The graph below shows the relationship between maternal age and the incibsk k -*1h0wmrdence of non-disjunction. What relationship is swmkr0* kb-sh1 uggested by the data in the graph?

  Which stage of meiosis is represented in the diagram 6fzsxl.-jkyy152 t grbelow?

  The diagram below shows chromosomes du z6d 6)t)5 z1au97v5px uxkwzg xzcg8xring 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 which im1pi d3e )r4k;g7shz would be present in the nucleus of a cell as a result of each pr;sg z1eh 3m krp4i)i7docess?

  Which keyword is matched to the correct definiti+k,iydr n ua+:s1b.lt pen5b3on?

  Which statement(s) about mitosis is/are 3elfk / up./b)8sqj- baqhv8ntrue?
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 (.n;/ipcu,s rzf 4 yvlin anaphase?

  During which stage of mitosis does the nuc+e5 g+zqlv d1flear envelope break down?

  Which one of the following transport protei7ws gw,r5hid)sd fi27 ns only carries out active transport?sh )dir7wd75gfs 2w, i

  Which process does not happen :( h4h2z hvrimin the shoot apex?

  Which type/s of membrane transport do/does not require energy expenditure-) b+dgx:hzqo zya7*l?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below reoan)nb 6 a0p4hpresents a cell with a diploid number of 4. Which stage of cea)4n an 0bh6poll division is the cell currently undergoing?

  The photomicrograph below shows a rootz,be;2wv; w3g +js -3wy fxubo tip meristem. Which of the following sentences correctly de;sy3vw fe+z gwbu;-,x jb3ow2fines a meristem?

  When does the random or-. v m31a4cbxpm.wzln)j0npgientation of homologous chromosome pairs occur?

  Which process does not occur dur)6q6r o1the3 toxkq+m ing meiosis?

  If a cell with a diploidpxho p s.:9 oau6w t6+aer2nh3 number of 36 undergoes mitosis, how many chromosomes willut6+ewh a9ppo3hxo 6n s2ra.: be present in each daughter cell after cytokinesis?

  The image shows a micrograph of a celbvo m* 8q56neft28*k *qie jjjl.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/ared l(hvy b27+gpv,ld4v 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 indtq0o1 yl7 diw9a.9b e4vcb m b+8/tyldividual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis I thews-ozmg 0k+x63uo -uxre are 64 chromosomes. What is the haploid numbko -wuz-s 6u 03oxxgm+er of chromosomes?

  Which arrow is pointing to a chiasmapwih,qj 2e0(p (dwb o5?

  The diagram below represents the structure of a shoot apical meristem. Wh;goh,a n ak7l z-ts9o4q24 jrhich row in the table correctly identifies the prog7,l9 jorqo2; k4taza-4 hsnhcesses occuring in the structures labeled in the diagram?

  How does meiosis promote variatiooor: f1.wc9 cmn?

  Which of the following statements is/are co it:fvq++ f4kpy::x:gf,qe swrrect for meiosis?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametez gwti5ka:p0 ,s 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 formation of secondary tum1lzgq0iwn o- 5n(oi3h ours from primary tumours as a result of the movement of ch nin(q1-ogow5lzi 03ells?

  How many chiasmata are preshhn m0 pz 0o/wqp(0bpdr9v02kent in the diagram?

  Which statement is a similarity between cytokinesis in animal a bx,t enia143*ovf j,lnd plant cells?

  Which stage of meiosis is matched to 8 pkw(c; 1qofqiru /k/n2 eqr*the correct description?

  Which statement(s) are true of meiosis I but not meiohgkkmle6 9l7;ruc7 t,sis 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 cw6mc0d)fad e)xw3d7 jy 62ryoocyte after the first meiotic division. This results in the formation of one large cefym 7ecd0)d 2)j6 ra36wc yxdwll and one small cell. What is the fate of the large cell?

  Which row correctly y5cq0(or lt uw .rr/.l(v;fbz describes diploid and haploid cells in humans?

  The following table sxnnh 7ba 13e 07w8)zik grya5uhows the diploid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn hykb0o4 oe:s4m.q)pp from the karyogram below?

