Statements below show three double-stranojuv; 96n+xp.fb)k boded nucleotide sequences. Which of these sequences of base pairs is xju;bo .kvfn p)9+o6 bpossible 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 tetranucleojvs o; c t4l383d3o(65-wyk ufruxecbtide hypothesis proposed by Levene that DNA was made up of equsoudl4u 8wrxtovb3y(j3;eckc3-f 56 al 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 in the micrograp0.txxzd 2b +fth?

  A strand of nucleotides reads CCUAGAGCUUACCG. Which type of pentose sugar couj k14lr-ez t;jld be found in the nucleotides in t kz;4let1- jrjhis strand?

  Which of the following processes is moszov .g 34pj r-txc0zzr(f+,hpt directly involved in the formation of nucleic acpz3+h,to-r.cj(g0r zfv4 z x pids such as DNA?

  What distinguishes uracil fromv*4t6:qogl x6 4d2/el sut.,j tumgc j thymine?

  Which statements are characteristics of a DNA moleuh ;b*:)lj;igbqq. dyz 2hl9bcule?
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 d 2ynv. n u8:b:aimqd:and genome size (number of base pairs, bp) for dif vbuy::. 8:amdidnq2nferent species.

Which conclusion can be drawn, based on the table?

  How does the genetic code provide evidence of universal 8aw)y0dm qa e/common ancestry?

  The diagram depicts nucleosome cy34g:qjm ()tg8espv 8s xyu6s.

Gel electrophoresis is a technique often used tonhp74us1 8 *nmy b fbc-(gv+py analyse DNA molecules. It includes a gel and an electrichbg-ps7+v4 * n(cpy8fm ybnu1 field. The diagram below shows 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 three1c6 uvlvr92 h)l3n 9z hfw/uyh mature mRNA transcripts where the introns hcvny9 hr)vu6 u3hhll1z92w /fave been removed.



What is an advantage of the above process?

  Which of the following is a similarity between4ryuofv* yb :x-/)ionpx+iu p:ec/2u transcription and translation?

  The diagram shows the structure of a DNA2bloj0)o sz;* g5g8wcg e rxw0 fragment. Which bonds easily break and re5xwoge 0w zjs 0*r)2 g8b;lcgoform?

  What would make one DNA moleca1j pze -zx)m w6ot/aw3 ,jx2cule 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 protein aun4y s:isn **se* u: y4ssna*inrves as the genetic material. 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 process are correctly matched in ana9ic(z+y l) the table below?

  Which statement highlights the importance of nucleb 2)jouf,mxew405t dj5a5hdcosomes in DNA supercoiling ?

  The image shows many ribosomes on a mRNA molecule. How many uni8qpjey,ed 4*mque polypeptide chains are bei*e8 qp ,mdye4jng translated?

  Which of the labelled structures shows the correct sy77-1ueh4+ ug--o kqshp ij xdirectionality of the DNA moleh k-7x-ysh o1s -p +7qiujgu4ecule?

The diagram below shows the f9l gpdz-*vc8,tm+ v x- 4fuemgw j -;c8zp*qzstructure 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 iuq wtnjpn+ vr84 (-th5n 1952 involved cultured viruses that were radioactively labelled with either sulv-wt4p+ n8 qu(rtnhj5fur ($^{35}$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 p01rai jbu bkh1kcndm8q6 /;(u yrimidine?

  How did radioisotopes help make the investigations by Hershey and Chase pos d 3yv;)1y+ar1ezocu vsible?zaoyu1 +ec rv)d1y;v3

  What feature of the DNA molecule was utilise2+*dxd7fi ppkdp tu97d by Hershey and Chase in order to identp 9* 7kdp+dxutf2 pi7dify that viral DNA is able to enter host cells, but most of their protein is not?

.

The image below shows a short fragment of the DNA molecule9gnfgw1 :dtd ,.



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 correcti:nnpcks0z6 a23au 4 b components of one nucleosome?

  Hershey and Chase conducted experiments q aosu8bmw/- )h-..i :z cxbv8*hznwrusing 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.kgpoc 1:d.tr akljx3 9-h s6m team of researchers investigating the relationship between the composition and melting point of different DNA samples. Atr:kl-m xd9jcg1a ko3 st.6.h p 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 pd;+nf4o 4u. 9ksuw0fs f4hb qessential 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 of the DNA molecu2zmct.x to7j h)9o) ywle.


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.