Statements below show three double-stranded nuclle21saalqt;ys -ax 1 :eotide sequences. Which of these sequences of base pairs is possible in a DNA molecul:x-ltya2sqs1e1l a;a e?

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 sp9xnel 18up 3ttructure 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 baseteu39ppnx 81ld 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 micr.qyef 6+a9kc f x,qa6lograph?

  A strand of nucleotides reads CCUAGAGCUUACCG. Which type of pentose sugar could qwc2m)f 9jal .be found in the nucleotides in this strawl 2f9).caqmjnd?

  Which of the following processes is most directly involved in the formation 2p x7ai+u5n6gjtpoq 7of nucleic acids t77 a ppgn6uxo5qji+2 such as DNA?

  What distinguishes uracil zbk25 rvd,fs5from thymine?

  Which statements are cha.fxu(l jk:n)h racteristics 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 nucleotide base sequence and genome m7/kp)v2l r:pusry1a47 rgbhj80 r ml size (number of base pairs, bp)lrvl8r07 b1ak)y 4m:hj/ur2pm psg r 7 for different species.

Which conclusion can be drawn, based on the table?

  How does the genetic code provide evidence of universal commo4n6 m g yu66sagd)vwngjt5y s3 b/0fu/n ancestry?

  The diagram depicts nucleosomes. t +odstuq-t mfrwp8*6v/gy66

Gel electrophoresis is a technique often used tom:bk17jc5iq58zmo 00exbf gb analyse DNA molecules. It includes a gel and an elf k07m: zjicgbo5b50xbe18qm ectric 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-m9w4at,aam 0c m)l //5f dgacxtRNA and three mature mRNA transcripts where the introns hava f0a/a4clmd,ta 5xtm)cgw9/e been removed.



What is an advantage of the above process?

  Which of the following is a similarity between transcriptiop je64 wouzdex3* z34xn and translation?

  The diagram shows the structure of a DNA fragment. Which z vosgus-a qux1 9,l**bonds easily break and refo*uvs,1slux 9o- *qz garm?

  What would make one DNA molecule more stable than anothezd052mzv+ dcmta7 d( oela1tw8 s1ih )r 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 expe2weeq12-nmb3av3g 7um , c lqtriment to investigate whether DNA or protein serves as the genetic material. They cultured 22me72qaevqmnw3gbul c, 1- 3t 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 5z potvsl153hmatched in the table below?

  Which statement highlights the /zxtxs 3(.g;s+joow 5.nrzpkimportance of nucleosomes in DNA supercoiling ?

  The image shows many ribosomes on a mRNA molecule. ka s8umv8+j t2How many unique polypeptide chains are being translated? 8mu+vsj 8ak2t

  Which of the labelled structures shows the correct directionality of the 6tc zbv (;r.csDNA molecule? z cs(;vt cr6.b

The diagram below shows the structure of DNA nucleotidesyv6hhzwv0 e9;13f z kv.

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 plnf4+ wac;c2that were radioactivelpc4l f+2; cnway 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 pyrim5y;en 8,s v0t:kxxese idine?

  How did radioisotopes help make the investbicn7 ejd7q5 :zs:l (aigations by Hershey and Chase possiblebs:7n:c7q5jd(a lei z?

  What feature of the DNA molecule was utilised by Hershey and Chas- w:dc r)rnh3re in order to identifncrd) w:-rhr 3y that viral DNA is able to enter host cells, but most of their protein is not?

.

The image below shows a short frz.932oh5. x, q*2m :ogkv j 5ajpibjyavgfbk3agment 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 the correct components of one nucleosohk2:7tfna v, lunsb t h-- wleg)aymx5 qj)9+(me?

  Hershey and Chase conducted experiments using the radioactive isotopes8j6 jb a3(ei 8tlpia2t $^{35}$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 co 3;+pcdcx7wg knducted by a team of researchers investigating the relationship between the composition and melting point of different DNA samplesxd 3 c;ckgp7+w. 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 are essential to all livi( eqlo(j ;snq nhx7:.vng 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 sx(2l gbm/3cet l0k6, ,emwma5d : fmwfhort 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.