The graph below shows the relationship between maternal age and tzs:pa4)utpu+eg bn69 yh +8oohe incidence of non-disjunction. What relationshe aop ) uty6zpu+g9o4:h +ns8bip is suggested by the data in the graph?

  Which stage of meiosis is represented in tbwm6-(t be ;hqhe diagram below?

  The diagram below show bpwd.dxcn3 s1quwi4*c.y 4d5 s 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 o0u2 f qboch31z0k) jeff alleles of a single gene which would be present in the nucle3jqfouzchf0 b21 )k 0eus of a cell as a result of each process?

  Which keyword is matched toze+4.do vyid zj8)-8cffw5 d d the correct definition?

  Which statement(s) about mitosis is/are true*n zuofr 4vzc0oddb +17hbg3/ ?
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 ana f62 u,w8*ilfe wxu) xmqe:n)yphase?

  During which stage of mitosis does the nucl+t38iawd.u hj ear envelope break down?

  Which one of the following transport proteins only carries out j 6tv7xh 1u-fyactive transport?1- fjuy76htv x

  Which process does nvtvt nqkyg.j : b1rnp81:;* jrot happen in the shoot apex?

  Which type/s of membrane transport doy ss5ztruf8k/ 2aid+6u nqdn1 zz 17+r djv/.l/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploiv) hjhoigdy7 s13t 0- hm;utdrfr 5i:)d number of 4. Which stage of cell divd 0 tvg1 hm-7hif)ij3r5u; ohdy:rt )sision is the cell currently undergoing?

  The photomicrograph below shows ak0 unm bn;;s5h root tip meristem. Which of the following sentences correctly defines a ;k0;m5bnu snhmeristem?

  When does the random orientation-/hlgoe/3 e,ezqrai9 of homologous chromosome pairs occur?

  Which process does not occur duringpv4vx9tvb)h res qg *b9b c27. meiosis?

  If a cell with a diploid number os3egu. m1u9hi;p s :ojf 36 undergoes mitosis, how many chromosomes will be present in each daugu.i e;g s3hpjo9mu1s:hter cell after cytokinesis?

  The image shows a microgra z8 e,6bkji7v 1si5vdzph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/are non.uhxr 1.aclys/(tzxt , w)8wt 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 Dow) po p2ime-j;sn syndrome.

Which statement is not correct?

  In the cells of a hor;im)* hu4r7*vo s gpzvse (E. caballus) during prophase I of meiosis I there are 64 chromosomes. What is the haploidvp7;*mr) * izhsv4 guo number of chromosomes?

  Which arrow is pointing to a chiasma? .wa g3*np2d ipy4 hjj*

  The diagram below represents the structure o 42)k+ajvn/duup+s8 9 voyyq uzyr) -ef a shoot apical meristem. Which row in the table correctly identifies the processes occuring in the structures la+uz 8y/yyojv4)ar dksup e92v+q )- nubeled in the diagram?

  How does meiosis promote 7r 3 lajd 4xiv s:ak-u2)vy(mgvariation?

  Which of the following statements irw; in/8fasdt ni(k8 0s/are correct for meiosis?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gam7ougsbdd:n,*e/ lc4m etes 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 secondp(7r76 enxc9xre( pcrary tumours from primary tumours as a re7c p9(rexxrr(npce67sult of the movement of cells?

  How many chiasmata are present iou0 ha5zm zo9d-g7jnc0 n4lw- n the diagram?

  Which statement is a similarity between cytokinesis in animal and plant kb 7byxb/cw piz qh*hp, ;o/d;84nt4s cells?

  Which stage of meiosis is matched to the cvu :ads gmw2g ro59fdggy1y57;2mbk2 orrect description?

  Which statement(s) arem:rn,cg-7uvtkc 6 mb 5 true of meiosis I but not 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 firstvs9w gz ne9gd 0:8hs-(j/:l buz;yypm meiotic division. This results in the formation of one large cel:z wh(9y0s9 ju/v gg :d-nym8spe; bzll and one small cell. What is the fate of the large cell?

  Which row correctly describes diploid anc7 );wv ngb.ngd haploid cells in humans?

  The following table shows the diploid chromosome number 49lpy9 sf. ullof a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyogram b m-ygk ito)8-zp2 6l5 cxrr/zuelow?

  Which of the following proceszb3p2m pbq,+; r0 g v.lqcayo*ses is characteristic of the meiotic and not the mitotic cell cycle? ,b2p+0.a3ov;q*qzrlgpc m b y

  The diagram represents c*fs4dsy/o3u2wu;k va bud with a shoot apical 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 (Paa3fpc3;zs w p1n troglodytes) is 48. Which row shows the correct chromosome number for different cell types and cell division st3;cazspf3wp1 ages?.

