Statements below show three double-stranded nucleotide sequences. Which of these4h pogt g,bw ahh(ax:)ra /,si80p6fr sequences hb4 a 8:fwhh/gaps ,o,r)xa(prit 60 gof 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 bdu28z;u, 2smzojom g+ ased on the tetranucleotide hypothesis proposed by Levene that DNA was made up of equal amounts of adenine, gudj 2mgo,;2s+ u8z umozanine, 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 thetue8ga 2z75n b micrograph?

  A strand of nucleotides reads CCUAGAh q;kmyg .i z3m9i0ge.GCUUACCG. Which type of pentose sugar could be found in the numh0.;gm.k ge3iz i9qycleotides in this strand?

  Which of the following processesibu+-t2c 6fwd is most directly involved in the formation of nucleic acids such a+ctbd-w 2u if6s DNA?

  What distinguishes uracil from thymin9jz/ e3y ((3r0asd vqqtjfc9c e?

  Which statements are cha/e zao4vj /wd8racteristics 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 sz key l:r oo/;6u1rvd5equence and genome size (number of base pairs, bp) for different spoy;v 6/d1eu5kz:lr ro ecies.

Which conclusion can be drawn, based on the table?

  How does the genetic code providei k:kdkf;uotp+ : g sl2och.(mk;-(bh evidence of universal common ancestry?

  The diagram depicts nucleosomes.vf(f*.t zr,gu

Gel electrophoresis is a technique often used to analyse DNA moleculpe. h jv-vjntz /misr+d;b6:,b)6h oyes. It includes a gel and an electricyv-hmj jbv.nhts:, 6 +;)/dr6eizbpo 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 three mature mRNA try4yu sf..r q2yi-,disanscripts where the introns.fr. yq i4sy2uys,id- have been removed.



What is an advantage of the above process?

  Which of the following is a similarity between transcription and trsn9te2) a 8dylanslation?

  The diagram shows thqm7f 9k.6lz mze structure of a DNA fragment. Which bonds easily break and refo 7fmz96qzlk.mrm?

  What would make one DNA molecule more stable than another DNA mol)db:v5vsjde29/ okc 0ftj v c2ecule?
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 wh pag(c/9khy8c5 8bjrp ether DNA or protein serves as the genetic material. They cultured 2 batches of viruses, one in c acy89ph r5pk(/ j8bga 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 .xsl 6t7ut.n0m6jiuv in the table below?

  Which statement highlights the importance of nucleosomes in DNA )ln bceybn5 l7at, 7o3supercoiling ?

  The image shows many ribosomes on a mRNA molecule. How mayfcqyic,nd 2 0apkx 2h4a /c:.ny unique polypeptide chains hai kq:f42xd 0n2p,c/yc.ya c are being translated?

  Which of the labelled structures shows thx9j 7za5jywf7h*n +sq fyo5 n3e correct directionality of the DNA molecul*3qy59jw n jf7o7+hnfxs5zaye?

The diagram below shows the structure . s,.aq0vx*, o dfd 8wopi,npeof 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 1952w -e yaf-owa plq 1b5*+6ryi8w involved cultured viruses that were radioactively labelled with eitbafq18w-wi*y+65w ya p-el o rher 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 pylg ww8mhpv0. hbm4txy67a h12rimidine?

  How did radioisotopes help make the investigations by Hershey a5ghntk1jb6 kw62e1u dnd Chase possiblen6 wgkjt1e 5u6bkd1 h2?

  What feature of the DNA molecule was utilised by Herzlq (lo)z 4hzdr4c ..xshey and Chase in order to identify that viral DNA is able to eo.crlxq zhdl ).4(zz4 nter host cells, but most of their protein is not?

.

The image below shows a short fragment of the DNA (n1hanc:s+wi 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 componj; uu3hid:f;vcqqptf+u.:xmbh62 -m ents of one nucleosome?

  Hershey and Chase conducted experiments us82; ,vfyrsb,i ed0bjxing 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.yeim3 *b aws0 w tw-j;htwp12 conducted by a team of researchers investigating the relationship between the composition and melting point of different DNA samples. A*wp 2 h;ai3 w.1j- w0ebtymwstt 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 estqd4f1, d u4blsential 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 et(,o5+uf sopa short 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.