B3a Molecules of Life Questions

B3a Molecules of Life Questions

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  • Created on: 10-05-12 07:27
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B3a Molecules of Life
1. ................ carries genetic information.
................ ................ controls the movement of substances in and out of cells.
................ is where many chemical reactions happen.
................ occurs in the mitochondria providing energy for life processes.
2. Label these parts on the animal cell
diagram:
Cell membrane / mitochondria /
nucleus / cytoplasm
3. Chromosomes are found in the
.......................... of cells. They carry coded
information about the organism (which the cell
comes from). The coded information is called
......................, which are made of a chemical called .............................
4. Proteins are needed for the g............... and r................ of cells.
5. A person's DNA is u................. This means two individuals cannot have with identical genes
(one exception to this is identical twins)
Higher only
6. Pepsin is an enzyme that digests (breaks down) protein.
Pepsin is produced in the stomach.
Mary investigates how pepsin works at different pHs. She adds pepsin to
protein and measures how much product is produced in 20 minutes.
Apart from repeating the experiment at different pHs, she keeps everything else the
same.
The table shows her first three results.
pH mass of product after 20 minutes
(in mg)
1 22
2 54
3 54
4
5

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Plot a graph using her first three results.
Finish the graph by drawing the best
curve. (2)
(b) What results would you expect at pH 4 and pH 5?
Extend the line to show your answer. [1]
(c) What is produced when pepsin digests protein?
7. (a) Many chemical reactions in cells are controlled by enzymes.
Amylase is an enzyme that breaks down starch.
Clare is investigating how pH affects the time it takes for amylase to break
down starch.
The table shows her results.…read more

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Look at the graph. What is the optimum pH of amylase?
......................................................................................................................................
(b) Amylase takes much longer to break down starch at pH 12.
Suggest why.
..............................................................................................................................................
(c ) The optimum temperature for another enzyme is 40°C. The activity of this
enzyme decreases above this temperature. This is because the enzyme loses it's
shape and becomes .................... at higher temperatures.
4. Genes are made of DNA.
(i) The diagram shows DNA replication (copying).…read more

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Complete the diagram to show the bases in the new DNA strands
(ii) describe the stage is involved in the production of human insulin, by genetically
modified bacteria
Human ................ that produces insulin is removed
This gene is inserted into the chromosome of a ................
These chromosomes are called ................
Then the bacteria are ................ in a ................ .…read more

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