Interactive Example Candidate Responses Paper 3 (May/June 2016), Question 1 Cambridge International AS & A Level Biology 9700

Interactive

Version 1.0

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Select page

Your Mark

1(a)

1(b)(i)

1(b)(ii)

1(b)(iii)

1(b)(iv)

1(b)(v)

1(b)(vi)

1(c)

QHIGH

Q1 Mark scheme

(a)(i) (risk assessment)(hydrogen peroxide) harmful or irritant + medium or high ; [1]

(b)(i) (measures room temperature)whole number or to half a degree + °C ; [1]

(b)(ii) (decides on interval for temperature)at least three additional temperatures + whole numbers + even intervals ; °C ; [2]

(b)(iii) (recording results)1. table drawn + heading, temperature + °C ;2. heading, time + seconds ;3. records results for at least five temperatures ;4. correct pattern of results ;5. times recorded as whole seconds ;6. records results for repeats + means calculated ; [6]

(b)(iv) (source of error with reason)appropriate error with reason ;e.g. concentration of hydrogen peroxide decreasesappropriate error with reason ;e.g. different volumes of extract on each square of filter paper [2]

(b)(v) (conclusions)(as temperature increases, activity increases) more successful collisions ormore enzyme-substrate-complexes / ESCs ;(decreased / no activity) denatures or changed shape of active site ; [2]

(b)(vi) (modification to investigate another variable)1. (to standardise temperature) stated temperature + thermostaticallycontrolled water-bath ;2. (independent variable) at least five concentrations of catalase ;3. (method) simple dilution / proportional dilution / serial dilution ; [3]

(c) (chart)1. (x-axis) different plant species + (y-axis) initial rate of activity of catalase /s–1 ;2. (scale on x-axis) even width of bars + (scale on y-axis) 0.05 to 2 cm, labelledat least each 2 cm ;3. correct plotting of five bars ;4. five bars labelled with each horizontal line drawn as a thin line + eachcolumn labelled ; [4]

[Total: 21]

Select page

Your Mark

1(a)

1(b)(i)

1(b)(ii)

1(b)(iii)

1(b)(iv)

1(b)(v)

1(b)(vi)

1(c)

Q1 Mark scheme

(a)(i) (risk assessment)(hydrogen peroxide) harmful or irritant + medium or high ; [1]

(b)(i) (measures room temperature)whole number or to half a degree + °C ; [1]

(b)(ii) (decides on interval for temperature)at least three additional temperatures + whole numbers + even intervals ; °C ; [2]

(b)(iii) (recording results)1. table drawn + heading, temperature + °C ;2. heading, time + seconds ;3. records results for at least five temperatures ;4. correct pattern of results ;5. times recorded as whole seconds ;6. records results for repeats + means calculated ; [6]

(b)(iv) (source of error with reason)appropriate error with reason ;e.g. concentration of hydrogen peroxide decreasesappropriate error with reason ;e.g. different volumes of extract on each square of filter paper [2]

(b)(v) (conclusions)(as temperature increases, activity increases) more successful collisions ormore enzyme-substrate-complexes / ESCs ;(decreased / no activity) denatures or changed shape of active site ; [2]

(b)(vi) (modification to investigate another variable)1. (to standardise temperature) stated temperature + thermostaticallycontrolled water-bath ;2. (independent variable) at least five concentrations of catalase ;3. (method) simple dilution / proportional dilution / serial dilution ; [3]

(c) (chart)1. (x-axis) different plant species + (y-axis) initial rate of activity of catalase /s–1 ;2. (scale on x-axis) even width of bars + (scale on y-axis) 0.05 to 2 cm, labelledat least each 2 cm ;3. correct plotting of five bars ;4. five bars labelled with each horizontal line drawn as a thin line + eachcolumn labelled ; [4]

[Total: 21]

Select page

Your Mark

1(a)

1(b)(i)

1(b)(ii)

1(b)(iii)

