The graph below shows the relationship between maternal age and the inc*v2;e sj+mukkrsjzzd3 3q/lai5s +s (idence of non-disjunctiolks ek a v+d u;3+m3rqsj/*s (sjz2zi5n. What relationship is suggested by the data in the graph?

  Which stage of meiosis is represented in the diagram d6a kb1e*+aj: *u9ratd7l dufbelow?

  The diagram below shows chromosomes during meiosi2gds;swub hk55p-c38; zugz ns.


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;9x0t nm0rbngrng)aeq dl1 (2 would be present in the nucleus of a cell as a res0;t2g nar( ql9b1 n d0g)mnxreult of each process?

  Which keyword is matcheh ket osnwd*tz*+ g19y50 -deqd to the correct definition?

  Which statement(s) about mitosisc bhk,5m4i dv4 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 letter6cy7p7g acc1ps ,z( iv points to a cell in anaphase?

  During which stage of mitokq 5lc1 8k,5sw fdo rzh5tmg;6 ubo,qqx2jl19 sis does the nuclear envelope break down?

  Which one of the following transport proteins only carries out active t2(pt f prt8(ltransport? lt8f(rppt t(2

  Which process does not happen )in3rq;dfc 1 win the shoot apex?

  Which type/s of membrane transport do/does not require energrw /gne2kv8pe5gvd0r9/hs0 tgsc+;p y expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4. W jifz1d2ao2s9gb9 qyv ao*gbwz8::s9* 8rxjq hich stage of cell division is the c1*9bw xjd9sgz8q8q: s:vfya i agjbzr2* 9oo2ell currently undergoing?

  The photomicrograph below shows a root tip meristem. Which of the following senw m j7)yv8t0lutences correctly definety)u 08vml7 wjs a meristem?

  When does the random orientation of homolomr7irf c cv2) /kzer0utf2),tgous chromosome pairs occur?

  Which process does not occur dunlog 0h vbl6maj-7+en 5 l0w7sring meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, hdnk)o:b wi :8o-3 oysnow many chromosomes will be present in each daughter cell after cytok obyd:3n w:o -ksi)n8oinesis?

  The image shows a micrac.xu ey /+b2.yikn-fj6 s7r tograph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chrovxo52 t.gw3z,r4 gbm b6 ge:oaxa)v1e7ddsy7mosomes 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 synd8zc-vmy di h(y, azciq;8 ji 9+i xobkr4)-v.srome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis I/77 erwqsr7v83 ccg3xkxux ,v there are 64 chromosomes. What is the haploid number of ch77xg 8c7vs/xwk xec3rv3q,ru romosomes?

  Which arrow is pointing to a chiarucfc,j e vn1w1,5k: :j z*wb7o94jwbz /bdmgsma?

  The diagram below represen3rf9wy9 : qeizts the structure of a shoot apical meristem. Which row in the table correctly identifies the processes occuring in the structures labeled rywq:993fz eiin the diagram?

  How does meiosis promote vx/ntit4qy 45zariation?

  Which of the following statements is/are correct f/n l 0b r:ygkckweeul (4-su .u9c2ky8or meiosis?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametes produced from tws5t(gu q,:6 zp unixz;o 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 mgc5y y9ehl- hynmk3c4bz *. q5 :ny,ztumours from primary tumours as a :h ng9n5zb,kc-z4hyyce 5mq3 lm.y*yresult of the movement of cells?

  How many chiasmata are present in th z:nf l59in7tzash:b*e diagram?

  Which statement is a similarity betwee tg0a *junlgcq 9*)6aon cytokinesis in animal and plant cells?

  Which stage of meiosis is matched t;u5. nq 4:cx2c-)jyvpk mjvj 5 pe8moso the correct description?

  Which statement(s) are true of meiosis I but not mei.)d+bodqa wk9osis 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 firsterbq- 8/x4tcf meiotic division. This results in the formation of one large cell and one small cell. What is the fate of48trxb e -c/qf the large cell?

  Which row correctly describes dip(+nanth i4cr3 loid and haploid cells in humans?

  The following table shows the diplvk1hm +* k qbcy1oe67ioid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the kyd eq3agt 30st cwe9:+aryogram below?

  Which of the following processes is characteristicu49d d*at2fqu0a yjw8 of the meiotic and not the mitotic celludu2 a9t*84 qyjfw0a d cycle?

