Statements below show three double-stran,jg(5/ nz 2o4cpxkl lxded nucleotide sequences. Which of these sequences of base pairs is possible n,ll pjg x2kz(/4 x5ocin 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 tetranuc6ui hi7 4yc+tbleotide 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 understani6+ u7ihcy4tb ding of the structure, leading to the falsification of the initial hypothesis.

  What is the main role o0 m7 qkraekn8kc)e0* if the ribosomes labelled in the micrograph?

  A strand of nucleotides reads CCUAGAGCUUACCG. Which type of pentose sugar chioqkx*nbka,2 ky2l5 et27 p7 ould be found in the nucleotides in 5h ,7x7iakp22 nektblq2* oykthis strand?

  Which of the following processes is most directly involved in8n+kmfy1-i r: o.e8wxvd3mkq the formation of nucleic acids sum yn1.i+8-xm dkqwek:3 8vrofch as DNA?

  What distinguishes uracil from thymine;f1bvje j fc24?

  Which statements areya9khgt)b - a, characteristics 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 (nu5z+vdfa l1xpe; w2op+mber of base pairs, bp) for difx pow+l5fea2p1+ z;d vferent species.

Which conclusion can be drawn, based on the table?

  How does the geneticm* fz4m ;.e(oy ua-ina code provide evidence of universal common ancestry?

  The diagram depicts n uzf2):j-r48oxwrnpax 3vn r,dv8f 6hucleosomes.

Gel electrophoresis is a technique often used to analyse DNA molecules. It ia5rx .at,capdb48j8 l ncludes a gel.pc 4,dtajala x858br and an electric 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 mRNA transcripts whereahlch5xj ay,n1- x.7 5lgsfo+ the introns have been removexhlhgafj o, 75ans-l 51y.+c xd.



What is an advantage of the above process?

  Which of the following is a similarity byl 3v8z.ewq3 qetween transcription and translation?

  The diagram shows the structure of a DNA fragment. Which bonds easily break an+ xs. u/ex i4zf0 ppw:l9:zr j+v+hfjtd refor9fis:x0 p+4 vfu:jwlhz.+rtz xjp/+ em?

  What would make one DNA molecule more st6-ev3uazn ) (g(janimable 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 whether DNA or (8fb c; c;7tmd tozhk3protein serves as the genetic material. They cultured 2 batche;8kdmfc37;chb zot t (s 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 belowc+sx)ze ( nn/3csy.n b?

  Which statement highlights the importance of nucleosomes in DNA supercoilvuqi8a6 lg xh,;*;6lgvkzwx)ing ?

  The image shows many ribosomes on a mRNA molecule. H()el-06 a. zhqbe1:wwnigw kv ow many unique polypeptide chains are being( i.6lkgbz wa1ne w:h)w-eqv0 translated?

  Which of the labelled structurl3ej,+ly v(d-m a b(znes shows the correct directionality of the DNA molecule?a (jd v(-b3m,le+yznl

The diagram below shows the structure of DNA nuclesrte) 3iyl r)z .3t0rmotides.

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 thaihbfh;b9+kj 6h 2apk 9t were radioactive k;hbhi99 ajbph+k2 6fly 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 0o*j +fonl7 juis a pyrimidine?

  How did radioisotopes help make the investigehpf b08y)6af+wv4qvq ij) v(ations by Hershey and Chase possible?fjq) bpa8vf 0vv6eq(wiy )4+h

  What feature of the DNA molecule was utilised by Hershey and Ch* g-ggb p, szrvqqu/mwj.e3:6ase in order to identi.* ggmz6swvj -/qqb p reu,:g3fy that viral DNA is able to enter host cells, but most of their protein is not?

.

The image below shows a short fragment of the DNA molecullqh:3n hwzs 0*e.



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 :n-;feb)(;u7x 8kj d+f gcmntphma0 r correct components of one nucleosome?

  Hershey and Chase conducted i:p: is,aw,,gnnkt k0 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 of an experiment conducted by a team of resue /k9 inhlc 75ahwk(zy1b22bearchers investigating the relationship between the composition and melting point of different DNA samples. At the melting 7huyh kb5(kc19l ane/z wi22b 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 thzi7;mq fr)lst6 sp,j0w9 he2 qat 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 DNAqh 3/s 1j+gqr1bk qy/x 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.