Statements below show three double-stranded nucleotide l:ke ;w.lb /iesequences. Which of these sequences of base pairs is possible in a DNA .:w/lieeb ;klmolecule?

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 shl+ qq;j3 ;m*fnx:irob v+ ap3eows 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. ;bqxfjql+ipr; m no* :+3vae3Subsequent 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 i1eh8zz*d; ezlabelled in the micrograph?

  A strand of nucleotides reads CCUAGAGCUUACCG. Which -cyiht 58g u;w,xfo o2type of pentose sugar could be found in the nu8yc ut; h2wi- oofg5x,cleotides in this strand?

  Which of the following processes is most directly iba uykkcik;ztcv( n-43b ,5l+v32i x vnvolved in the formation of nucleic ybalbn+v345 k2 cct;vu,ixv zk k-3i (acids such as DNA?

  What distinguishes uracil from thymine?a6krkz 44i3mub 67 w;mhzk6zt

  Which statements arer,7 seyjp4ha *v onn;) characteristics 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 base sequence and genom3d,8oxs;08isvhor: cr 4qnjfe size (number of base pairs, bp;0 f83hvo8xqj4 riss,n c:odr) for different species.

Which conclusion can be drawn, based on the table?

  How does the genetic code provide evidence of universal common ancestrva4fa*+x7*xrcuj 7 fd y?

  The diagram depicts nunt;e;b..:an8;i feafbn8 dz zcleosomes.

Gel electrophoresis is a technique often used to analyse DNA moleculq bp5j)nkx9vj2m w;u2w3 ed -ses. It includes a gel aqd 3j;nm bw2)xuj kwvp-59se2 nd an electric field. The diagram 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 mature mRNA transk,9ajj*r naec a.n td)n 7:wk,cripts where the introns have be*9eacrnkaa ,.nj)kd7n tw, :j en removed.



What is an advantage of the above process?

  Which of the following is a similarity between transcriptiv; 19 nnlj0owson and translation?

  The diagram shows the structure of a DNA fragment. Which bonds easily break qmd3r15k crtyi1+5; wh/nk 46 odcy vkand reforkh tr ;c +v/iyc14 d56nro5mk dqky1w3m?

  What would make one DNA molecule more stable than ano 4z: o,hlsk,:afxpx3dther 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 d 52m-s8 vq;j/lyy3 xd:rayxwwhether DNA or protein serves as the genetic material. They culta;v :rxw52y -/sy3 yjx dmd8lqured 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 matchei99-ps,vs 1vsksr0 bzd in the table below?

  Which statement highlights the importance of ne6em qq:d6t d)ucleosomes in DNA supercoiling ?

  The image shows many ribosomes on a mRNA molecule. How many ffomfr8b,6(d u+an, zn+bp:u,o -nei unique polypeptide chains,u(a+e:fp 8ni-nnuzm,o,f fb6d o+r b are being translated?

  Which of the labelled structures shows the correct directionalityw8s3z.)jt ,wrctf zn3 of the DNA molecule?ttc)j3 rzsz w3wn8. f,

The diagram below shows the structure of DNA nucsjz4wfs9 pie d 08k* .dv/3rvyleotides.

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 cultur)- l 0sfr,h(lrww.7mpb)js hy ed viruses that were radioactively -wsr0hhr ybs(m,.f) ljl7w p)labelled 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 Su tw1,sb ,4kez is a pyrimidine?

  How did radioisotopes help make the investiga r;s-iu0c:sg2mydn:4sfg g j4tions by Hershey and Chase possiblegn0 rsjgf4g4;:md y s2-c:s iu?

  What feature of the DNA molecule was utilised byg0wwdyz/p0 n111b,hlqm1i.b (zqxj z Hershey and Chase in order to identify that viral DNA i01j/w dqzb mgzw.xn q11 zh by(0lpi1,s able to enter host cells, but most of their protein is not?

.

The image below shows a shnog1 r+h:bv2pe ,ff j9ort fragment of the DNA molecule.



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 thevgpa7 n8q :w3ju8r(w8lk36 ya+zdw rq correct components of one nucleosome?

  Hershey and Chase conducted experiments using the radioy h) p:5awi1h f .yadt-weq44xactive 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 -unv-gzv o:pe w m3:,a9f*pduconducted by a team of researchers investigating the relationship betwu*: u dppn :a- ,fgmvezw3vo-9een the composition and melting point of different 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 alavzu;xh:r* 5+i cqd m/ uvv.d(l 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 short fragment;ohvl 73 zxjo)6c7qx2wh w0gv 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.