The diagram shows a DNA profile taken from a crime la8zq2 eytj. a-ntr7 0+1nmrh scene.


Following are the DNA profiles of the suspects in this crime. Which one is the guilty individual?

  What is the function of the Polymerase Chain Reactijrr. 1iy s(ujq/l7m*won?

  Unlike the majority of other DNA polymerases, Taq polymerase, which is used/df) jj4cfsq gx6 e/+x in PCR reactions can withstand high temperatures without denaturing. Which ojf/sxx + 4j)e gq6cd/ff the following is a likely source for Taq polymerase?

  What bond is formed between two glucose mo6ct5; sel hi:/ /p j4srmmh3thlecules to form maltose?

Gel electrophoresis is a technique often uoe 4bmote wp1ah; 83v0i 2hta,sed to analyse DNA molecules. It includes a gel and an electric field. The diagram below shows the outcome of g h41taehwp,2 b aoe80v3;omtiel electrophoresis.


1.DNA is a type of nucleic acid. State one location where DNA is found in cells.

2.Deduce, with a reason, which direction the DNA fragment moves through the gel.

3.Distinguish between the functions of DNA and RNA in unicellular organisms.

  Which event happens qbmsvjzw6-kxx -*7 li8nh ;(zo3mks: in the leading strand but not in the lagging strand?

  Which of these answers is true in relation to the polymerase chq9p w-gnd, wou efj 9g)o 98mgi:7nao/ain reaction?

I. High temperatures are used
II. It produces exact copies of a segment of DNA
III. It requires DNA ligase and restriction endonucleases

Below is an image showing the results from a pater t a. /cpfi/a:pbtx(+8b3vgr 1mv 6ctcnity test.

1.State the two properties of DNA fragments that allow them to be separated on a gel.

2.Outline the method used in DNA profiling in paternity testing to reach the stage shown in the diagram.

3.Deduce, with a reason, who is most likely to be the father of:

3.1.Child A

3.2.Child B

4.State one use other than paternity testing for DNA profiling.

5.Draw a circle around the heaviest DNA band in father 4’s sample.

6.Suggest why it is important to analyse the DNA of the mother, as well as the father in paternity testing.

7.State one potential source of error in DNA profiling.

  The diagram below show)on43)r s v)0dy qhaows the replication of DNA.


Which of the following are correct functions of structures P, Q and S?

  What distinguishes DNA polymhwy*r9:2tr sb(e*c)( p ymdljerase from RNA polymerase?

  Which of the following are examples o 2 sfs;+mp7ytxo0+suo f discoveries made using radioactive isotopm+so+ pyxsouf t 70s;2es?

I. Discovery of the light-dependent photosynthesis pathways using the $^14$C and $^12$C isotopes.
II. Discovery of DNA as the main genetic material using the $^32$P and $^35$S isotopes.
III. Discovery of the semi-conservative replication of DNA using the $^15$N and $^14$N isotopes.

The diagram below shows a replication fork which forms during DNA replicatiots1jujw., -tln.



1.On the diagram above, label the following structures.

1.1.The 5' and 3' ends of both template strands.

1.2.With the letter E, label the strand in which replication is continuous.

1.3.With the letter P, label the protein that keeps both strands separated.

2.Compare and contrast the role of DNA polymerase I and DNA primase.

  The table below shows the percentage of nitrogenousn 44 /pry xpbjksm e.7fg6j2w- bases found in the DNA of Escherichia coli m4n4jgxfby-j. 6e7p/s r pwk2bacteria.
Adenine Cytosine Guanine Thymine
32% 18% 18% 32%
What conclusion can be made based on the data shown in the table above?

Data was collected on the protein composition of venom samples takhw l67q/i6zpag 23 nwden from the Malayan Krait (B. candidus) found in three localities; Malaysia, Indonesia and Thailand. All samples were carefully transported and preserved ag6i/wnahwz 372l6pd qt temperatures below 20$^{circ}$C. The graph shows the number of different types of protein found in each venom sample.


1.1.Identify the independent and dependent variables in this investigation.

1.2.Venom samples were collected from different snakes, in different localities. Suggest two controlled variables, other than temperature, that would support the collection of comparable samples.

Below are the results from gel electrophoresis of one group of venom proteins.


2.1.Identify the group of venom proteins shown.

2.2.Explain how proteins are separated using gel electrophoresis.

Different mice were envenomed with samples from each of the three localities. It was observed that the venom with the lowest neurotoxicity was from the Malayan krait sampled in Malaysia.

3.Suggest why it was important to transport venom samples at temperatures below 20$^o$C.2
4.List two advantages of using mice as model organisms for humans

The venom samples were further analysed, and it was suggested that the Three Finger Toxins group (3FTx) of proteins contributed significantly to the neurotoxicity of the venom. This prompted a closer analysis of the different types of 3FTx proteins found in each venom sample. The data was presented in a graph.


5.Based on the data, suggest which type of 3FTx protein is most likely responsible for differences in the levels of toxicity observed between the different venom samples. Justify your answer.

The diagram below shows the replication of DNAv63ftc0as 8d h*vck*h .

1.Describe the characteristics of the enzyme Taq polymerase.

2.Suggest what the consequences for a cell would be if transcription were to stop.

3.Outline the roles of all enzymes involved in the replication of DNA and in the synthesis of mRNA through transcription.

  Which row represents the steps of the polymerase chain reaction (PCR) in the +( 46cumvl jdo ..lzfvwruvr0f*r w :8correct ol+w:.fv(jdm r4 v6vrwuzrf u .8c*0 olrder?