1(b)(iv)

1(b)(v)

1(b)(vi)

1(c)

Q1 Mark scheme

(a)(i) (risk assessment)(hydrogen peroxide) harmful or irritant + medium or high ; [1]

(b)(i) (measures room temperature)whole number or to half a degree + °C ; [1]

(b)(ii) (decides on interval for temperature)at least three additional temperatures + whole numbers + even intervals ; °C ; [2]

(b)(iii) (recording results)1. table drawn + heading, temperature + °C ;2. heading, time + seconds ;3. records results for at least five temperatures ;4. correct pattern of results ;5. times recorded as whole seconds ;6. records results for repeats + means calculated ; [6]

(b)(iv) (source of error with reason)appropriate error with reason ;e.g. concentration of hydrogen peroxide decreasesappropriate error with reason ;e.g. different volumes of extract on each square of filter paper [2]

(b)(v) (conclusions)(as temperature increases, activity increases) more successful collisions ormore enzyme-substrate-complexes / ESCs ;(decreased / no activity) denatures or changed shape of active site ; [2]

(b)(vi) (modification to investigate another variable)1. (to standardise temperature) stated temperature + thermostaticallycontrolled water-bath ;2. (independent variable) at least five concentrations of catalase ;3. (method) simple dilution / proportional dilution / serial dilution ; [3]

(c) (chart)1. (x-axis) different plant species + (y-axis) initial rate of activity of catalase /s–1 ;2. (scale on x-axis) even width of bars + (scale on y-axis) 0.05 to 2 cm, labelledat least each 2 cm ;3. correct plotting of five bars ;4. five bars labelled with each horizontal line drawn as a thin line + eachcolumn labelled ; [4]

[Total: 21]

Select page

Your Mark

1(a)

1(b)(i)

1(b)(ii)

1(b)(iii)

1(b)(iv)

1(b)(v)

1(b)(vi)

1(c)

Q1 Mark scheme

(a)(i) (risk assessment)(hydrogen peroxide) harmful or irritant + medium or high ; [1]

(b)(i) (measures room temperature)whole number or to half a degree + °C ; [1]

(b)(ii) (decides on interval for temperature)at least three additional temperatures + whole numbers + even intervals ; °C ; [2]

(b)(iii) (recording results)1. table drawn + heading, temperature + °C ;2. heading, time + seconds ;3. records results for at least five temperatures ;4. correct pattern of results ;5. times recorded as whole seconds ;6. records results for repeats + means calculated ; [6]

(b)(iv) (source of error with reason)appropriate error with reason ;e.g. concentration of hydrogen peroxide decreasesappropriate error with reason ;e.g. different volumes of extract on each square of filter paper [2]

(b)(v) (conclusions)(as temperature increases, activity increases) more successful collisions ormore enzyme-substrate-complexes / ESCs ;(decreased / no activity) denatures or changed shape of active site ; [2]

(b)(vi) (modification to investigate another variable)1. (to standardise temperature) stated temperature + thermostaticallycontrolled water-bath ;2. (independent variable) at least five concentrations of catalase ;3. (method) simple dilution / proportional dilution / serial dilution ; [3]

(c) (chart)1. (x-axis) different plant species + (y-axis) initial rate of activity of catalase /s–1 ;2. (scale on x-axis) even width of bars + (scale on y-axis) 0.05 to 2 cm, labelledat least each 2 cm ;3. correct plotting of five bars ;4. five bars labelled with each horizontal line drawn as a thin line + eachcolumn labelled ; [4]

[Total: 21]

Select page

Your Mark

1(a)

1(b)(i)

1(b)(ii)

1(b)(iii)

1(b)(iv)

1(b)(v)

1(b)(vi)

1(c)

Q1 Mark scheme

(a)(i) (risk assessment)(hydrogen peroxide) harmful or irritant + medium or high ; [1]

(b)(i) (measures room temperature)whole number or to half a degree + °C ; [1]

