The graph below shows the relat3o3y; go9xc bodlg4:qionship between maternal age and the incidence of non-disjunction. What relationship is suggested by the data in the graph?g c:odg;olqb 39xyo4 3

  Which stage of meiosis is rep-f1aio 6 fy n+)hg5jfn-kz s7vp :c2haresented in the diagram below?

  The diagram below shows c3qk-x i()b pmahromosomes during meiosis.


1.Identify the stage of meiosis from the diagram.It is    I

2.State one process, other than the one shown in the diagram that promotes variation during meiosis.

3.State when the process you named in part (i) occurs in meiosis.It is    I

  Which row correctly scsz3pg4u419o,r nr;i vzmsn *tates the number of alleles of a single gene which would be presn1vi rz4ro ,c;spsu3zn49*m g ent in the nucleus of a cell as a result of each process?

  Which keyword is matched to the c s4ck9.xvv/c correct definition?

  Which statement(s) ano )izjncl )53o4u xd6bout mitosis is/are true?
I. Sister chromatids are pulled apart during metaphase.
II. The nuclear envelope reforms during telophase.
III. Chromosomes supercoil and become visible during prophase.

  In the micrograph below, which lette;cn(i(js g6kej0q vv /pb dou26dg u/4r points to a cell in anaphase?

  During which stage owz:ys,;* jlwff mitosis does the nuclear envelope break down?

  Which one of the following transport proteins only carries out active transpo1f/shj;. e:im yod( lxrt?dmsio/. : ;e1fhjl( xy

  Which process does not happen in th7r a:ravhx9 2 /vcmm6ue shoot apex?

  Which type/s of membrane transport do/docf ck0,kbv4, ces not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4. Which stagt(.n kp2ez6 cke of cell division is the cell curre6c.tekz 2pn k(ntly undergoing?

  The photomicrograph below shows a root tip meristem. Which of the foc.o9moe ybssv0g; 1o,7j3f eyllowing sentences correctly defineoj c7om1seof s,;y9vbe.yg03 s a meristem?

  When does the random orientation of homologo, .l,k2uz*fat; bw+umbu /mslus chromosome pairs occur?

  Which process does not occur during y1riw 8e15 1;:rwwzhi x upxz/meiosis?

  If a cell with a diploid number of 36 undergoeyzb:t(e/ 0fy8:wb uh as mitosis, how many chromosomes will be pre btyzbefy: w hu:0a/8(sent in each daughter cell after cytokinesis?

  The image shows a microgcrc+w84u emyp 1:9 xmsraph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/arv 9e 4uv5czlm0e not true?
I. Homologous chromosomes have the same centromere position.
II. Homologous chromosomes have genes with the same loci.
III. Homologous chromosomes are identical to each other.

  This karyogram is for an individual with Down syndro3l263pej1owqmjh+xw me.

Which statement is not correct?

  In the cells of a horse (E. caballus) :ai- lzz 7i)gnduring prophase I of meiosis I there are 64 chromosomes. What is the haploid n7 zn )gal-izi:umber of chromosomes?

  Which arrow is pointing to a chiasujyw /y 4 (-j9s+fg4 pl;,b-j ejvuknyma?

  The diagram below represents th-- *wt/7 1e yg3ludn vuhstc1te structure of a shoot apical meristem. Which row in the table correctly identifies the ptgwv/3*ulyd1e s- tn7ct- 1uhrocesses occuring in the structures labeled in the diagram?

  How does meiosis promote variation?y yp7)g,syxqx;x),l ;jinia mjd ,o ,1

  Which of the following state794,v(yxr2h sqom0fx h+ xfml ments is/are correct for meiosis?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametes produced frowni kcogmi6j05./ as,obcivo p *4)(om two homologous chromosomes.


What single crossover event could have occurred to produce the gametes?
I. Crossover between Gene A and B
II. Crossover between Gene B and C
III. Crossover between Gene C and D

  Which word describes the formation jwv s6t/;yr9un(nu1im ed:o ,of secondary tumours from primary tumours as a r u6n/e t91juv(wy rsnm;od,i :esult of the movement of cells?

  How many chiasmata aro)yf or0x/s so8 + ch4yhkuv37e present in the diagram?

  Which statement is a similarity between jm+thr: ggc(013plog cytokinesis in animal and plant cells?

