Statements below show three double-stranded nucleotide sequenc(5f2z s*t sshnes. Which of these sequences of base pairs is possible in a DN*sf25hssz (t nA molecule?

I. 5’- GGA CAG AGC -3’
3’- CCT GTC TCG -5’


II. 5’- GGA CAG AGC -3’
3’- TTC ACT CTA -5’


III. 5’- AGG GAC CGA -3’
3’- TCC CTG GCT -5’

  The diagram below shows the structure base2 meu.mcu// jkd on the tetranucleotide hypothesis proposed by Levene that DNA was made up of equal amounts of adenine, guanine, cytosine and thymine. This hypothesis was a problem of in.kum jmec/ u2/duction, because it was based on a limited set of data. Subsequent evidence and data revealed a more complex and accurate understanding of the structure, leading to the falsification of the initial hypothesis.

  What is the main role of the ribosomes labelled in the microglupnvfbic* +m /vxh-9bz973 qraph?

  A strand of nucleotides reads CCUAGAGCUUACCG. Which type of pentk r,qiwz f(9w+v1vg q5ose sugar could be found in the nucleotides in this stqi, 1 gzk5v f(qvw+rw9rand?

  Which of the following processes ih14v4 o 2iyxczs most directly involved in the formation of nucleic axoz21v hy 44cicids such as DNA?

  What distinguishes uracil froau s :((nt)ye(ryaw1 qm thymine?

  Which statements are characteristics of a DNc :.898gyooqivp .y lcA molecule?
I. The two strands are identical.
II. The two strands are antiparallel to one another.
III. The sugar-phosphate backbone is held together by covalent bonds.

  The table shows the nucleotide bas45mbjk r8ei-1prbi y 0e sequence and genome size (number of base pairs, bp) for different species. m8br i54 1kr-e0pybj i

Which conclusion can be drawn, based on the table?

  How does the genetic92ggpfe2*ezljat o80zr* - bb(z lv 1m code provide evidence of universal common ancestry?

  The diagram depicts nucleosomes.4zv6k *yz1on ct6-0u zq vk+4thb rba*

Gel electrophoresis is a technique often used to analyse DNA moleculesn+ -mkxesubmzn1.9 l+. It includes a gel and an electric field. The diagram below shows the outco nm9x-lz+nbsmu +e1k .me of gel 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.

  The diagram below shows pre-mRNA and three mature mRNA transcripts whereb16j wc9*nd:tz 3o qnp the introns have been r*czo1ntjq b p6w3:d 9nemoved.



What is an advantage of the above process?

  Which of the following is a similarity between transcription and 3uo kuq/a0 ;943xjlfj*2w3ns sjnqme translation?

  The diagram shows the hz*ol d /b*mk+* u6nrcstructure of a DNA fragment. Which bonds easily break and refor+r hbn**m 6/dzl*oukc m?

  What would make one DNA molecule more stable than ank;wweep vrg39n* ii.nc9m 5/apl 0w:dother DNA molecule?
I. More G-C base pairs than A-T base pairs
II. More hydrogen bonds between base pairs
III. Greater distance between A-T base pairs than G-C base pairs

  Hershey and Chase conducted an experiment to investigate whether DNA or proteinj2z xs4rc d 1e,dwns5y5;/uhk vzv65 n serves as the genetic materiadzh/nu v5,wn 154xe rd6 yvkzss2c;j5l. They cultured 2 batches of viruses, one in a medium containing radioactive $^{35}S$ and one in radioactive $^{32}P$. They then introduced each batch of viruses to separate cultures of bacteria. After allowing time for the viruses to infect the bacteria, the culture solutions were centrifuged to separate the viral remains from the bacterial cells, forming two layers, the pellet and the supernatant.


Which component of the tube would provide evidence that DNA is the genetic material?

  Which function and process are correctly matched in the table be/2ezbbzz ;lm o-+vo4dlow?

  Which statement highlights the importance of nucleosomen e2gu id;c(6js in DNA supercoiling ?

  The image shows many ribosomes on a mRNA molecule. How many unique polytun-.0t3o 7egk1hjm upeptide chains 3umt-h7 egn .0jk t1ouare being translated?

  Which of the labelled strucy nd 6c:a1i,at641f oh* eaa81 ijvxxatures shows the correct directionality of the DNA molecul1nvafa 8aa 6cxxiei4y6d 1aht1 o:j*,e?

