The graph below shows tshz(kx lm,hy6. 9rvn.he relationship between maternal age and the incidence of non-disjunction. What relationship xhk(s6lm.zn9vyrh ,.is suggested by the data in the graph?

  Which stage of meiosis is represented i: 4n,dv( qkgxfn the diagram below?

  The diagram below shqjxcfcef( 457ows chromosomes 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 allelesxt.pped d t v3pl(v9wr(l0b xx)+,u4 l of a single gene which would be present in the nucleus of a celxpltevt(u)p3 4x0.w+ bplddr 9 v(x, ll as a result of each process?

  Which keyword is matched to the correct defi l,vcet.3 qbjdk *e.)tnition?

  Which statement(s) about:s63 e+zc17l isifw; -lr5 wjyc+zwhi 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 letter points to a cell in anapg2xoro1gy+c/5- t( y ho/b koehase?

  During which stage of mitosis does 2bsm42 vrgr :o.lp7il1q gyp, -xb+rvthe nuclear envelope break down?

  Which one of the following transport proteins only carries out active transp xf xet5 xnd9y5,vmhr,7ah+:sort?ye t:vf 5axd+7xh, 59,hsnmxr

  Which process does not happen as-+vnl7zoeu( 2 iv x4in the shoot apex?

  Which type/s of membrane transport do/20(xk jaxlp*r8e lv3*kjr +jg does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents 2zpjd vkodhr7ja0( 6z6vk,/b a cell with a diploid number of 4. Which stage of cell divisiovk(hj2j 7/ad66,0 rz pvdokz bn is the cell currently undergoing?

  The photomicrograph below a)xc un;pvcx. g+9ml4 shows a root tip meristem. Which of the following sent+x9xg;p4.c cna)uvl mences correctly defines a meristem?

  When does the random orientation of homologous chromosoh (bm jk 43pna z+zdq4uh,( rchi751jpme pairs occur?

  Which process does not occur during met-mo(s hc pp,,y9etbdh i; +o:iosis?

  If a cell with a dip tgw 6;4d2kn4pgi olu+7b g1nbloid number of 36 undergoes mitosis, how many chromosomes will be present in each daughter cell after c i7b pk4ngtl6wg+2 ;n4bu god1ytokinesis?

  The image shows a microhyzicl dzuf e6s2g 3l(dyxc71 p-1 )6ggraph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/are not true? l4g ;7eo1uk xxa*p7z lm14c,3ltddsb
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 iny0)p +;o xdqpgdividual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) durinkm 1m6vv do9l5:x0jnpg prophase I of meiosis I there are 64 chromosomes. What is the haploid number of6lp51dkv9 ox0: mjnm v chromosomes?

  Which arrow is pointing to a chiasma?y )gs122o oqeq

  The diagram below represents the structure of a shoot apical jqtprbf*, f 0-nl dr:(kf:ez1meristem. Which row in the table correctly identifies the processes occuring in the structures labeled in k z pq*r:0jtb nf,el:f(-frd1the diagram?

  How does meiosis promd*yk l ,n6:4-nyqym) gx-po n* hcm.hyote variation?

  Which of the following :0 uue kuz)8yustatements 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 gametvfimu24n v;s 44* xd cijuf:2ies produced 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 formathtv1a9 am:ffv0l.v /wion of secondary tumours from primary tumours as a result of the t /hv9flmvw:v1a. 0 famovement of cells?

  How many chiasmata are present in the/ no w11jl0lut diagram?

  Which statement is a simila s,; o(b.kpc)rvgub 8+j vghc(rity between cytokinesis in animal and plant cells?

  Which stage of meiosis is matched to the correct dgm l8e:*y d,jlescription?

  Which statement(s) are true of meiosis I but no* h)ukrvlkikv) .f99lg u k)f1t meiosis 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 division.dn, a-i6.y9 lwuj8bj a0k8bn;+mftsd This results in the formation of one large cell and one small cell. W +n;sfb9it0y.aunj , 8ddwl b6 ja-m8khat is the fate of the large cell?

  Which row correctly des7y c;ru 55fdfx)pw f0vcribes diploid and haploid cells in humans?

  The following table shows the diploid chromosome number of a range m9jhrccs2pb/cb* )s7 2 :xbboof species.


Which of these statements is correct?

  What conclusion can be drawn from the tdzkay3qj,(y l7 bm8( karyogram below?

  Which of the following processes is cha+e;ze/mk ( rakjpd(w 8racteristic of the meiotic and not the mitotic cell cyclem8k (j;(k+ezpa r/d we?

