Enzymes and Scientific skills

Question 1

What is a catalyst?

Answer 1

Catalysts are substances which speed up chemical reactions by lowering the activation energy. Without a catalyst it would take a long time for the particles build up enough energy required for successful collisions.

Question 2

What is activation energy?

Answer 2

The minimum amount of energy that is required to activate the reactants to undergo chemical change (energy required to start a chemical reaction.

Question 3

What is an enzyme?

Answer 3

A protein biological catalyst that speeds up the rate of reaction by lowering activation energy.

Question 4

What are some signs of chemical reactions occurring?

Answer 4

-Effervescence
-Colour change
-Temperature change (exothermic or endothermic reactions)
-Light

Question 5

What are the two types of catalysts?

Answer 5

-Chemical
-Biological

Question 6

What would happen without enzymes?

Answer 6

-Without them, essential reactions like aerobic cellular respiration would occur so slowly that life could not exist.

Question 7

Describe the active site of an enzyme?

Answer 7

-The active site is complementary and specific to the substrate in terms of shape and charge.

Question 8

What needs to happen for an enzyme to work?

Answer 8

-For an enzyme to function it relies on successful collisions to happen between the enzyme and the substrate
-Reactions only occur if the particles or molecules collide with the correct orientation and the correct energy

Question 9

What are the factors affecting enzymes?

Answer 9

-1. Concentration (of either enzyme or substrate)
-2. Surface area to volume ratio
-3. Temperature
-4. pH

Question 10

How does concentration affect enzyme activity?

Answer 10

-Increasing the concentration of enzyme or substrate increases the rate of successful collisions as there is more enzyme or substrate to react with.
-This means that more enyzme-substrate complexes will form and the reaction will occur faster

Question 11

How does SA : V affect enzyme activity?

Answer 11

The smaller the object, the higher the SA : V ratio
-Higher surface area has the same effect as increased concentration
-More space is available to react which means more enzyme-substrate complexes are formed

Question 12

How does Temperature affect enzyme activity?

Answer 12

A higher temperature means a greater amount of kinetic energy,
so more there will be a higher chance of successful collisions and more enzyme-substrate complexes will be formed

Question 13

How does pH affect enzyme activity?

Answer 13

Enzymes will function best within certain pH levels.

Question 14

What are the two things that must happen for enzyme function? (Collision theory)

Answer 14

-Molecules will move randomly in solution
-Enzyme and substrate will collide
-If these molecules collide with the correct ORIENTATION and ENERGY, they will be able to bind, and the enzyme can act on the substrate

Question 15

What happens to enzymes at very high temperatures?

Answer 15

-The enzyme becomes denatured.
-The bonds that hold together the shape of the active site have been broken
-This means that the active site has changed shape, and it is no longer specific to the substrate

Question 16

What is the average human body temperature?

Answer 16

-37 degrees Celsius (range is 36.5-37.5)

Question 17

Describe scaffold:

Answer 17

(Key term) this means that…
Example: Describe what happens to an enzyme when the temperature rises above the optimum.
-Denatures. This means that the bonds that hold together the shape of the active site have been broken. This means that the active site has changed shape, and is no longer specific and complemetary to the substrate

Question 18

Explain (why) scaffold:

Answer 18

-Because (provide the key term/ background biological information necessary to answer the question)
-Then (what is happening in the situation. Use data/specific evidence if it is given)
-Therefore (what is the outcome/effect)

Question 19

Define Independent variable

Answer 19

-The independent variable is a factor that is changed or manipulated in an experiment to determine it’s effect on the dependent variable

Question 20

Define Dependent variable

Answer 20

-The dependent variable is a measurement to determine if the change or manipulation of the independent variable has had any effect

Question 21

Define Control variable

Answer 21

-A controlled variable is one that is kept constant throughout the experiment, so it is not having an effect on the DV

Question 22

Describe the graph
-https://www.google.com/search?q=Sulphur+emissions+worldwide+graph&tbm=isch&sa=X&ved=2ahUKEwi0krnukMz_AhVQ9jgGHdvXDUYQ0pQJegQIDBAB&biw=1920&bih=933&dpr=1#imgrc=0MvtKr6HZ-rljM

Answer 22

As time increases from 1850 to 1980, the emissions of Sulphur dioxide (millions of tonnes) increases from 0 to 150 million tonnes.