The diagram below shows t0w1tzq de ssi9a)o 2atzg.(:uhe structure of DNA nucleotides.

1.State the component of DNA that is attached at position X.

2.Identify the type of bonding shown as dotted lines in the diagram.

3.The 5’ and 3’ linkages in DNA play an important role in replication, transcription and translation.

3.1.On the diagram, label the 5’ prime and 3’ prime ends on both strands to show the direction of the DNA.

3.2.Outline how the processes of transcription and translation occur with regards to the formation of 5’ and 3’ linkages.

4.Explain how the DNA helix maintains its stability.

5.Erwin Chargaff’s data on the relative amounts of purine and pyrimidine bases played an important role in determining the structure of DNA.

5.1.Outline how Chargaff’s data contributed to our understanding of the structure of DNA.

5.2.State a proposed model of DNA that was falsified by Chargaff's data.

The Hershey-Chase experiment in 1952 involved culturd+xf i z1wsbe: w1/6aged viruses that were radioactively lab+f1z 1gx/bwdea w:6sielled with either sulfur ($^{35}$S) or phosphorus ($^{32}P) in two separate flasks. Each batch of viruses was then added to separate cultures of bacteria. After allowing time for the viruses to infect the bacteria, the culture solutions were centrifuged to separate the viral remains from the bacterial cells, forming two layers, the pellet and the supernatant.


1.State reasons for using radioactive sulfur ($^{35}$S) and phosphorus ($^{32}$P).

2.Suggest one technological development, other than radioisotopes, that helped open up possibilities in understanding the overall structure of DNA.

3.1.Outline the results of the experiment that provided evidence to support the conclusion that DNA is the genetic material.

3.2.Describe how the 4 nitrogenous bases of DNA enables polypeptides to be coded for.

4.Explain how DNA can be packaged into compact units to form chromatin.

  What bases are P, Q, and R if S is a p8w3atw32 wavc dy9*;b9wu aad yrimidine?

  How did radioisotopes help make the investigations by Hershey and Chase possn8dsqx1asy .bm w*0+i ible?m+ 8 awxyqsi.b10 s*dn

  What feature of the DNA molecule was utilised by Hershey and Chase in 2,azq*7 4hcgt( f5wxsf20d 8ovea wmg order to identify that viral dgwac80f h ev7a s42*m2fz5,o(xgqwt DNA is able to enter host cells, but most of their protein is not?

.

The image below shows a short fragment of the DNA 5tsklg ;g7yq89vx n) gmolecule.



1.Suggest one possible outcome if DNA consisted of two parallel strands instead of two antiparallel strands.

2.The structure of DNA is described as being a 'double helix'. Explain how this structure is related to the DNA function.

3.Compare and contrast the nitrogenous bases thymine and uracil.

  Which of the followi)pb,i buw2tf *ng shows the correct components of one nucleosome?

  Hershey and Chase conducted experiments using lh7+gs nfucz. b-8t+oaha/1c the radioactive isotopes $^{35}$S and $^{32}$P which demonstrated that DNA is the genetic material. What would they have observed about the distribution of isotopes in the centrifuged sample if protein, rather than DNA, were the genetic material?

  The graph below shows the results of an experiment conducted by a team of t,jdzy mu)2x8researchers investigating the relationship between the composition and melting point of differez8tmj ,yd2 )uxnt DNA samples. At the melting point, the DNA double helix separates into two individual strands.

Two DNA samples were compared, one consisting of only PQ pairs and another one consisting of only RS pairs. Letters P, Q, R and S represent different nitrogenous bases found in the DNA.


Based on the results presented in the graph, and your knowledge of nucleotide base pairing (between purines and pyrimidines), deduce which nitrogenous bases correspond to the letters P, Q, R and S.

DNA and RNA are nucleic acids that are essential to all living organis71gaz *;ocf9 d odked1ms.
1.Draw and label a diagram of a nucleotide.

2.Explain how the variation in base sequences leads to the ability of DNA to have an enormous capacity for storing genetic information.

3.DNA is a polymer of nucleotides. Describe the structure of DNA.

The image below shows a shorlk ziw k(ul5+5t fragment of the DNA molecule.


1.Suggest one possible problem that could arise if DNA consisted of two parallel strands instead of two antiparallel strands.

2.State one place where DNA is found in cells.

3.Compare and contrast the structure of DNA and RNA.