Statements below show three double-st ofpj*(zp6y j+randed nucleotide sequences. Which of these sequen z*p6(fjojpy+ces 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 on1ggabpc7q)7 g w bmer z(*/5ue 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 datu7qrg /7*pz5bgg1e c ba )mwe(a. 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 rr7 g*bubix mx7.b(6kun ekxw 1q+)j1in the micrograph?

  A strand of nucleotides reads CCUAGAGCUUACCG.k*03 l-;sj dssv(wl vkdp*z (q Which type of pentose sugar could be found in the nucleotides ink*lspvw0vksq*sd z3( -(d;j l this strand?

  Which of the following processes is most directly involved in the formationg+5,mb uo zm(9mp 2rvk of nucleic acids such asu(brmo,g2 mp+ 5 9vkzm DNA?

  What distinguishes uracil from tif(uc *pvrv. ,gkp6v:by7g y;hymine?

  Which statements are gm7z.v/ 3vta pcharacteristics 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 genome size c7 d:;j/qvhyi (number of base pairs, bp) for diffe/jviq7 hcy;: drent species.

Which conclusion can be drawn, based on the table?

  How does the geneticpqtd c 2izb8 zybr3+,( code provide evidence of universal common ancestry?

  The diagram depicts nucleosomel w/sc5 i n0mea.k4vc1 ppf9c(s.

Gel electrophoresis is a technique often used to analyse DNA molcvawm943m2f.ma *y gxecules. It includes a gel and an electric field. The diagram below shows the outcome of gel electrophowgmam9f2* .a m xv4y3cresis.


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 transcwq:7c.p) nf ltripts where the introns haw:qp l )c7.fntve been removed.



What is an advantage of the above process?

  Which of the following is * 6n;tgvkn9 ;r0x.xjzxyc6hna similarity between transcription and translation?

  The diagram shows the structure of arw :px7z/b3 ;nrdz+kx DNA fragment. Which bonds easily break and reform:prx + x7kw3r ;/zbndz?

  What would make one DNA molecule more stable than afj6h9kgy udb 9ok*56k 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 whemfbjk a 68guelz,2u(2 ther DNA or protein serves as the genetic material. They cultured 2 batches of viruf28 j bz2(klau, m6ugeses, 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 prox.zo v gl adn02ra6z:h0y,hy+ cess are correctly matched in the table below?

  Which statement highlights the importance of nucleosomes in DNA supercoi+0t;vbl r hj9eling ?

  The image shows many ribug-ai r1za p: u.3cp*uosomes on a mRNA molecule. How many unique polypeptide chains are being translatz1a-g:u.ur 3ip*apc u ed?

  Which of the labelled structures shows the correct nd, z-n*zc+szkwzka: *y ; rn,directionality of the DNA moleca :d y,k+n*,z rzz*n s;nwz-kcule?

The diagram below shows the structure of DNA nu094f1w l uzwzncleotides.

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 that were radioak0a9hpjys69ov3e6 hrn d9 a.jctively labelled with jpo0e r jahn36h6dvk9sa9y9.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 7k3g2ze r)w+ pa.xt yjif S is a pyrimidine?

  How did radioisotopes help make the investigavukw+*bp jmv6* l9;le tions by Hershey and Chase possible?*9blw+;eupvjv lk* m6

  What feature of the DNA molecule was utilisw* bo(gp+p ydx0uy;1 ded by Hershey and Chase in order to identifo;(x+y0y* 1g pubwpddy that viral DNA is able to enter host cells, but most of their protein is not?

.

The image below shows a short fragment oflhbrx q;nz,:9 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 correct x9irf5yuw+ 8acuo1d ;v*r p,hcomponents of one nucleosome?

  Hershey and Chase conducted experiments using the rado4n6ea*cr)4x9zsc+ hj ho:njioactive 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 resultc lj jhtwt cj d v;y;9m)1lv9j72ezp67s of an experiment conducted by a team of researchers investigating the relationship between the composition and melting point of difjhejlmv;d96y t; v2zl7)j1 w7 jpcc9tferent 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 ey(v( h9yf-s:b o.hw: ,oqndxmssential 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 DNAu2 cmi x.f2s(rpgru7t/m.5/c l/k q py 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.