Question 23

Describe graph scaffold:

Answer 23

As (IV) increases/decreases from (…) to (…), the (DV) increases/decreases/plateaus from (…) to (…).

Question 24

Describe the relationship
-https://www.google.com/search?q=Human+Amylase+Starch+Glucose+graph&tbm=isch&sa=X&ved=2ahUKEwj86PiMl8z_AhUHR2wGHcgbBUIQ0pQJegQIDBAB&biw=1920&bih=933&dpr=1

Answer 24

As temperature increases from 0 to 40, the relative reactivity increases from 0 to 80.
As temperature further increases from 40 to 67.5, the relative reactivity decreases from 80 to 0.

Question 25

Explain the graph from 0 to 20 degrees (pre-Enzyme)
-https://www.google.com/search?q=Human+Amylase+Starch+Glucose+graph&tbm=isch&sa=X&ved=2ahUKEwj86PiMl8z_AhUHR2wGHcgbBUIQ0pQJegQIDBAB&biw=1920&bih=933&dpr=1

Answer 25

Because the temperature is too low between 0 and 20 degrees C for optimum enzyme activity
Then there is not enough kinetic energy and there are not many successful collisions between starch and amylase
Therefore resulting in low relative amylase reactivity

Question 26

Explain the graph from 40 to 100 degrees (Denatures)
-https://www.google.com/search?q=Human+Amylase+Starch+Glucose+graph&tbm=isch&sa=X&ved=2ahUKEwj86PiMl8z_AhUHR2wGHcgbBUIQ0pQJegQIDBAB&biw=1920&bih=933&dpr=1

Answer 26

Because the enzymes start to denature above 40 degrees
Then the enzymes have changed shape and the active site of the enzymes is no longer specific or complementary to the substrate
Therefore there are not many successful collisions until 68 degrees when no collisions occur. The relative reactivity reaches zero.

Question 27

Explain the graph at 40 degrees (optimum)
-https://www.google.com/search?q=Human+Amylase+Starch+Glucose+graph&tbm=isch&sa=X&ved=2ahUKEwj86PiMl8z_AhUHR2wGHcgbBUIQ0pQJegQIDBAB&biw=1920&bih=933&dpr=1

Answer 27

Because the enzyme and substrate have optimum function at 40 degrees
Then there will be more successful collisions and more enzyme substrate complexes will be formed.
Therefore the enzyme activity peaks at 40 degrees as the most complexes are formed.

Question 28

Explain the graph between 60 - 100 ug I^-1 (Concentration)
-https://www.google.com/search?q=Enzyme+concentration+and+initial+velocity+formed+graph&tbm=isch&sa=X&ved=2ahUKEwi-nJ7Zncz_AhXVqFYBHcZcAdgQ0pQJegQICBAB&biw=1920&bih=933&dpr=1#imgrc=fVEEtyBxFUNN1M

Answer 28

Because the concentration of enzyme increases
Then there will be a higher chance of successful collisions between 60-100 as there is more enzyme for the substrates to bind to
Therefore, as more enzyme substrate complexes will be formed, enzyme activity increase between 60- 100.

Question 29

What do you have to remember when doing explain graph questions?

Answer 29

PROVIDE CONTEXT IN EITHER THE “BECAUSE” OR “THEN” STATEMENT.

Question 30

What should a collection method include?

Answer 30

-Numbered steps
-One point per step
-The names of any laboratory equipment used
-Clear quantities, temperatures and timings
-At least two controlled variables
-Repeats (at least 5 times)

Question 31

Scaffold for collection method:
-Remember to put 2 control variables

Answer 31

In the experimental group, (dependent variable) is changed by (independent variable).
1. Add… to a flask
2. Add
3. Put this in/add (control variable)
4. Measure (dependent variable) by using stop watch etc
5. Repeat steps 1 to 4 for (other independent variables)
6. Repeat whole experiment 5 times

Question 32

What should you always include in a explain question?

Answer 32

-Enzymes
-Enzyme-substrate complexes
-Successful collisions