Statements below show three double-stranded nucleotide sequences. Which of thesefq(3 nldhr44 i sequences of base pairs is possible in a DNA molecqf3hlid44rn (ule?

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 tetranucleo:v8fzyuatbh1i2y lm8e: wz*8tide 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 struibhef 8tza*:yy8m81vu wz :l 2cture, leading to the falsification of the initial hypothesis.

  What is the main role of the ribosomes pgxruw.+7m/lv5p4gf labelled in the micrograph?

  A strand of nucleotides readsp u-w 3 zu1c/jxwok.2s CCUAGAGCUUACCG. Which type of pentose sugar could be found in the nucleou 1c3joz-p2xs. wk/uwtides in this strand?

  Which of the following processes is most directly involved in the formation ;a jnqg5.zba3of nucleic acids su3q.nb 5aj ;azgch as DNA?

  What distinguishes uracil from thymine?cq lj+fhh9 d qpk9*59t

  Which statements are characteristics of a m, aaugk2,(: j;twi vlDNA 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 nuclz sm qodgc*;lrq *0y -51vbj7oeotide base sequence and genome size (number of base pai507vzc d ymg-jloo;sqr* b q*1rs, bp) for different species.

Which conclusion can be drawn, based on the table?

  How does the genetic code provide evidence of universal commonu6q8o6 4a1s 7g6 *cfogqke0 wsftl9jp ancestry?

  The diagram depicts nucleosombff8e 9ar7x,so3 gdh, es.

Gel electrophoresis is a techniquedu:iyo mop)s;hltk5ez9u 146 often used to analyse DNA molecules. It includes a gel and an electric field. The diagram below shows the outcome of gel imt:k souuh4z1l)e op 5;6 yd9electrophoresis.


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 tr3ke qykk,c0 4panscripts where the introns have been k3kpe y, 40kcqremoved.



What is an advantage of the above process?

  Which of the following is l0-ypfm:x0, zb8zuyq fb,:pka similarity between transcription and translation?

  The diagram shows the structure of a DN )ilu5vxi(5lx A fragment. Which bonds easily break and r uxil)x55 vli(eform?

  What would make one DNA mol3 +hs flbb/j7hecule more stable 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 protevp,l bjy53bf9:8a1 g si ghl,ein serves as the genetic material. They cultugl3vs,:p by gehf1 ,ja 5li8b9red 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 processy2m/b )edz. d46kejfu are correctly matched in the table below?

  Which statement highlights the importance of nu2 ,nwe)cepnld 18lq0zcleosomes in DNA supercoiling ?

  The image shows many ribosomes on a mRNA molecule. How many unls ng j 7qt8gxj7 jqdu4:+-um/b*w2 inique polypeptide cha2 n/tj:xul-g+jus mn7d*jq7i q48bgwins are being translated?

  Which of the labelled structures shows the corre ,bh hry9 tucw0k-/s/47diezd muri6/ct directionality of the DNA molec,hd d46- t/79 wrikh u0// rzemcisbyuule?

The diagram below shows +a3o(yfb kry9 )zsyv.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 viruses th c*ej.xo 83f f1rimfj. 4fap(tat were radioactively labelle3.o eifcj4 .pm1xrfat 8(fjf*d 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 is a 1qr o9e/ g.hywpyrimidine?

  How did radioisotopes help make the investigattfl .i) o3 w4drk;ngp:c.lsx -ions by Hershey and Chase possible?nc.)4- kflgi t; l:sd r3xpow.

  What feature of the DNA molecule was utilised by Hershey and Chase in ordiu ,lji(n57jr0a+uu w er to identify thati+,0n a 5lwj7u( ujuri viral DNA is able to enter host cells, but most of their protein is not?

.

The image below shows a short fragmen9bnvq/ft5zq ) t 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 z/)cv(51u hkc2f ewsda 6vfb6shows the correct components of one nucleosome?

  Hershey and Chase conducted 9;ve msbqs na7pl+2w8experiments 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 rxpz9 t x-g.m5o +ti:lh2-mikbesults of an experiment conducted by a team of researchers investigating the relationship: -2. mil+ki5tptx mxh9- gbzo between the composition 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 living o hb mcpo95doit /9 4us+udatqbb g)e 1m;s74f0rganisms.
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 fragnb.7d4 cn/v(,xopntw :co l ;wment 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.