The graph below shows the relationship between maternal age and the inciiyc *l+bhzl,m27pg 6idence of li*,gchp i7b 6+mly2z non-disjunction. What relationship is suggested by the data in the graph?

  Which stage of meiosis is represented in the diagram bel5h)a au) q,aio:hc+cm ow?

  The diagram below shows chromn(p 3ih7 epl:nosomes 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 states the number of alleles of a single gene go.7yz9q9 xdm which would be present in the nucleus of a ce xzd9 .oyq7mg9ll as a result of each process?

  Which keyword is matched to the correct hnm7.z; ua11vd(kakt definition?

  Which statement(s) about mitosis is1fj, c0o9b4dsoe 8gn f/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, which6wjbm2f hflt)e66i) y letter points to a cell in anaphase?

  During which stage of mitosis does the nuclear envelope b8dti3dsd :-c5zqjys: reak down?

  Which one of the following transport proteins only carries outz- 6st xi6iqt+ active transport?x6t -it +zqs6i

  Which process does not happemix yy;-50s5kh c 0sbo ow36eun in the shoot apex?

  Which type/s of membrane transport do/does not requiu6t*6 1ku5iu qyuw +vkre energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell witus v4bu-xza9:curi)* h a diploid number of 4. Which stage of cell division is the cell currently undergoingbuu:*uc x4i)rz 9s-a v?

  The photomicrograph below shows a root tip meristem. Which of the folsbnh 9 pv81ncf crq2,/lowing sentences correctly defines a meristem? s/cpr ,ch19q2 nn8fbv

  When does the random orientation of homologous chromosomd)e b5y8e:1nz/(d vy yxolt*ce pairs occur?

  Which process does not occur dufa:lf yem+/x5ep*t g0ci vsn98+spz(ring meiosis?

  If a cell with a dip:.5gv /de0z44nnqhys:ssu th loid number of 36 undergoes mitosis, how many chromosomes will be present in each dss4 hzn 4vu y:qngh5 e:0/sdt.aughter cell after cytokinesis?

  The image shows a micrograph of a h +v. (z lb-j-wxs/5xve yqt5mcell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes i+/jusiv hgcs+ ;ud6d u;ht4t/s/are 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 withhfw ;a, lrp8(wd ta1/e Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) dur dp*euc+14a q)y0cd uxing prophase I of meiosis I there are 64 chromosomes. What is d c)e dc1*a4xq0y+puu the haploid number of chromosomes?

  Which arrow is pointing to a xc.24.m u.wq qolymk 32o0 vqachiasma?

  The diagram below represents the structure of a shoot apical meristem. Which rowx2ab7wtxmxo4x2b6 +f1hw -) uzn zzt0 in the table correctly identifies the processes occuring in the structurex 122zahtx-nw zbtmuxz04w76bf+o) xs labeled in the diagram?

  How does meiosis promo i) -qdz:zr7rxte variation?

  Which of the following statements is/are correct for meios a/e msl.:u:axis?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametes prouthcu lrb* *3-duced from 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 of secondary tumou42iu adte9d k+ej,v ob;/j:k)t-u .b lftndi3rs from primary tumours as a result of the ud4.u-ej);i9o3f +jd itta,e2t/vnk:db bklmovement of cells?

  How many chiasmata are present in tppc5i: 1 )8rw-p ifeeqhe diagram?

  Which statement is a similarity between cytokinesis in animal3lcbp+ 5wu ls* and plant cells?

  Which stage of meiosis is matched to the2jik,,ot4xu i gza) 2q correct description?

  Which statement(s) are true of meiosis I but not meiosisaj; b q)td *xr5t*lng8 II?
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 after the first meiotic divi9v* voo01 5(aqxrkp ubsion. This results in the formation of one large cellv0o pk9 bau v*o5(xq1r and one small cell. What is the fate of the large cell?

  Which row correctly describes a.*5hk 1ilqe) f:ps-ibp4bi a diploid and haploid cells in humans?

  The following table shows the diploid chromosome number of a range of species.rir,bxy -hv* .ar)4 mw


Which of these statements is correct?

  What conclusion can bjzg+i up.e) ew+;f vfy-k m e8g:4b,hce drawn from the karyogram below?

  Which of the following processes o 7*rglvyp f, hfkmxz()cwj56op.8y :is characteristic of the meiotic and not the mitotic ceow 7 offg:*,c) z .py(vk hpr6l85jxmyll cycle?

  The diagram represents a bud with a shoot apical merg(lo4/ au; jjbistem.