(b)(ii) (decides on interval for temperature)at least three additional temperatures + whole numbers + even intervals ; °C ; [2]

(b)(iii) (recording results)1. table drawn + heading, temperature + °C ;2. heading, time + seconds ;3. records results for at least five temperatures ;4. correct pattern of results ;5. times recorded as whole seconds ;6. records results for repeats + means calculated ; [6]

(b)(iv) (source of error with reason)appropriate error with reason ;e.g. concentration of hydrogen peroxide decreasesappropriate error with reason ;e.g. different volumes of extract on each square of filter paper [2]

(b)(v) (conclusions)(as temperature increases, activity increases) more successful collisions ormore enzyme-substrate-complexes / ESCs ;(decreased / no activity) denatures or changed shape of active site ; [2]

(b)(vi) (modification to investigate another variable)1. (to standardise temperature) stated temperature + thermostaticallycontrolled water-bath ;2. (independent variable) at least five concentrations of catalase ;3. (method) simple dilution / proportional dilution / serial dilution ; [3]

(c) (chart)1. (x-axis) different plant species + (y-axis) initial rate of activity of catalase /s–1 ;2. (scale on x-axis) even width of bars + (scale on y-axis) 0.05 to 2 cm, labelledat least each 2 cm ;3. correct plotting of five bars ;4. five bars labelled with each horizontal line drawn as a thin line + eachcolumn labelled ; [4]

[Total: 21]

Select page

Your Mark

1(a)

1(b)(i)

1(b)(ii)

1(b)(iii)

1(b)(iv)

1(b)(v)

1(b)(vi)

1(c)

QMID

Q1 Mark scheme

(a)(i) (risk assessment)(hydrogen peroxide) harmful or irritant + medium or high ; [1]

(b)(i) (measures room temperature)whole number or to half a degree + °C ; [1]

(b)(ii) (decides on interval for temperature)at least three additional temperatures + whole numbers + even intervals ; °C ; [2]

(b)(iii) (recording results)1. table drawn + heading, temperature + °C ;2. heading, time + seconds ;3. records results for at least five temperatures ;4. correct pattern of results ;5. times recorded as whole seconds ;6. records results for repeats + means calculated ; [6]

(b)(iv) (source of error with reason)appropriate error with reason ;e.g. concentration of hydrogen peroxide decreasesappropriate error with reason ;e.g. different volumes of extract on each square of filter paper [2]

(b)(v) (conclusions)(as temperature increases, activity increases) more successful collisions ormore enzyme-substrate-complexes / ESCs ;(decreased / no activity) denatures or changed shape of active site ; [2]

(b)(vi) (modification to investigate another variable)1. (to standardise temperature) stated temperature + thermostaticallycontrolled water-bath ;2. (independent variable) at least five concentrations of catalase ;3. (method) simple dilution / proportional dilution / serial dilution ; [3]

(c) (chart)1. (x-axis) different plant species + (y-axis) initial rate of activity of catalase /s–1 ;2. (scale on x-axis) even width of bars + (scale on y-axis) 0.05 to 2 cm, labelledat least each 2 cm ;3. correct plotting of five bars ;4. five bars labelled with each horizontal line drawn as a thin line + eachcolumn labelled ; [4]

[Total: 21]

Select page

Your Mark

1(a)

1(b)(i)

1(b)(ii)

1(b)(iii)

1(b)(iv)

1(b)(v)

1(b)(vi)

1(c)

Q1 Mark scheme

(a)(i) (risk assessment)(hydrogen peroxide) harmful or irritant + medium or high ; [1]

(b)(i) (measures room temperature)whole number or to half a degree + °C ; [1]

(b)(ii) (decides on interval for temperature)at least three additional temperatures + whole numbers + even intervals ; °C ; [2]

(b)(iii) (recording results)1. table drawn + heading, temperature + °C ;2. heading, time + seconds ;3. records results for at least five temperatures ;4. correct pattern of results ;5. times recorded as whole seconds ;6. records results for repeats + means calculated ; [6]

