Statements below show t:a(x: dm lk(d:e si6vphree double-stranded nucleotide sequences. Which of these sequences of base pairs is possible in a DNA : lxsdei:6k:md apv( (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 bah1de3n/a2t qm sed 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 and data revealed a more comple3 mt1qhe/da2nx and accurate understanding of the structure, leading to the falsification of the initial hypothesis.

  What is the main role of the ribosomes labe4t e0pq 5tp-nzlled in the micrograph?

  A strand of nucleotides reads CCUAGAGCUUACCG. Which type of pentose sugaefogyr: 3eiv tdz0jhk: t 32*0r could be found in the nucleotides in this stranedf2h y :gi*0v:z3trko t3 e0jd?

  Which of the following processes is most directly invvgw 9un42cvp(h l0da qqs.sm o + rv7u7687jpkolved in the formation of nucleic acidsp +.aldc6 o7rj7 v 4g8v7vs0uqks qhnum2p9(w such as DNA?

  What distinguishes uracil from rkr6n k,p;wg +thymine?

  Which statements are characteristics of a 2rm4hsquej/ .* s z7) zgcmdi,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 sequence and genome size ( yh3x;jim 6q)lnumber of base pairs, bp) y3xm6)q;jh il for different species.

Which conclusion can be drawn, based on the table?

  How does the genetic code provide evidence of un8c(:.wyx.lykc 0b z6r2hpb nxiversal common ancestry?

  The diagram depicts nucleosomes.dyb9 qo5)t 7vk

Gel electrophoresis is a technique often used to analyse DNA mouc*omla v5(i- y1s 7hglecules. It includesc1mig yol*hv-(7sa5u a gel and 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 juxn2zgk+*it( 9 umt* mRNA transcripts where the int(9 +t*xkmun2utgj *zirons have been removed.



What is an advantage of the above process?

  Which of the following is a similarity between transcription andny(4 :4 9gdh)miwcm( (tfqx pq translation?

  The diagram shows the structure of a DNA fragment. Which bo, xdu8w9ugt.) hhbcb102s df mnds easily break and rud bs, h91 8dbtu2m0.hgx)c fweform?

  What would make one DNA molecule more stable tm1 pec7ayh5wu,+tb)fg1 4py 1.oyqec han 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 conducteo ib kk4xc(h2:d an experiment to investigate whether DNA or protein serves as tk: ix(obh4kc 2he genetic material. They cultured 2 batches of viruses, 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 o1cr+vho ; a3bmatched in the table below?

  Which statement highlights the h:n5 (s1 fc .vhvnc+,b0igjggimportance of nucleosomes in DNA supercoiling ?

  The image shows many ribosomes on a mRNA mxlr5 b8-c.f gwolecule. How many unique polypeptide chains are being transl wxfrg.l8c -b5ated?

  Which of the labelled strucljf5iz 8hpipjihx14n+79 3d qtures shows the correct directionality of the DNA molecule5z 8d9lj p14fx3iihhijnpq+ 7?

The diagram below shows the ,tndc la; 5)etvc8iq1structure 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 viruseb(r:r jd8fs33u bc;v exs(qi 2s that were radioactively labelled with eithe3f rdb: c sxv3s((ruje ;82qibr 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 pyrimidi;p:i+5,yf(o hm k uozvne?

  How did radioisotopes help make the investigations by Hershey and Chao5:e0v(qdxtb fpg3 5 cse possibleb0 v53gte:d q(xc5fop ?

  What feature of the DNA molecule was utilised by Hershe4uot1mev m9.a oblg)4 y and Chase in order to identify tha).4tvul1 bo ma4m9 oegt viral DNA is able to enter host cells, but most of their protein is not?

.

The image below shows a short fragment of the DNA 03wrfax np8/ c1rryd )j7t5to 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 showo1sw .cyw n8i2s the correct components of one nucleosome?

  Hershey and Chase conducted09 qsp wou t;zph,,n1u 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 re6bxc,vgpjps (:wq bxd;c a4h):q,c/t searchers investigating the relationship between the composition and melting point of different DNA samples. At the melting point, the DNA double helix separates into two individual strands.:b/:xgxq6p,(sb cd )vqjhct p;4,wa c

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 essi fj svg6 zpt.z,+kix0ol(/3 bential 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 onj t4+ g3q/ypl rean mkq+ a(7366rusvf 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.