Statements below show three double-stranded nucleotide sequences. Whicu;tsthep -982o oyd/g h of these sequences ouooe8h t 9; s2dyp/gt-f 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 structurzzz b/edf-(fpd( ;7br e 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 a limited set of data. Su(dr d;bz/f- (pbzz f7ebsequent 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 ribosomo.7 2sxpkpf:hes labelled in the micrograph?

  A strand of nucleotides reads CCUAGAGCUUACCG. Which type of pentose sugar cou nmlhs ipx r6xjy1( ,f000doc6ld be found in the nucleorn0hoyp6i0lxsdjcxm6 0f ,(1tides in this strand?

  Which of the following proco.+ kr 0h/ cfevwgvtka/,t;p8esses is most directly involved in the formation of nucleic acids such/vw+tv8c;0 g fop /hrte.kk ,a as DNA?

  What distinguishes uracil from tn zri2e97c8ab hymine?

  Which statements are characterwx/a- fzfy+ad xaof8ml ;h2z) u)q;9fistics 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 nrte p,,x7xf4a5v,fo fucleotide base sequence and genome size (number of base pairs, bp) for differenr,e7fa ,xtf f4vpxo5, t species.

Which conclusion can be drawn, based on the table?

  How does the genetic code provide evidence of u ;garj47.nkvbh 62+d a pvz+coniversal common ancestry?

  The diagram depicts nu(; g gtw/s8ponppgq+8 cleosomes.

Gel electrophoresis is a tekpgj.4g ko0 f.chnique often used to analyse DNA molecules. It includes a gel and an electric field. The diagram bo.p 4kfg0jk.gelow 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 trgnb750mbhg v9 anscripts where the introns have been removedngm bbv 0h97g5.



What is an advantage of the above process?

  Which of the following is a similarity between transcrip-iqzl; g8j+w 3akz6 ul,smy/dtion and translation?

  The diagram shows the structflfh.f 4jg1:u pf3eecd()o79 zf2w raure of a DNA fragment. Which bonds easily break and reform?a l j.ff g e49fcewf23hzpu1(fo7:d)r

  What would make one Db5 ;3w.la0l kpz(vpsw NA molecule more 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.d ms52j j eb2:q* okyofyli)e(n2m*a or protein serves as the genetic material. They cultured 2 batch je5k2:j* y(fq)oy2m e il* b2m.nadoses 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 aa2pjmja fu617re correctly matched in the table below?

  Which statement highlights the impor* f78zn;z6ssqje0,s cbn/axa tance of nucleosomes in DNA supercoiling ?

  The image shows many ribosomes on a mRNA molecule. How many unique polyf +33vcfctrt1 lualb3r*f ,r/peptide chains are being translated?fl+/ f13r *clb ,fv 3c3ttarur

  Which of the labelled structures sh19yofbk5tr5gnp;v k 0qx9 1 bpows the correct directionality of the DNA moley;11kxbrfp 95 9pgtn0ovk 5bqcule?

The diagram below shows the structure o+xup +ovkb/(hj+9h c xf 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 involynp b;c*ig6g x)74xpwved cultured viruses that were radioactively labelled ;xnibwx74gpp*6cgy) 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 pyrimih*y a kj;z-bq6dxe*e-dine?

  How did radioisotopes help make the investigations by Hershey a0vsmw+tje b id)/4 ;idnd Chase possiblew;ms+i)v4/i0eb tdjd ?

  What feature of the DNA molecule was utilised by Hershey and Cxi+7/kwac f vc6h.uw (hase in order to identify that viral DNA is able to enter host cells, but most of their proteincva6i/ uw.x7fc(wh k+ is not?

.

The image below shows a short fragmz8/o70mnim scnux2 y3 ent 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 corrlvf 5o5aw;z7k kgy 6.bect components of one nucleosome?

  Hershey and Chase conducted experiments using the radioa+5n opet4(wxbq)hk +y/n29mopnfloub93 k e;ctive 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 do7t;3np4igt 6j io ;aa team of researchers investigating the relationship between the composition and meltoajig; 7n ;i3dtpo46 ting 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 thatv;(i3 to7uav z:fic i,a,la0j 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 of the DNA molen3w ai w/uf*46xc: 1fzau* vuscule.


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.