(b)(iv) (source of error with reason)appropriate error with reason ;e.g. concentration of hydrogen peroxide decreasesappropriate error with reason ;e.g. different volumes of extract on each square of filter paper [2]

(b)(v) (conclusions)(as temperature increases, activity increases) more successful collisions ormore enzyme-substrate-complexes / ESCs ;(decreased / no activity) denatures or changed shape of active site ; [2]

(b)(vi) (modification to investigate another variable)1. (to standardise temperature) stated temperature + thermostaticallycontrolled water-bath ;2. (independent variable) at least five concentrations of catalase ;3. (method) simple dilution / proportional dilution / serial dilution ; [3]

(c) (chart)1. (x-axis) different plant species + (y-axis) initial rate of activity of catalase /s–1 ;2. (scale on x-axis) even width of bars + (scale on y-axis) 0.05 to 2 cm, labelledat least each 2 cm ;3. correct plotting of five bars ;4. five bars labelled with each horizontal line drawn as a thin line + eachcolumn labelled ; [4]

[Total: 21]

Select page

Your Mark

1(a)

1(b)(i)

1(b)(ii)

1(b)(iii)

1(b)(iv)

1(b)(v)

1(b)(vi)

1(c)

Q1 Mark scheme

(a)(i) (risk assessment)(hydrogen peroxide) harmful or irritant + medium or high ; [1]

(b)(i) (measures room temperature)whole number or to half a degree + °C ; [1]

(b)(ii) (decides on interval for temperature)at least three additional temperatures + whole numbers + even intervals ; °C ; [2]

(b)(iii) (recording results)1. table drawn + heading, temperature + °C ;2. heading, time + seconds ;3. records results for at least five temperatures ;4. correct pattern of results ;5. times recorded as whole seconds ;6. records results for repeats + means calculated ; [6]

(b)(iv) (source of error with reason)appropriate error with reason ;e.g. concentration of hydrogen peroxide decreasesappropriate error with reason ;e.g. different volumes of extract on each square of filter paper [2]

(b)(v) (conclusions)(as temperature increases, activity increases) more successful collisions ormore enzyme-substrate-complexes / ESCs ;(decreased / no activity) denatures or changed shape of active site ; [2]

(b)(vi) (modification to investigate another variable)1. (to standardise temperature) stated temperature + thermostaticallycontrolled water-bath ;2. (independent variable) at least five concentrations of catalase ;3. (method) simple dilution / proportional dilution / serial dilution ; [3]

(c) (chart)1. (x-axis) different plant species + (y-axis) initial rate of activity of catalase /s–1 ;2. (scale on x-axis) even width of bars + (scale on y-axis) 0.05 to 2 cm, labelledat least each 2 cm ;3. correct plotting of five bars ;4. five bars labelled with each horizontal line drawn as a thin line + eachcolumn labelled ; [4]

[Total: 21]

Select page

Your Mark

1(a)

1(b)(i)

1(b)(ii)

1(b)(iii)

1(b)(iv)

1(b)(v)

1(b)(vi)

1(c)

Q1 Mark scheme

(a)(i) (risk assessment)(hydrogen peroxide) harmful or irritant + medium or high ; [1]

(b)(i) (measures room temperature)whole number or to half a degree + °C ; [1]

(b)(ii) (decides on interval for temperature)at least three additional temperatures + whole numbers + even intervals ; °C ; [2]

(b)(iii) (recording results)1. table drawn + heading, temperature + °C ;2. heading, time + seconds ;3. records results for at least five temperatures ;4. correct pattern of results ;5. times recorded as whole seconds ;6. records results for repeats + means calculated ; [6]

(b)(iv) (source of error with reason)appropriate error with reason ;e.g. concentration of hydrogen peroxide decreasesappropriate error with reason ;e.g. different volumes of extract on each square of filter paper [2]

