Statements below show three double-stranded nucleotide sequenceem7g:bb d:d hbrfv+y b 9yqq00 ao8:1ds. Which of these sequences of base pair 1d:q 98efd7 0:d:0qyrvba g+ohybb bms 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 try00i hjisc+1wg1-2v g6w ln khe 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. Subsequent evidence and data revealed a more complex and16h2lygsw g +r1 0ivjc0wk-i n accurate understanding of the structure, leading to the falsification of the initial hypothesis.

  What is the main role of the ribosomes la q2 m(p7qy.m-psg-m*(v kvjg nbelled in the micrograph?

  A strand of nucleotides reads CCUAGAGCUUACCG. Which type of pentose sugar coul+snrt hwf +5nl-fyt1 :d be foth t-n+rnws1 l5:yff+und in the nucleotides in this strand?

  Which of the following processes is most directly involved in the formation of sme s+hn6 b,u;1qprk3nucu6eh + sbsr,;k1mn3qp leic acids such as DNA?

  What distinguishes uracil from thymi* dk 4kn;:j( +sz)dkllfq: 3f7gina igne?

  Which statements are pvfzy2rj .3 f8b2:iaocharacteristics 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 sequence and 8 s;. nodnb1mju3tl/vgenome size (number of base pairs, bp) for differe18bto3su;/nnm d.lv j nt species.

Which conclusion can be drawn, based on the table?

  How does the genetic code provide evidence of universal comm sdq) rn72 xndn(,cwq7on ancestry?

  The diagram depicts nucleosomes.(9 bl)/aav(5xdlsnkb

Gel electrophoresis is a technique often used to analyse Dapvj5fm*i5wx ch(y; dl5 :+ myNA molecules. It includes a gel5:jw;+ycm 5ixpfm h5l(v*d y a 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 mt b*w6b9was2eRNA transcripts where the introns s ba2be96wtw*have been removed.



What is an advantage of the above process?

  Which of the following is a similarity between transcription tcbbi wbk 130n pe1 382tv,lkuand translation?

  The diagram shows the structurhx83u whe2( fve of a DNA fragment. Which bonds easily break and refhhv 8u2 xf(e3worm?

  What would make one qqmp 2 ri35a7lDNA 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 invel-amfvf +s+ wo.qbv p/9;l)g rstigate whether DNA or protein serves as the genetic material. They cultured 2 batches g/)o-bfmaw;s.lv9pq rflv++ 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 are correctly matchedi*9t)c* zu0mkn o e0 h9soqg8y in the table below?

  Which statement highlights the importanck0ga60(xpq z db*cz+6cbv/ vy e of nucleosomes in DNA supercoiling ?

  The image shows many ribosomes on a mRNA molecule. How many unique poo4s8j :5ywhml2 nr at.lypeptide chains are being tjwln.yrm:2t ho a85s4 ranslated?

  Which of the labelled structures shows the correct directionality of the4o+nx* jysla o4 5 ul*(ph4ja msdcw-0 DNA molecule? +xu4h*map0 anl* 4d45swc ljo(j y-os

The diagram below showsl8fqpsa 47q z- the 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 experiment in 1952 involved cultured viruses that were radioaan l 3ggqofou v+29-c-ctively labelled with either a-3 gulof -q+noc92 gvsulfur ($^{35}$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 pywd1vq*4or95 l bani4 grimidine?

  How did radioisotopes help make the investigations byzj 4v4.j pc-qq:4 xree Hershey and Chase possible qp-vjj4eq4: zxe4c.r?

  What feature of the DNA molecule was utilised byxvg3dkav,;4k e:k d3 t Hershey and Chase in order to identify that viral DNA is k adk :xg,v3t4 d3v;ekable to enter host cells, but most of their protein is not?

.

The image below shows a short fragment of the ;t4 c7)ex wmwme .da-e51l6 tb b1kecdDNA 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 t zmm(:y;cd ;zjhe correct components of one nucleosome?

  Hershey and Chase conducn8j, 6qoaybon np- 20o6 *ptsated experiments 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 a team of researyd ya7+te : 37lyv:qayv )b0fjchers investigating the relationship between the composition and melting point of different DNA samples. At the melting point:ya v at)e:73 l jbyyv0ydfq7+, 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 thoj.k xj+w5u/ bat 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 mol:t-evkux 0 31cijs;o kecule.


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.