Download Cells N5 Homework book - Deans Community High School

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Cells
N5
Homework book
Deans Community High School
Biology Department
N5
2
Homework 1
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Biology Department
N5
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Biology Department
N5
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Biology Department
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Homework2 Cell Ultrastructure and Membrane
1. Name and give the function of the numbered organelles in the cell below:
A
E
B
D
C
2. Name 3 structures you might find in a plant cell but not in an animal cell.
3. Identify one similarity and one difference between a plant cell and a
fungal cell.
4. A newly discovered species was being classified.
The organism is unicellular, has no organelles and several plasmids.
Should it be classified as an animal, a plant, a bacterium or a fungus?
Why?
5. When examining the cells of a carrot under the microscope, which plant
organelle would you not expect to see? Why?
6. Use your own words to describe the structure of the cell membrane.
In your description make sure you include the terms:
bilayer, protein, phospholipid and fluid mosaic.
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Homework 3
1. The diagram below shows a cross-section of a plasma membrane.
a. Describe the function of the plasma membrane.
b. A plasma membrane is sometimes described as consisting of a phospholipid bilayer. What does
this mean?
c. Draw labels onto the diagram to show the position of a: phospholipid molecule; protein molecule.
d. Suggest one possible job of a protein embedded in the membrane.
e. Plasma membranes are said to be selectively permeable. Explain what this means, giving
examples.
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Homework 4
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Homework 5
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Homework 6
Protein Task to demonstrate secure learning.
Use all you know to make a poster to show how DNA codes for proteins by
following these instructions:
1.
Choose one of these DNA sequences (or make up your own)
TACTCGAATCGATTTATC
TACAGCCGTGTCCCAATT
TACTTAGGCCATGGGACT
2.
Arrange the DNA sequence into triplets
3.
Use the protein decoder (see below or in class) to identify the amino
acids coded for by your triplets
4.
Arrange the amino acids in the correct order to form a protein
Your poster must be colourful, informative and in easy to follow steps to
show you understand how DNA codes for a protein.
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Biology Department
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Homework 7
1. The diagram below shows a yeast cell.
a. Name the structure shown in the diagram that contains genetic information.
b. In a unicellular organism like yeast, a type of cell division called mitosis occurs. What is the
importance of mitosis to yeast cells?
c. During mitosis the genetic information inside the cell is copied. This is called DNA replication. Why
does this happen?
d. Describe what could happen if a mistake is made during DNA replication and the DNA is incorretly
copied?
2. Mitosis also occurs in multicellular organisms. The graph below shows the results of an
experiment to measure the increase in shoot length of germinating pea plants over a forty day
period.
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a. Which five day period shows the greatest average increase in shoot length?
b. What is the total increase in shoot length between day 15 and day 30?
c. In this investigation a total of one hundred plants were used. Explain why using so many plants
makes the results more reliable.
d. Suggest another way that the student who did this investigation could have measured the overall
growth of the shoots.
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Homework 8
Mitosis Homework
Use the information found at web address shown below to complete the tasks
about mitosis.
http://www.abpischools.org.uk/page/modules/ce
lldiv_cancer/cancer4.cfm
1. Identify three important function of mitosis.
2. Why are the cells in an organism said to be genetically identical?
3. Explain what is meant by a cancer cell.
4. What is a tumour?
5. Describe how medicines used to treat tumours work.
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Homework 9
DNA Code Cracking
1. DNA is a code for making proteins.
a. How does the sequence of bases in a DNA molecule control which protein is made?
b. Explain how a mistake during DNA replication could result in the wrong protein being made.
2. The DNA code is copied then translated before a new protein is made. During the copying process
the base Thymine is relaced with a base called Uracil, represented by the letter U. This means that
the codes for amino acids all contain the letter U instead of letter T. Use the genetic code to identify
the amino acids being coded for in each of the sequences below.
See if you can complete this example first:
a. AAAAGUUACUUGGGACCG
Now crack the next two codes!
b. GCCACCAACAGCGUUCAC
c. CUGGGGACUUCCCAGGUG
d. Identify the amino acid that would be inserted into the sequence above if the first base was
changed from a C to an A. (use the table on the last page to help you)
3. The diagram below shows how long chains of amino acids form to make proteins. This model is
actually insulin, which your body needs to control its blood sugar levels. As you can see it is two
separate chains of amino acids joined together by chemical bonds.
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Name of amino acid
Phenyalanine
Leucine
Isoleucine
Methionine
Valine
Serine
Proline
Threonine
Alanine
Arginine
Abrreviation
Phe
Leu
Ile
Met
Val
Ser
Pro
Thr
Ala
Arg
Name of amino acid
Tyrosine
Histidine
Glutamine
Asparagine
Lysine
Aspartine
Glutamic acid
Cysteine
Tryptophan
Glycine
Abrreviation
Tyr
His
Gln
Asn
Lys
Asp
Glu
Cys
Trp
Gly
a. In what part of the cell are amino acids joined together?
b. What is the name of the molecule that carries the copy of the DNA code for making
proteins?
c. What name is given to a long chain of amino acids?
d. What kind of chemical bonds join amino acids together?
The genetic code
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Homework 10
Enzymes 1
1. As you (should) know by now enzymes are made of protein and speed up chemical reactions.
Explain exactly why it is important for enzymes to be the correct shape.