  Which of the following proc,n 1dg 6;xo6p(wnzpifesses is characteristic of the meiotic and not the mitotic cell cycle?1i;fz6 pn xo w6pgn,(d

  The diagram represents a bud with a shoot apiu svl44m qemi.sg:35zcal 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 chimpanzee (Pan troglodytes) is 48. Which rom sz70 2wn4thjw shows the correctzmj7s42nw0th chromosome number for different cell types and cell division stages?.

  At the end of which phase*e:+ucg x)ais : i-qal of meiosis I does crossing over occur, and what is the outcome of crossing ov )sclu*i:xqaae + gi:-er?

  Which of the following statements does not descri p8f nk: pm+,jwcrdhwjzd:w(s.)0xn1 be a step in the sodium-potassium pump cycle in the neuronal cells? d(j1m :j:r np+)k8nwwdzfw0.p,h csx

  Which row in the table belo3m w3f nd1efn:w is true of meiosis?

Membrane transport is important for allowing particle0jw:vn zt6go4 s to move across the cell membrane and respond to changenw t64g: 0vojzs 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 regulats o/6uxcjkgbj,;m ge36rf2,u5zsk fr;i: sp) ed 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 s(c vc5k-mo* d1epegskne;;cjy h1; 0the concentrations of different cyclins during the cell cycle. Which cyclin is nc(pcesoe ce1 *1-0vyj;d;m;ksg5 khinvolved in preparing for DNA replication?

The diagram below show gwczr9y :hg48s 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 su(0 ka **pjc;x z1gxvyeparation of homologous chromosomes?

  The mitotic index of throat tissues takoin// y lyiycp dq6:13en from 4 different patients is shown below. W cdqy3i/o/ 6:n1lyi pyhich patient is most likely to have cancerous throat tissue?

1.Draw a labelled diagram to represent the proz-eh2rgq7 d6s:ygks5 cess of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal human karyo0e:5ausdt1opuo3 t w+;2uojh type.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNyil xg9zj7anv5n (z+-A in one cell during one complete cell cycle. Each letter represents one sta-n(+z 95yiajvxl g nz7ge 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 vazn8e+ dq)l9n/ p7sf that is homozygous for brown, long hair and a female cat that has black, a pd8)vlzsn qfn97+/eshort hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normaxin(+yig i2 k 6lk vq3l c;,p3shi*9xyl 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 crossiofz8k2xgni:ml,m ms3j8ce * ;ng over of non-sister chromatids shown in the diagram below? ik3o; 8gf: m8,jx*mn2lsmez c

  The photomicrograph shows a pollen grain from L. candidum (Lily). Which saf)ym/r. jz d1tage of meir 1d.z)fjy/m aosis is shown?

1.Outline the events which would lead to an individualclc1 q)y.qm6new f3k , being born with Down syndrome, which is characterised by thn)3ec.qf 6ylq,c m k1we 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 om2r;cupvhc 5x hv:chw -9l 67af measuring plant growth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the effect of soil pH 2ahhl9 c cu6-ch;v7xpr:5wmvon 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 diwj;ixq: y lt):agrams below show two cells from an organism with a diploid number (xt;jl )wqi: :y2n) 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 stem gro 5hpbwz2d sq; )3ykko2dr(6n dwth.

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 stages 0 ji.6:w rh9pyfwy*hq of meiosis. Which row correyjifw y6w .rh: h*9pq0ctly names each stage?

  The micrographs show fo68rurhxtg2fq5w9 v5l. k vy9f ur phases of meiosis I in a plant. In what order do these phases occur?u 9vqrxf2 5y9fr6 gk85 t.lwhv

Mitochondria are responsible for supplyik//dbomcc5 vhesc1. 2 ng metabolic energy in eukaryotic 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 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 resulmk.v chsoc1ce 5 2db//t 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 numbt84a+ 5r nwgmt+ri qo5tos.jwv+1 sw 1er of cells in different stages of the cell cycle in four samples of lung tissue from four patien.titv+4gons5 ws +w58wqar1t 1 jom+rts. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at different timei bo .5ut lc bx+ote4r7zb/;n6 points in the cell cycle. Whic7biubtz6 n4 o;e+.b/xlr co t5h cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin De y5u)q,3*qmnx;i aj lfpendent Kinase 3 (CDKN3) are highly overexpressed in cervin5xy )qajium3; , fq*lcal 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 during the cell cycle ?1. ohsin;k (jqp:3t gs