Statements below show three double-stranded;i+j pqn7s 8q)e+rhhyr h+j: d nucleotide sequences. Which of these sequences of base pairs is p++jqh ;hri+eq:7y hds)rn p8jossible 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 s*;ti m1zw /coltructure based on the 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, wz1mlt/coi *; 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 ribosome pj1vcz,vt(eg9ha9u5n9 r( a p+qj)9djzv4 urs labelled in the micrograph?

  A strand of nucleotides reads CCUAGAGCUUACCG. Which type of pentose ;p; i9 0ktnmown+j;eato: */ fzw8 krzsugar could be found in the nucleotides in:ma/0i pzwnnootw ;+ e*8f9tk;j z ;rk this strand?

  Which of the following processes is mggt8(in b ;yb:ost directly involved in the formation of nuc; gbnb8tgy( :ileic acids such as DNA?

  What distinguishes uracil +czc/vdvp* op b,,)x4lf e(v xfrom thymine?

  Which statements are characsm qinl4-2 qh 14zlvi,teristics 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 genome gk,2krt.r c/usize (number of base pairs, bp) for drk/t2r.u,g kc ifferent species.

Which conclusion can be drawn, based on the table?

  How does the genetic code provide evidence of universal common an:(p(xt:8 *rkwe6 qe+pfqzkhecestry?

  The diagram depicts nucleosomes.0 hh qhv:hn 0izp0ix:.

Gel electrophoresis is a technique often used to analyse DNA moleculesnsx1oh 0;a :tb. It includes a gel and an electric field. The diagram below shows the outcome of gel elect xsbhnt1o:a; 0rophoresis.


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 pr bnrerv/v u7*to.n k/dn.s4 1xe-mRNA and three mature mRNA transcripts where the introns have bee.krodun*e ntb/xs4. rnv1 /v7n removed.



What is an advantage of the above process?

  Which of the following is a similarity bet(gslpb +;* t6u4k vkjaween transcription and translation?

  The diagram shows the structure of a DNA fragment. Which bonds easily brep 5q,wjusd,8h *cu alk1/j(ni+l1jqeak and reform? + s *qal(8w e 1cqhpkju/jnl, ,5d1jui

  What would make one DNA molecule more stable than anothuq5tja,iw+2sp1o o- k-rc, kj cb u9;ger 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 conducte 1eec/ b2n3 myxem9r .rs0g-asd an experiment to investigate whether DNA or protein serves as the genetic material. They cultured 2 batches of 31 yxb /r9c-s.en ege mrm0s2aviruses, 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 correctl 0a5v,:ekyoh)a 6 rd3ghue9ary matched in the table below?

  Which statement highlights the importance of nucleosomes in DNA supj7 x/f88qpxkfercoiling ?

  The image shows many ribosomes on a mRNA molecule. How many unique polypep8 kt.duh.c1ra tide chains are. 8h at.cd1kru being translated?

  Which of the labelled structures shows the correct directionality of the DNA7l5,n:f7 sxqubub*/h jea5 qh moleculeuh:n7sxb/ fju5q57*la,h qbe ?

The diagram below shows the strucr3lgk).ir5n p qay (k ;9nvi8 .j5ntqoture 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 3ia.p6 ha(zjrmlu .6q 1952 involved cultured viruses that were radioactively la .jqza rm.i3l(6a6uhp belled 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, a1dicjuw +)xcj:9n dv:g7 x 3uond R if S is a pyrimidine?

  How did radioisotopes help make the investigations by Hershey and b a cwq2yx1i/568cw czChase possible? qi1wxz86/cbyw c5c2a

  What feature of the DNA molecule was utilised by Hershey/1f hvwz a0jkno5m2c 4 and Chase in order to identify that viral D04n5f2wkav1mz hjoc/ NA is able to enter host cells, but most of their protein is not?

.

The image below shows a short fragment of the D8 + sb3u oam38 uykfh1 9tsdo8ol;3mtqNA 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 corre jap ;vsvxy9r 8v55me:ct components of one nucleosome?

  Hershey and Chase cond9zkn,d -e6cs 1 ydna-pucted 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 9n60cdw9 mpgn ;jxnm: experiment conducted 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 ind0mncm 6jnp9wnx g:9;to 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 organis xs0yv0apg8;b ah7m/ims.
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 o a)bbt9gs gi4,hbab;( f 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.