Statements below showt2pd,. pfu1,qki3u a bdsg+ w1 three double-stranded nucleotide sequences. Which of these sequences of base pairs is possi1 pk1u tibdq3sp. uw +af,d,2gble 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 onpr;.cws9 wp, ji/ q+lk 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;9pwl+./iksp rj qw,c 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 k8t6ob/tbw4 y micrograph?

  A strand of nucleotides reads CCUAGAGCUUACCG. Which ypp/;esh3)k s type of pentose sugar could be found in the nu3spphe s/y k);cleotides in this strand?

  Which of the following processes is most directly involved in the format72 2c+mc ye pcxk9mfk:ion of nucleic acids suchke27m:m2 +cc xk9yfcp as DNA?

  What distinguishes uracil from thymine?q1cl f g 40lll7mn./g 1on:xej

  Which statements are characteristics of a Do7pfrj6bt h nnau vzy3f.,nvi2rocc )5,c (2;NA 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 nucleor+8nf :z.m 1zogrrs i c4y3e2ztide base sequence and genome size (number of base pairs, bp)i cryn1+z r4ofsme8 :32rzgz. for different species.

Which conclusion can be drawn, based on the table?

  How does the genetic code provide evidence of universal commtdnoyp 0;eh4r 25v.g)bhyu4q on ancestry?

  The diagram depicts nucleosbhjd 87uvj /qx7 )r0x ql3xy/aomes.

Gel electrophoresis is a technique often used to qf6.jwy -o c;ianalyse DNA molecules. It includes a gel andwi o6 ;.q-jycf an electric 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-mRN f 0tsb(pw9p xwc:+3akmaf 8;oA and three mature mRNA transcripts where the introns have been rem8f(afwc3w9 +px;mbao 0p: k stoved.



What is an advantage of the above process?

  Which of the following is a similarity between transcription and transl;zrk t2h xog9+ation?

  The diagram shows the structure of a DNA fragment. Which bonds easily breakqlry5v c9eszz0gq 741to v7tsrj* 5d0 and refossl4 195yr5oqdvzc r ve0tjq gt77*0zrm?

  What would make one DNA molecule more stable than an 3mv.sab, z0v*jle xr;other 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 experiment to investigate whether DNA or proteiwiv8k8( l- oyhn serves as the genetic material. They cultured 2 batches of viruses, ( 88ykw -volihone 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 correctly matched in xhd)v nn4n-d4 the table below?

  Which statement highlights the importance ligif +03 .liuhb u9+gof nucleosomes in DNA supercoiling ?

  The image shows many ribosomes on a mRNA molecule. How many unique polypeptid6e mz.r.q vxvyu5.ls rcs4z: 4e chains are being translated? rc.z. sxu46ryz. veql4 m:s5v

  Which of the labelled structures shows the correct direc0zhu 7ls0uuj/w 7q*m u (i9zxjtionality of the DNA molecuz /*i hjmz( q07wj9sux07lu uule?

The diagram below shows the structure l pvm -b0) v 9n+hywmr0k:r)opof 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 virusgn ;ac,w4kk(m es that were radioactively labelled with either,akgcwm( n; k4 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 pyrimka.t: stg n;q6idine?

  How did radioisotopes help make the investigationsrkn m9h/rbt)h)sch+8 by Hershey and Chase possible?rmtkchs h9 rnb)+h) /8

  What feature of the DNA molecule was utilised by Hershey and Chase in order g(i flnzfg9go/c+z;d.p2i -mto identify that 9+-nzl.;g gfdm iz(/fco2 pgi viral DNA is able to enter host cells, but most of their protein is not?

.

The image below shows ym0at1ulwv * .a short 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 cc-j 8ma, sx0sxyg-czz3 w 0j4eorrect components of one nucleosome?

  Hershey and Chase conducted experr*ffe-ejk9 iik 2/iu 0iments 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 anny)3*;r.doh j bu ;cuo 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 into two inhc )bdn*uu;j;3yo r.o dividual 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 almlp-9* ,xwpyx l 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 fn,vasb e)yl3a:. hjb* ragment 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.