Statements below show three double-stranded nucleotide seqr5gfi *e o2;ra, ogdcs6m0i.yuences. Which of these seqg o.o,r c6eaf0sdmr; g2y* i5iuences of base pairs is possible in a DNA 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 based on the tetranucleotide hccpq1ib+ 7 bj)ypothesis proposed by Levene that DNA was made up of equal amounts of adep)ci1bq 7+cjb nine, guanine, cytosine and thymine. This hypothesis was a problem of induction, 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 labell zfa /-o5c6w s p(x+hibc(+bhved in the micrograph?

  A strand of nucleotides reads CCUAGAG*m)x- oux-x4 .q5 4swnsns obfew9c; bCUUACCG. Which type of pentose sugar could be found in the nucleot)xows n* esbs.m;o4b- cfx n9u-wqx 45ides in this strand?

  Which of the following processes is most directly ia3* 8,ojbr ,kghsn4* fpie7ozr)mg0 m nvolved in the formation of nucleic acids suc m*kr7,h,n3zpr og) if4g0ejbamo8 * sh as DNA?

  What distinguishes uracim*76 ,bdm64xonysirp ho , t+l0m;o cnl from thymine?

  Which statements are characteristics of qk y 9kj6,dd*ka 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 nucleotimki: jt..z b*q/ija08bgmbvc +g30de t s8 l4dde base sequence and genome size (number of base pairs, bp)8*kbddte bm vj0..4gbc0mq/: li3i j t s8+zga for different species.

Which conclusion can be drawn, based on the table?

  How does the genetic code provide evidence of bya ut;umfkn+/m. x +z) q2x8nuniversal common ancestry?

  The diagram depicts nucleosou8z bs bnc:1b0mes.

Gel electrophoresis is a technique often ujxy5 j1 m 6kbby2 fnad)d :ryi8qi/)5qsed to analyse DNA molecules. It includes a gel and an )qfyj8 x56irmy)1j q/ya dbb2 :5dkinelectric 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 mRNAf:r4sgvs 6y,l3q8 amz transcripts where the introns have been removed4m83 rlq,vsys fz:6ag.



What is an advantage of the above process?

  Which of the following is a similarity between transcription andae71t/ya*15zzv; c zdn m6f;it ccaj/ translation?

  The diagram shows the structure of a DNA fragment. Which bonds easil5u2 x1d5tj za4ziw ap+y break and re u45jxi+d a z2zwat1p5form?

  What would make one DNA molecule more stable than abc2:uh/0beo vb 3b4ry nother 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 h n. 8+3ctnhl k,i+s* )jwehpsprotein s cs+w)+h eh nt,8hk3 nl.isj*perves as the genetic material. 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 correcu *7ne.xa oyp5 urc**jtly matched in the table below?

  Which statement highlights the impor3;jdx9hgg: i2g 0qafv2j zj6d0oep noe-w o);tance of nucleosomes in DNA supercoiling ?

  The image shows many ribosomes on a mRNA molecule. How ma+xg ) lntp4nk:ny unique polypeptide chains are being xtg4n:l) pn+ktranslated?

  Which of the labelled structures s9v 8dt/dlidhtdi2fw us*+5i2hows the correct directionality of the DNA molfh25 d it*d9w/i utvi +l82ddsecule?

The diagram below sho9oa7y5xnlqt-c 8v)vg ws 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 experiment in 195rrfyv9r 0:.bs2 involved cultured viruses that were radioactively labelled withv:fs0r9 .by rr 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 py*zl3 a1(md yk0u jdgd-qyel :.rimidine?

  How did radioisotopes help make the investigations by Hershey and Chase lna5txu3nh 3 e4hj8 4hpossible?5n jt4x4he3ua h3 8hnl

  What feature of the DNA molecujwh2-5n ji0tfqbb) k9 le was utilised by Hershey and Chase in order to identify thj 9bhb0f5 qw)2tnk ij-at viral DNA is able to enter host cells, but most of their protein is not?

.

The image below shows eq/p(w(m3u0*dj 1r bo4 lfeoua short 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 the corrq+r)9 q ttn-4gjg6q lyect components of one nucleosome?

  Hershey and Chase conducted experiments usingjsd,1i)ck 8pk5to:t u 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 bygnu/m q)ze, bgk*qdbyjh b b.fn19+p(v7 6w:j a team of researchers investigating the relationship between the composition and melting point of different DNA samples. At the melting point, the DNA double hel1mb qbjn 9,d/g) f(wj6e n7u y.bq pzkv:hg+b*ix 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 l/bacc w)ygdyykv/c68yn,;) that are essential to all 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 fraj7ekhboxwtsl/y31 /g07aw / hgment 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.