(b)(v) (conclusions)(as temperature increases, activity increases) more successful collisions ormore enzyme-substrate-complexes / ESCs ;(decreased / no activity) denatures or changed shape of active site ; [2]

(b)(vi) (modification to investigate another variable)1. (to standardise temperature) stated temperature + thermostaticallycontrolled water-bath ;2. (independent variable) at least five concentrations of catalase ;3. (method) simple dilution / proportional dilution / serial dilution ; [3]

(c) (chart)1. (x-axis) different plant species + (y-axis) initial rate of activity of catalase /s–1 ;2. (scale on x-axis) even width of bars + (scale on y-axis) 0.05 to 2 cm, labelledat least each 2 cm ;3. correct plotting of five bars ;4. five bars labelled with each horizontal line drawn as a thin line + eachcolumn labelled ; [4]

[Total: 21]

Select page

Your Mark

1(a)

1(b)(i)

1(b)(ii)

1(b)(iii)

1(b)(iv)

1(b)(v)

1(b)(vi)

1(c)

Q1 Mark scheme

(a)(i) (risk assessment)(hydrogen peroxide) harmful or irritant + medium or high ; [1]

(b)(i) (measures room temperature)whole number or to half a degree + °C ; [1]

(b)(ii) (decides on interval for temperature)at least three additional temperatures + whole numbers + even intervals ; °C ; [2]

(b)(iii) (recording results)1. table drawn + heading, temperature + °C ;2. heading, time + seconds ;3. records results for at least five temperatures ;4. correct pattern of results ;5. times recorded as whole seconds ;6. records results for repeats + means calculated ; [6]

(b)(iv) (source of error with reason)appropriate error with reason ;e.g. concentration of hydrogen peroxide decreasesappropriate error with reason ;e.g. different volumes of extract on each square of filter paper [2]

(b)(v) (conclusions)(as temperature increases, activity increases) more successful collisions ormore enzyme-substrate-complexes / ESCs ;(decreased / no activity) denatures or changed shape of active site ; [2]

(b)(vi) (modification to investigate another variable)1. (to standardise temperature) stated temperature + thermostaticallycontrolled water-bath ;2. (independent variable) at least five concentrations of catalase ;3. (method) simple dilution / proportional dilution / serial dilution ; [3]

(c) (chart)1. (x-axis) different plant species + (y-axis) initial rate of activity of catalase /s–1 ;2. (scale on x-axis) even width of bars + (scale on y-axis) 0.05 to 2 cm, labelledat least each 2 cm ;3. correct plotting of five bars ;4. five bars labelled with each horizontal line drawn as a thin line + eachcolumn labelled ; [4]

[Total: 21]

Select page

Your Mark

1(a)

1(b)(i)

1(b)(ii)

1(b)(iii)

1(b)(iv)

1(b)(v)

1(b)(vi)

1(c)

QLOW

Q1 Mark scheme

(a)(i) (risk assessment)(hydrogen peroxide) harmful or irritant + medium or high ; [1]

(b)(i) (measures room temperature)whole number or to half a degree + °C ; [1]

(b)(ii) (decides on interval for temperature)at least three additional temperatures + whole numbers + even intervals ; °C ; [2]

(b)(iii) (recording results)1. table drawn + heading, temperature + °C ;2. heading, time + seconds ;3. records results for at least five temperatures ;4. correct pattern of results ;5. times recorded as whole seconds ;6. records results for repeats + means calculated ; [6]

(b)(iv) (source of error with reason)appropriate error with reason ;e.g. concentration of hydrogen peroxide decreasesappropriate error with reason ;e.g. different volumes of extract on each square of filter paper [2]

(b)(v) (conclusions)(as temperature increases, activity increases) more successful collisions ormore enzyme-substrate-complexes / ESCs ;(decreased / no activity) denatures or changed shape of active site ; [2]

