The graph below shows the relationship between maternbd t/d*h xoa4 owl62-ial age and the incidence of non-disjunction. What relationship is suggested by the dat* 4h2odowxab/-6dl ita in the graph?

  Which stage of meiosis is represented.,bov i 1v0+v5eex+-j khxobd in the diagram below?

  The diagram below shows chv(q iqk4 c:cyqwxdu u; ,:07xdromosomes 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 gepwx88gjoi8p0x;gned2 dx n/d7io m 0 ,ne which would be present in the nucleus of a cell as a 0mox/0xdgw8no gdj2pi; pe7xd8,8 niresult of each process?

  Which keyword is matched to the correk;m6bcdj rtcemp6c)n 1.e35 a ct definition?

  Which statement(s) about )b.4hjzb k1j p;b;i hqmitosis 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 anapl,w h13+xol f ax)gsfoj*4q y:hase?

  During which stage odouj56h i k/a4 .cyk/6*eaetkf mitosis does the nuclear envelope break down?

  Which one of the fol fh e.:;z2hyixlowing transport proteins only carries out active transport?z. f xyhh:e;i2

  Which process does not happgi.9ggq pfy;4t;z.j c en in the shoot apex?

  Which type/s of membrane transport do/does not require energw8qyznrp0qf6l0 x67 et ( ,vwey expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represek2pjetje4 jw6r on7.w 0 bfqx9w:vy75nts a cell with a diploid number of 4. Which stage of cell division is the cell currently undergoikq rpjwen7j yw4t92jw6ob f7 5.:ex 0vng?

  The photomicrograph below showspbs29 w 8:hx6md7or3ws d2jis a root tip meristem. Which of the following sentences correctly defines a meristem2oimx9wj :pw6rhdb ds 28s3s7 ?

  When does the random orientation of homologous chromosome pairs occ4 / qxq6ul-ouzy4ao a.wwrxiic,i8 6.ur?

  Which process does not oc0 -0sndq6gbvi ef .sc /d* irvocs7jt */(ay*tcur during meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, how many chrorahrw. - y 99p)u 70ddpzkv3qvmosomes will dha97u-3pzpqrk9 )0v ydv .rwbe present in each daughter cell after cytokinesis?

  The image shows a micrbv hn8 7,2i2tch:rf:ivyvz t(ograph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homolpdest. f391hmi:wvzc/:ca o. ogous chromosomes is/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 with Down syndroiml am7l e03q;: ytl3ime.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophasels.9oo,oj5xx I of meiosis I there are 64 chromosxo j.o ,o9sl5xomes. What is the haploid number of chromosomes?

  Which arrow is pointing to a chipa,o+ p wa7s,*jocnj0 asma?

  The diagram below represents the (bo. fb6 6hegfy,bzu kfc7l06structure of a shoot apical meristem. Which row in the tablfz b0 efuhfb 7y(c. 6bol6kg6,e correctly identifies the processes occuring in the structures labeled in the diagram?

  How does meiosis promote vari6*4 urwv9l8byrb+4n,qk9 u +zla 5k; yrnzdpxation?

  Which of the followingu1z xp)woh6b+ statements 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 from two hoq;3ykk ) 1zd2hc rzo0pmologous 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 11 clhdhhu:zru5 16d gsecondary tumours from primary tumours as a result of the movement zdur6uhg1h:cl 1h1d 5of cells?

  How many chiasmata are present in the diagram? m b-, 0qvwgtd(aw.oh 0

  Which statement is a similarity b9vjak*+ bck v-53r2wl bawpfn8brp 9.etween cytokinesis in animal and plant cells?

  Which stage of meiosis is matched to the correct dxlju h)e 7dw gpw.l o(:0u 5ox7tqi70sescription?

  Which statement(s) are true of meiosis I but nmwo/ w-v-lesoyx55+ )uik0cv8q2 ppiot 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. T/*.c*dibwbt( v5 lambhis results in the formationb / dl5b(i vc.mwb**ta of one large cell and one small cell. What is the fate of the large cell?

  Which row correctly describes diploid and hapi5k c/m,qhj k7y k.a3eloid cells in humans?

  The following table shows the diploid chromosome number k. lpm-+xqx.oh 9b 6ii iv1,ueof a range of species.


Which of these statements is correct?

  What conclusion can be b,8kfr(6i w)n1 m-0dl ns iwxtdrawn from the karyogram below?

  Which of the following processes is characteristic of xk2 gn ym).a:18hdgm ethe meiotic and not the mitoen18.hmd kax:g y2) mgtic cell cycle?