  The diagram represenx6yu- m4n9xmuqy gh*1j2 a; e4nkh: ltts a 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 (Pan troglodytes) is 48. Which row shows n0 o p*uofi v:0k.ga*vth.v*oa fv00inpukg:*oe correct chromosome number for different cell types and cell division stages?.

  At the end of which phase of meiosi 6tg)yonyb*s 3s I does crossing over occur, and what is the outcome of cros ygy)*ob63st nsing over?

  Which of the followinb pels.:qknhr 5k/q82g statements does not describe a step in the sodium-potassium pump cycle in the neur5q8kr l.ks2 qhb :enp/onal cells?

  Which row in the tabla-m6/ okd5n aqe below is true of meiosis?

Membrane transport is i;*imu35r,he v-og , v5ic oqjzmportant for allowing particles to move across the cell membrane and respond to changes in the chemical composition of the extracej;i3oh5r ,qv i*-5cum,v eo zgllular 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 m5vh1g97kwjp1n ex heq 1(-nf 0wd5ww.

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 cyclins during zkvwn(+ e8xy 4the cell cycle. Which cyclxe+n w8ky4 vz(in is involved in preparing for DNA replication?

The diagram below shows chl f80 1ppfdd;wromosomes 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 homologous chromosometm/ o3qz6b zwj 3-4*kg*ttz*e 6dbdq ss?

  The mitotic index of throat tissues taken from 4 differewe1as, ;khal .h6 lbs:e h(pkvb(1 d+k2m; jyfnt patients is shown below. Which patient is mosthhl;2k bjyfs1a p1ds k(+.wa,lkh(6 em;v b:e likely to have cancerous throat tissue?

1.Draw a labelled diagram to represent the process of crossing over, vzxw )jlf)9s.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal human karkydzyo 0u,9clh/dxr +,e *(kb yotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cell duringn3y :no-eqat-c j, w3n one complete cell cycle. Each leto n3 nawq,y -tj-:nc3eter represents 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 cr2 3tpz c8.abrsoss between a male cat that is homozygous for brown, long hair and a femts 8b32raz c.pale cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can5 6oin8 ylf ;5wo*1 u1mpquwjx 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 crort h/,pb,z tq3mo 5. opmmy68vssing over of non-sister chromatids shown in the dia rqmb,z5/vo83 t6o tpy.mh, pmgram below?

  The photomicrograph shows a pollen grain from L. candidum (Lily). Which sta2 7cfi7piz:, u osi/rlge of meiosis is shu/s lpf7,o :2 ii7crizown?

1.Outline the events which would lead ,aiffoiln- 7s(8 f5z n; s,qwhto an individual being born with Down syndrome, which is characterised by the pres os 8finn(a7w;z, shqf5,i- lfence 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 t3jl ylr,ndngy*(( * ;kt r4vhmeasuring plant growth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigatelj *rtt k (ryl*,nh4(gynvd ;3 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 celma 5k/l 1-wctels can divide. The diagrams below show /cwlkm-1 tae 5two 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 gro5u k83a zhwok)rf *k3ewth.

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 staw34t 3bie/xitrqp y .4ges of meiosis. Which row c3wy /4.ix 3brtqp ei4torrectly names each stage?

  The micrographs show four phases of meiosis I in a plan) iokw-tzfk89v t tmyt+2v7w8 t. In what order do thesekw-ttti7vfv o2+ 8z) wm8ykt9 phases occur?

Mitochondria are resp0 ft rcktc+ 53z)6bwqponsible for supplying metabolic energy in eukaryotic cells. In most eukaryotes, which reproduce by sexual reproducw56 k cp3z0qrtt c+)bftion, 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 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 different stages 4 nkw53ya k :6kmjofp2of the cell cycle in four samples of lung tissue from four patients. Which kyk kpwjm256of 4na:3tissue has the lowest mitotic index?

  The diagram shows the dominant kmt ror):5ua2 6 o5ig xqo7ex7cyclin/CDK complexes at different time points in the cell cycle. Which cyclin/CDK complex activates DNA replication mo2q6o)x: 7m rgetak7 xo5 ir5uachinery?

  Studies have shown tsk bk3p j twamq*zu y71q 1agvj23;c*:hat genes such as Cyclin Dependent Kinase 3 (CDKN3) are highly overexpressebqsc kta7;z aq yj**v1 k:331pguj2mw d 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 cell cycle ? : yolb(btyq-nb:+wr b ;2b6z zkto9c1