Statements below show three double-stranded nucleotide sequences. Which 1bbry*h8vr,ws0 n* - h ocam/zof these sequences of base pairs is possible in a DNA moleculoa v b8 /*wbhzry-sm0 n,hr1*ce?

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)po-oqclz73wwm 4o; o the structure based 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 induction, because it was based on a limited set of data. Subsequen3p o-w;o m lw)zoqoc74t 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 t5g-kkg. hmb-khe micrograph?

  A strand of nucleotides reads CCUAs o48qy o(+rwyGAGCUUACCG. Which type of pentose sugar could be fouq+sy(yo 84wr ond in the nucleotides in this strand?

  Which of the following processes is most directly involved in the formation of.a bgln31 .:-wrpo w/y ojk3ii nucleic acids sw: ljpr13og/k.3y iaobin w-.uch as DNA?

  What distinguishes uraci 2,ul8 q*8mfwh0azklz5e+ ny :dvs3q sl from thymine?

  Which statements are yij ph:s-s gz2( 3ne;ccharacteristics of a DNA 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 basedp-oc,djdz1h i42 xx2 sequence and genome size (number of base pairs, bp) for different spec4,hp-1 xj2zdidx doc 2ies.

Which conclusion can be drawn, based on the table?

  How does the genetic code provide evidence of universal common ancestz;;(-kuuud k+ ggw b3 mdw/h8mry?

  The diagram depicts nucleosk- . ctn9tirpo; v.n4eomes.

Gel electrophoresis ) nek8ocavp 4yc-( 4ouis a technique often used to analyse DNA molecules. It includes a gel and an electric field. The diag(k n 8ypcv44oacoue-)ram below shows the outcome 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 matur6f*sdt*.lgy)n :t ar l) m+pahe mRNA transcripts where the introns l)h)apy:tmd r.*ns+6ga ftl* have been removed.



What is an advantage of the above process?

  Which of the following is a similarity between transcription and tr/ )ns,gsm:fjc9 hqou)f32 cr zanslation?

  The diagram shows the structure of a DNA fragment. Which bonds eja/1 (v-.j 2vzydcyn8z+vnyeasily break and reform? ydvzz v j-y1a8c(yjnn2v./e +

  What would make one DNA molecule more stable than anothe7w 8silq1.ttd u 6xh6 jro09) korhz+fr 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 investigat l y2vu*;)qidxft8; eqe whether DNA or protein serves as the genetic material. They cultured 2 batches of viruses, one in a mediuty*8d v ; x;qli)2eqfum 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 pro;eet(it5 5rg cir9.yycess are correctly matched in the table below?

  Which statement highlights the im eqd6.; 7sub v2msr/ynportance of nucleosomes in DNA supercoiling ?

  The image shows many ribosomes on a mRNA molecule. How many unique polypeptide-n7bt6 x4yhua chains u- 4tb6xy 7hnaare being translated?

  Which of the labelled s n06 4er60oahdvn( w4a il4iixj:+rcttructures shows the correct directionality of the DNA moleicwnvr60i4 xt4a6an r j0:lho (ied4+cule?

The diagram below show l -, cn2f5/tpbhfr;ohs the 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 expev 241pewmng8sriment in 1952 involved cultured viruses that were radioactively labelled withe4vps gm 2nw81 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 pyrimidir-rjj,dzgjyb r2 04 u.ne?

  How did radioisotopes help make the investigations by Hershey ani f44)hhl4vb8 xd3kezd Chase possible?b)ihe4x4 3 khz84dvf l

  What feature of the DNA molecule was utilised by Hershey :m jl ;zkect-sxch:k6)w 76*fj(zdskand Chase in order to identify that viral DNA is able to enter host cells, but most of theirfjk 6z*xc;ht ( dem:jswc s 76-zk:lk) protein is not?

.

The image below shows a short fragment of the DNA molec-)ft c5 c.z5 bg4ypm+2 vpdvi4wi x8r7lpl1mzule.



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 following shows the correct componenig* ,ciwbxh m,u* )6crts of one nucleosome?

  Hershey and Chase conducted experiments using the radioactpu ocsg )z2x v5(hi1z4ive 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 d8pqm.fd/ug52 7oyeu no2s9d the results of an experiment conducted by a team of researchers investigating the relationship between the composition and melting point of different DNA samples. At the meltinu.s2du /ygf2o e9 odqm5 d8np7g 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 al wtff71i+ tfp 1x:0nbml living organisms.
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 shorec7 c8i5xg ,h+p uigd/t 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.