  Which stage of meiosis is matched to the correct descriptiqai cl+gs3wj)(p (: mton?

  Which statement(s) are true of meiosis I but not meiosis II? 4t(qi9vq.olv5ctb;kfa6 k, rqvv 52j
I. Crossing over occurs during prophase
II. Sister chromatids are pulled apart during anaphase
III. Chromosomes supercoil and become visible during prophase

  The micrograph shows an oocyte a+ l7vqec j0se7fter the first meiotic division. This results in the formatiqlv0ece+7 sj7on of one large cell and one small cell. What is the fate of the large cell?

  Which row correctly describes di)0 /joi sge6j0 iobma:ploid and haploid cells in humans?

  The following table shows the diploid chromosome number of a (ux l (.t ;ov9jqvd /uol+aex/range of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyogram below? pv3im5f;)i 1v avb gb9rz0zk (

  Which of the following processes is character8n s;gu.1t(aratur uf.7av mo3 g- :alb77dlaistic of the meiotic and not the mitotic cellg( 8odasf7:a1 u gur;b-a 3a7nu7.all.mt rvt cycle?

  The diagram represents a bud with a shoot apical mei96,j;n7 myft9a9nlr4sj 8rge zl 5ff ristem.

1.State the type of cell division that occurs in the shoot apical meristem.
   is the type of cell division which occurs in the stem tip.
2.Outline what happens to the cells produced in the shoot apical meristem.

3.State two types of tissue that are produced by the differentiation of cells found at the shoot apical meristem

  The diploid number of the cp2zk. 7p*djdb himpanzee (Pan troglodytes) is 48. Which row shows the correct chromosome number for different cell types and cell division stagesz j*bp2dkd7 .p?.

  At the end of which phrg/op-l-vgpa f )+ b/uase of meiosis I does crossing over occur, and what is the-rg+ov/l /)au pbpf- g outcome of crossing over?

  Which of the following statemen1 gpug,bgy 6w51/ rt ma n2p;hbjr5(lcts does not describe a step in the sodium-potassium pump cycle in g5b1j/ uc;l apwrpt(r51mn ygg ,62bh the neuronal cells?

  Which row in the table below is truf7 3p9*59 gnhiea) l2t q2nejevc2 lage of meiosis?

Membrane transport is important fn jo08jx-2)yst. cln kor allowing particles to move across the cell membrane and respond to changes in the chemical composition of the extracellular fl8n kc )y.jx s-tl2onj0uid.

1.Outline the effects of placing a liver cell in a hypotonic solution.

2.Outline how the fluidity of membranes allows materials to be taken into cells or to be released from cells.

3.Compare and contrast four types of membrane transport. Include an example of each.

1.Explain how mitosis is r6an+3f ab m: rgz7*otsegulated in cells.

2.Describe the stages of interphase and their importance to the process of mitosis.

3.Discuss the importance of mitosis to living organisms using named examples.

  The diagram below shows thed pmyw/n)c qb ,i-ilj::. af:-mg4rhn concentrations of different cyclins during the cell cycle. Which cyclin is involved in preparing for DNA replinb ihm4:: q grjp/fwm d-:c )-.lyan,ication?

The diagram below shows chromosomes during meiosis.f(--fagj3qyfj 0px 3m

1.1.On the diagram above, label chiasma with the letter R.

1.2.On the diagram above, label a chromatid with the letter Q.

2.Describe the process of crossing over.

3.Explain how crossing over results in the formation of genetically unique nuclei.

  Which stage of meiosis involves the separation of homologou ;:6xdpo :sf)lh+xv ias chromosomes?

  The mitotic index of throat tissues taken from 4 different patients *)osm 1w8 jgmvs 3)ffeis shown below. Which patient is most likely to hsog)fj) mv1e m8 s3*wfave cancerous throat tissue?

1.Draw a labelled diagram to represent the process of crossing ovfd9()v,z2 ytwhuycncejw4c -ff+ ,s ;er.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal human karx(/j kbfq +.+om)ot lbyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative a;6 8 iiwqdv:d2,po fnfmount of DNA in one cell during one complete cell cycle. Each letter represents one s nvi;f6 d8qiow2 ,d:pftage of the cell cycle.


1.1.State which stage of mitosis or interphase is represented by stage B in the graph.

1.2.Explain your answer to part (i).