  The diagram represents a bud with a shoot apical meri bn1ty+d yxhum29u.9ig;hm 8e .ora/istem.

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 (P 3fgpv m.hu2i2an troglodytes) is 48. Which row shows the correct c.2 u 2pgmif3hvhromosome number for different cell types and cell division stages?.

  At the end of which phase of meiosis I does crossing over occur, and whpr .pk0l)y4n;t +7 z lmd,dgmoat is the outcomem yl.,om0tpddz+7nk pg;r)l4 of crossing over?

  Which of the followinon88ock(mr u7-:nli t1yf 2leg statements does not describe a step in the sodium-potassium pump cycle in try8l 28focmoe:7k1-tuin n l (he neuronal cells?

  Which row in the table below;* gv2sk. 0rp uv0ehct is true of meiosis?

Membrane transport is important for allowing particles to move across t x3rgy*4e wc:the cell membranwy34t xcge*r: e and respond 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 ,iradiyb,nrub3 * 2l- z9g6 ;gf-novain 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;om99w by 7ba3j /hwog cyclins during the cell cycle. Wom9j bgh/ 9wa3bo;wy 7hich cyclin is involved in preparing for DNA replication?

The diagram below shows chr-nq n vbq, 3pc51;+ f)srpmzrgomosomes 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 homoloawywh):q l a2(vb md-ypp/t-9gous chromosomes?

  The mitotic index of throat tissues taken from 4 different patients is shown grib86l4. psoeoq:8ebelow. Which patient op8egr6i.q84s:e lbo is most likely to have cancerous throat tissue?

1.Draw a labelled diagram to represent the process ofv-hkr1 yj: v+, ubez:m l:-hse2a5osd crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an ar7dz7;wqc et *bnormal human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of g ,vl/p5j d5cvDNA in one cell during one complete cell cycle. Each letter reprl5v5 gdjv,cp/ esents 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 between a male cat that is homozy:vf9lkr f wr9(gous for brown, long hair and a female cat that has b 9:klvwrf9 fr(lack, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a nor ldvxjs (;w4)pmal 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 over of non-sisn ;l ,apq7haq g*vrih9qao1+ksufj,q*:-1j l ter chromatids shown in the diagram bekn;h-1:jq71*qp sul la,f,a+ir*h jgaq qo9 vlow?

  The photomicrograph shows a pollen grain from L. cand:g6 iqd (:l8oix+yf9:s wussaidum (Lily). Which stage of meiosis isa6sgu f:(ii q o:s:sdx+98wly shown?

1.Outline the events which would lead to an individual being bo(s 001ka *n7retwvof obf .)torn with Down syndromf. w0 vf 1(*)ttnrk0ooeba7ose, which is characterised 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 measuring plant gr0)yxiiay-i) z ngf9j+owth. A study was conducted on white onions 9+)giy0 z ia-fijn) yx(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 ways in which cells can divide. The diagrams bw)cn( 5)ll4k pcfn fn8elow show twol (nclc8)nkwf f45p )n 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 stem grow7xk mz t9ylbg zp(*/)eth.

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 diploijbb8wnp8:.1- )zwot(3dg*a tduexus d number of 8, in different stages of meiosis. Which row correctly names o -uzg*abj x1s bdn8w(d put)8:ew.3t each stage?

  The micrographs show four phases of meiosis I in a plant. In what ordo.roziqw ct1q) 4qs ry) .0;-yuvd(h xer do these phases occurt(w i1q)ycrd0 . qsuxq)4v-.rhoo; zy?

Mitochondria are responsible for supplying metabolipm tu- 6lp8jl8c energy in eukaryotic cells. In most eukaryotes, which reproduce by sexual reproduction, mitochondrial DNA (mtDNA) is inherited from onlyp uj lmlp8-8t6 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 )ba b cnd:j5.0v)f; kvhj s mzu6,csq7in different stages of the cell cycle in four samples of lung tissue from b) jm;s5q fvs6zac,cjn.v: 0hku7db) four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyc/m/(9hb c6y)wgkgo5g.od n hb lin/CDK complexes at different time points in thbo/ggg w ).dnmk hco956y/hb(e cell cycle. Which cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes sue ,xrgxxch0q3)dw 07 uch as Cyclin Dependent Kinase 3 (CDKN3) are highly overexpresxqgxdx00r3e h cu ,)7wsed 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 during the cerxylu q/vc*/(g;ckww1jl /y 6ll cycle ?