Statements below show three double-stranded nucleotide sequences. Whicdqr5ukhwknlro+z9ix 278 twkh+) j- 9h of these sequences of base pairs is possible in a DNA mol5jkulrzn wi rh9 2qhk-d+ o+ x98k)7twecule?

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 tetran18 uh*;yzm-+qj wsrihucleotide 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 s; z- 1+i 8rhjumyq*hswet 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 of the ribosomes labelled in th8qbj(cz c gd0/e micrograph?

  A strand of nucleotides reads CCUAGAGCUUACCG. Which type of pentose s5s k:r6)irsraf*pmr0ugar could be found in the nucleotides in th0 5 kr)a*r rsrfspi:m6is strand?

  Which of the following processes is most directly involved in the formationf prfv+ qh4et lf12f)pu(n(;i of nucleth 4lpf;f)ff 1rv 2(ne+u(qpiic acids such as DNA?

  What distinguishes uracil 1/hg)8 ozkfxn from thymine?

  Which statements are characteristicnceu)se ; 0(35w abweqnbu3h2s 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 ppsl(0d1x3d yimbr - :genome size (number of base pairs,dr 3 1p-l0 d(mpbsiy:x bp) for different species.

Which conclusion can be drawn, based on the table?

  How does the genetic code provide evidence of unive3+pisg(v b rg/9f8fxx( axs ;orsal common ancestry?

  The diagram depicts nul; u 4ere.4xto. vxip9cleosomes.

Gel electrophoresis is a technique often used to analyse1o*81wuxswa3d yt n6gmi9 **c /ihnag DNA molecules. It includes a gel and an electric field. The diagram below showsm8a g6 n wwguoi a1*3sh*xd in*91tc/y 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 transcripts47fh oescu*6h*v5di,u zwyd8 where the introns have bedisdhcf 5vyh6o**8euu ,z w47en removed.



What is an advantage of the above process?

  Which of the following is a similarity between transcription and translation? rki747d sa;fn.hh/ : en*cgye

  The diagram shows the structure of a DNduw dp. m :xoj-;pq1b:m9m n1oA fragment. Which bonds easily break and q9pb w: -o1mn1 :m;.xpjdodum reform?

  What would make one DNA molecule more stable than another DNA molecule? k6xxkh(7xtu (u19 qm8* aybud
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 prote(mly ,ojvs8 b g6y-w5 nn)s(kdin serves as the genetic m8w mbg,5s6ydkv((l n -onsjy)aterial. They 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 prew2;(8p mln92ab)ac)9dbn 22mtkkks,bdtpsocess are correctly matched in the table below?

  Which statement highlights the importance of nucleosomes in DNA q3ubm8q 2abo /5- gknten)n4tsupercoiling ?

  The image shows many ribosomes on a mRNA molecule. How many unique polypm:hgwpiiewv6p2zp q 99 /jp 24eptide chains ar ve4hp2zig6 w9 wmipp2/9q :jpe being translated?

  Which of the labelled structures shows the correct directionality of theyb4p/d9 jhe+2l xn9jh DNA molecule? hlj+9dn y4 2x9ejph/b

The diagram below shxahj/5vg2d *onk,k:wid :+h mows 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 involved cultured)1 j6axv uvkswt7f(*j w8a; il viruses that were radioactively labelled with eitsjxvula 8v*k7ijwa; f1w() 6ther 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 - qemm-bt .sh+b)a)ux bnd-f*S is a pyrimidine?

  How did radioisotopes help make the invu e8;1z*qi8 (n3tj e6fjwnharestigations by Hershey and Chase possible?ae nn1;w3hu(e j8tr zq*8jif6

  What feature of the DNA molecule was utilised by Hershey and Chase in o0kebilu +k5vznai b 9y79cgm08 dk3,nrder to identify that vir9iklvu b d835ab9iy7n+,0 m zknecgk0al DNA is able to enter host cells, but most of their protein is not?

.

The image below shows a short frag/dp. a*tud7m mment 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 componentsti*7gq2yywo - of one nucleosome?

  Hershey and Chase condu8v 4asn0a:yyv*f w b z86uh-n,2yprifcted 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 experimentc2 t +qgtoxa,+ conducted by a team of researchers investigating the relationship between the compositix+aq2ct g, t+oon and melting point of different 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 livingq qu3iv87pls,rmykc y 2fh/7 *e4avj1 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 feevz1l: emd) +(x gks:ragment 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.