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 t3 lf u*4ic 8 zn+fj6sh;/slbhuhe chimpanzee (Pan troglodytes) is 48. Which row shows the correct chnl i4f8u3hzb* js;f s/uc6h+lromosome number for different cell types and cell division stages?.

  At the end of which phase of meiosis I dod s4gns1:i:fhjqmmh)ss * a3(es crossing over occur, and what is the outcome of cro)41 shjidh*:( as 3:nsqf sgmmssing over?

  Which of the following statements d suvks o+67;ufoes not describe a step in the sodium-potassium pump cycle in the neursfskv7 ou+;6 uonal cells?

  Which row in the table r pw9/.hob u zaoz2t,9below is true of meiosis?

Membrane transport is important for allowing k/p o4wxyi*yy z0/8uaparticles to move across the cell membrane and resppu y/aywo4/0zx8 i*kyond to changes in the chemical composition of the extracellular fluid.

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 regulated in cells. fjhuj(0 :bjk ,

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 the concentrations of diff pfbj qu)bj/f36z5rd7erent cyclins during the cell cycle. Which cyclin is involved in preparing for DNA replicq6 jb5z3ufrp) 7bfj/dation?

The diagram below sho,fip (cxsreu8y51 /lhws chromosomes during meiosis.

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 3+ dj umel vg5 do))o*,idppl,homologous chromosomes?

  The mitotic index of throat tissues taken from 4 different patients is shown bel,a*i j:ii-t44hxxtu d ow. Which patient is tx:uii ,da 4i4ht*-xjmost likely to have cancerous throat tissue?

1.Draw a labelled diagram to represent the process of af)bg0 4 -nwjgcrossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal hu6vjxx.u/xh h6fl k(b ieuw2/( man karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one celiy k-b st -9-d)ny+gzrl during one complete cell cycle. Each le ryg-b +dt- )sk-9ziyntter represents one stage 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 shd/ + dwd2q6fpcy4t-udo jx1/kows a cross between a male cat that is homozygous for brown, long hair and x2/tcdwjkd p6dd/1 yoq4 + uf-a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic thd d9s::yd2sm ktjq5y 3x p:7kraits can show 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 cro/78ynepbr-cpbe k; c+ h:9bkissing over of non-sister chromatids shown in the:7kcie8kp9prc h e-+ ynb /;bb diagram below?

  The photomicrograph shows a poe)su0tt 4e6g p w3 e.txry4ar1llen grain from L. candidum (Lily). Which stage of meiosis is r rt1y.u604esa4ttgwx pe3)e shown?

1.Outline the events which would lead to an individual being born with Doe l.)z13 ei;trl0atubwn syndrome, which is chararzti0 ; ll1 3)tba.ueecterised by the presence of three copies of chromosome 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indirect way of measuringgv(/qprh*a*t) m2cs k plant growth. A study was conducted on white onions (Allium cepa), under controlled )pcm*v2r g/qkt ash( *conditions in a lab, to investigate the effect of 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. The diagrams belkfbcxx)m-q18c9 1lk lvb)2fnv7;zcg ow show two cell)nvq1f;mb g l-lc18x vkcxbf k)7zc29s from an organism with a diploid number (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 gene expressiosj(mli:ejk7 zxz9 :/lq d7f,rn 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 number of 8, in different sta(aj a67q kq)svges of meiosis. Which row correctly name(k67avqq a) sjs each stage?

  The micrographs show four phases of mei* lxui0o4jb ;dosis I in a plant. In what order do these pha * ;o0dblxiuj4ses occur?

Mitochondria are responsible for supplying metabolic energy in eukaryoticol/45ejek c cx09f- g; *rqhipekh. :s cells. In most eukaryotes, which reproduce by sexual reproduction, mitochondrial DNA (mtDNA) is inherited from only one of the parents: the mother in the case*/c e4 .k kqf-oi5xl0eh p;e jsrh:c9g 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 differen*1alj21sec gi yt/k(c t stages of the cell cycle in four sa c2gsc(yi*1a kte l1/jmples of lung tissue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the d4 7gvc, )wtilu6 fesq1g.d +urift-g0ominant cyclin/CDK complexes at different time points in the cell cycle. Wu 0s f,r)-v4wdtq61g 7+.fcti iglueghich cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependent Kinase 3 (CDKNlzj 5bm*7gfne llvz u59l.. x/ b+y-su3) are highly overz-bz*v.s.7guy/lj5l 5ex f n+u l9lbmexpressed in cervical tumours.


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 the highest dur3vtmh1;gws28y*x tb lxh1 w5j ing the cell cycle ?