Statements below show three double-stranded nul/ph 73vwjb v6 t*pej4cleotide sequences. Which of these sequences of base p t jevw74pbl/*j h6vp3airs 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 ba8trn.e3 dcf lw8n13p lsed on the tetranucleotide hypothesis proposed by Levene that DNA was made up of equal amounts of ce.lfd nwn p1rt 833l8adenine, 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 micrograpu 5.en;( +enc+qp n6rxtl 6habh?

  A strand of nucleotides reads CCUAGAGCUUACCG. Which type of pen6 t/4yagu2.j(p lm sl.px0dgbw :vf k w3e:ac+tose sugar could be found in the n3m.elpct602aa j/vl y( :+4: dgukw .pfs xwbgucleotides in this strand?

  Which of the following processes is most directly involved in the forwj *ni1ipva .qc+l2i.ji.c/ t mation of nucleic aci t1cpi* +c/2.lijvn a.jiw i.qds such as DNA?

  What distinguishes uracil fw 1y o60)eofv0qs(9zsu*h addrom thymine?

  Which statements are characteristics of a DNA molec md 32e-a9uae .p*ao(fr i(uddule?
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 genvd4 a+-kr+ireome size (number of base pairs, bp) for different spev -a4irr +ed+kcies.

Which conclusion can be drawn, based on the table?

  How does the genetic code provide evidence of universal common ancest,69 k ynj7jlwtry?

  The diagram depicts nucleosorgulo/ecjn ) r2k 7)3n/+koi jmes.

Gel electrophoresis is a technique often used to analyse c+9fth2p o;a je2)tj)x;bzde dyk3 ,xDNA molecules. It includes a gel and an electric field. The diagram below)2 ,f9j bac)2tdexdkpjy x3;e;zto+h 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 meah6hz 61 m zwla*b7tk4 fu-(eature mRNA transcripts where the introns have been removed. 4 hkm17bz*ehfztlewa (a 6-u6



What is an advantage of the above process?

  Which of the following is a similarity between transcription amr15(ts o *oftnd translation?

  The diagram shows the structure of a DNA fragment. Which bonds easily breac jqj)f2dqbb(89iq f 4k and refoqcqb) 8(jdb4 fijqf29 rm?

  What would make one DNA molecule more s,k r 7ew1vxp ,t7-lybstable 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 kcp,a7,(mv) mgx +qd fgd// l,klg o-hinvestigate whether DNA or protein serves as c(,7 g/,ld) g l f,ap+kqv/xokdmmhg- 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 process on wo0 4juee+t bu4xi3olc79,are correctly matched in the table below?

  Which statement highlights q; m-i1sx92hux sfq9 ethe importance of nucleosomes in DNA supercoiling ?

  The image shows many ribosp enlrfl g,-0-b(e2w,xxp 8zhomes on a mRNA molecule. How many unique polypeptide chains are bn2(r,lfhe0 pxp-z,g8be lw -xeing translated?

  Which of the labelled structures shows the correct directionali/yqv:rpf-d w s:2afn:kf) cs5 ty of the DNA molf :c kpfy2nq: w5-/:)safs dvrecule?

The diagram below shows t3 swadhdkz)tq79 jq, 7he structure 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 experime.2fi+s-xv,2 vtq ci uint in 1952 involved cultured viruses that were radioactively labelled withu+f iicstv2, 2i-xq.v 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 ia 7jr 4m zz5o4tsu1(sis a pyrimidine?

  How did radioisotopes help make the investigations by Hersheyjdkd/4k*o-ut6 h ;bzy and Chase possiblet;od/- yk4bzk d 6*uhj?

  What feature of the DNA molme 6*1e4eav4c ki m7q9.b .qzk( t tag3gmjjt5ecule was utilised by Hershey and Chase in order to identify that vii kqz449 ma a1mb63q 7 gt.cgeetmke*j.t(5jv ral DNA is able to enter host cells, but most of their protein is not?

.

The image below shows a short fra.+0vjxk az+l jgment 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 s e 0.*vkdqbzc3hows the correct components of one nucleosome?

  Hershey and Chase conducted experiments usdc7 x b(1gr 6oerjsl5ad9q6v .ing 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 ubmm+24outcu+l0 :h g by a team of researchers investigating the relationship between the composition and melting point of different DNA samples. At the melting point, the DNA double helix separates into two indiviu2tum4hm:+ b 0 +uoglcdual 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 ess,j/ x4uuh 9.iwf(3gjyx+eo ije/ljtz+ 3f5ocential 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 mr,x 9mr0liaf )olecule.


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.