1.Enzymes are needed for genetic modification. Outline the role of named e 2i*lgnyu2/ftsf1 g9e5l5p ni nzymes in ge1fyt2pis2*nu5 gfli59/gne lnetic modification.

2.Outline the stages of the polymerase chain reaction (PCR).

3.Discuss the potential risks and benefits associated with Bt corn.

The image shows a basic principle hb7cc8,cs7b bo/0ui.v ; pib wbehind the polymerase chain reaction (PCR). The use of PCR revolutionized the biotechnology industry and opened up possibilities 07i/bsc ivc7 ;8uowb .hpbbc,for many applications.

1.List three uses for the DNA copies that are produced.

2.Outline the function of DNA primers in the polymerase chain reaction.

3.Explain the reason for using Taq polymerase in the polymerase chain reaction.

4.Describe one application of the DNA profiles that are produced by PCR and visualized by gel electrophoresis.

The cloning of plasmibi,hg7ebm n ;3ds is an essential skill for many research projects. There are various techniques for this type of cloning, but the first steps involving the use of rh3igb;b,n7e m estriction endonucleases and DNA ligation are long and often inefficient. The development of more reliable and economical techniques has been important in increasing our ability to manipulate DNA.
In vivo techniques have been successful in yeast and E.coli using DNA fragments with overlapping nucleotide sequences. However, if the overlapping sequences are too long it becomes problematic and sometimes more expensive because of the size of the primers required. To try to increase the efficiency of this method, further research was carried out, using E. coli and DNA fragments with homologous ends prepared using the PCR technique from template plasmids using Q5 DNA polymerase. In the first experiment, 2.6 kB plasmids were formed inside E. coli from 2 DNA fragments with varying lengths of overlapping nucleotide sequences (nt OL). Successful recombinations could be identified, as only these plasmids led to the fluorescence of the cells.


1.Describe the pattern of successful recombinants for the E.coli colonies shown in the photographs.

2.What is the function of DNA polymerase in the PCR technique?

The cloning accuracy was calculated as the percentage of the total colony number that was fluorescent. The total number of colonies and the cloning accuracy for the different overlapping nucleotide lengths are shown in the table and graph below.


3.Calculate the number of colonies with successful DNA recombinations on the agar plate with 25 overlapping nucleotides.

4.1.Explain how DNA recombination occurs with overlapping nucleotides.

4.2.Suggest a reason for the results seen in the agar plates containing E.coli with DNA fragments with 0 or 6 overlapping nucleotides.

5.Suggest a possible reason for the high cloning accuracy with 9 overlapping nucleotides.

Cloning efficiency was then investigated with different numbers of DNA fragments which had 18 or 25 overlapping nucleotides. The results from the experiment are shown below.


6.From the photographs of the petri dishes, deduce what effect the number of DNA fragments has on the number of colonies with successful DNA recombinations.

7.Calculate the percentage increase in the number of colonies for the 25 nucleotide overlap compared to the 18 nucleotide overlap for the recombination of 2 DNA fragments.

The investigation was extended to see how plasmid size and the number of DNA fragments affected DNA recombination in E.coli. The graphs below show the colony numbers resulting from either 2 DNA fragments or 3 DNA fragments being joined together to form different-sized plasmids (measured in kilobases).



8.Compare and contrast the results for the number of colonies produced from 2 DNA fragments and 3 DNA fragments.

Lastly, the accuracy of the cloning of the plasmids in colonies was tested. Colonies containing the 3 different sized plasmids were selected at random, plasmids were extracted and these were tested using gel electrophoresis. The results of 6 plasmids from each of the 3 different sizes are shown below.


9.Identify the plasmid number and size that has not been cloned accurately.

10.Using all the results provided, discuss whether they support the hypothesis that the most efficient process for bioscience research using plasmid recombination and cloning in bacteria is to use 2 DNA fragments, with 25 nucleotide overlap to form 2.6 kB plasmids.

  A DNA profile was made using DNA from a crime scene. Locus TH01 was used to idezrzj6/bis bq,s1 ;t9i ntify whether a suspect’s DNA matched the crime sz ibzirt1s/9 6bjs,q;cene DNA. The suspect’s two alleles of the gene at Locus TH01 are shown below.


The alleles TH01-6 and TH01-4 were separated and visualised with gel electrophoresis. The resulting gel, with two bands of DNA, is shown below.

What is the DNA in Band B and why is this DNA at this position?

  Which of the following is/are characteristic(s) of Taq polym* ./tjoi,tgi qerase?
I. Requires a DNA primer
II. Works well at temperatures above 98°C
III. Used in gel electrophoresis to fluorescent tag DNA molecules

  The diagram below shows the DNA band pattern from the first twz .mz6h:qff vh;8 1:o fwhl;gzo generations of a bacterial culture. Generation numbers are indicated at the bottom of the diagram. Bacteria were grown before the experiment in a medium containing a heavy isog.o m z;h8:fz6f hf;:lqvhwz1tope of nitrogen, $^{15}$N, and then transferred to the medium with the light isotope, $^{14}$N which marked the beginning of the experiment (generation 0).

  The diagram shows a DNA profile of a child angk spbez ldc* m9:oy0w80)(nc q7r,k bd the profiles of three potential pairs of parents. Which pair(s) could be the actual parenbk(c0o9y: p 0* 7gzdsnwm)e ,qc8lkb rts of the child?