Statements below show three dh xa :n4e:7 (q-lapija0 z:xgqouble-stranded nucleotide sequences. Which of these sequences ozej(a :a0p-g 7h 4nax: xli:qqf 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 bas + sl 81xoz)yfhn,.mdied 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 andl n.)y8+z1m odxf ,hsi 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 inut( m(/tlj kmikn2c ::l 3v,jb the micrograph?

  A strand of nucleotide9f n;m:ju 7 lgslu8*qls reads CCUAGAGCUUACCG. Which type of pentose sugar could be found in the nucleotides in thmu g ll7uqn8*l; fs9j:is strand?

  Which of the following processes is most directj+ gy r3mo .c.bjtz (xa183jpnly involved in the formation of nucleic acids sxjmjz jg31n.+yp otr .3b( ac8uch as DNA?

  What distinguishes uracil from thymi4ds(bv-(bm o5,br8z 7z os nrqne?

  Which statements are characterist mmxhs6t) jg18ics 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 ycw;6rd8 by(fsequence and genome size (number of base pairs, bp) for different species. 6y;db frw(y8c

Which conclusion can be drawn, based on the table?

  How does the genetic code provide evidence oc.bh n4rk2j4pj buf 1+f universal common ancestry?

  The diagram depicts nucleosor4 g, srlr* m.9mkc5btmes.

Gel electrophoresis is a technique often0cmen 7b7ip-*s9svav ( x8l jt used to analyse DNA molecules. It includes a gel and an electric0ipcem ( 79ls8 j7sv-bnx v*ta 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 mRNA transcripts where the intwoj09p nt+1ny rons hawp y0j1+tnn9 ove been removed.



What is an advantage of the above process?

  Which of the following is a similarity betwu.rpk7pd8j ; lu;pqppn;u3e; een transcription and translation?

  The diagram shows the structure of a DNA fragmen ci 0mr+ t;b)fagf7yv*t. Which bonds easily break and refo0y 7c*)rm+vtifbfa ; grm?

  What would make one DNA molecule more stable thq4;/n*h ov u 6upk,qdsan 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 eaoe-s6a , c3p wuob*c0xperiment to investigate whether DNA or protein serves as the genetic material. They cultured 2 batches of viruses, one in a medium contain, wuoccop6a0a3b-*se ing 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 matched in the tab8tt(-g5ghdij b, heq uf;2x4ele below?

  Which statement highlights the importance of-z 4ho+c9xtau +mb g:r nucleosomes in DNA supercoiling ?

  The image shows many ribosomes on a mRNA molecule. Hn2kh 4i(b h2ga:vu 5ncow many unique polypeptide chains are beiubh2a2 :4ikgnn h( cv5ng translated?

  Which of the labelled xj;i 13p55arf oogw b;jr.k j3structures shows the correct directionality of the DNA molerof5 g;3.o bi1jjk 5 jpr;axw3cule?

The diagram below shows thea*n1v+ivzxuko9:m 8q 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 8( .*nhk mav.vjhgdjub/ w(1r71nuoe0 )wefs viruses that were radioactively labelled with e/s n1rjgka vvn((hd.fu1eh 0o)mww7eb8 .*juither 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 iixk nmk 7t6g w7/espc708 xaw5 01e c-ljsvab8s a pyrimidine?

  How did radioisotopes help makbrv.j *+lqxj 53tnu(gvmzv y,(axbu/6c ;n x8 e the investigations by Hershey and Chase possible?(bb cy6+;u3,vxxjgm*ujaxn /5tnr(z . qlvv8

  What feature of the DNA molecule was utilised tf b)n./bde*x.h1 ywuby Hershey and Chase in order to identify that viral DNA is able to enter host ce* 1fny/ )b. dwetub.hxlls, but most of their protein is not?

.

The image below shows a short fragment of the DNA a3xl *yzkp(wagh/1 y-b(w8qj 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 mpib:iu: (5bz:5u/ y: qxa.k)oajldi shows the correct components of one nucleosome?

  Hershey and Chase conducted experiments using the radioactive isotopes8(pak95u +lem m,lh dgxy ay/; $^{35}$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 rrs6*7uxn-j lch zi0 v)esults of an 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 helixucl niz*v) -rhx0j67 s 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;bh.( vh 1jbnmoeob 09 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 tecjj o0bp568f/ dysd- he 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.