GCSEBiologyOCR GatewayExam Questions1. Cell Level Systems1.2 What Happens in Cells (& What do Cells Need?)

What Happens in Cells (& What do Cells Need?) (OCR Gateway GCSE Biology)

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1.2 What Happens in Cells (& What do Cells Need?)

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1.2 What Happens in Cells (& What do Cells Need?)

1a
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Fermentation involves enzymes that break down sugar releasing carbon dioxide gas.

The volume of carbon dioxide released can be used to measure how fast these enzymes are working.

A student investigates if fermentation works faster at 25°C or 30°C.
She measures the volume of carbon dioxide released in 10 minutes.
The diagram shows the apparatus she uses.

q18-paper1h-nov2020-ocrgcsebio

The student could have measured the volume of carbon dioxide by collecting the gas over water in a measuring cylinder.

Why is it better to use a gas syringe?

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1b
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The student’s results are shown in the table.

Temperature (°C) Volume of carbon dioxide gas ( cm3)
released in 10 minutes
Trial 1 Trial 2 Trial 3
25 23 25 22
30 34 27 33



(i)
Calculate the mean rate of gas produced at 25°C in cm3/minute.

Give your answer to 1 decimal place.

Mean rate of gas produced at 25°C = .................. cm3/minute [3]

(ii)
The rate of gas produced at 30°C is greater than at 25°C.

Use ideas about enzymes to explain why.

[3]

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1c
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Phenols are chemicals that inhibit enzymes during fermentation.

They bind to amino acids on enzyme molecules.

Suggest how phenols inhibit enzymes.

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2
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Some students make a model of DNA.

They use four different colours of round sweets to represent the bases and attach them to two candy laces. Fig. 16.2 shows their model.

fig-16-2-paper1f-nov2020-ocrgcsebio

Fig. 16.2

(i)
Why did the students use four different colours of round sweets in their model of DNA?

[1]

(ii)
Write down the names of the two types of chemical group represented by the candy laces.

1 .....................................
2 .....................................

[2]

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3
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Higher Tier only

Protein synthesis takes place inside cells.

Describe what happens during protein synthesis.

Use terms from the list in your answer.


amino acids    DNA    mRNA    transcription   

 
translation    ribosome

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