(b)(vi) (modification to investigate another variable)1. (to standardise temperature) stated temperature + thermostaticallycontrolled water-bath ;2. (independent variable) at least five concentrations of catalase ;3. (method) simple dilution / proportional dilution / serial dilution ; [3]

(c) (chart)1. (x-axis) different plant species + (y-axis) initial rate of activity of catalase /s–1 ;2. (scale on x-axis) even width of bars + (scale on y-axis) 0.05 to 2 cm, labelledat least each 2 cm ;3. correct plotting of five bars ;4. five bars labelled with each horizontal line drawn as a thin line + eachcolumn labelled ; [4]

[Total: 21]

Select page

Your Mark

1(a)

1(b)(i)

1(b)(ii)

1(b)(iii)

1(b)(iv)

1(b)(v)

1(b)(vi)

1(c)

Q1 Mark scheme

(a)(i) (risk assessment)(hydrogen peroxide) harmful or irritant + medium or high ; [1]

(b)(i) (measures room temperature)whole number or to half a degree + °C ; [1]

(b)(ii) (decides on interval for temperature)at least three additional temperatures + whole numbers + even intervals ; °C ; [2]

(b)(iii) (recording results)1. table drawn + heading, temperature + °C ;2. heading, time + seconds ;3. records results for at least five temperatures ;4. correct pattern of results ;5. times recorded as whole seconds ;6. records results for repeats + means calculated ; [6]

(b)(iv) (source of error with reason)appropriate error with reason ;e.g. concentration of hydrogen peroxide decreasesappropriate error with reason ;e.g. different volumes of extract on each square of filter paper [2]

(b)(v) (conclusions)(as temperature increases, activity increases) more successful collisions ormore enzyme-substrate-complexes / ESCs ;(decreased / no activity) denatures or changed shape of active site ; [2]

(b)(vi) (modification to investigate another variable)1. (to standardise temperature) stated temperature + thermostaticallycontrolled water-bath ;2. (independent variable) at least five concentrations of catalase ;3. (method) simple dilution / proportional dilution / serial dilution ; [3]

(c) (chart)1. (x-axis) different plant species + (y-axis) initial rate of activity of catalase /s–1 ;2. (scale on x-axis) even width of bars + (scale on y-axis) 0.05 to 2 cm, labelledat least each 2 cm ;3. correct plotting of five bars ;4. five bars labelled with each horizontal line drawn as a thin line + eachcolumn labelled ; [4]

[Total: 21]

Select page

Your Mark

1(a)

1(b)(i)

1(b)(ii)

1(b)(iii)

1(b)(iv)

1(b)(v)

1(b)(vi)

1(c)

Q1 Mark scheme

(a)(i) (risk assessment)(hydrogen peroxide) harmful or irritant + medium or high ; [1]

(b)(i) (measures room temperature)whole number or to half a degree + °C ; [1]

(b)(ii) (decides on interval for temperature)at least three additional temperatures + whole numbers + even intervals ; °C ; [2]

(b)(iii) (recording results)1. table drawn + heading, temperature + °C ;2. heading, time + seconds ;3. records results for at least five temperatures ;4. correct pattern of results ;5. times recorded as whole seconds ;6. records results for repeats + means calculated ; [6]

(b)(iv) (source of error with reason)appropriate error with reason ;e.g. concentration of hydrogen peroxide decreasesappropriate error with reason ;e.g. different volumes of extract on each square of filter paper [2]

(b)(v) (conclusions)(as temperature increases, activity increases) more successful collisions ormore enzyme-substrate-complexes / ESCs ;(decreased / no activity) denatures or changed shape of active site ; [2]

(b)(vi) (modification to investigate another variable)1. (to standardise temperature) stated temperature + thermostaticallycontrolled water-bath ;2. (independent variable) at least five concentrations of catalase ;3. (method) simple dilution / proportional dilution / serial dilution ; [3]

