Statements below show three double-stranded nucleotide seque,3r4 td+a x yjnf y(a cg.x.cxpl592nrnces. Which of these sequences of base pairs(9xcxyf.3.d pryncg5 x2a4 ta+rl n, j 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 tetranucleotide hypo-u.9c)xwf 7paoujuw /x p5 n8h;vraw:thesis proposed by Levene that DNA was made up of equal amounts of adenine, guania 8pa/p5 jufwxv)9 :r nhww- 7.cxou;une, 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 rolest2hqm rfrd9b 0mh6d .k 57-et of the ribosomes labelled in the micrograph?

  A strand of nucleotides reads CCUAGAGCUUACCG. Which type 9nuel-k+s0yi;am1cd of pentose sugar could be found i1+dauise0c-m9 n kyl;n the nucleotides in this strand?

  Which of the following processes is most zivh 2* gm:w+do*w qku )on+y-)nsz h;directly involved in the formation of nucleic acids sucnhzz:uno;mwd h g yv2i +w )os-*k+q)*h as DNA?

  What distinguishes uracilg.l+yo8y phgbx ncer w2; ;6w5 from thymine?

  Which statements are characteristics of a DNA molec2pa s3iq0fj2k ule?
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 ocy 5exmr,lp;)f base pairs, bp) for different species. rp c;xm l5y,e)

Which conclusion can be drawn, based on the table?

  How does the genetic code provide evidence ofc8bb1c r*4m zznqt 5x8 universal common ancestry?

  The diagram depicts nuclecm-ssle8:, smt.pbl 4 osomes.

Gel electrophoresis is a technique often used to analyse DNA molecules. 2j:f*a2uintg ll8 fkwfg-3-qwko f(/ It includes a gel and an electric field. f lgwf8 k2(- ol*tua/jqw32kf-n gfi: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 three mature mRNA transcrx mnqs09elb f;vt6s z) ji496eipts where the introns have been removed.men;j06 i s9svxf)tl 4qb6ze9



What is an advantage of the above process?

  Which of the following is a similarity between transcription and trao3w6vc mp0wp, ;o/qppnslation?

  The diagram shows the structure of a7f2 vdc9tep,n s rz)y8n /k:bj DNA fragment. Which bonds easily break and re p:yst de7k 8z2rfjv,nb9c/n)form?

  What would make one DNA molecule more sq-iomw;oqekix77 4*a table 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 w7pve + 9,xo ruq:zu8cinvestigate whether DNA or protein serves as the genetic material. They cultured 2 batches of viruses, one in a mediuw u:u+eo,r8cpv 9 xq7zm 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 cpega+,rja :o1+ nmjg or),9osorrectly matched in the table below?

  Which statement highlights the importance of nucleosomes in DNA supflcrribt4*,;pb (27t-ku bi lcvgr ml; m+4 (iercoiling ?

  The image shows many ribosomes on g6 fhcie gs813+xc,xs a mRNA molecule. How many unique polypeptide ch1gc xsh x3+efi8g,cs6 ains are being translated?

  Which of the labelled structul8x/1qenh 2* v/ediuy q3v,y njwkl 58res shows the correct directionality of the DNA molece 8/id2 3lhj8/kw,vqluxyney*5n1qvule?

The diagram below shows the structure of DNA nucleotq0sd4m8 n+;;htks azw ides.

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 )to8is uqyj;x.zq1, g cultured viruses that were radioactively labelled with q iyq)g1xz.,sju o 8;teither 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 iftooasw y) cvo -0 77y utm871awx7m qon7ym0o/ S is a pyrimidine?

  How did radioisotopes he -n+p- kg)iedclp make the investigations by Hershey and Chase possible?i-d-negc ) k+p

  What feature of the DN x5n9 clzg)y7fA molecule was utilised by Hershey and Chase in order to identify that viral DNA is able to enter host cells, but most of their protein i5 z7flc )9nxygs not?

.

The image below shows a short fragment of theor9x3v*e)f w ,az)r9e m3wz ye 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 the correc31: tmcrz.15u muxxzgs.prq ,t components of one nucleosome?

  Hershey and Chase conducted expm oprvk5- zv;+qd 3;coeriments 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 experiment conducted by a teqzm g7:v28eofc z7 bt-am of researchers investigating the relatiof7gmo-:zv qc2z etb 87nship 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 arer- j e(cuwxilj2;(o/*jqjo 2 s 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 shorw0r ea-neyb,(uv3j /-lq7 rj pt fragment 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.