Statements below show three double-stranded nucleoti bh,ty(rosw z;r/+i2qtliy n-r)ov -9de sequences. Which of these sequences of base pairs is possible in a o y - i z;n9br-vit)r(th/w2slqyo+, rDNA 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 tetranuc6gbqh06bb2n xg 4. ipkapp5d1leotide hypothesis proposed by Levene that DNA was made up of equal amounts of adenine, guanine, cytosine and thymi 4p2h.kqb0i d6nbap6gb51x gpne. 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 understanding of the structure, leading to the falsification of the initial hypothesis.

  What is the main role of dr7t5v(q4dv xthe ribosomes labelled in the micrograph?

  A strand of nucleotides reads CCUAGAGx/vhc 3s .q6gdCUUACCG. Which type of pentose sugar could be found in theq.c hdgs3vx 6/ nucleotides in this strand?

  Which of the following processes is most direcb3/* ol*2azbbe+u wy5 m6gsxftly involved in the formation of nucleic acids sucaeb zluf bw 2so6*g3m*+b/y x5h as DNA?

  What distinguishes uracil from thymv m0.ae/tovd*(i:kp m7 h a-grine?

  Which statements are characteristics of a DNA d 3;x+z2 xgibcjoo l5l+ei/7f 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 size (n0y i).(d) 6 husml7wjju5f miiumber of base pairs05jju6iywi 7hmf.d)um(i l s ), bp) for different species.

Which conclusion can be drawn, based on the table?

  How does the genetic code provide evidence of universal c 2:2mzrl ;vbv8eqd,zqommon ancestry?

  The diagram depicts nucleostj z)hmw .())- ofvsjeomes.

Gel electrophoresis is a;ejt52u rmjb kx v y1j)9 /5r3-dgtnlh technique often used to analyse DNA molecules. It includes a gel d;j-u e ny tx5jg2)rtr91j3vb5/ klhmand 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-mRNA and three mature mRNkg :av*qtov95o w1izaz6m9s/ kx ) )fiA transcripts where the introns have beea59 vi 1v/sq6*k zio9 ogmfw)tx:ak)zn removed.



What is an advantage of the above process?

  Which of the following is a similarity between transcy0m *9 g0ckuej2zt z7nription and translation?

  The diagram shows the structure of a DNA fragment. tpgv+t*l 4z8bycc -o5dgkld3j1o(c+ Which bonds easily break and reformt+ gv4b1*c8 +(goo y5p-z 3dk cjdtlcl?

  What would make one DNA molecule more stable than -wg 6:wkcbtv. 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 experiment to investigate whether D a* 9*8sy ydqzfrnior97onc4/NA or protein serves as the genetic material. They cultured 2 batches of virusyzn7 4ri* sqry* a/fcdono9 89es, 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 correctly matched in the tablym*s3r+. fl nke below?

  Which statement highlights the importance of nucleosomes in DNA supercypnhh )zqcnye)q2s2rckl - nc3p/+5+ oiling ?

  The image shows many ribosomes onei1my +vhc0j syhh. 4 7m:pt:x a mRNA molecule. How many unique polypeptide chains aremx07yi ph+.hc4 thj :e1s ymv: being translated?

  Which of the labelled structures show5+l; saz /.i+g *uew9snd9 3pl wyxlzxs the correct directionality of the DNA molecu gl.slp+wsx39x*ydui/lew9 zz5+an; le?

The diagram below shows the structure of DNA nucleotides.+adey 4n.l1 :wtkmtzza7 3am (

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 cultuq11zch(fe m w o+(jl6lwj bn:5red viruses that were radioactively labelled q1b+eco1m(6 j zwl w5(h nlf:jwith 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,kzu+a9oy0 me0f *cs *wvtk :y4 and R if S is a pyrimidine?

  How did radioisotopes help make the investigations by Hershey and C-a/jwhrc .5u whase possibleh- r/ua j5wwc.?

  What feature of the DNA molecule was utilised by Hershey 5bix3n g)ahz. and Chase in order to identify that viral DNA is ablzgi.h3 a5x n)be to enter host cells, but most of their protein is not?

.

The image below shows a short fragment off vy q,deh0-u, gno3p+ 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 of5g3ne2)6bf e: eexu h:wic9vf one nucleosome?

  Hershey and Chase conducted experiments using the rc*-eo2fm :g weadioactive 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 teamfadx51 j 0)toqd9 vt)gv0i)i,9en esr of researchers investigating thev 51fidt re0nq,0j)9e )9)xgtisaodv relationship between the composition and melting point of different DNA samples. At the melting 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 esse,j.6ubp8gkn g*tl, k 2wfkq,mntial 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 fragment1npsxh3k75l;eebdop+xv;gz4 xj h* 7 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.