HL IB Biology I – Nucleic Acids  Practice #1	                     Name: _________________________ Block: ____
1.	Compare and contrast between the structure of DNA and RNA. (8 marks)
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2.	Compare and contrast the genetic material between eukaryotes and prokaryotes. (8 marks)
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3. List the four macromolecules and give an example and function of each. (4 marks)
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4. Annotate the structure of a DNA structure (double strands) with three nucleotides long.  (10 marks)																	             

5.  	Outline replication of the DNA strand. (8 marks)			
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6.	(a)	Determine the strand of DNA that will be replicated from the DNA strand below.
		A - T - C - C - A - G - G - T - C - A - A - G
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(b)	List three of the other molecules required for replication and give a function for each.
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7. 	Annotate the DNA replication diagram below. 
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8.	The respiratory quotient (RQ) is a measure of the metabolic activity of an animal. It is the ratio of CO2 produced to O2 consumed. In general, the lower the RQ value the higher the energy yield. The RQ is dependent on the diet consumed by the animal. The following table lists the typical RQ values for specified diets.
Diet	RQ	
Lipid	0.71	
Carbohydrate	1.00	
Protein	0.74	
	In an experiment to assess RQ values for house sparrows, the birds were fed a diet of pure mealworms (beetle larvae) or millet (a type of grain). The graph below shows the RQ values of a house sparrow fed on a high carbohydrate diet (millet) and a high lipid diet (mealworms).

(a)	Compare the RQ values for millet and mealworms between 1 hour and 6 hours after feeding.
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	The expected RQ value for house sparrows metabolizing millet is 0.93. The expected value when metabolizing mealworms is 0.75.
(b)	Explain why the expected RQ values for millet and mealworms are different.
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9.	The enzyme aspartate carbomyltransferase (ACTase) is a key regulatory enzyme in nucleotide metabolism in bacteria. The activity of this enzyme was studied in the bacterium Helicobacter pylori, an important human pathogen. ACTase activity and the growth of H. pylori were measured at different concentrations of carbomoyl aspartate (CAA), the end product of the reaction catalysed by ACTase.

(a)	(i)	State the growth of H. pylori at a CAA concentration of 30 mmol dm–3.
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(ii)	Calculate the change in ACTase activity between CAA concentrations of 20 and 40 mmol dm–3.
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(b)	Compare the effect of increasing CAA concentration on the growth of H. pylori and ACTase activity.
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IB Biology I: Nucleic Acids Practice #2		Name: ___________________________ Block: ______
1.	The diagrams below show various molecular structures.

	Identify which of the diagrams represent
(i)	the structure of a carbohydrate and give two functions
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(ii)	the structure of an amino acids and give two functions
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(iii)	the structure of a lipid and give two functions
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(3)
_____2.	What is the composition of the backbone of DNA?
A.	Alternating sugar and phosphate molecules
B.	Complementary base pairs
C.	Alternating sugar and base molecules
D.	A polysaccharide
3.	The following diagram represents replication in DNA.

(a)	State the name and describe the function for the enzymes labelled A and B on the diagram.
(i)	A:	Name:.........................................................Function:...........................................................
(ii)	B:	Name:..........................................................Function.............................................................
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(b)	Identify the cellular location of DNA replication in eukaryotic cells...................................................................
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(c)	State at which period during the cell cycle DNA replication occurs.
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(d)	Explain the significance of complementary base pairing during DNA replication.
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_____4.	What is the function of helicase?
A.	It forms bonds between DNA nucleotides.
B.	It adds new nucleotides to the DNA helix.
C.	It forms the DNA helix.
D.	It separates DNA strands.
_____5.	The diagram below shows a short section of DNA molecule before and after replication. If the nucleotides used to replicate the DNA were radioactive, which strands in the replicated molecules would be radioactive?

A.	II and III only
B.	I and III only
C.	I and II only
D.	I, II, III and IV
6.	Rice (Oryza sativa) is usually intolerant to sustained submergence under water, although it grows rapidly in height for a few days before dying. This is true for one variety, Oryza sativa japonica. The variety Oryza sativa indica is much more tolerant to submergence. Three genetically modified forms of O. sativa japonica, GMFA, GMFB and GMFC, were made using different fragments of DNA taken from O. sativa indica. The plants were then submerged for a period of 11 days. The heights of all the plants were measured at the beginning and at the end of the submergence period.