  At the end of which phase of meiosisngu- 2 p 13s / brsc4hmoib4inga*fd./ I does crossing over occur, and what is the outcome of crhm/- i/ fr3o 2.p* ns iu4bs1gbngcda4ossing over?

  Which of the following statements does not describe a step in the sodi fugq- jmqnp4-k*xvc4v6c 43bum-potassium pump cycle in the neuronal cjf-b-q k*n64 vuxqgvmc4c4p3 ells?

  Which row in the table bw .z-h n6:u2;5nnjth bdav)i6 k*qpztelow is true of meiosis?

Membrane transport is important for allowing particles to move aw,5dup: kttmdb/.0mh cross the cell membrane and respond to changes in the chemical composition of the extr.:5tk, uhbmwtp0 dd/macellular 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 cellulvh w45rb) k ro(,d,cs.

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 c3 yx 9b;1rufdwvn2;fun e ry. y.)/ozzyclins during the cell cycle. Which cyclin is involved in prepzuw9yo rzyn2/.vf3)u1;ne.drxyf b ;aring for DNA replication?

The diagram below shows chromosomes during meioj3r ayai2(j/r.yl *e rsis.

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 inqx19 +zy/ uvicvolves the separation of homologous chromosomes?

  The mitotic index of throat ti z wh37hhs*1q hyvw-f)ssues taken from 4 different patients is shown below. Which patient is most likely to have cancerous throat ti3yhq *zf7ws)hh 1h w-vssue?

1.Draw a labelled diagram +,bnxy8lk; 20 qpavfz to 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 human2pxpu )6)pol2xwkd u w9ti9 f) karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cell d(t:uhewx ok q /8w4/bfuring one complete cell cycle. Each letter represents one stage of the cell cycle. ebw:f4x/wt(/uqhok 8


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 homozygou)t:x i 2w3x k3kjzynr380g/y; cccclts for brown, long hair and y3jt3 c)tx8/rlizwck n: ;kxc c3yg02a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normal distribwp*tqhpk 41*v-g n9ycution.

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 no r3n (*9ajg mi:q0qqysn-sister chromatids shown in the diaq0*n 9 saygr3qjmq:i(gram below?

  The photomicrograph shows a pollen grain from L. candidum (Li6f9oc a /pypf7ly). Which stage off7ap96oc p y/f meiosis is shown?

1.Outline the events which would lead to an individual beinjeng1nt(80p -vn k efljq,a2c+/+vcdg born with Down syndrome, which is characterised by the presence of three copies of chromosde nt,/1a(cp 2-njf0jvcn8+gql+ev k ome 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indirect way of measuring plant growth. A study was cond9rp7;e/nlt t uxlqy7cq,o; x 7ucted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the effect of soil pH on,p;toyl/e7q77rcxn xq utl 9; 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 below x5lhyr3.-,nq ca2n t gshow two cells from an organism with a diploi qhc5 y2-a3rtn.g ,lxnd 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 ofuxdk2hsp vl;l(): eq+ gene expression 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 diplo+a(a56g q .omr9umpzwf ;qhl4id number of 8, in different stages of meiosis. Which row correctly namea6.+u q(ofm mlw4 9;qhpg5az rs each stage?

  The micrographs show four phases of meiosis I in a px7f* gzgt gtm (p81gflz(++os 9zy 5.akk +lrzlant. In what order do these 5 +8krzsz*x9yzzgf7la(o f+(g1tp+glkt m.g phases occur?

Mitochondria are responsible fok a u6yg 88tto0e3xvv;+frcc3 r supplying 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 inheri8kxger3u3 8cfa;0cvo vy6+tt ted 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 differen01whagvp1f7v ;c p0 rlt stages of the cell cycle in four samples of lung tissue from four patients. Which tissue has the lowest mitotic index?h71w 0cap;l1 gvfvp r0

  The diagram shows the dominant cyclin/C toa hltu(ol5ns6h3w2z ) 2p-rchh :g5DK complexes at different time points in the cez6 )lhtg:25hpr3hsho 2u - ln(a5octw ll cycle. Which cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependent Kinase 3 (CDKN3) are : pko0:3blond,nvb b 3highly overexpressed in cervicannbd0,kb: blvo: 3 op3l 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 highes/v)r3xd27so sgx* umdt during the cell cycle ?