Genetic Control Questions

7/29/2019 Genetic Control Questions

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AS LEVEL BIOLOGY ASSORTED QUESTIONS

Chapter F: Genetic control

9700_s04_qp_25 Fig. 5.1 shows part of a DNA molecule.

Fig. 5.1

(a) (i)Name U to X.U ...............................................................................................................................W ..............................................................................................................................X ...........................................................................................................................[3](ii)Name the bonds indicated by Z................................................................................................................................[1](b) Describe three features of a polypeptide molecule that are different from those found in

a DNA molecule......................................................................................................................................[3]

[Total: 7]

5 (a) (i) U - phosphate / PO4; Rphosphoric acid / phosphorus / P

W - deoxyribose; R pentoseX - cytosine; R nitrogenous base / pyrimidine / C 3

(ii) Z - hydrogen; R H 1


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(b) Assume answer is about polypeptide unless indicated otherwise.A comparison is not required. Information given below is for either polypeptide or DNA features. A ideasfrom either column. Do not penalise if points are not corresponding on one line / sentence. Mark all points

on line. Only Rif biologically incorrect.polypeptide DNA

amino acids nucleotides ;one / single strand / chain two / double strand / chains ;peptide bonds R between peptides / polypeptides phosphodiester ;20 monomers / sub units A > 4 monomers / sub units only 4 monomers / sub units ; R4 basesno phosphate / PO4 has phosphate / PO4 ;

2 / 3 structure double helix ;3 max

[Total: 7]

9700_s05_qp_2.pdf

1 Fig. 1.1 shows the replication of one strand of a DNA double helix.

Fig. 1.1(a) Name W toY.

W .....................................................................................................................................X ......................................................................................................................................

Y ................................................................................................................................. [3](b) Explain how the structure of DNA enables it to replicate semi-conservatively.............................................................................................................................................................................................................................................................................. [3](c) Explain why it is important that an exact copy of DNA is made during replication..................................................................................................................................... [2][Total: 8]


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1 (a) W cytosine;X deoxyribose;Y nucleotide (triphosphate); [3]

(b) base pairing/A-T and C-G; A purine - pyrimidineref to complementary/explained with ref to H bonds; R complementary in wrong context(free) nucleotides pair with both, strands/each strand/polynucleotides/sides;both strands act as templates;

to produce two DNA molecules that are identical to one another; [max 3](c) (all nuclei/cells) are genetically identical; A genetic stability, same genetic information,exact genetic material, genetic material does not vary, same genotype;no mutation;any consequence of mutation;e.g. cells not recognised, cells divide uncontrollably, substitution of 1 amino acid resultsin disease e.g. sickle cell anaemia, enzymes active site altered, forms different proteinwith different function. [max 2][Total: 8]

9700_s05_qp_2.pdf

4 Collagen is found in the extracellular matrix of muscles, tendons, ligaments and bones.Fibroblast cells in these tissues make collagen by synthesising polypeptides that formmolecules with a triple helix shape. These are secreted from fibroblasts into the extracellularmatrix where enzymes assemble them into collagen fibres.


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Fig. 4.1 is a diagram summarising theseevents.

Fig. 4.1(a) (i) Name the processes occurring at A, B and C.A ...............................................................................................................................B ...............................................................................................................................C .......................................................................................................................... [3](ii) Name structures D and E.D ...............................................................................................................................E .......................................................................................................................... [2](iii) Name molecule F.F ........................................................................................................................... [1]

4 (a) (i) A transcription; (ignore mRNA synthesis)B translation;C exocytosis; R secretion [max 3]

(ii) D (sub unit of) ribosomeE Golgi apparatus/body; [2]

(iii) F mRNA; [1]9700_s06_qp_2


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3 (a) Complete the table by indicating with a tick () or a cross () whether the statementsapply to proteins, DNA, messenger RNA and cellulose.You should put a tick or a cross in each box of the table.

statement protein DNA messenger RNA cellulose

hydrogen bonds

stabilise themolecule

glucose is thesubunit molecule

subunits arejoined by peptidebonds

may behydrolysed toamino acids

contains uracil

[5]

During an immune response, B-lymphocytes become plasma cells and begin to makepolypeptides that are assembled into antibodies.Fig. 3.1 is a diagram showing the formation of a polypeptide at a ribosome in a plasma cell.


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Fig. 3.1(b) State the sequence of bases at J......................................................................................................................................[1](c) Use the information in Fig. 3.1 to describe the role of transfer RNA molecules intranslation................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................

.........................................................................................................................................

.....................................................................................................................................[5][Total: 11]

3 (a) one mark per row

statement protein DNA messengerRNA

cellulose


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hydrogenbonds stabilisethe molecule

x ;

glucose is thesubunitmolecule

x x x ;

subunits arejoined bypeptide bonds

x x x ;

may behydrolysed toamino acids

x x x ;

contains uracil x x x ;

[5]

(b) CAG; [1](c) tRNA, combines with amino acid / carries amino acid to ribosome;idea of specificity; e.g. each type of tRNA is specific to an amino acidanticodon matches amino acid idea;example from Fig. 3.1;codon on messenger RNA pairs with anticodon on tRNA;example from Fig. 3.1;two sites on ribosome;further detail; e.g. P and A site (and E)leave ribosome after amino acid joins polypeptide;continually reused; [max 5]

[Total: 11]

9700_s10_qp_21.pdf

5 (a)Name the stage during the mitotic cell cycle when replication of DNA occurs...................................................................................................................................... [1](b) Fig. 5.1 shows details of DNA replication.