2. Draw a labelled diagram to demonstrate the ‘lock and key’ hypothesis.
3. Enzymes are described as being substrate specific. Explain what this means.
4. The table below shows five enzymes that you may have heard of, along with their substrates and
products. They are all mixed up! Re-draw the table and match the substrate and products up with
the correct enzyme.
Substrate
Enzyme
Product
Fat
Pepsin
Maltose
Glucose-1-phosphate
Lipase
Water and oxygen
Starch
Catalase
Amino acids
Hydrogen peroxide
Phosphorylase
Fatty acids and glycerol
Protein
Amylase
Starch
5. Four out the five enzyme controlled reactions shown above are degradation reactions. Only one is
a synthesis reaction.
a. Define the terms degradation and synthesis in relation to enzymes.
b. Identify the synthesis reaction from the table above.
c. Describe an example of a synthesis reaction that happens inside your body every day, naming the
substrate, the enzyme and the products.
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Homework 11
Enzymes Homework
1. As you (should) know by now enzymes are made of protein and speed up chemical reactions.
Explain exactly why shape is important for enzymes.
2. Define the term ‘optimum conditions’ in relation to enzyme activity.
3. Name three factors that could affect the activity of an enzyme.
4. The graph below shows the results of an investigation carried out by some students into the
action of the enzyme catalase on hydrogen peroxide. The students wanted to know how changing
the temperature affected the activity of the enzyme.
a. What is the optimum temperature
for the activity of catalase?
b. Describe what happens to the
activity of the enzyme as the
temperature of the experiment
is increased from 10oC to 55oC.
c. Predict the height of the foam that
would be produced if this experiment
was carried out at 70 oC. Explain your answer.
5) This question refers to the graph below. Enzymes of the digestive system work best at different
pH conditions. In the mouth, pH tends to be neutral so amylase works best at around pH 7. The
stomach is very acidic, with conditions of around pH 2. The enzyme trypsin, found in the small
intestine, works best at about pH 9.
a. Use the letters on the graph to identify
amylase, pepsin and trypsin.
c. Which enzymes would both still work at
pH 8?
d. Enzyme A does not work at pH 6. Why?
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6. The diagram below shows an investigation into the enzyme amylase. Amylase is an enzyme found
in saliva that breaks down starch in food into a sugar called maltose.
a. Suggest one improvement to the way this experiment has been set
up that would make the results more valid.
b. What is the purpose of test tube B?
c. After one hour the water outside of the visking tubing in both test tubes was tested with for the
presence of starch and maltose. What results would you expect? Explain your answer for both Tube
A and Tube B.
d. Suggest two ways that the rate of the reaction in Tube A could be increased.
e. The experiment was repeated using the enzyme catalase in test tube A instead of amylase. After
one hour the water outside the visking tubing water tested for the presence of starch and maltose.
What result would you expect in Tube A? Explain your answer.
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Homework 12
Genetic Engineering
1. The diagram below shows some of the stages of genetic engineering which are used to produce
new medicines such as human insulin.
a. Complete the table to identify the labelled parts of the diagram.
Name of Structure
Bacterial cell
Plasmid
Insulin gene
Label
b. Describe the next stage of the process needed to create insulin as a medicine, after the gene has
been successfully inserted into the plasmid and the plasmid reinserted into the bacterium.
c. Name another useful product produced by genetic engineering.
d. State two advantages and two disadvantages of genetic engineering.
2. Part of the process of genetic engineering
is shown in the picture opposite.
a. Describe what is happening at this stage.
b. Name an enzyme needed at this stage.
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Homework 13
Proteins
1. Describe the basic structure of a protein molecule. You may draw it but you need to write a
description as well.
2. Name the chemical elements needed to make proteins.
3. Where are proteins made? See if you can find a diagram of one being synthesised and make a
labelled drawing of it.
4. Why do different proteins have different properties?
5. Find out, using the internet, the library or by asking someone (or all three!) about the proteins
keratin and haemoglobin. You should compare them, e.g. what they do, and where they are found
and any other interesting information (a table might be a good way to do this). You should also
explain why they have different properties.
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Homework 14
When peas germinate they carry out aerobic respiration. An investigation to
find out if heat is produced by germinating peas was carried out using the
apparatus below.
The change in temperature inside the
flask was measured over a period of
Time (hrs)
72hrs. The results are shown below.
1. Calculate the total rise in
temperature. (1)
2. Calculate the average rise in
temperature per hour. (1)
Temperature (0C)
0
18
12
26
24
40
36
48
48
50
60
52
72
54
3. Using your graph paper draw a line
graph of the results from the table. (3)
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4. What conclusion can be drawn from these results? (1)
5.
Why would it be necessary to set up a control for this experiment and what
would make a suitable control? (In other words, how can you tell that the peas
are responsible for the heat that is produced?) (1)
6. State one factor which must be kept the same in order for the control
experiment to be a valid comparison. (1)
7.
a.
b.
c.
d.
Respiration can be described as a two stage process.
What molecule is glucose broken down into during the first stage?(1)
How many ATP are produced in the first stage? (1)
How many ATP are produced in the second stage? (1)
Name the waste products of respiration. (1)
8. Name four uses of ATP by cells. (2)
9. How could the rate of respiration in animals be measured? (1)
Deans Community High School
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