1.3.Bortezomib is an anticancer medication and arrests cells in the G$_2$ phase. If a cell shown in this graph began the cell cycle at A with 3 relative units of DNA, and Bortezomib was applied to the cell culture at stage A as well, estimate the relative amount of DNA in the cell at the end of C.

2.Explain why the amount of DNA in one cell remains the same in stages C and D.


3.The diagram above shows cells in different stages of mitosis. Label one cell that is in prophase and one cell that is in anaphase.

  The diagram below shows a cross between a male cat that is homozygous for brow(o-eik+xuk 64zd e( ydn, long hair a(xzukio-6( dkye +4ednd a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can srpnpur.qz5:i oxl*w mxb 5d.55 e v.8show a normal distribution.

2.Outline the differences and similarities between homologous chromosomes.

3.Explain why expected and observed Mendelian ratios may differ.

  Which gamete can result from the crossing ove5jhd9-l d5d4xdto1 0hl )u cczr of non-sister chromatids shown in the diagram be01dou9)-z t5 lhlch5cxj4dddlow?

  The photomicrograph shows a pollen grain from L. candidum (Lily). Wgu g1 r6 t-sqfbp0ep67hich stage of meiosis u 6grq-7 6s01tg pebfpis shown?

1.Outline the eventsv 6 qqdea/j 3c+sm /t*bm,ye8k which would lead to an individual being born with Down syndrome, which is characterised by the presence of threma+m3/e6 vyqdqjc8 *e s,/bkte copies of chromosome 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indirect way of measuring pldikro.e8x2 0d ant growth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the effect ofore id0xkd.82 soil pH on the mitotic index of the roots.


1.Describe the trends shown in the graph.

2.Outline how the mitotic index is calculated.

3.Discuss whether the data support the hypothesis that onion plants should be grown in soil with a pH of 5.5.

4.Suggest how a pH of 9 affects the process of mitosis.

5.1.Explain why measuring the mitotic index in the root is an indirect way of measuring the overall growth rate of the onion plant.

5.2.Suggest another method, apart from measuring mitotic index, that could be used to measure plant growth.

6.State one of the variables that must be controlled to make this experiment valid.

Mitosis and meiosis are two ways in which cells can divide. )d2mkb9n w zg5ieems /hh-*-q The diagrams below show two cells from an organism with a diploid nuwm9h2* qbs-i gme- hk d5zne/)mber (2n) of 8.


1.Deduce if Cell A is a gamete or a somatic cell. Justify your answer.

2.Identify the stage of meiosis represented in Cell B. Justify your answer.

3.1.Draw a diagram which represents Cell A during metaphase I.

3.2.Draw a diagram which represents Cell A during prophase II.

4.Compare and contrast meiosis and mitosis.

1.Outline the role of ge+ew1e4 -cnb 7-nzt 4d*lv-mfiuoa a0cne expression in stem growth.

2.Outline how growth is controlled in the shoot apex of plants.

3.Explain the process and applications of micropropagation.

  The diagrams below show a cell, with a diploid numb bfb:zl8h24vj:l6das 7n9wh zer of 8, in different stages of meiosis. Which row correctly namea2fj7b dwv hslzzh69: 8bn: 4ls each stage?

  The micrographs show four phases of meiosis 6so zx-:iuj:jI in a plant. In what order do thesex z -:ijj:6ous phases occur?

Mitochondria are responsible for supplying metabolic energy in azhqcet0h -q7x )w: (leukaryotic cells. In most eukaryotes, which re:ct0 ha xqzh wql(-7)eproduce by sexual reproduction, mitochondrial DNA (mtDNA) is inherited from only one of the parents: the mother in the case of humans. This is in contrast to nuclear DNA which is inherited from both parents. It has been suggested that, in some eukaryotic organisms, inheritance patterns of mtDNA found in hybrid cells, which are the result of sexual reproduction between two different yeast species, could be influenced by the parent’s genetic background.

In an experiment, scientists investigated if environmental factors could influence the inheritance of mtDNA in hybrid cells resulting from the sexual reproduction between two closely related species S. cerevisiae and S. paradoxus.

The first step in the experiment was to produce hybrid cells, which were then grown on different agar plates, each providing different growing conditions, which simulated different environmental stresses. Cultures were then taken from each agar plate and grown in a liquid medium, with the same respective environmental conditions. The procedure is outlined in the diagram below.