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Fig. 5.1

(i)Name the bonds shown by the dashed lines on Fig. 5.1............................................................................................................................... [1](ii)Name the nitrogenous bases, M and O.M ..............................................................................................................................O .......................................................................................................................... [1](c) Explain why DNA replication is described as semi-conservative...................................................................................................................................................................................................................................................................................

.........................................................................................................................................

.........................................................................................................................................

..................................................................................................................................... [2](d) The enzyme that catalyses the replication of DNA checks for errors in the process

and corrects them. This makes sure that the cells produced in mitosis are geneticallyidentical.Explain why checking for errors and correcting them is necessary.

.........................................................................................................................................

.........................................................................................................................................

.........................................................................................................................................

.........................................................................................................................................

..................................................................................................................................... [2]

[Total: 7]

5 (a) interphase / S phase / synthesis phase ; R G1/G2 unqualified by interphase [1]


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(b) (i) hydrogen ; [1](ii) M = adenine and O = cytosine ; [1](c) each strand, of DNA acts as a template (for the synthesis of a complementary strand) ;

A described in terms of base pairingnew DNA (molecule) has one, old / parental / original, strand and one, new / daughterstrand ;R half old and half new unless clearly referring to two strands [2]

(d) accept ora(errors are) mutations / named type of mutation ;ora if corrected there are no mutations(may lead to) production of altered proteins, so, impaired / loss, of function ;

A altered amino acid in, protein / primary structure(may lead to) different antigens, so cells are rejected (by immune system) ;idea that cells cannot function together / impaired coordination ;ref. to cancerous cells / cancer(s) / tumours / sickle cell anaemia or other named monogeniccondition ;further detail ;e.g. uncontrolled, division / mitosis / cell replication / cell growthe.g. lack of contact inhibition / no apoptosis or described / (proto)oncogene(s) [2 max]

[Total: 7]


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9700_s11_qp_21.pdf3 A molecule of messenger RNA (mRNA) was produced during the transcription of a gene. Part of the

template sequence of DNA was ATGC. Fig. 3.1 shows the part of the molecule of messenger RNAcorresponding to that sequence of four bases.

Fig. 3.1

(a)Name the parts of the mRNA molecule shown in Fig. 3.1 labelled D, E, F and G.D .....................................................................................................................................E .....................................................................................................................................

F ......................................................................................................................................G ................................................................................................................................. [4](b) Complete the table to show three ways in which mRNA differs from DNA.

mRNA DNA

1


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2

3

[3](c) Describe the role of mRNA after it leaves the nucleus and enters the cytoplasm of a eukaryotic cell.

.........................................................................................................................................

.........................................................................................................................................

.........................................................................................................................................

.........................................................................................................................................

.........................................................................................................................................

.........................................................................................................................................

.........................................................................................................................................

..................................................................................................................................... [4]

[Total: 11]

3 (a) D uracil ;E adenine ;F ribose ; I pentose / sugarG phosphate ; A phosphate [4](b) answers must be in pairs

mRNA DNA

ribose deoxyribose ;

differences between pentoses / sugar may be described in terms of OH on C2

uracil / no thymine thymine / no uracil ;

single, polynucleotide / strand / chain two, polynucleotides / chains / strands ;Adouble

no hydrogen bonds hydrogen bonding ;

not a helix / straight chain (double) helix ;

ratio of A+G to C+T varies / AW ratio of A+G to C+T = 1 / AW ;

no base pairing (within molecule) base pairing ;

base pairing A-U with, tRNA / base pairing is A-T

anticodon

shorter longer ;

found in cytoplasm / leaves nucleus found in nucleus ;

attached to ribosome(s) not attached to ribosome(s) ;

short-lived long-lived ;

transfer of information (to ribosome) information storage / AW ;

codes for one polypeptide codes for more than one polypeptide ;

produced by transcription produced by (semi-conservative)

replication

[max 3](c) 1 translation ; R if transcription given as well, unless in correct context

A use of, nucleotide / base, sequence, to make, amino acid chain / polypeptide / protein


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I protein / polypeptide, synthesis2 moves towards / combines with, ribosome ;3 ref to small and/or large sub-units ; I small / large ribosome4 codon(s) ; only accept in correct context5 transfer / t, RNA, bringing, amino acid(s), to mRNA / ribosome ;6 anticodon(s) ; only accept in correct context7 (complementary) base pairing ;

8 any e.g. of codon:anticodon base pairing ; need six bases9 ref to polyribosome(s) / used by many ribosomes ;10 (mRNA short-lived) ref to production of protein for short period of time ; [max 4][Total: 11]

COMPILED BY: MD. EMRUL HASAN, A LEVEL BIOLOGY TEACHER, SFX GREENHERALD

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Genetic Control Questions