First Assessment (9.2.1)

Question 1

Define Independent variable

Answer 1

Variable in which you change

Question 2

define dependent variable

Answer 2

the measure of the independent variable, it depends on the independent variable.

Question 3

define Controlled variable

Answer 3

The variable kept constant

Question 4

What is an enzyme, what are they made up of ?

Answer 4

• biological PROTEIN catalysts - produced by cells are responsible for all chemical reactions in living organisms

Question 5

what are proteins made up of ?

Answer 5

lomg chains of amino acids held together by peptide bonds

Question 6

what is an catalyst ?

Answer 6

control the rate of a reaction, speed up chemical reactions

Question 7

what does an enzyme act on ?

Answer 7

a substrate (bind to active site)

Question 8

when a substrate acts on an enzyme what happens ?

Answer 8

Bind together creating an enzyme substrate complex

Question 9

Active sight ?

Answer 9

where an enzyme can bind to a substrate

Question 10

What is Metabolism, list 3 examples

Answer 10

The chemical processes within an organism for example: digestion, respiration and photosynthesis

Question 11

what is the lock and key model ?

Answer 11

the substrate is simply drawn into a closely matching cleft on the enzyme molecule

Question 12

PH ? give an example

Answer 12

a measure of the acidity or alkalinity of a solution - pepsin found in the stomach

Question 13

what happens when an enzyme becomes denatured

Answer 13

(affects the rate of reaction) the enzyme is less effective and useless as it affects the shape of the enzyme

(change shape, becomes inactive)

Question 14

What factors can cause a enzyme to become denatured ?

Answer 14

high temperatures (50-60 degrees celcius)

extreme pH (very acidic or alkaline)

Question 15

what is a conclusion to an investigation ?

Answer 15

• summary statement
• state relationsjip between independent and dependent variable/s
• name enzyme
• tell reader about investigation

Question 16

Induced fit model ?

Answer 16

provide a surface or active site where a reaction can take place(induces a temporary change in the shape of the enzyme known as induced fit)

Question 17

what is the maximum point of activity (most suitable for enzyme activity) of enzymes in relation for temperature

Answer 17

Optimum temperature

Question 18

what is the maximum point of activity (most suitable for enzyme activity) of enzymes in relation for pH

Answer 18

optumum pH

Question 19

saturation point ? define

Answer 19

the max. level at which all available enzymes are being used to catalyse a chemical reaction

Question 20

digestive enzymes in the stomach work best under conditions of what pH

Answer 20

7

Question 21

what happens when changing pH or temperature from optimum ?

Answer 21

temperature too high =work slower/denatured

ph too extreme= no act efficiently/denature

Therefore if the enzymes are not working properly than reactions cannot be maintained at a stable rate than metabolic efficiently cannot be maintained as a constant and stable internal environment as it is needed so that enzymes will always be working at an optimum rate, thus metabolism will be at optimum efficiency.

Question 22

the role of enzymes in metabolism

Answer 22

metabolism refers to all the chemical reactions which occur , enzymes are biological catalysts which speed up reactions, without enzymes metabolism would be much slower

Question 23

optimum pH for pepsin, trypsin and urease

Answer 23

2, 8, 6.5-7

Question 24

what is the internal environment of a cell

Answer 24

intersitial fluid and the cytoplasm

Question 25

the contant internal environment for a human ?

Answer 25

37 degrees celcius

Question 26

which speed to chemical reactions work at best ?

Answer 26

optimum

Question 27

feedback systems ?

Answer 27

monitor activity of cells (requirements and wastes produced) ## Footnote regulates enzyme activity and is a key factor in metabolic efficiency as enzymes continually react with substrates to produce a product, these products are then metabolised by another enzyme

Question 28

what is homeostasis

Answer 28

Homeostasis is the process where the internal environment is kept constant/stable regardless of conditions in the external environment.

Question 29

what does an inbalance of the internal environment do to metabolic efficiency ?

Answer 29

Enzymes can only act within a limited temperature and pH range. If the enzymes are not working properly then reactions cannot be maintained at a stable rate then metabolic efficiency cannot be maintained. ## Footnote Enzymes control all the metabolic processes within the body, and work optimally under certain conditions. If these conditions are not met, they don’t work efficiently or at all.

Question 30

factors effected by enzyme efficiency

Answer 30

pH, temperature, substrate concentration

Question 31

what makes an substance acidic ?

Answer 31

hydrogen ions

Question 32

how does temerature affect the internal environment (terefre metabolic efficiency)

Answer 32

Enzymes have a temp they work best at (optimum). They can be irreversibly damaged or denatured when a temp goes too high. At low temps they are made inactive, but can become active again at normal temp.

Question 33

how does pH affect the internal env. (metabolic efficiency)

Answer 33

Also, they have an optimum pH level for activity. A change can change an enzymes shape, therefore making it not fit correctly with its substrate, which leads to a decline in metabolic activity. The further the pH is away from optimum, the less effective they become.

Question 34

how does substrate concentration affect the internal environment (metabolic efficiency)

Answer 34

The amount of the substrate present. The rate of reaction tapers off when all of the active sites of the enzyme molecule are full (saturation point).

Question 35

explain why the shape of an enzyme is so important

Answer 35

as it determines its function, and how it will bind to a substrate (each enzyme has a particular function)

Question 36

# fill in the gaps: They are ____ to a ____ reaction but can be ____ many times meaning the body has limited numbers of hundreds of specific enzymes that it uses \_\_\_\_\_

Answer 36

specific certain reused repeatedly

Question 37

4 examples of processes controlled by homeostasis

Answer 37

- blood pressure - internal body temperature - oxygen levels - carbon dioxide levels

Question 38

validity ?

Answer 38

using a control

Question 39

reliability ?

Answer 39

repetition

Question 40

a substance on which enzymes act

Answer 40

substrate

Question 41

all the chemical reactions in the body

Answer 41

metabolism

Question 42

speeds up chemical reactions without reacting itself

Answer 42

enzyme

Question 43

provides the conditions for optimal enzyme activity allowing for a rate of metabolism that can sustain life

Answer 43

homeostasis