(c) (chart)1. (x-axis) different plant species + (y-axis) initial rate of activity of catalase /s–1 ;2. (scale on x-axis) even width of bars + (scale on y-axis) 0.05 to 2 cm, labelledat least each 2 cm ;3. correct plotting of five bars ;4. five bars labelled with each horizontal line drawn as a thin line + eachcolumn labelled ; [4]

[Total: 21]

Select page

Your Mark

1(a)

1(b)(i)

1(b)(ii)

1(b)(iii)

1(b)(iv)

1(b)(v)

1(b)(vi)

1(c)

Q1 Mark scheme

(a)(i) (risk assessment)(hydrogen peroxide) harmful or irritant + medium or high ; [1]

(b)(i) (measures room temperature)whole number or to half a degree + °C ; [1]

(b)(ii) (decides on interval for temperature)at least three additional temperatures + whole numbers + even intervals ; °C ; [2]

(b)(iii) (recording results)1. table drawn + heading, temperature + °C ;2. heading, time + seconds ;3. records results for at least five temperatures ;4. correct pattern of results ;5. times recorded as whole seconds ;6. records results for repeats + means calculated ; [6]

(b)(iv) (source of error with reason)appropriate error with reason ;e.g. concentration of hydrogen peroxide decreasesappropriate error with reason ;e.g. different volumes of extract on each square of filter paper [2]

(b)(v) (conclusions)(as temperature increases, activity increases) more successful collisions ormore enzyme-substrate-complexes / ESCs ;(decreased / no activity) denatures or changed shape of active site ; [2]

(b)(vi) (modification to investigate another variable)1. (to standardise temperature) stated temperature + thermostaticallycontrolled water-bath ;2. (independent variable) at least five concentrations of catalase ;3. (method) simple dilution / proportional dilution / serial dilution ; [3]

(c) (chart)1. (x-axis) different plant species + (y-axis) initial rate of activity of catalase /s–1 ;2. (scale on x-axis) even width of bars + (scale on y-axis) 0.05 to 2 cm, labelledat least each 2 cm ;3. correct plotting of five bars ;4. five bars labelled with each horizontal line drawn as a thin line + eachcolumn labelled ; [4]

[Total: 21]

Select page

Your Mark

1(a)

1(b)(i)

1(b)(ii)

1(b)(iii)

1(b)(iv)

1(b)(v)

1(b)(vi)

1(c)

Q1 Mark scheme

(a)(i) (risk assessment)(hydrogen peroxide) harmful or irritant + medium or high ; [1]

(b)(i) (measures room temperature)whole number or to half a degree + °C ; [1]

(b)(ii) (decides on interval for temperature)at least three additional temperatures + whole numbers + even intervals ; °C ; [2]

(b)(iii) (recording results)1. table drawn + heading, temperature + °C ;2. heading, time + seconds ;3. records results for at least five temperatures ;4. correct pattern of results ;5. times recorded as whole seconds ;6. records results for repeats + means calculated ; [6]

(b)(iv) (source of error with reason)appropriate error with reason ;e.g. concentration of hydrogen peroxide decreasesappropriate error with reason ;e.g. different volumes of extract on each square of filter paper [2]

(b)(v) (conclusions)(as temperature increases, activity increases) more successful collisions ormore enzyme-substrate-complexes / ESCs ;(decreased / no activity) denatures or changed shape of active site ; [2]

(b)(vi) (modification to investigate another variable)1. (to standardise temperature) stated temperature + thermostaticallycontrolled water-bath ;2. (independent variable) at least five concentrations of catalase ;3. (method) simple dilution / proportional dilution / serial dilution ; [3]

(c) (chart)1. (x-axis) different plant species + (y-axis) initial rate of activity of catalase /s–1 ;2. (scale on x-axis) even width of bars + (scale on y-axis) 0.05 to 2 cm, labelledat least each 2 cm ;3. correct plotting of five bars ;4. five bars labelled with each horizontal line drawn as a thin line + eachcolumn labelled ; [4]

[Total: 21]

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