Statements below show three double-stranded nucleotide sequences.*d m(wn :fecg6 Which of these sequences of base fn dwec6g:(*m 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 os8 tfegeocy3ixc*ccxjq yh) 713 o9 5,n 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 eo xheycqic,oxc3*8 j1gtc3 ys5 )f7 9a 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 ss, lx:jcl5;j of the ribosomes labelled in the micrograph?

  A strand of nucleotides reads CCUAGAGCUUACCG. Which type of pentose sugar could vxuzg3i6: 2lm be found in the nucleotides in this strand 6z3imuv :l2xg?

  Which of the following processes is most directly involved in the formation o2hmdk7xu z .ta,jr (3kf nucleic acids such asdmru(x.akztkh2, j73 DNA?

  What distinguishes uracil from thymineq)di1d 6am /x0*khcey ?

  Which statements are -f3d *daj:c v,xnw*rkcharacteristics 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 b-we3ixbfm0 : (number of base pairs, bp) fo0w:3 ifbmx e-br different species.

Which conclusion can be drawn, based on the table?

  How does the genetic code provide evidence of univeu 57(oweq 9b p/nnj(xjrsal common ancestry?

  The diagram depicts nucleosomesr d2rsvebn:8mz . j81i4f 6iqs.

Gel electrophoresis isiy: *h,wr2zp+ ypu+ly a technique often used to analyse DNA molecules. It includes a gel and an electric field. The diagram below shows the outcompp*yuwzryh 2 y,l+i+: e 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 trassve;ai, p)8q nscripts where the introns have been remove,q;vps8)a si ed.



What is an advantage of the above process?

  Which of the following is a similarityi 8tc(e,gyad8t9c -fs between transcription and translation?

  The diagram shows the structure of a DNA fragm sidsue qpph0d,lc 30rv3k4ofo 6b bg)w())8kent. Which bonds easily break and resb )k dps)ob d8 p604ec,lu3o3)wqi0 kv(grhfform?

  What would make one DNA molecule more stable than another DN +k3b vwej 9ecxfvtu(/;kb3m)A 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;2lb ygz dk/ lj79f.xl DNA or protein serves as the genetic material. They culturefglzl/.x7j2 l9d;ybk d 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 matched in the table bt* jo8cghnq3 3:b5 dslrc )l4 cx5gp.zelow?

  Which statement highlights the importance of nucleosomes in D6 h*sewsn m yzjzsk2)x6g(p( -NA supercoiling ?

  The image shows many ribosomes fpiyphsc8k:)c9-p,)m3dna n on a mRNA molecule. How many unique polypeptide chains are being trans)-)p8d s 9n hmiyc3p:apfnck,lated?

  Which of the labelled structures shows thi(f)y4zb b4xzrit;-7hp fi8jp, :v6 m;dg nule correct directionality of the DNA molecule?pim iu,z -bn d6b8fp glx)v;f7th;4zr: y4ij(

The diagram below showtsi) 4b+(tuum-4fcay 9x jv/ .-nqiqks 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 1952 involveu9otftylbtts/4 )6- xt(p 1 9h f(czrmd cultured viruses that were radioactively labelled with either sulfur l(oxh r fty9-/ubzt c19f6t mps4 (tt)($^{35}$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 pyrimidine? w7g)5frs8f h8g hwn2h

  How did radioisotopes help make the il2ud on3. (xcy(mq4e 1/tbiytnvestigations by Hershey and Chase possible?i tqlmxuo(4ntec 1.(y3 / 2dby

  What feature of the DNA molecule was utilised by Hershey and C a-fnz5 o kp26v*w4zxrhase in order to identify that viral DNA is able to enter host c*a vpz w624 nxo-krzf5ells, but most of their protein is not?

.

The image below shows a short fragment of the DNA molecule b;xur)ohokt ;s(n/w2.



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 followin(s ex tp;sa m8wd7tpm71vebhji *(c 88g shows the correct components of one nucleosome?

  Hershey and Chase conducpp/y. mp l7gw.sjb18h:h *ixxted experiments using 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 ow g )7a03 oykokz,;cxkf an experiment conducted by a team of researchers investigating the relationship between the composition and melting point of z wg;x)7k y0kk,acoo3different 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 all living ;/ob/k qghll- 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 wf7khr wpc9v1 z n1uf-:0l6sfshort fragment 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.