Statements below show three double-stranded nucleotide sequenceh:*p o0acbj8xs. Which of these seqx:o0*c ba8h pjuences 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 tetranucw pv2jo-;n+n- xqf(j vleotide 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 falsification p;ov j--wjnf+ 2(xvqnof the initial hypothesis.

  What is the main role of the ribosomes labelled in the micrograph?3i6m7g cnpm,o;eg xc;

  A strand of nucleotides reads CCUAGAGCUUACCG. Which type of pembg5: y.v/: hanrj,z;c9up k wntose sugar could be found in the nucleotides in this strand? vj mw,z95kr ubgn:; ych/pa:.

  Which of the following processes is most directly involved in the formatgs8col-4,6 i o7 va:l kd5striion of nucleic acids sg4isai vtk osl6 7 l,8c:5rod-uch as DNA?

  What distinguishes uracil from r4bnn u9mjkh9b2 i:d 2thymine?

  Which statements are charactn ty /k)vz9vt*zfe;8y eristics 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 bah9vel hc zj* qgcro/4g o5+3-ose sequence and genome size (number of base pairs, bp) for diffh-qocoer9g+ 4c*l 3 / hgj5zvoerent species.

Which conclusion can be drawn, based on the table?

  How does the genetic code provide ev5 diqs )a6bx2ud5/p faidence of universal common ancestry?

  The diagram depicts nucleosom8r 9o /inzl-rses.

Gel electrophoresis is a tau-hj/p* pb 7xechnique often used to analyse DNA molecules. It includes a gel and an electric field. The diagra*p pbua7/-hjxm 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 *daw 6lits8: .vqr so8x82gwwtranscripts where the introns have been rem s l8w6wi to2gx*wv:d8qr.a8soved.



What is an advantage of the above process?

  Which of the following is a similarity between transcription and translatihpqo7hsfu1t08 (-lx )eny i8 don?

  The diagram shows the structure of a DNA fragmeitw20- luce n+nt. Which bonds easily break and rew ln+ui -t02ceform?

  What would make one DNA molecule more stable eyjrysr1s-ml l;) /l66 5phnq than another 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 wheth2wx/m,;f-s ws sei wp:er DNA or protein serves as the genetic material. T;w2 mw,:ssx ef-/wisphey 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 correctl ahi uyb:j1rj,t5awi9 5 r5tz6y matched in the table below?

  Which statement highlights the importance of nucleosomes in DN.iyv t/62v a+ogu h2leA supercoiling ?

  The image shows many ribosomes on a 9snu*wn-y(67ix/l;0 h o ne 0mmalkfn mRNA molecule. How many unique polypeptide chains are being translaikn us l6y0we 7f9n0a( nmn-;x/hlom*ted?

  Which of the labelled structures shows the correct directionality.oov z:m x x;a.*m/di:jlr-lz of the DNA molecule? *arojl/d.mo m.l:z:- i;z vxx

The diagram below shows the structure of DNA nucleotides. )dn vrep35 1cgug 4x*b3of ejn.- u;yp

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 cultureiefk i32 x) (,oon0adwd viruses that were radioactively labelled with either suf( )o2, 0ioiakned 3wxlfur ($^{35}$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 R4 ,h f*yf9qvzijl r /b8t,hb /te-xyl2 if S is a pyrimidine?

  How did radioisotopes heol*4uodc2*h.h vv;s wrymzy 1-c.l a3lp make the investigations by Hershey and Chase possible?holc v.dv ;a1 4yrlm**h o3s2cz- .ywu

  What feature of the DNA molecule was utilised by Hershey 3brs )owo e,2tand Chase in order to identify that viral DNA ibortwo3,e s2)s able to enter host cells, but most of their protein is not?

.

The image below shows a short fragment of the DNA molecule.4r y.zq;cwqu0



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 components of one nucleosome-t.+s(ebnqa r40v go6rovp :m ?

  Hershey and Chase conducted experiments using thf v11,pgnhdit) i-*ry e 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 resulk9rb9fm2o a7dgz6 6li ts of an experiment conducted by a team of researchers investigating the relationship between the composition and melting point of different DNA samples. At the melting point, the DNA double helix separates into two individual2l6r dob6gfika79m 9z 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 all living organisms.kra+e8lx6l io6q jo )3
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 f, uc+t(a wj:kwragment 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.