Statements below show three double-str7iw/i -o v fk*przi 7*0eo,*gyrz u+psanded nucleotide sequences. Which of these sequences of base pairs is possriwgky i*foo* 7/+ e7vupp-*r z,z0isible 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 structbn:sghcqv55l72u1a eure based on the tetranucleotide hypothesis proposed by Levene that DNA was made up of equal amounts olqvsb2:acg7 1u 5h5nef 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 understanding of the structure, leading to the falsification of the initial hypothesis.

  What is the main role of the ribosomes labelled in the microg960cdyvov t8braph?

  A strand of nucleotides reads CCUAGAGCUUACCG. Which type 7 p71olilmgyoh h/46u3yxy ,f of pentose sugar could be found in the nucleotide6x7oh 31yify,glm oph/ u 7y4ls in this strand?

  Which of the followin9;c+zes3k d fhg processes is most directly involved in the formation of nucl9z;sc h fed+k3eic acids such as DNA?

  What distinguishes uracil fr*w8 pchxo-:)oql -z diom thymine?

  Which statements are characteristics of a ,+ 9l qoaz,vagzvw9fojsk6 01DNA 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 sequencf*(8hl xuxxqt vmu758e and genome size (number of base pairs, bp) for different specxm*(xu8uq vtf5 l8 7xhies.

Which conclusion can be drawn, based on the table?

  How does the genetic code provide evidence of universal cofhdhnrk ,3xma9:4zi 4mmon ancestry?

  The diagram depicts nx6 j1/uc7 k99e j(a.cg fgjzacucleosomes.

Gel electrophoresis is a technique often used to ana,i2no )y wd.qdlyse DNA molecules. It includes a gel and an electric field. The d d).,owiy2qn 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 f+.x ++fauwraa9l v1zmature mRNA transcripts where the introns h +vzafa1uw+lr. x9+a fave been removed.



What is an advantage of the above process?

  Which of the following is a similarity betjol i pe) //9r:ykyt7+tl a3ipween transcription and translation?

  The diagram shows the structure of a DNA fragment. Which bonds easily break an1a*zx8.eyo dfd reform?8* eax1z .yodf

  What would make one DNA molecule more stable than another DNA molecul/3 8ed o9nkhcse?
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 exper wix9v4qs0i9zxt;s a0gnpw) 9iment to investigate whether DNA or protein serves as the genetic material. They cultured 2 batches of viruses, one in a mediumia ;s9v)09izt 0qx9 sgx4wwnp 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 proceslek9kfcm- cbu) /*r8u s are correctly matched in the table below?

  Which statement highlights the importance of nucleosomes in Dl 77lnr t,cl:zNA supercoiling ?

  The image shows many r-k04dyy )ve 1dg8upso ibosomes on a mRNA molecule. How many unique polypeptide chains dg 4 vpso)e1u8y0- kdyare being translated?

  Which of the labelled structures shwofo1 i2/f8muows the correct directionality of the DNA molecuf8i fom1w2 ou/le?

The diagram below shows the structure of DNA nucleotii l wix7+:34vxyqfsm ,des.

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 cy-6 va6tsz/r 1952 involved cultured viruses that were radioacc/yza s -r6v6ttively 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 S is 6nm;b7cgxek7 slo;x 8 a pyrimidine?

  How did radioisotopes help make the in7ka8 0imbm pwngf)yo//lp:o6vestigations by Hershey and Chase possible?f pka7oy 6 m wpb/8:0li)nm/og

  What feature of the DNA molecule was utilised by Hershey and Chase in o iz /y0jj om0pieq 5erxo*50ne6(-mp irder to identify that viral DNA is able to e0p(o5e-yp/je 5z r0 0 nmmiei joq*6xinter host cells, but most of their protein is not?

.

The image below shows a ebo b. 5(zv3pxshort 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 correct components of one n9m/-iwavapx 1 ucleosome?

  Hershey and Chase conducted experiments using the ioqmsc4s99wtfj k) 9 :v+xc1e 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 ru1 rlrcv: fhnes:8. f6oy6l l3esults of an experiment conducted by a team of researchers investigating the relationshi1lh8c:o vnyf6r s.er6ll: 3fup 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 essential to all0 q-d)wmo7 turgct3 fpg5id)* 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 molecs60w(fn 1o4pc wm wd,qule.


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.