Statements below show three double-stranded nucleotide sequenc-6-5*zoxau lpgfk, jzym 6fu2es. Which of these 6fgk om f z-azx 5-*u2ypl6,ujsequences of 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 tetranucleotide hy:5wgl +a + xkkii-jbw:pothesis proposed by Levene that DNA was made up gk :+- liia 5x:bwwk+jof 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 complex and accurate understanding of the structure, leading to the falsification of the initial hypothesis.

  What is the main role gbwydy0a- f 1.r;gww: of the ribosomes labelled in the micrograph?

  A strand of nucleotides reads CCUAGAGCUUACCG. 59z9e* xrb pzpWhich type of pentose sugar could be found in thez*bppx59rze 9 nucleotides in this strand?

  Which of the following processes is most directly involved in the formation of hl j2)gbrf0*hnucleic acids such *0lh fjb)g 2rhas DNA?

  What distinguishes uracil frot6mto g*oqmrd 0ug1+wz 0+0m pm thymine?

  Which statements are):i1 pw.cl cz6p1btk o characteristics of a 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 nuclb z 0pn529 mnkx9++3coz clg,:cd)nsxp b- kjueotide base sequence and genome size (number of base pairs, bp) for diffem +bol3ccn 9:pp5g k9,b+ ndux2xncz-ks0)j zrent species.

Which conclusion can be drawn, based on the table?

  How does the genetic code provide evidence of universal common ancestry?x)o 7fzid85o6sw b 9rg

  The diagram depicts nucleos rjl/)b20enq sd7xxm9o ni6z4omes.

Gel electrophoresis is a techniquufe;sd.2 o3y 1v wz:bxe often used to analyse DNA molecules. It includes a gel and an electric fdf:. wv1 zeys3xuo;b2ield. 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 prex) bnvy7:l/ fa-mRNA and three mature mRNA transcripts where the introns have bebf 7):/ynla xven removed.



What is an advantage of the above process?

  Which of the following is a similarity between t 2.3yd wr3oi)j phivo4w,)iksranscription and translation?

  The diagram shows the str6bcu+bz m5+svhaoy6e- 5t7by d3kxk :ucture of a DNA fragment. Which bonds easily break and refoe5c-vubb+ 73d+st myko6bh5xz kay: 6 rm?

  What would make one DNA molecule yl i55hf3+ btu(py/myq;k*lmmore 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 wheth4p2if0wd jh+ xer DNA or protein serves as the genetic material. They cultured 2 batches of virujd4+h i0fwxp 2ses, 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 tabl i,of; g qo2hwi7val84e below?

  Which statement highlights the importance of h 7;mq vxo(*io:8snednucleosomes in DNA supercoiling ?

  The image shows many ribosomes on a mRNA molecule. How many unique (u4k,r3sl 1f*ie15 bo audgfcpolypeptide chains are sfdbo fe*grla(c4 ik5u3 11u, being translated?

  Which of the labelled structures shows the correct direg-zvx mb y:4*xjf j(3xctionality of the DNA moleculev-3xfgjzxy4 x (*m:jb ?

The diagram below shows the structure of DNAoz-j4 4vh)kfg 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 1: jh*w8;vppfr 952 involved cultured viruses that were radioactively labelled with either sfhr j8v*;wp: pulfur ($^{35}$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, anyr8ba.qgsx,8ce ( m++1*avuih2 kugp d R if S is a pyrimidine?

  How did radioisotopes help make the investigations by Hershey and Chase possibze4nss:a2k wo3cp+ d3le3+s:zkseod an2 4cp3 w?

  What feature of the DNA mo 1kcejwxk;371gl vo:i;owf f+lecule was utilised by Hershey and Chase in order to identify that viral DNA is ablv ;1wkwxe+co 1fk:i7 ofjl;3 ge to enter host cells, but most of their protein is not?

.

The image below shows a short fragment of the DNA molecp1 xq+wjtm6 :e:ofjscn( 2friyj-;h, ule.



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 xphlp- wc p*-.z :p8mdy/i3oz components of one nucleosome?

  Hershey and Chase conducted experiments using the radioactive isotopes c utg2vr f0v:;$^{35}$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 o3: ee fsh j-nggu.b:+djsq u1,rv10 gof an experiment conducted by a team of researchesjhv:ef.0-+nubgedsr 1ju31 :gq, o grs 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.

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 taa6dj*f 8vri9,g3 b eehat are essential 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 moleculexny)18 aczqk u32rv;h.


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.