enzymes

Question 1

biomechanical pathways

Answer 1

the chains of steps in photosynthesis and cellular respiration, in which the product of one reaction becomes the substrate in another
- represented by a series of letters and arrows

Question 2

cells have ways of removing the final product so that biochemical pathways keep operating in the right direction.
-photosynthesis

Answer 2

the final product is glucose. it is converted to starch (insoluble) and stored. this allows the plant to keep producing and storing more glucose

Question 3

cells have ways of removing the final product so that biochemical pathways keep operating in the right direction.
-cellular respiration

Answer 3

the products of the breakdown of glucose- CO2, h2O- diffuse out the cell, allowing the reactions to keep proceeding

Question 4

metabolism

Answer 4

the range of biochemical process that occur in living organisms

Question 5

cellular metabolism

Answer 5

the sum of all chemical reactions that take place in all living cells

Question 6

the two types of cellular metabolism

Answer 6

• anabolic
• catabolic

Question 7

endergonic

Answer 7

reactions requiring an initial input of energy to get started

Question 8

exergonic

Answer 8

reactions NOT requiring initial energy input to get started

Question 9

endothermic

Answer 9

reactions reaction that absorbs heat energy from its surroundings

Question 10

exothermic

Answer 10

reactions that release heat energy (e.g. cellular respiration)

Question 11

what reaction is cellular respiration

Answer 11

exothermic- energy is released in the form of heat

Question 12

photosynthesis

Answer 12

the process where photoautotrophs use light energy to convert CO2 and h2O into glucose

Question 13

where can photosynthesis occur

Answer 13

in chloroplasts of plant cells and some protists

Question 14

why is photosynthesis an example of a biomechanical pathway

Answer 14

as it is a complex series of reactions, with each step within each reaction being catalysed by a specific enzyme of enzymes

Question 15

photosynthesis pt 2- endo

Answer 15

photosynthesis is not endothermic reaction as although energy input if required (endergonic), it is not heat.

Question 16

cellular respiration

Answer 16

the series of chemical reactions in which energy from organic compounds (glucose) is converted into an energy form that can be used by cells (ATP)

Question 17

cellular respiration can be:

Answer 17

aerobic (in the presence of oxygen)
anaerobic (lacking oxygen)

Question 18

where does cellular respiration occur

Answer 18

cytosol and mitochondria of eukaryotic cells

Question 19

why is cellular respiration an example of a biochemical pathway

Answer 19

it is a complex series of reactions, with each step within each reaction being catalyzed by a specific enzyme of enzymes

Question 20

enzymes

Answer 20

• a protein
• biological catalysts to speed up chemical reactions in organisms - life would not exist without enzymes as reactions would occur too slowly (or not at all)
• are usually specific to a specific reaction

Question 21

enzymes do not..

Answer 21

produce more product, they just speed up the reaction, which may produce more product in a given time period

Question 21

how do enzymes speed up the reaction

Answer 21

by reducing the activation energy (the amount of energy needed to begin the reaction)

Question 22

cofactors

Answer 22

some enzymes require additional molecules to enable them to catalyze a reaction
- inorganic molecules
- BINDS to the enzyme which enables the enzyme-catalyzed reaction to occur
- FRY PAN

Question 23

cofactors include:

Answer 23

• Mg2+
• Fe2+
• Zn2+ ions
• vitamins

Question 24

coenzymes

Answer 24

- non-protein organic substances

Question 25

coenzymes in photosynthesis and cellular respiration;

Answer 25

- coenzymes are reversibly loaded and unloaded with the groups of atoms they carry - they accept electrons and protons, and chemical groups (like phosphate) during reactions and transfer them to another reaction in a different step.

Question 26

unloaded enzymes

Answer 26

unloaded enzymes accept electrons, protons or a chemical group. the coenzyme is now considered loaded.

Question 27

enzymes are sensitive to:

Answer 27

- temperature - changing pH - this means the rate of photosynthesis and cellular respiration can be affected by changes in temperature and pH

Question 28

the rate of photosynthesis and cellular respiration can also be affected by:

Answer 28

- enzyme concentration - substrate concentrations

Question 29

temperature

Answer 29

most chemical reactions increase in speed as the temperature increases due to the greater speed and collision rate of molecules.

Question 30

temperature- for enzyme catalyzed reactions

Answer 30

the enzyme denatures- bonds are broken and the protein changes shape, thus altering the shape of the active site, making the enzyme non-functional

Question 31

at lower temps

Answer 31

molecules move slower and fewer collisions occur between the enzyme and substrate, resulting in lower rate of reaction. - in low temps the enzymes are inactive but not denatured

Question 32

pH

Answer 32

each enzyme has an optimal pH - the pH at which it works best. - optimal pH of the enzyme varies depending on where it is

Question 33

changes in pH

Answer 33

effects the amino acid and therefore the enzyme - if charges on the amino acid change, then the bonds maintaining the tertiary structure of the enzyme may be broken

Question 34

enzyme and substrate concentrations

Answer 34

increases in enzyme concentration will increase the rate of reaction -there is usually a greater concentration of substrate than enzyme so any increase in enzyme should result in an increase in reaction rate

Question 35

the increase in the rate only continues until...

Answer 35

the saturation point where all of the active sites become full

Question 36

regulation of enzyme concentration

Answer 36

in response to the needs of the cell.

Question 37

regulation occurs via

Answer 37

- controlling the expression of the enzyme - controlling the rate of enzyme degradation - activating the enzyme in response to a stimulus

Question 38

enzyme inhibitors

Answer 38

- change the rate of reactions, either slowing them down or stopping them completely; - can be non-competitive or competitive

Question 39

non competitive inhibitors

Answer 39

- do not bind to the active site. - bind to an alternative site called the allosteric site- causes the active site to change shape and no longer bind to the substrate

Question 40

feedback inhibition

Answer 40

a way cellular respiration can be regulated through non-competitive inhibition

Question 41

competitive inhibitors

Answer 41

directly compete with the substrate for the active site - the shape of the inhibitor is complementary to the shape of the active site.