Statements below show three double-stranded nucleotide sequenc skl) u/q7cvxx-:vzmq hc2 6-p4l av2zes. Which of these sequences of base pairs is posszxv74/:q-xllu 6a m2cq2s- pcv) zkvhible 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 bf*3 fc-:faynx n6ss+ zased on the tetranucleotide hypothesis proposed by Levene that DNA was made up of equal amounts of adeni y: f-nfs36 nz*ax+scfne, 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 o k68dt-(wp ucy9qxb-l0x)nji f the ribosomes labelled in the micrograph?

  A strand of nucleotides reads CCUAGAGCUUACCG. Which type of pentose suga5sxl: +ua1ru o kg +f/r9:q6hq jknnk-r could be found in the nucleot:njgl9+n khq- k 16 rua rqu:os/fkx5+ides in this strand?

  Which of the following processes is most directly involvu6j7 2fg*jj t ahwshxp9+ )/xged in the formation of nucleic acidp7)uxw/f gj 96sthx +ghjj a2*s such as DNA?

  What distinguishes uracil frosf1,bj w9-5g*ekb a e6fz8 qqnm thymine?

  Which statements are characteristics o,y-, w+lg;oarbweltivb */3lf 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 6 ozrk)hulq:;;a .rqqbase sequence and genome size (number of base pairs, bp) for different shr.k6l; ; u)aq: qrzqopecies.

Which conclusion can be drawn, based on the table?

  How does the genetic code provide evidence of universal cw; ktj )r2 fa6kfqa 3ohn, h+g 2r4fjo/5+jyymommon ancestry?

  The diagram depicts nuccq p njb/*) hscr4/3frj n0zy6leosomes.

Gel electrophoresis is a technique often used toustb1rd f(h7 ey1:t4ei -gu )8 ahk(le analyse DNA molecules. It includes a gel and an electric field. The diagr1 8u(kt be su7ht4 agdey-i1hl)r( :efam 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-mRNf3u. ihq,de0y A and three mature mRNA transcripts where the introns haud yeh., i0q3fve been removed.



What is an advantage of the above process?

  Which of the following is a similarity between transcriptim7/.zcr u -tdhon and translation?

  The diagram shows the structure of a DNA fragment. Which bonds easily b;w8kb sp7 2lcg5i jr7ireak and cp5bk2li8 g7w7ijr s ;reform?

  What would make one DNA molecule more stable than another DNA mf:oai93rh p g6olecule?
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 or prote2x ypw.3pqsmjuu1vx a.0o)l7io2:ru in serves as the genetic material. Tho02jp2sr)wuoau1x 73.ivy x: q .lpumey 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 probo fv 0ntt7pn8 ym8,(zcess are correctly matched in the table below?

  Which statement highlights the importance of nucl(0c3d j ) myzve5xduh4eosomes in DNA supercoiling ?

  The image shows many ribosomes on a mRNAx5r) f7qtg;*prdm +t+ dh5yrx molecule. How many unique polypeptide chains hmy7 x;)gdfr5 *rrdxp5 +q tt+are being translated?

  Which of the labelled structu; 5u+ i co+h7)ynnpdzhuaz9;uhg: x9 eres shows the correct directionality of the DNA moldgouui+pz9x5u7)hze +an nhh :;9; ycecule?

The diagram below shows the sthx;f xzzj1)2n5:u*) 3jnvhy.swl y db ructure 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 q4+gs(86ms 1zqbmz fjin 1952 involved cultured viruses that were radioactively labelled zj(mq684gzs 1qmfsb+ 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 pyrimidi6 i5pcfw.u 9umne?

  How did radioisotopes help make the investigations by Hershey and 3v:4;ao ybp9xs.z nzn Chase possiblez o.zs :9ayb3xnn;v p4?

  What feature of the DNA molecule was utilised by Hershey and Chax6vxb1.zx(-nqj 1f/y *tis) hv:wwgu se in order to identify that viral DNA is able to enter host cells, but most of their protein is not/()x:xvwy1gib.h-vx w* 1 sqnu6jf zt?

.

The image below shows a short fragment of thzz-;o z:8kim f4frn b6e 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 shc t wdbv3yp;zuv6d(7rv qh* ,3ows the correct components of one nucleosome?

  Hershey and Chase conducted experimweycb6 1:(i5 iwy x vceo 82sj8*/apftents 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 expm43xf0n h co0reriment conducted by a team of researchers investign0r cfxom430h ating 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 acidrq3o5,bpwts c9qj9w0 s that 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 DNxkp,f. a0)*w3quampu A 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.