Statements below show three double-stranded nucleotide sequences. Which of these5g3ynzjow v2: sequences of base pairs is p3gw :ny5o2vzjossible 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/xcck2tz;2 rc nk xg2tpz. +2un3wmv) 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 a2zt cxn )3n2. m2tukkwvr+xcp2zc; /g 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 /w;*knroiutw g0qpcrvi 6io;7l2w2 3 ribosomes labelled in the micrograph?

  A strand of nucleotides reads CCUAGAGCUUACCG. Which type of pentose sugar coul+ +qyuzsu9:e/+mi -u, qe vmbgns4f4ad be found in the nuc ue4ugqs vi-um,q:n4 zy+a+ m+ /b9esfleotides in this strand?

  Which of the following processes is most directly involved in the formatio/ 2gal(j6zo iwn of nucleic acids such as DN/i o(zjw la62gA?

  What distinguishes uracil fro;,xz*z u.r kvqm thymine?

  Which statements are charac8.fcuv) s ,m wee9d-utteristics 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 nucleotii,b:t g9jcw ;h t.jm:gqf.5dwde base sequence and genome size (number of base pairs, bp) for different specigt:;.cjwbj9,i. qm d h: tf5gwes.

Which conclusion can be drawn, based on the table?

  How does the genetic code provide evidence of universal common ances;kw fca*gxr6-f zkm 8m-* hz7atry?

  The diagram depicts nucleoszh;mem 7xy:3:wo xxuv:-s 2azomes.

Gel electrophoresis is a technique often used;fs wa(3n,z jb03zfkk to analyse DNA molecules. It includes a gel and an electric field. The diagram below shows the outcb k3; kws,ja03f nfz(zome 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 transcripts wh8rhz6 t bx0bf.ere the introns hb8rhzx6t0 b.fave been removed.



What is an advantage of the above process?

  Which of the following is a similarity between transcription and 6jp7i:+fy-l06 qf finvn6toi translation?

  The diagram shows the structul c za t,5d :k6z2)agl4kb)oisre of a DNA fragment. Which bonds easily break and reformc,a) a4bo l6 d:gzt5lk)si z2k?

  What would make one DNA molecule q+brke026 +ddqr l 2cumore 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 s 71ua j5kkxa:or protein serves as the genetic material. They cultured 2 batches of viruses, one in a medium containing radioactivk1sk5j u 7ax:ae $^{35}S$ 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 ar*v a x:ff*a o (xq5 tk+lrl/wi9g,ztm1e correctly matched in the table below?

  Which statement highlights the importance of nucl mch z d,vcs2e8y754m*b bqsqb 5vo3cdzdw* +.eosomes in DNA supercoiling ?

  The image shows many ribosomes on a mRNA molecule. How many unique polypepti/c 5ih2d5ov*q 1q u3wsvlat trwda 1 v,5gt0n9de chains are being translatu9 v,t* o q2a5/5c d3n1vwi d1slv5hwrgt taq0ed?

  Which of the labelled structujw m : ;;*xj4hbwk.yn)cv*lt bres shows the correct directionality of the DNA molecul * hl.:bn;w);m k*jvy4jwctxbe?

The diagram below shows the structure of DNA nucleotid+ ,uvgay*m 9yres.

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 exp5v+q u aqci8r;vwsei 1(lf-ajzp 2*b2 eriment in 1952 involved cultured viruses that were radioactively la5f lcasju ia; pzeq(q*v2ibw1v-+r8 2belled 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 pyp-9m+cp i bt9urimidine?

  How did radioisotopes help make f 87:drv/ yrixthe investigations by Hershey and Chase possibler/: f8rvd7 iyx?

  What feature of the DNA molecule was utg4)ji(,a6w2rshrc xw, zp3 ,szsaj(ailised by Hershey and Chase in order to identify that viral ( ,c zr2zjsj,aari ,gpw hxs(3)4w6saDNA is able to enter host cells, but most of their protein is not?

.

The image below shows a short fragment of the DNA f; lbqfv4l(:9gxe-my 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 components of one nucleosom9 pyvjt 2-vx)fe?

  Hershey and Chase coog)fm+k0j.ggo/ ju7g3 q6tso nducted 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 expo+,eaju)qgi-m wu m05eriment conducted by a team of researchers investigating the relationship between the composition and melting point of different DNA samples. At the melting point, the - +, 5qoe)wmguuam0ijDNA 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 e r;n/oc6ytk -acids that are essential 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:g;d 6 kspnjxvp7 iuo(4b2iq0 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.