  The diagram represents a bud with a shoot a ax burcewow+16tr79 fr k20t1pical meristem.

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 cf*5 ,x* naugljhimpanzee (Pan troglodytes) is 48. Which row shows the correct chromosome number for different cell types and cell division gx *f n,ua*lj5stages?.

  At the end of which phasevix 7j/o0i9*9 r n.em9y flhaz of meiosis I does crossing over occur, and what is the outcome ofl9.nehxiz9o a0vrfim y/ 7*j9 crossing over?

  Which of the following statements does noiohd 3 v1m6hvi ;rw0;jt describe a step in the sodium-potassium pump cycle in the neuronal cells;1imo rd3w ;vh6h vij0?

  Which row in the table below is true of meidnbx+arnvk5 p l .nz)79d 9u)e0zla .losis?

Membrane transport is importy.fb bjcphx1eqc2x*mvm04,-gx x5 t:s-tv ;fant for allowing particles to move across the cell membrane and respond to changes in the chemical composition of*- vyvs4xt5gq0em ;c,1p -2jh.bmffxx t b:cx 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.,gju ya *a)ef(uhi2y is regulated 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 the concentrations of different c z:2. 4n2 zjc2jytecdqyclins during the cell cycle. Whicd.t22qn2ejcj4z :z cyh cyclin is involved in preparing for DNA replication?

The diagram below shows chromosomes during meiosih-32hrz nl/v1i k6hw kmz6l.ss.

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 thef/:9a x(uyefz/vx sd6 separation of homologous chromosomes?

  The mitotic index of throat tissues taken fha0jnw/,( xtw7 j c,avrom 4 different patients is shown below. Which patient7 wt,w0 a(jcxa/,jhnv is most likely to have cancerous throat tissue?

1.Draw a labelled diagram to represent the process of crossing zf6m 7nz*b6q1 u,waghb,v+o w, rodk8over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnorw,mgamyz orh5qar ;. wn4(0b9mal human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cell during o1i00 xva omx/pne complete cell cycle. Each letter represen0/oix m a1vxp0ts 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 shows a cross by3aw3 6a 4wmazetween a male cat that is homozygous for brown, long hair and a feyz m3 4wawa36amale cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic gm p8 u :7 :+cnms.*flxaxn8nbtraits 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 crossing ovellk2 +fr)iz+r+ln*oc *fqr t*r of non-sister chromatids shown in the diag2 ++fr*rl*lilrk otnfqcz) *+ram below?

  The photomicrograph shows a p(ls 2x2sep yl.ollen grain from L. candidum (Lily). Which stage of meiosis is shown?lpsly2.x se2 (

1.Outline the events which would lead to an individual being born with Down sy 0zza:q 4wcay7e(elm,ndrome, which is characterised by the presencmqey47ez ca z 0,awl(:e 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 measuring p3,e*v g;6) mvl f-kxhkjpaq(tlant growth. A study was conducted on whix ;qavtk3 p)mk6lj-gf e (hv*,te onions (Allium cepa), under controlled 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 waydr-+e yvef8a4c uhp*1 s in which cells can divide. The diagrams below s 1av*+puf r-h48yece dhow two cells 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 expression in stco xlt2b( -9ns*u8u(rx-n etzem 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 numberkszxap(6rxly e,(du f6 f3v63 of 8, in different stages of meiosis. Which36xf,d eu(z(6 kfs l3 prvaxy6 row correctly names each stage?

  The micrographs show four phases of meiosis Iqlzy,v c95p4. 5d y,q/ic9yh xgnn +vl in a plant. In what order do these phases oc/,v c iql 5n94.9v ly5dzxgq +h,ynpcycur?

Mitochondria are responsible for supplying metabolic energy in eukaryotic cells6l nmho3z4j(ew. jz tppzm*97. In most eukaryotes, which reproduce 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 w l69ez z3zjh7mom*jwt (p4p. nhich 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 rf dv9)2zzrv 3of cells in different stages of the cell cycle in four samples of lung tissue from9f)2vv r3 zrdz four patients. Which tissue has the lowest mitotic index?

  The diagram shows the do9zna h:d-x* uu62nniui 84g xkminant cyclin/CDK complexes at different time points in the cell cycle. Whin *i-:2d84 au9hnku iugnxx z6ch cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cq,*kfd80-rx ve1ov :q hw9xzb yclin Dependent Kinase 3 (CDKN3) are highly overexpressed in ck8v- zq:o* debh9wv,r x1fx0q ervical 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 cy5nkhzp/*4 9rog4bz a kclin E the highest during the cell cycle ?