Statements below show three double-stranded nucleotide sequences. Which of ,u/ exyapf 8osqg/m* :these sequences of basem/ e,qs*y8p:g/xfou a 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 tetranucleotide hl iahe 8bj/m,sc:n 4q3ypothesis 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 datab /h8cm:n,34eql iasj revealed a more complex and accurate understanding of the structure, leading to the falsification of the initial hypothesis.

  What is the main rolz8s05 8 )vfql t jbpp9jx9pxz;e of the ribosomes labelled in the micrograph?

  A strand of nucleotides reall /-eo4qd s*r/hwk )25vocvhds CCUAGAGCUUACCG. Which type of pentose sugar could be found in the nucleotides in thiwh4 ls/ vc2ro/eq-vhl*ok5 d)s strand?

  Which of the following processes is most directly involved iqex0n8r,loyx4bl ay4jzq 0;1n the formation of nucleic al4q 00l,z4nb eqx1ja8xo yy r;cids such as DNA?

  What distinguishes uracil from txl7 zhhq g+ oqs;a.-pu8u5ab. hymine?

  Which statements are characteristics of a DNA molecula)d 76itymm16cnjn 0te?
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 nucleotidej*8)- yisj gje*x)ule base sequence and genome size (number of base pairs, bp) for differen8s*ye-jegjlu* ) )i jxt species.

Which conclusion can be drawn, based on the table?

  How does the genetic code provide evidence of univerhgz 70;;f kj1ljr(sppsal common ancestry?

  The diagram depicts nu s5(ok n2u1d o elnz.gi3n6oa0cleosomes.

Gel electrophoresis is mqkxyvbd0t q(p25 d8i;: ty7 wa technique often used to analyse DNA molecules. It includes a gel and an electric field. The diagram below shows the outcome of70tk8 y xi:y qmdvwb5tq2p(d; 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 sh o4opz dsy2wdr9r 984x0al fg2ows pre-mRNA and three mature mRNA transcripts where the introns have bex8 20ryofo apsd4d2w 9gr4 zl9en removed.



What is an advantage of the above process?

  Which of the following is a similarity -t1 i 1mkk( qh,ztefqlfbuf4a-xd3 5+between transcription and translation?

  The diagram shows the structure of a DNA zwuevsr1 (y1k 9ld. fn0t:j-gfragment. Which bonds easily break and r.( zd9v0wj gn-etfsl:rku y11eform?

  What would make one DNA molecule more stable thalttecm89 d(gi9csxf7w eey2l)m 2 +-fn 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 experimentkktz4r 88eo)e to investigate whether DNA or protein serves as the genetic material. They cuek o)tzkre8 84ltured 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 thigkh8fjg rur-* e6h e*:z0,tse table below?

  Which statement highlights the importance of nucleosomes 3c9(ij)+m wae nt,sza c q+mxy36s5vl in DNA supercoiling ?

  The image shows many ribosomev t8t awz7o, su:2r4xus on a mRNA molecule. How many unique polypeptide chaos tu :uz2w8,t4xrv7ains are being translated?

  Which of the labelled structures shows the correct directioa2cm3 p73ol cmnality of the DNA molecule327cla ommc p3?

The diagram below showsu vv78um ipulnh( cd+( y4/a*k 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 experimentdc6 4ze*1z0xfdksx -x in 1952 involved cultured viruses that were radioactively labex 4xzdxec 6fd*1-s kz0lled 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 .(,;;-og)du qtpa:e f skz bxnS is a pyrimidine?

  How did radioisotopes help make the investigations by Hershey and euwqhe q9w7f:5(xr6q*:u t tkdsg l39Chase possible7q w6 ::ue*fw9k9gqut xq d5st3(lerh?

  What feature of the DNA molecule was utilised by Hershey and Chasfj e p-5)yne9 po)ze.be in order to identify that viral DNA is able to enter-) bpzeej5. y)npoe9 f host cells, but most of their protein is not?

.

The image below shows a short fragmenbra0k0w9g )kdt 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 shows the correct componl:geoy3 u cn j avo07m;32ihn7ents of one nucleosome?

  Hershey and Chase conducted experiments using the radioactive isotopesm ig8+,ul1dx8)4kgp b)k j dtasx01rd $^{35}$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 gef+p(*.vr0x;hg b p5 jvnh.eby 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 indivi5xve p gjph.n(e0 vf*rhg+ ;b.dual 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 livinrwhs gy,dpjc x+9: q;8g 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 molecule.q).+mladi6 j u1wtt -y;;ks7f c6vl m)chz7es


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.