Statements below show three double-stranded nucleotide s1 s)lt/n.gonif ta1y7equences. Which of these sequences of base pairs is possible in a DNA moleculeniso .ltg f)1/nay17t ?

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 z7 te)lhah+h4 p2zvk /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. Subsequent evidence and data revealed a more complex and accurate understanding of the structure, leading to the falsi /h tveh+k)42a7pz hzlfication of the initial hypothesis.

  What is the main role of the ribosomes labelltod5cw7:u1 ztj.qe 1 ied in the micrograph?

  A strand of nucleotides reads CCUAGAGCUU5(p wp9s oxcv9ACCG. Which type of pentose sugar could be found in the99p (xo5vcswp nucleotides in this strand?

  Which of the following processfb ;+cw.9rm bj c,ci1ies is most directly involved in the formation of nucleic acids such as.+9fjm cibc r;wicb,1 DNA?

  What distinguishes uracilj)xef7o 63gak from thymine?

  Which statements are charsta 5f(,0qqceacteristics 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 xhb6izzmm r9g,t) 2n+69 -jcjepdqf , sequence and genome size (number of base pairs, bnjmh r6,m )gpd,+2ti 6fzjx9q z-e9cb p) for different species.

Which conclusion can be drawn, based on the table?

  How does the genetic code provide evidence of unsqyv0d +7fw, (j vbdx,iversal common ancestry?

  The diagram depicts v h chd1o0r7fr8thma2 q5cd3,9 jq nf.nucleosomes.

Gel electrophoresis is a technique often used to analyse DNA mjfsr.7m x*x2en crdj. 014ugsolecules. It includes a gel and an electric field. The diagram below shows the outco n4d 20fmgecr 1*7jxj sxr.s.ume 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 whef4liitb.1i* oak op:ob+,g;o re the introns have be.faob4pi* ik ,t+ :1o;ogl iboen removed.



What is an advantage of the above process?

  Which of the following is a similarity between : q 4rpha wmcdqr4:ay)5(s4rstranscription and translation?

  The diagram shows the structure of a DNrs4ar2j724)urhv fp e A fragment. Which bonds easily break and reforphvrrae4 j) f22s 7ru4m?

  What would make one DNA molecule more stable than another DNA mol5m+xavv6k fxf (rp7 : w(lc(g9fzgp- fecule?
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 invest5re)dxu- m9my0q cto3 igate whether DNA or protein serves as the genetic material. They cultured 2 batches of viruses, one in a muemqtm-d39cor xy 0)5edium 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 ar echf6tc27h/ldcg t/ 7e correctly matched in the table below?

  Which statement highlights the i:e rlu6ywed 93mportance of nucleosomes in DNA supercoiling ?

  The image shows many ribosomes on a mRNA molecule. How many unique p:wa xe2b8zz(ctq6 uo :olypeptide chains are being translaq28:6 bw:xetuco zz (ated?

  Which of the labelled structures shows the correct diro9*k,zhp(ewaqq vji.u( hs 97ectionality of the DNA molqq.7o(e,h*iwz9j (u as h k9vpecule?

The diagram below shows the structure of DNA nuclc/ yq /tpakwj(v 9/j-keotides.

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 cultured viruses e)- n 4a:jgzwjpmwd 9 hcp..9dthat were radioactiv9z.4 nhgc-wd9j pp .djme )aw:ely 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 S 6-m dlkpl29gjis a pyrimidine?

  How did radioisotopes help make the investigations by Hershey and Chasexf9adle5xmd:4j;8 i r 6m mx9zzwb21k possible 59mxe m6lbk x12:aizd;w xr8jf 4mz9d?

  What feature of the DNA molecule was utilised by Hershey and Chas zsvqxl b,nq3 *y+a,5xec5d zr;-cq)ce in order to identify that viral DNA is able to enter host cells, but most of tx5zd3-y)s a ;,c vxle,r zqcqq n*5+bcheir protein is not?

.

The image below shows a short fragmeo-/e9 qqq( wyar cle+)ns1p(nnt 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 shoypdd- 5me.*j;eqouei 21lx7 zws the correct components of one nucleosome?

  Hershey and Chase conducted experiments using the radioactive p 7l mu1qpxm4u, .w,gwisotopes $^{35}$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 redia;+wf2d5 hickjn8q-; br b7 searchers investigating the relatibqh ;7cai+d8k 2 f -bwrdjn5;ionship between 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 acid,z ak2c10v-ct okjca5 s 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 fragment of the DNA mol1rf45l1j+zyt fwi. zsecule.


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.