The graph below shows the ref/om f1:ei e,v01zv qj5de3yxlationship between maternal age and the incidence of non-disjunction. What relationship0,xeovd1f:mqe e v1yz / j5fi3 is suggested by the data in the graph?

  Which stage of meiosis is represented in the diaeeg ..(uu:w--fh xyrvgram below?

  The diagram below shows chromosomes during meio2;diskeb5t58 rz7 pcisis.


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 sts9w f 7bakq0m+ates the number of alleles of a single gene which would be present in th7fbwsmaq0 +k 9e nucleus of a cell as a result of each process?

  Which keyword is matched to the correct defin4g k,p4vgn,i2h r.hgcition?

  Which statement(s) aboi3f-v.vi: 1u,+8,bfeqogv euaw1 nv z ut 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 pol;ce 9q b;)t/zej cfg (h fv6xj5i (ci(mk0y/tints to a cell in anaphase?

  During which stage of mitosis does the nuclear envelope.8zslxm*x 0tt break down?

  Which one of the following trsh szsq5 (5 .eyr:z,hwansport proteins only carries out active transport?zhwsqy ( 5,5.ss zrhe:

  Which process does not happen in th2ro(ca udt(b.e shoot apex?

  Which type/s of membrane transport k5j25 iofn:n -6bel2m1vy phk do/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a celj gm-w;4o5ufw l with a diploid number of 4. Which stage of cell divisio5fu 4-oj mwwg;n is the cell currently undergoing?

  The photomicrograph below shows a root tip meristem. Which of the fol sdsr1yoy-. m3lowing sentences correctly defines a m13omssryy d.- eristem?

  When does the random orientation of homologous chromosome pairs occurk 5 ida dn;m.ucygot: t65/9pk?

  Which process does not occur du y+w2x o:yjw8pring meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, how ryq2 6+6i ft.ju,ftyvs :de8vfm +g s:many chromosomes will be present in each daughter cell after c 6dm2tqyf +,fig :8.vveu:rf +sjs6 tyytokinesis?

  The image shows a micrograph of a cell.cisn:i v7ptuj0mf/4*


What explains the appearance of the cell in the micrograph?

  Which statement(s) abo(7r.qg (rir/lcy g:m7yiw +gj ut homologous 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 sy ktp:n7d i6-cm y9k5dtndrome.

Which statement is not correct?

  In the cells of a horse (E. caballlo3wy +79py aemi6r3jxft qbd b7 g641us) during prophase I of meiosis I there are 64 chromosomes. What is the dg9 y bblaiorwm6t61y3j4eq x+7 p7f3 haploid number of chromosomes?

  Which arrow is pointing to a chiastk+ oho.6blk;pauqfy h k2--2ma?

  The diagram below represents the structure o7v;vr cce 9dsoorm (t*x:yk:-f a shoot apical meristem. Which row in the table correctly identifies the processes occuridos ve *cy7vm- (t;k 9rr:cxo:ng in the structures labeled in the diagram?

  How does meiosis promote variat3xef gmo k5a4u07bnfo1v, y6 +ehbwx+ion?

  Which of the following stxd-wbp nhp4 e*,d;c :tatements 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 homoj ,u 9od69mimjmh:c9xlogous 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- vud88oj2i wf*zn9v6xa( wke formation of secondary tumours from primary tumours as a result of wfz vd(v6i8*j- xk8au on9e2wthe movement of cells?

  How many chiasmata are pres y;8 tm77b 3gxpis2vfp l*v:unj(*lvcent in the diagram?

  Which statement is a simit2r*,9z)dmq hpih w1r larity between cytokinesis in animal and plant cells?

  Which stage of meiosis j k+dbu(n4w) vis matched to the correct description?

  Which statement(s) are true of meiosis I but not meiosis :g zppm)o *mr d6t*w1wII?
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. Th k08 7q)mgeu2u0xwich22wuvwtvea: .l21zxzis results in the formation of one large cell and one small cell. What is the fate of t w ) 20 27zuwuw1im vek:0gxalu8hx.c z2v2eqthe large cell?

  Which row correctly describv9-p 0a)qovdr es diploid and haploid cells in humans?

  The following table shows the diploi3f+c cvsu.z : :n)n30bvdkclpd chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can ; h,b1 nk:d90nyavizsbe drawn from the karyogram below?

