What happens in cells (and what do cells need)?

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Question 23
Medium

Pepsin is an enzyme produced in the human digestive system. It breaks down proteins.

a.

Fig. 16.1 shows the steps in protein digestion.

Fig. 16.1 Fig. 16.1: Step-by-step diagram of protein digestion. Step 1 shows a long chain representing a protein molecule. Step 2 shows the protein chain next to three small active molecules representing enzymes, labeled with a dotted line as "... molecules". Step 3 shows the three enzyme molecules bound to the protein chain. Step 4 shows the protein broken down into smaller individual products, labeled with a dotted line as "... molecules", and a remaining structure labeled as "... molecule".

Complete the labels in Fig. 16.1.

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b.

Pepsin is found in the stomach where the pH is acidic.

Draw a curve on Fig. 16.2 to show the effect the pH will have on the rate of reaction for the digestion of proteins by pepsin.

Fig. 16.2 Fig. 16.2: A blank graph template. The vertical y-axis is labeled "Rate of reaction". The horizontal x-axis is labeled "pH" with tick marks from 1 to 9 (1, 2, 3, 4, 5, 6, 7, 8, 9).

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c.

In acidic conditions of pH 2, pepsin digests the protein albumin (components of egg white suspension), causing the cloudy white suspension to turn completely clear.

A group of students investigate how temperature affects the enzymes that break down proteins.

Describe an experiment that the students could use to investigate the effect of temperature on the breakdown of albumin by pepsin.

In your description include:

  • how the independent variable could be changed
  • the observations that should be made
  • two variables that need to be controlled.

To change the independent variable, I will ………………………………………………………\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots………………………………………………………

…………………………………………………………………………………………………………\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots…………………………………………………………………………………………………………

The observations I make will be to ………………………………………………………\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots………………………………………………………

…………………………………………………………………………………………………………\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots…………………………………………………………………………………………………………

I will need to control ……………………………………………………………………\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots……………………………………………………………………

…………………………………………………………………………………………………………\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots…………………………………………………………………………………………………………

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What happens in cells (and what do cells need)? Questions

  1. GCSE
  2. /Biology
  3. /What happens in cells (and what do cells need)?