Statements below show three double-stranded nucleotide sequ ,7ey lo*a;9 sodypse*ences. Which of these sequences of e,pea97* s soy;y*ldobase 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 thqol0*uny), n+6 coe 2mk+zclme structure based on 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 a limic)z*moon,clm6+ qk0ynu +2l eted 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 of the ribosomes labellef0+h:y/7nhon jm/nf(td -m ehd in the micrograph?

  A strand of nucleotides reads CCUAGAGCUUACcqum* a1pdsc. h5/.bhCG. Which type of pentose sugar could be found in the1 /hc.um*.shd5 bcpaq nucleotides in this strand?

  Which of the following processes is most directly involved in o (/*gy:( ony n.x az +hz-hexpxs6*jfthe formation of nucle6ns g/z*e :ax+ yjhh.xpn -(o*(ozfyxic acids such as DNA?

  What distinguishes uracil f5; :xu3s*8/ cg.*aeyf xf dr;uuj ynotrom thymine?

  Which statements are characte5r;6h6 *buw 9mm(vqi g(pmu wwristics 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 nucleoa g;;)n3us2y rn3 gbhbtide base sequence and genome size (number of base pairs, bp) for differeh 3a3r ; )bnn;bgsgu2ynt species.

Which conclusion can be drawn, based on the table?

  How does the genetic code provide evt d2gi2j)t *(cvj1yqw5 .hrh vidence of universal common ancestry?

  The diagram depicts nucl 9-roia(wo4uteosomes.

Gel electrophoresis is a technique often used to ack0:mxym5l *087 y r7uty5ag ef2nq 2;odlagznalyse DNA molecules. It includes a gel and an electric field. The diagram below shows the outcra50yzlo;mfyk c7mu :nayg528ltd g7xq2e*0ome 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-mgg2ti q6dqb., RNA and three mature mRNA transcripts where the introns have been,qq . dt6bg2ig removed.



What is an advantage of the above process?

  Which of the following is a similarity between transcrzfg z)t l0 k.:i eh2xw0eyz4m1iption and translation?

  The diagram shows the structure of a j ck:nmt),zw ek 8**gmDNA fragment. Which bonds easily break and refke,m 8mkw) nz:*c*tjg orm?

  What would make one DNA molecule more stable than anothedd0vgfttl(;p56t9 l xr 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 investpzz3ih: yg9+wci3 0itigate whether DNA or protein serves as the genetic material. 30ih pyz w:ii 3+gz9ctThey 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 process are correctlylraji,q 3+;lh matched in the table below?

  Which statement highlights the kb98 w7h ekh;i2 q ndnplm58o/importance of nucleosomes in DNA supercoiling ?

  The image shows many ribosomes on a mRNA molecule. How mx0vmfb17t z4yrm0w:dx m q w)-any unique polypeptide chains b:0wvx-7m0zf y qdt)xwm r m41are being translated?

  Which of the labelled structures shows top ;5u:oja5iphe correct directionality of the DNA molecule?i5u5o:pj pa;o

The diagram below shows the structure of DNA nucleotir6bp 4 pa1 gw6dv;ntl*des.

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 cultur3fpe )h7 )vnpeed viruses that were radioactively labelled wivpneef7 hp3))th 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 pyrimidine? ofp1(de v 1ihys1q 0brxv m,*/

  How did radioisotopes help makews d 7(4/tnnfi the investigations by Hershey and Chase possiblewfnt7n s(/id 4?

  What feature of the DNA molecule was utilised by Hershey and Chase in order to 7u v 8wb2g wiunt9hkx.o0sq65jg:g f7identify that viral DNA is able to enter host 5:0u8.i twqx ug79g jov 7bknwf6sg2h cells, but most of their protein is not?

.

The image below shows a s13 qt(zwvw q4yhort fragment 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 thee+:7b,bf ygy c correct components of one nucleosome?

  Hershey and Chase conducted experiments usi*/ fa z5 t3aivhgwk+b-ng 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 reuouo.83zttax a )(k2 xkm(3 iysearchers investigating the relationship between the composition and melting point of different DNA samples. At the melting point, the DNA double helix separ8 3uzx m kttoiay(32xu (o)a.kates 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 k2o81ub988:yp-hx dljucqro 9ez u;tessential 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 a4dn eku1;;,oby m9yz6x5yh 05 sp( z trdcyk3of 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.