Statements below show three double-stranded nucm u/oi0 8.hwdlleotide sequences. Which of theseh.u/ lo0wd 8im sequences of base 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 tetrai86va gu(b9if/c) ,bw;c fbrsnucleotide hypothesis proposed by8ivgab9i/ f, cb uc6f);ws(r b 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 structure, leading to the falsification of the initial hypothesis.

  What is the main role of the ribosomes labelled in12 c4xdn sc vlm8/km(bg0fcj 4 the micrograph?

  A strand of nucleotides reads CCUAGAGCUUACCG. Whicp6eh9qns1ec: yu2mr 9 h type of pentose sugar could be found h12eu q996n:mpyc esrin the nucleotides in this strand?

  Which of the following processes is most 1;qtb.c srjuk)xfq:8ob8c ,j 9v1xzhdirectly involved in the formation of nucl fq.sj)ox:bv kcc,88h9; xzqj1t1rbueic acids such as DNA?

  What distinguishes uracil from thyfql * ir,mru 8o m4ii -dy,il-)pt,dk7mine?

  Which statements are characteristics of he slef;73.s3ok 1eucd9jjvk5a3h44 ekbfk+ 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 (number of basexyb* 3a ngo9i3 pairs, bp) for different species. aiy* nbo93g3 x

Which conclusion can be drawn, based on the table?

  How does the genetic code provide evidenc(zd agk6( ; 0bhhm3ekgz)ndf/ e of universal common ancestry?

  The diagram depicts nucleo --r gpdli, +9sdgk9+ic*xzvxsomes.

Gel electrophoresis is a technique often used to analyse DNA molenh q0*rhz6 9jo3oly5 hcules. It includes a gel and an electric field. The diagram below shows the0jl5 nq y6r9o*ohzh3h 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 tranfrua1s )n8aj*i3 0ai sscripts where the introns have been removed.rua*3a80 fij sia) sn1



What is an advantage of the above process?

  Which of the following is a similarity between transcription ai050f za-.dpdorxcd s,n7u q; nd translation?

  The diagram shows the structure of a DNA fragment. Whicwax dt7 ;ijd( k8 nye.,0hxi.gyap9;e h bonds easily break and refoka70x t; n,i.8; (ddw9i.yajgyexp e hrm?

  What would make one DNA molecule more stable than another DNA me/ 8l2x a+ntc6wul8s oolecule?
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 infn q ty*7d8k,ivestigate whether DNA or protein serves as the genetic material. They cultured 2 batches of viruses, one in a medium containing radioactive8qf7,*ny itdk $^{35}S$ 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 tabl;pnh 8 si0zdtm3l* 5gre t-wf*e below?

  Which statement highlights the importance of nucleosomes in DNA supercoiling ?6 / v8a.8uw8ngmaayqps 4vqc,

  The image shows many ribosomes on adke)s)t)kum - mRNA molecule. How many unique polypeptide chains a ))tdkesmu)-kre being translated?

  Which of the labelled structures shows the correcyh i -lka7;qz+t directionality of the DNA molecule? -a7ky ihzl+ q;

The diagram below shows the structure of DNA nuqu10zllo2a*v n w6 hk6cleotides.

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 that were radik2jo 634 nx.biykk+e zoactivel4nz2e jk3.xikb+ o 6yky 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 is a pyrimidine? p2nr4- v2uh3(hmwpo vz+d 3ny

  How did radioisotopes help make the investigations by Hershey and Chase possiuw o/ 3u2av3qoble a3ou 3ovwq/u2?

  What feature of the D(jev 3ypki :d.NA molecule was utilised by Hershey and Chase in order to identify that viral DNA is able to enter host cells, but most of theiy.j pid(ek:3 vr protein is not?

.

The image below shows a s9 zqy+p,ilm6 ;/wb+ssc 8cvjzhort 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 ,bm0fx cl + 8i5hmq)ohthe correct components of one nucleosome?

  Hershey and Chase conduct4 l1znit(5cby1sys b3ed 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 resulm.f.e*t,kemora 6; z its of an experiment conducted by 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 separa a.etzimm6k,;. erof *tes 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 li .w:1lxp+t fwmnad02b ving 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 y(t:ro9k 1c onwy*:d3zl6 st-/u gru lthe 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.