Statements below show three double-stranded ,.y,v : ljo 1m5 czl7lvrgxiq/nucleotide sequences. Which of these sequences of base paivo y,q/57l .xvcm:l1z,rgl jirs 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 hypothes q4l*bppl/+ ihis 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. Subsequent evidence and data revealed a more complex and accurate understandingl4/ blip+*qph of the structure, leading to the falsification of the initial hypothesis.

  What is the main role of thes7e 2;lc0fkb c ribosomes labelled in the micrograph?

  A strand of nucleotides reads CCUAGAGCUUACCG. Which type of pentose sugar could .0rlq)xvjxy:p/nd-j tq95x f be found in the nucleotides in this st:j)59 .ql /rpnjqvdt-f0xx yx rand?

  Which of the following proqi,tu3m;,xgz- os :k ocesses is most directly involved in the formation of nu-o3: i,mksq;tzguxo,cleic acids such as DNA?

  What distinguishes uracil from efu+uzp - f26tes0g)uthymine?

  Which statements are characteristics of a DN7c5/ uezep84j efysik,2dpq )A 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 seqk(a22r8yx eve;cimt d, nm+yuq4c9m+uence and genome size (number of base pairs, y2cu2(x cy+ kvmnr+q8m ed;t49 ae,mibp) for different species.

Which conclusion can be drawn, based on the table?

  How does the genetic code provide evidence of uningf :))zb.+wj 6ekdxnix7k 1 aversal common ancestry?

  The diagram depicts nuc67nk(k5g f3gf/ cek -gjhdx j7leosomes.

Gel electrophoresis is a technique often used to analy- ) (bp: cqdsd.b/7 q1nzexvtyse DNA molecules. It includq.n)qpxcs-b /bv ez17d:t (ydes a gel and an electric 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 transcripts where9 kon xa5bv) 9;l,sct4 6sq;+kxmyjfw the introns have been remokxa,oq9ytnjvcb95f;;64s)xk w l+ sm ved.



What is an advantage of the above process?

  Which of the following is a s-s9l 3da;0qirzw s 8rrimilarity between transcription and translation?

  The diagram shows the structure of a DNA fragment. Which bon lxsjp )1/jck7ds easily break and ref1ps k7xc )/jjlorm?

  What would make one DNA mozk ,kmnzvo 4yrpt5x.*-spz.(, -qoaflecule 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 DNgwj+)m.jft/f )yzj 5 nA or protein serve zwmt)yjffjj5/+g. n) s as the genetic material. They cultured 2 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 prwqn;cjvd5bjef0x sb;)u0 v( .0:jw w eocess are correctly matched in the table below?

  Which statement highlights the importance of nuclem/ 8.asn sf3liiq6:b .zsi xn.osomes in DNA supercoiling ?

  The image shows many* y u3z./otmj5 +avmzi ribosomes on a mRNA molecule. How many unique polypeptide chains are being trajmva5+y /izto*. 3 umznslated?

  Which of the labelled struct zrur1m2nmz+a4h5: hsures shows the correct directionality of the DNA mol4 nh szz:hu+m1rm5ar 2ecule?

The diagram below shows the s. +bazf6:pvdqczx+ dfj2+g6q): v nwvtructure of 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- dlci)h8, cf-dv e o/rii,nn: 1952 involved cultured viruses that were radioactively labelled with e hi8o/ cf:ddniier ,,-- lncv)ither 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 iz:1 y :5kr,nn-ynbd vurx0*bm s a pyrimidine?

  How did radioisotopes help make the investigations by Hershey and Chase possi 9jvw5epp*1r tblee*rp1tvp95wj ?

  What feature of the DNA molecule was utilised by Hersheyob3zqk.ae(6xm -, 0nkx*lt es and Chase in order to identify that viral DNA is able to enter host cells, but most of their protein3e0 *kl6.t e ,xsm(oza-xbk qn is not?

.

The image below shows a sc.kcx lz)u f+c- 5 )spswtjz90hort fragment 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 om2y2m b4q+p xaiman(e-f42r/ifd o j2ne nucleosome?

  Hershey and Chase conducted experimenzg t) yjjbcqc be1i,1. kq+t z,:l*;atts 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 ths w -y3f: 5o+qoali4a team of researchers investigatq-i5+3fyhls 4otoaw:ing the relationship 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 are essential to all living organismsn j9zrcgd7w +;.
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 ttq;1uv3c.znp b6+t ko he 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.