Statements below show three double-stranded(h*2m5k a iymd nucleotide sequences. Which of these sequenck(a 5hdm* my2ies of base pairs 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 hypothesis 6r lp)v-a ps.qproposed 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. Subsequentla6pv-q. s rp) 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 rj6s1 o5q3c u-fw.vvein the micrograph?

  A strand of nucleotides reads gj t k*9m3b9zl9k.+ahsf vc w5CCUAGAGCUUACCG. Which type of pentose sugar could be9gst3kbv m l5+h.kfca*9w9 z j found in the nucleotides in this strand?

  Which of the following processes is most directlyebqdorg+.1 vj , ) (:t d9xx jm5e92goz-efwjv involved in the formation of nu +jd- bvrox9ejqgz xedfev92om)j. (:,wt15 gcleic acids such as DNA?

  What distinguishes uracil from thyg v b1z jowwsj8y(*i13nquy s/y)o6.emine?

  Which statements are characteristics of a DNA moleculv9ac8l k2b cuz9n-pl, e?
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 h6y,fbxv5(a r of base pairs, bp) forb(rh5,xyva f6 different species.

Which conclusion can be drawn, based on the table?

  How does the genetic code provide evidence of universal common ancestomsvh qzs9e9t ;0x -y(ry?

  The diagram depicts nt;4kp-n u/eu mq;9kk w urmq0.ucleosomes.

Gel electrophoresis is a technique often used to analyse DNA molecules. It i)6ztgc 2u.;5my pcfgo ncludes a gel and an electric field. The diagram below shows the outcome of gel electrophoresis t5)u6m2fog ;cgcz.py.


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 m); on3yo1y1 te zieh1s1dzyh5ature mRNA transcripts where the introns have been re1yzhhn 3z)tysiy1 e1deoo 1;5moved.



What is an advantage of the above process?

  Which of the following is a si*a ofwk1nlk+,5y tk7zmilarity between transcription and translation?

  The diagram shows the structure of a DNA fragment. Which bonds easily b0p)vu wlte-j6reak and reforvp j-6) l0tuwem?

  What would make one DNA molecule more stable than another DNA mv+dus9d kyxcpdn(c .-3 6)uf polecule?
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)1bo h6pi/ wv/+*4l qfsg ggznzq1l;q investigate whether DNA or protein serves as the genetic material. They cultured 2q+z fbh l/gigg)w;/1 6qnop 4sv*ql1z 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 cfxh,/i:pj0q7 bk 2 yxlorrectly matched in the table below?

  Which statement highlights the n;q qpdd. c,0mimportance of nucleosomes in DNA supercoiling ?

  The image shows many ribosqzun .b y3,po5omes on a mRNA molecule. How many unique polypeptide chai nbq.z, op53uyns are being translated?

  Which of the labelled structures shs cg )c(f*itrx0hs p h6xxl txg;2e5zp7dt:-:ows the correct directionality of the DNA molecule? f(xlcte)0-h: hrg cd iz:ptss7*xpx2g5 ;t6x

The diagram below shows the z me0w7p;9 xz q8wfi;8ttb+fa 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 k hqto/rqr)b0vb1poe25- j ;nviruses that were radioactively q;1eo oth bvj-2r/p5 n)qb r0klabelled 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, ani v* oh( i9pyrn5sfug(/w2bp9:i p zeu)iq ((ld R if S is a pyrimidine?

  How did radioisotopes help make th1flpe70u v*v ;4b+khldi+ amve investigations by Hershey and Chase possible?l 4u*phi01 lf+; dm7evkb+vv a

  What feature of the DNA molecule was utilised by Hershey and Chasek zqfk8f-j,1wlx q z/m./o5+o xdtbl* lz)yc8 in order to identify that viral DNA is able to enter host cells, but most of theo8/d 8zjmko.q/k*w bfxf)z ll, yxl5t -q+z1c ir protein is not?

.

The image below shows a shoy e71puvdga ;*rt 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 oljbcp ; ,2r;eine nucleosome?

  Hershey and Chase condubnhw/a *q-ta :cted 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 cow48o.crcx a at5jh; )hnducted 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 heli4 h choa)raw t.8;5cxjx 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 livitcd,2*a wug f 9hhz-q8k4i2n sng 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 showy-2,v;cnp tj0 cp3crns a short 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.