

Back 15

1/1000 dilution of your saliva in the blank (as the enzyme source)

so its saliva, dns, starch

Front 16

One way (not enzyme) to increase the number of molecules with sufficient energy is to shift the entire curve rightward by increasing

Back 16

Temperature from T1 to T2.

Front 17

However, cells preferably do not increase temperature and instead use enyzme b/c ...

Back 17

**incr. in temperaturet will increase most reactions and would not allow regulation. **most biological molecules are damaged at higher temperatures.

Front 18

Boltzman energy distribution curve

Back 18

lowering the Ea, there are more molecules with sufficient energy to react and be converted into products

Front 19

what is an isozyme?

Back 19

various forms of the same enzyme (have same function), but different structure and catalytic characteristics (b/c they are in diff. environment)

Front 20

Enzyme-substrate affinity

1. an enzyme has a low affinity for the substrate if the rxn

Back 20

1. proceeds at a respectable rate only when the substrate is present in high concentration **the enzymes behaves as if there is no substrate around

2. high affinity (love enzyme). A high rxn rate w/ only a very low concentration of substrate. **reacts with substrate readily even when it is scarce.

Front 21

Affinity= 1/Km

Thus Km with a low Km value____ and Km with high affinity has _____ affinity

Back 21

has high affinity, low affinity

Front 22

[temperature experiment]

temperature has three major effects what are they

Back 22

1. temperature is a measure of kinetic energy of reactant and product. **kinectic energy determines the rate of reactions

2. when rxn is at equilibrium, the addition or removal of heat may result in one rxn rate becoming greater than the other.

3. temperature will affect the shape of the proteins (by its effect on intramolecular bonds).

Front 23

what kind of information do you know about enzyme when using temperature

Back 23

**higher temperatures will give you the information the process of denaturation, in which the enzyme loses activity as its shape changes.

Front 24

[pH experiment] what are the major effects of pH on enzyme

Back 24

1. it may cause denaturation of the enzyme.

2. it may affect reaction rates without causing denaturation

Front 25

most cells, and most enzymes, are in an environment near pH____. most enzymes are not denatured by pH's between

Back 25

75.5 and 8

Front 26

name the bond that is hydrolyzed by amylase

Back 26

alpha 1,4-glycosidic

Front 27

briefly explain why increasing temperature increases amylase activity at first.

Back 27

increase the number collisions b/w E + S. thus increasing the probability of # collisions successful in E + S coide at right ---> speed to form ES complex.

Front 28

what does increasing the temperature past the optimum do to ionic bonds, hydrogen bonds, the orientation of R groups, etc.

Back 28

**break ionic bond, hydrogen bonds b/c they are week bonds
**incre rotation around bonds--- R groups not pointed at each other to form H bonds, ionic bonds ect....

Front 29

what type of bond are broken when DNS denatures amylase: covalent or noncovalent

Back 29

noncovalent