The mtDNA genotypes of the resulting hybrid cells were then identified and compared to that of the original parents.


1.Describe how the pattern of inheritance of mtDNA in the hybrid cells is affected by the different conditions.

2.Identify the liquid medium which resulted in the greatest AND smallest difference in number between hybrid cells with mtDNA from S.cerevisiae W303 and S paradoxus YDG197.

3.Calculate, for the 2% glucose condition, the percentage of hybrid cells which contained mtDNA genotypes of both S. cerevisiae and S. paradoxus.

4.Compare and contrast the results from the first and second experiments for the 2% glucose condition.

5.Identify the liquid medium condition which resulted in the greatest difference in the number of hybrid cells with mtDNA genotype from both parents between experiments 1 and 2.

In a final experiment, the team of scientists wanted to examine the activity of mitochondria, as indicated by respiratory competency, in the hybrid cells grown under each of the aforementioned growing conditions.
Respiratory competence was measured by using a stain, which stains respiratory competent cells red. The absorbance of cells was then measured, with higher absorbances indicating higher levels of respiratory competency.
Note that hybrid cells which contained both parents' mtDNA were excluded from this experiment.


6.State the growing condition and strain which resulted in the highest levels of mitochondrial activity.

7.Discuss the hypothesis that hybrid cells inherit the mtDNA from parents who are best adapted to their environment.

8.Evaluate the use of S. cerevisiae and related strains in the study of mtDNA inheritance in humans.

  The table shows the number of cells in different stages of the cellboah f;o0u*4r) j4ts d cycle in four sampo4jbt;) 0ah*s4r duofles of lung tissue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at differ, f49w5/bz fzjh f7eqient time points in the cell cycle. Which cyclin/CDK complex achwj7 bq4fzie/ 59,fz ftivates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependent Kinkqa/w /y y/4ruase 3 (CDKN3) are highly overexpressed in cervical tumouy/u r/4qaky w/rs.


1.Calculate the percentage increase of CDKN3 gene expression in cancerous cervical tissue compared to healthy cervical tissue. Make sure you show your working.The number is   %.

Overexpression of CDKN3 in cervical tumours has been associated with decreased survival rates in cervical cancer patients and has been shown to trigger cells to exit mitosis and begin cytokinesis.


2.A hypothesis has been proposed that overexpression of CDKN3 in cervical tumours results in an increased chance of patient death. Evaluate the evidence for this using the data given.

3.Overexpression of CDKN3 results in increased levels of cell division. Describe how CDKs and cyclins are involved in the cell cycle.

4.CDKN3 has been identified as an oncogene. State the definition of an oncogene.

c-REL is another gene that has been linked to cervical cancer and its expression is correlated with the expression of CDKN3. Using CRISPR technology, cervical cancer cells have been created that do not express c-REL (c-REL -/-). Expression levels of c-REL were checked using protein analysis.


When c-REL is overexpressed in cervical epithelial cells it results in greater proliferation of cells and the cells spend less time in prometaphase (the phase between prophase and metaphase) compared to healthy cervical cells.


5.1.Looking at the photomicrograph above, identify the stage of mitosis that most of the cells are in.

5.2.Based on the evidence provided, suggest, with a reason, which of the labelled cells would be present in the highest numbers in c-REL -/- cervical cancer cells.

cREL-/- cervical cancer cells and cervical cancer cells with high expression levels of c-REL were treated with the chemotherapeutic drug, cisplatin. Both types of cells were exposed to different concentrations of cisplatin over a 21-hour period, and the effects on cell number were analysed.


6.Using the graph above, compare the response of cervical cancer cells that express c-REL and the cells that do not express c-REL (c-REL -/-) in response to exposure to different concentrations of cisplatin.

7.Suggest a reason for the different effects that cisplatin has on cervical cancer cells expressing c-REL and those that do not express c-REL (c-REL -/- ).

8.Suggest why some c-REL -/- cervical cancer cells have a similar level of cell death to those cervical cancer cells expressing c-REL.

9.Deduce whether cervical cancer cells expressing high levels of c-REL and CDKN3 will have a higher mitotic index than those with lower levels of c-REL and CDKN3..
Cervical cancer cells with a high expression of both genes will have a  ----待选择----higherlower  mitotic index, as they are dividing more rapidly.

  When is the concentration of cyclin E evcvj4z4) -xz the highest during the cell cycle ?