Statements below show three double-stranded nucleotide too:up70 xhv/ sequences. Which of these sequences of base pairs i 0ho7vutx p:o/s 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 st)*rpi8bl;o k yructure based on the tetranucleotide hypothesis proposed by Levene that DNA was madeipy;* b8 )okrl 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 understanding of the structure, leading to the falsification of the initial hypothesis.

  What is the main role of the ribosomes labelled in the micrograph? jlzwse o3i* ).

  A strand of nucleotid 7rfq/ t8wku5ves reads CCUAGAGCUUACCG. Which type of pentose sugar could be fo7k8q/tf r 5uvwund in the nucleotides in this strand?

  Which of the following processes is most directly involved inm1 zdxzmwah t/*+d. )l the formation of nucle z/dl1*t w.h+axzm) dmic acids such as DNA?

  What distinguishes uracil io8udx:i*6v fpc//4 x7 jcn wafrom thymine?

  Which statements are characteristics of a DNA t)ntmr-16ajcmolecule?
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 genome size (number of base p8gpo51 rwb sez8skd-( (uq( mn2hbr; lairs, bp) fpr;81( (z g bh5esnmkwlu(bdos- 82qror different species.

Which conclusion can be drawn, based on the table?

  How does the genetic code provide evidence of universal common ancestry?lm79 j+ s6+k6io:nzobop cru)

  The diagram depicts nucleosoc5a/g*gc:zeymm:7 or mes.

Gel electrophoresis is a technique ofte tbb 9pib7 01fwwirk-.n used to analyse DNA molecules. It includes a gel and an electric field. The diagram below shows the outc0itbb 1-kwb.p9 rfi w7ome 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 where the in.x3 he,ycl(gihjb+bz- t,t6c.h ;bz qtrons have been removed 3z.6bx c-ihglt;+q b( .,cet,ybhzjh.



What is an advantage of the above process?

  Which of the following is a similarity betweeb 4ret6j:dh r+g7 h 8esry6h.u3f2a brn transcription and translation?

  The diagram shows the structure of b swgi 5r)hzz2i*ow,8bfr1w.a DNA fragment. Which bonds easily break and reform? ,o irb*s g)z wihw8bf251z.r w

  What would make one DNA molecule more stable than another DNA molecule?h3y/uab:wy 7d tu,4zm
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 7vh uyco.dus.p1m3 r r 1-e5o0bdhoh;experiment to investigate whether DNA or protein serves as the genetic material. The bh1cyo per0r 7v1-3.dudhs ;uomoh.5 y 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 are correctlm o e :75yu ,sjywk/rp:udhc 4y6,9ohny matched in the table below?

  Which statement highlights the importance of nucleosomes in DNA supercoihx3ue esyxj)v0l 8 (;tling ?

  The image shows many ribosomes on a mRNA molecule. How many 0r7l/r bk *u8msete3qunique polypeptide chains ar/ul* r tb7r8m seq3ke0e being translated?

  Which of the labelled structures shows the correct directionality of 0cbf sinwr5r dw,tu2anw-zd- d49x/ 4 the DNA molecule?0- aw2,/ 9stdzdx fuin -rcr454nwbwd

The diagram below shows the structure o-93bcdoynynf c m9e6 2f 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 z.gz4ee1oh8 n l 02pebinvolved cultured viruses that were radioactively labelled with .eplon8be02g 1ezhz4 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 l f(*,jlurub -qukp;ga06k *ra pyrimidine?

  How did radioisotopes hel1d wsj-es.h- ob4afx. p make the investigations by Hershey and Chase possible?-xhdw4..s fa-1 ob esj

  What feature of the DNA mz 0g d0w9uuq 33ic*lvz)hq.haolecule was utilised by Hershey and Chase in order to identify that viral DNA is able to enter host cells, but most of their protein is nochg3wu*zu0 a93)l.i0 q vhdzqt?

.

The image below shows a short fragmem 5d+7qbs8izwz 3a,a qu(td 52pq mq d3b;*jaent 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 caucpg83apflqbbl58 jn- ) 9y ;omponents of one nucleosome?

  Hershey and Chase con6*h3faz c)nph ducted 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 tea6tqf qs0k4:rpm of researchers investigating the relationship between the composition and melting point of different DNA samples. At the melting point, the DNApsr4f: kq 0t6q 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 orga82-q yshx i.+z(fv ,hnu.nq henisms.
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 shortu+ 3 def),ayg5l lwy8t fragment of the 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.