 (a)	(i)	State which group of rice plants were the shortest at the beginning of the experiment.
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(ii)	Calculate the percentage change in height for the O. sativa japonica unmodified variety during the submergence period. Show your working.
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(b)	Explain how the error bars can be used to compare the results for O. sativa indica.
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(c)	Deduce the general relationship between the growth of all the japonica varieties and their stated tolerance level.
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	In the same experiment, the researchers hypothesized that the capacity to survive when submerged is related to the presence of three genes very close to each other on rice chromosome number 9; these genes were named Sub1A, Sub1B and Sub1C. The photograph below of part of a gel shows relative amounts of messenger RNA produced from these three genes by the submergence-intolerant variety, O.  sativa japonica, and by the submergence-tolerant variety, O. sativa indica, at different times of a submergence period, followed by a recovery period out of water.

(e)	(i)	Determine which gene produced the most mRNA on the first day of the submergence period for variety O. sativa japonica.
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(ii)	Outline the difference in mRNA production for the three genes during the submergence period for variety O. sativa indica.
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(iii)	Compare the mRNA production for the three genes during the submergence period between the two varieties.
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7.	The diagram below shows one DNA nucleotide and part of a second nucleotide.

(a)	State the names of structures I and II. (1 mark)
I. ..........................................................            II. .........................................................
 (b)	On the diagram above, draw the structures that are missing from the second nucleotide. (1 mark)
 (c)	The two nucleotides would be permanently separated during DNA replication. State one process during which they would be temporarily separated.
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(d)	Outline the method that can be used to amplify small quantities of DNA to obtain large enough quantities for DNA profiling.
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IB Biology I: Nucleic Acids  Practice #3		Name: ___________________________ Block: ______
1.	The information needed to make polypeptides is carried in the mRNA from the nucleus to the ribosomes of eukaryotic cells. This information is decoded during translation. The diagram below represents the process of translation.

(a)	Annotate the diagram to show the direction in which the ribosome moves during translation.
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(b)	State the name of the next amino acid which will attach to the polypeptide.
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(c)	Explain how the amino acid was attached to the tRNA.
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(d)	Identify two locations within a eukaryotic cell where translation occurs.
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2.	(a)	Determine the strand of mRNA that is transcribed from the DNA strand below.
		A - T - C - C - A - G - G - T - C - A - A - G
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(b)	List three of the other molecules, apart from mRNA, required for transcription.
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3.	(a)	State two differences between the structure of DNA and RNA.
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The diagram below shows the structure of a ribosome during protein synthesis.

(b)	State the names of the structures labelled above and give a function.
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(c)	State the name of a structure shown on the diagram that has an anticodon.
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(d)	Explain why the process used during protein synthesis in cells is called translation.
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(e)	Explain briefly how termination of translation occurs.
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_____4.	What is removed to form mature eukaryotic mRNA?
A.	RNA primers
B.	Exons
C.	RNA polymerases
D.	Introns
_____5.	A certain gene codes for a polypeptide that is 120 amino acids long. Approximately how many nucleotides long is the mRNA that codes for this polypeptide likely to be?
A.	30
B.	40
C.	360
D.	480
_____6.	Which enzyme removes the RNA primer during replication?
A.	RNA primase
B.	DNA polymerase I
C.	DNA ligase
D.	Helicase
_____7.	To which parts of the deoxyribose molecule do phosphates bind in DNA?