  Which of the following processu wc9c0xkk:;-ho7gxp es is characteristic of the meiotic and not the mitotic cellu9pxoc:k;kh7xc g0 -w cycle?

  The diagram represents a bud with a shoot ag7 4eu)imnlmmc c -v45ej guv jt-t7;9sh4n(h pical 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 cr :uurbq10r*gbn* t -48. Which row shows the correct chromosome number for different cell tuq *gr0 :-*ubbt rr1ncypes and cell division stages?.

  At the end of which phav0 j.8 pfalbt 9)xe)gkse of meiosis I does crossing over occur, and what is the outcome ofe k gjp)xfla 9bt.8v0) crossing over?

  Which of the following statemen))1x woo3ql wuts does not describe a step in the sodium-potassium pump c 3)x1w qu)owloycle in the neuronal cells?

  Which row in the table below is true of mlc: q+6rjt (i;gsl 8hfeiosis?

Membrane transport is important for allowing particles to move across the3dg1umu7 w*e2mkxlz o mgy)6+ cell membrane and resp7*ly d 3 u6zwu2k+g)meo1m mxgond 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.wzp1 f4 h6 jnp75ae0oi

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 5r3l2f1 kzzku different cyclins during the cell z uk5f2 lk13rzcycle. Which cyclin is involved in preparing for DNA replication?

The diagram below shows chromosomes during m aou.) vino(1*fb 3w ;b(bbdwdeiosis.

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 invdc3lrq,/eelh2p j .2solves the separation of homologous chromosomes?

  The mitotic index of1g;bk.vgi8lr gzrk3wr9 .q5xxr)av 9b6hv x: throat tissues taken from 4 different patients is shown below. Whicxlhv:v 96.kr 15 rxzr .8i bvarqg;x 3bg)w9gkh patient is most likely to have cancerous throat tissue?

1.Draw a labelled diagram to7)a 17l gt(q mj p4tib5jikj*z represent the process of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal hucmm e786 fu *-tsev9jzman karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cell during one 8 nkkcrd9n8kiq/2x7g complete cell cycle. Each letter represents onig9knnxq 8 kcdk82 7r/e 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 homozygous for brownc*a yp+auk yx4- 2i1zh, locaz+h* k4u -yiy12 xapng hair and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygen ;9i)imm 4ds:cm-xdy rhvv4i2ic traits 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 over of non-5hc+g)f 0l-pez:ztc nz ofz4 2sister chromatids shown in the diagramzf)p zhztclfg04: 5o-n2z ec+ below?

  The photomicrograph shows a pollen grain from L9 ;jvn2r3/ul flx 3(9n mmeiep. candidum (Lily). Which stage of meiosis is n( pe9le3m3;9f lu rj/ixm 2vnshown?

1.Outline the events which would lead to an individual being boik6 g9orvo39srn with Down syndrome, which is characterised by the presers 9okv963oig nce of three copies of chromosome 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is a wwc6klamb8 z1b 6a3)vn indirect way of 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)c1zm blkv a66wabw38 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 flhmo 3*/ )oqrwhich cells can divide. The diagrams below show two cells from an organism with a 3*o f qh)rm/lodiploid 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 exprx b6 +;)zt6 h5kph2ss2n ntaoression 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 diploieu 0jo;ces2p:d number of 8, in different stages of meios: oup;20jcese is. Which row correctly names each stage?

  The micrographs show four p*6kii on3buj( hases of meiosis I in a plant. In what order do these pji*( 36kobniu hases occur?

Mitochondria are responsible for supplying metabolikzm/uq i4 * pjvr5g1:gc 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 result of sexual reproduct5mvp1k* :gzqg i4u rj/ion 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 9 lrzn/kz1vwe7lgx5 abt2+6p different stages of the cell cycle in four samples of lung tissue from four patients. Which tissue has the 5brnk2w+l 1lvxtg7a 6 zp9e/zlowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes a 5xcj4fzhg;( .tk.sn zt different time points in the cell cycle. Which cyclin/CDK complex act g (;zzn jfk.4.5thsxcivates DNA replication machinery?

  Studies have shown that gene)0qgi l 1a+4nqj axxmz,ngn02s such as Cyclin Dependent Kinase 3 (CDKN3) are highly overexpregn,jx 1n)g+xanlq i a20 4mqz0ssed 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 0 //a( q93fcgajab usii 2nuk3r+a+fnthe cell cycle ?