Statements below show three is5 .u*f0h +ca- qh1tf gt,rde njh* j4c,fwe8double-stranded nucleotide sequences. Which of these sequences of base pairs is possible in a,j5*h. qsei 0-f1ge,ta+* 4ncuw rhth cdfj8f 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 showy- s5hwgrr 9 l8(*u4c.fyvajp s the structure 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, because it was based on a limited set of data. Subsequent evidence and data revealed a more complex and accurate 4cvyryh( .spl* faj9uw-5g8r understanding of the structure, leading to the falsification of the initial hypothesis.

  What is the main role of the ribosomes labelled in the micrograpfe rrg d4,af:-h?

  A strand of nucleotides reads CCUAGAGCUUACCG. Which type of pentose su).ubvft/fnum+61sj u gar could be found in the nucleotides in this str+.nv) u6jtf 1ufbm/suand?

  Which of the following processes is most directly involved in +q,egg*fmu0sf 4w b o/ri n-a*the formation of nucleic acids such aw+n-f gm *a0,qfu eis /gb*ro4s DNA?

  What distinguishes uracil from thymi)01coh7hko f ane?

  Which statements are characteristics of aag q7j0gx0t,y 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 anva +1;fzf9p lpd genome size (number of base pairs, bp) for d9v1;pfflpza + ifferent species.

Which conclusion can be drawn, based on the table?

  How does the genetic code01nm/ k:r*b6ax ozoea provide evidence of universal common ancestry?

  The diagram depicts nucle8)tm 5)zgh0 vhbeuyw7k )/7g2e fyvydosomes.

Gel electrophoresis is a technique often used to analyse DNA molecules. It incbtu cm7 h+ +r/t7oy1qkludes a gel and an electric fietyk+t7hmu/+c1b7rqo ld. 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 sh+odnkjpd 49k7v nb,p /ows pre-mRNA and three mature mRNA transcripts where the introns hav k kp4p/7,o+9d njbnvde been removed.



What is an advantage of the above process?

  Which of the following is a similarity between transcription and trans /,l+epbkzf) 3kori3ilation?

  The diagram shows the structure of a DNy gn4mwkqx4u9tqhk0dic)hj 0o. /-b3A fragment. Which bonds easily break and reformt o4 )qwkqihykdjb0 g0-n/.mxhc u943?

  What would make one DNA molecule mx dj1a,25qv*q2 luia 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 conduc7c,/jfty)gy ated an experiment to investigate whether DNA or protein serves as the genetic material. They cultured 2 batches of viry, cy)agjt/7f uses, 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 processeo0 zx7*)7r9mdg sqbx6m9cvaq w+ o9 z are correctly matched in the table below?

  Which statement highlig* 3o jc:nxzvu3hts the importance of nucleosomes in DNA supercoiling ?

  The image shows many rib s9, j6dwqcxp2osomes on a mRNA molecule. How many unique polypeptide chains are being translated? s wx6q9d2jc p,

  Which of the labelled structures shows the correctw6xzfpl 3u4 gad 7ny/4 directionality of the DNA molecl4fzw /d pxu3n4yg6a7 ule?

The diagram below shows the structure of DNA nucleotides +uk :w13jx bgnrpu;+y.

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 experimentqxdl4xu:ccj3pvw 85. us z(1dlub:)l in 1952 involved cultured viruses that were radioactively labelw) cdl ls jqp43uz8:.d5lu1v :(xbcuxled 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 6nyo )2o afjm5pyrimidine?

  How did radioisotopes help make the investigations by H j6;vk7sppq(mkvz-( mfi 5 7)ogf cqo9ershey and Chase possible 76pc(f)mqvo k- ;g5k(jsvimo f97pzq?

  What feature of the DNA molecule was utilisedi-yqm c)a*.f e by Hershey and Chase in order to identify that viral DNA is able to enter host cells, but most of their prote -ayqcimf )*e.in is not?

.

The image below shows a short fragment of theh6of80-j* c eihq 2wqy 8j*std 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 tkidim,m+ty,2 n mba x5i8,7f6/wmoythe correct components of one nucleosome?

  Hershey and Chase conducted experil2 ogx, te75apq8ow)n ments 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 tea;prc/;w8wyn i7 u xj/ yb7/iolm of researchers investigating the relationship between the composition and melting point of different DNA samples. At the myni ixyo7jr7w l/p// ;8b;u cwelting 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 acids that are ejs- sh*g:pn4e ssential 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 molec r, vxkp*j;pu;(tz9/t4 nwtzwule.


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.