Statements below show three double-stranded nu rxwa2g6 -h8p3:ki: nznx,g lycleotide sequences. Which of these sequences of3 ngaxyx h :rl 8gk-nwp6z:i,2 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 tetranuclca,cjo)f 0z h.eotide hypothesis proposed by Levene that DNA was. jz0 ,)faochc 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 in the (a0rfg) qfj; bmicrograph?

  A strand of nucleotides reads CCUAGAGCUUACCG. Which typ-x;as rxsaw:tk */7 gre of pentose sugar could be found in the nucleotides in th*-7:xg s;araxt s/wrkis strand?

  Which of the following processes is most 34 4f;xykbud afhwe3c0 ()x7bj/vwcddirectly involved in the formation of nuclbuahfdc/3kx04 3 fjdw7x )cv;be 4wy(eic acids such as DNA?

  What distinguishes uracil cm 4a48t7w2 ss tff m3d,at3ldfrom thymine?

  Which statements are characteristics of a DNA molew)7 e*,nptif( t/pygyl**b ckcule?
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 base pa+lgfq br 9u ico0+12bxnsm()lirs, bp) for differ1clrlbq 9)(x+ s0f+gum2bn oient species.

Which conclusion can be drawn, based on the table?

  How does the genetic cod (g7x:ndk s ocbo +3unl+;.vrxe provide evidence of universal common ancestry?

  The diagram depicts nucleosomes rykplm 5pb01/.

Gel electrophoresis is a technique often 5* me vdua2n znd1.12nehhak+used to analyse DNA molecules. It includes a gel and an electric field. The diagram below showsu dz* h+nd2kme.an 1vneh5 a12 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 transcripts where+wkg6;tavd3.i r qr-v the int;- 3kr 6qvtrigad.+vw rons have been removed.



What is an advantage of the above process?

  Which of the following is a similarity between transcription and ,a8q- t+xkzam wxce: i)+b;uctranslation?

  The diagram shows the structure of a DNA fragment. Which bt:+;y/35cs ovypt di80w tjdr onds easily break and rets;/v:d0t3wot pr jyyd58+ciform?

  What would make one DNA molecule more s mr1fifcy9 7s27bu 7ybtable 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 condu4n a j4b.l.gxycted an experiment to investigate whether DNA or protein serves as the genetic material. They cultured 2 batches of viruses, one in a medium c4 4a. nyljgbx.ontaining 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 mwmo82ij .)ctmgc4 j r2);zhlp atched in the table below?

  Which statement highlights the importance of nucleosomes in DNA u3 ,dh7 0*weu5;rfkhd5 kws23szpoq lv1dg)xsupercoiling ?

  The image shows many riboso7 :3bt o;banrqmes on a mRNA molecule. How many unique polypeptide chains are :b 7qan; r3tobbeing translated?

  Which of the labelled structures shows the correct directionalpn- m.yex4 7 rsn7vno-ity of the DNA molecup r nx-ve. nn7-m47soyle?

The diagram below shows the structure b;/t8p.g+ jcp j8jb lgj)appb q 74ns1of 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 in 1952 involved cultu+/c*k i7woj:-b vjq phd-.bupred viruses that were radioactively labelled jbu7h*w: q oc+pkp /-.-jvib dwith 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 iteg hw. ud(3nj9jfei( kf6/ 2kf S is a pyrimidine?

  How did radioisotopes help make the investigations by Hershey and Chax9cz :vvndh53 se possible?hv 5ncz x39vd:

  What feature of the DNA molecule was utilised by Hershey i3+mki: rntr* and Chase in order to identify th3i mr:kin+tr* at 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 mou xh+8,f dn9 nlx.vys+lecule.



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 m.xomk67l9 zbz5zg ,lcomponents of one nucleosome?

  Hershey and Chase conducted experiments using th t5,l3g ol7u2no9x rdie 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 resear-of.g5e bl+ga chers investigating the relationship between the composition and melting point of different DNA samples. At the melting po glf.abg-e5+oint, 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 nuclei dp/;k+vqvixa6ue to dr.)z(8c 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 f mx8ajzz.3 w-vragment 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.