Statements below show three double-stranded nu xvjuhv2*s5y7cleotide sequences. Which of these sequences o*sy5j2xh7 v vuf 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 based on the tetranucleotideou;vk+n,x4m3bmf(gn9b h x s1xd*km5 w+2izi hypothesis proposed by Levene that DNA was made up of equal amounts of adenine, guanine, cytosine and thymn iimdx ,vu*3mwf 5gh1b4z9 koxkb;+( sxn+2mine. 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 the rixkxbd6- 7q *jmbosomes labelled in the micrograph?

  A strand of nucleotides reads CCUAGAGCUUbae 7k flt4t)*a2 ga5sACCG. Which type of pentose sugar could be foun*l sf4be 2aa5)gk 7tatd in the nucleotides in this strand?

  Which of the following processes is most directly involved in the foz fd*n m; )f;rt;0heafrmation of nucle;fa ; fdt*;nmhfze )r0ic acids such as DNA?

  What distinguishes uracil :gm v s*9aoag/mux2,dx7 y)7wyj(yvzfrom thymine?

  Which statements are characteristics of a DN)9a)mvfu( qukj2 sv:vA 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 nu ; vfdv+56:xu2tij jl;i4u h7prz6pt)jd j6i lcleotide base sequence and genome size (number of base pairs, bp) for different surjtd4v zj6p j2:d7t;uvfph ;+lii65jlix )6 pecies.

Which conclusion can be drawn, based on the table?

  How does the genetic code provide ev):8 podo 2ucdh+ k5gucidence of universal common ancestry?

  The diagram depicts nucleuj6h,8fdfi( i h2dc z:co b8:fosomes.

Gel electrophoresis is a tech*m *w(jgk aa10z mdkw7x f5dk9nique often used to analyse DNA molecules. It includes a gel and an electric field. The diagram below shows the outcome of gel electrophores1dmwfkd*kaga(x k 7wzj*950m is.


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 a /zr;sc2xx11gcra -x three mature mRNA transcripts where the introns h1/sazxxrc2c1a-gr x ;ave been removed.



What is an advantage of the above process?

  Which of the following is a simsd/v njyn 8ig7(r3s/cilarity between transcription and translation?

  The diagram shows the structure p6k:u m4aur q4nc,6ypof a DNA fragment. Which bonds easily break and reform? 4pyp r:a,n4ck m6u6u q

  What would make one DNA molec r9h5la 3leiw6qq ck04*)lythule 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 conducted an experiment to investigate whether DNA or pro4nv*6ge x:urru3o-dv bn9ilp r(0h z,tein serves as the genetic material. They cultured 2 batches of viruses, one in a medium containing radio 6rb-u 4nlgrd*o:ex p(u,hni0 9vr 3vzactive $^{35}S$ 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 table below?kp u rx:0.p,por6x+hw

  Which statement highlights the il5* 3(ihzk rtzbr-*( u otjuz;mportance of nucleosomes in DNA supercoiling ?

  The image shows many ribosomes hcznqu8, pq+/on a mRNA molecule. How many unique polypeptide chains are beinq +,znpuc/h8q g translated?

  Which of the labelled structures shows the correct directionality4(-ck0u72owbto jxw p of the DNA molecule? 2 o -ojw0ub p(wt47kxc

The diagram below shows the s.fne.kw mbp 1lq9kd81 tructure 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 cultu ajba:v 6v6yi:red viruses that were radioact va: vaj6:6iybively labelled 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 S6rlef y2k7pe n*3)lgd 8hm,rxj zl8y5 is a pyrimidine?

  How did radioisotopes help make tk.f,h)q8xo 1gd c9uwzj6g l -lhe investigations by Hershey and Chase possiblegw- zjgk1 flc69, ud)8 ohlx.q?

  What feature of the DNA molecule was utilised by Hershey and Chase in ord0 f wjq+4 xr1)t;zwri jsq9r*ier to identify that viral DNA is able to enter h0i;qrwwfx*4)jt 1 zq 9ir+s jrost cells, but most of their protein is not?

.

The image below shows a )wkfp,v)a z.z 6 myhq9+) 1b) aqcr;g7ps tqrsshort 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 sh(f(2b 5mco9nx vvtns3ows the correct components of one nucleosome?

  Hershey and Chase colzg l :q+z;b/;y rn3pi6bp7wonducted 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 experiment conducted by a team of a;92nnneyg+8,pyf -o1 xrqop researchers investigating the relationship between the composition and melting point of differ qgpoyxfn8pn oa +n,y2e 9;-1rent 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 essenvne* fe 2gw9x;t88ffutial 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 mol0 xn :nm0lnabkj*ei 5c99qd4xecule.


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.