A.	I and V
B.	III and IV
C.	II and III
D.	III and V
_____8.	A biochemist isolated and purified molecules needed for DNA replication. When some DNA was added replication occurred, but the DNA molecules formed were defective. Each consisted of a normal DNA strand paired with segments of DNA a few hundred nucleotides long. Which of the following had been left out of the mixture?
A.	DNA ligase
B.	Helicase
C.	Nucleotides
D.	DNA polymerase
_____9.	What is a difference between the sense and antisense strands of DNA?
A.	Nucleotides are linked to the sense strand by hydrogen bonding during transcription, but not to the antisense strand.
B.	The sense strand has the same base sequence as tRNA, but the antisense strand does not.
C.	Nucleotides are linked to the antisense strand by hydrogen bonding during transcription, but not to the sense strand.
D.	The antisense strand has the same base sequence as mRNA but the sense strand does not.
10.	Compare DNA transcription with translation. (3 marks)
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11.	The diagram below shows two nucleotides linked together to form a dinucleotide.

(a)	(i)	Identify the chemical group labelled I...............................................................
 (ii)	State the type of bond labelled II.......................................................................
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(b)	Distinguish between the sense and antisense strands of DNA during transcription.
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12.	Alcohol dehydrogenase is an enzyme that catalyses the reversible reaction of ethanol and ethanal according to the equation below. The initial rate of reaction can be measured according to the time taken for NADH to be produced. In an experiment, the initial rate at different concentrations of ethanol was recorded (no inhibition). The experiment was then repeated with the addition of l mmol dm–3 2,2,2-trifluoroethanol, a competitive inhibitor of the enzyme. A third experiment using a greater concentration of the same inhibitor (3 mmol dm–3) was performed. The results for each experiment are shown in the graph below.

(a)	Outline the effect of increasing the substrate concentration on the control reaction (no inhibition).
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(b)		State the initial rate of reaction at an ethanol concentration of 50 mmol dm–3
in the presence of the inhibitor at the following concentrations.
1 mmol dm–3:...................................................................3 mmol dm–3:	.................................................................
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HL IB Biology I – Nucleic Acids   Practice #4	                     Name: _________________________ Block: ____
1.	Which enzyme removes the RNA primer during replication and what is replaced?
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2.	What are pyrimidines in DNA and give examples?
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3.	If mRNA has a codon CAU, what is the corresponding anticodon on the tRNA molecule and what amino acid will this code for?
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4.	The diagram shows part of a molecule produced by replication of DNA. What is the significance of the shaded and the unshaded regions? In addition, label the diagram below.

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5.	Up to two additional marks are available for the construction of your answers.
(2)
	(a)	Outline the structure of DNA.
(5)
	(b)     State a role for each of four different named enzymes in DNA replication.
( 5)
(c)	Explain the process of transcription in eukaryotes.
(8)
(Total 20 marks)

6.	Up to two additional marks are available for the construction of your answers.
(2)
	(a) 	Living organisms use DNA as their genetic material. Explain how DNA is replicated within the              cells of living organisms.
(8)
	(b)	Compare DNA transcription with translation.
(4)
 	(c) 	Outline the process of translation.
(6)
(Total 20 marks)
7.	Up to two additional marks are available for the construction of your answers.
(2)
	(a)	Most of the DNA of a human cell is contained in the nucleus. Distinguish between unique and highly repetitive sequences in nuclear DNA.
(5)
(b)	The structure of the DNA double helix was described by Watson and Crick in 1953. Explain the structure of the DNA double helix, including its subunits and the way in which they are bonded together.
(8)
(c)	Explain the methods and aims of DNA profiling.
(5)
(Total 20 marks)
8.	Gibberellin promotes both seed germination and plant growth. Researchers hypothesize that the gene GID1 in rice (Oryza sativa) codes for the production of a cell receptor for gibberellin.
The mutant variety gid1-1 for that gene leads to rice plants with a severe dwarf phenotype and infertile flowers when homozygous recessive. It is suspected that homozygous recessive gid1-1 plants fail to degrade the protein SLR1 which, when present, inhibits the action of gibberellin. The graphs show the action of gibberellin on the leaves and α-amylase activity of wild-type rice plants (WT) and their gid1-1 mutants.

 (a)	(i)	State which variety of rice fails to respond to gibberellin treatment.
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(ii)	The activity of α-amylase was tested at successive concentrations of gibberellin.
Determine the increment in gibberellin concentration that produces the greatest change in α-amylase activity in wild-type rice plants (WT).
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