The graph below shows the relationship between matem5n h(m :gtyqd(q 7vj8rnal age and the incidence of non-disjunction. What relationship is sng :v((qh5q7m8m dytjuggested by the data in the graph?

  Which stage of meiosb- jy:sm-dh k(/v: syxis is represented in the diagram below?

  The diagram below shows chromoe/w3-dn i 82swzg5 evy( l*slgsomes 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 of5vzx cc* 38zdy;qd1 jw alleles of a single gene which would be present in the nucleus of a cell x1*dcqw 5 cd3yz8zv; jas a result of each process?

  Which keyword is matche16039jjws3h hxgdsjrbuo1 j, i- hi/bd to the correct definition?

  Which statement(s) about mitosis imk,m+e(d:j1v z ) ejeds/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 anab ,ef j6u/j3dhphase?

  During which stage of mitosis does the ns :yd9h/t8 ybmuclear envelope break down?

  Which one of the following transport proteins only carries out active trl:y 4qjb(/cs ek9z .ghansport?. z4e/ j(9glbq:kc syh

  Which process does not ou33apm:1oaz happen in the shoot apex?

  Which type/s of memb.d )u: 3s.xjdrp-lm cirane transport do/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4n 8o2bj2x069 8uk*n6+a-8 ohclmvh r ryip ylx. Which stage of cell division is the cell currently undergoix p6 mryo+yi uv29*x8ch8lb08 o-6ra jhk2nlnng?

  The photomicrograph below shuwau+q6x rh7 h1l).ny ows a root tip meristem. Which of the following sentences correctly .q+ lahxu)7u6nyhw1 r defines a meristem?

  When does the random orientation of homologous chromosome pairsi 8o 6z9+nu6h ewr8ekg occur?

  Which process does nm jx*2nos(v)k ot occur during meiosis?

  If a cell with a diploid number of 36 undergoes 9)ub:s;uj.cdsr g,b tmitosis, how many chromosomes will be present in each daughter cell after cytod.s9,sgr)c j;utb b u:kinesis?

  The image shows a micrograph of a ctl2ldh :k*y9 eell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/are not tr7se9t t7 1 ycwp9-p:n ehnza2nue?
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 fo+ l(*obv xm7: l)shx3g7cmuaj r an individual with Down syndrome.

Which statement is not correct?

  In the cells of a horeu* -t d jz(pg9/o:hdyse (E. caballus) during prophase I of meiosis I there are 64 chromosomes. What idu yptdh/ -g: *o(zej9s the haploid number of chromosomes?

  Which arrow is pointing/ 7ttp2-vmqrxm+ew)u to a chiasma?

  The diagram below represents the structure o n. mus5 ecv 4c0fstew)c)+e-nf a shoot apical meristem. Which row in the tan+- w 5.nfu c)cs0vestem4e) cble correctly identifies the processes occuring in the structures labeled in the diagram?

  How does meiosis promote variap5b4* 3lyq /tnc75pu) pth,lshw2 tdltion?

  Which of the following statements is/are correct forbcs(vi3f-v 1: 0ed3e gx:c4owh y fpi8 meiosis?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametes produced froma 6ixa4w / c463z)2gfap bnuke 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(ieo7 9 +ynd2lrxx)mh the formation of secondary tumours from primary tumours as a rro9xyl+i n( 7mhde )2xesult of the movement of cells?

  How many chiasmata are t.-.fc woj ub-1reyk*present in the diagram?

  Which statement is a sp/+bqhw; capgkxxc:2/w *b .r6q8 ihkimilarity between cytokinesis in animal and plant cells?

  Which stage of meiosis is matched to the correct de i4j.;etg/jg-po( 6 pj0gvc rlscription?

  Which statement(s) are true of meiosis I but not meio6keh.9dk e+fe k.d *zhsis 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 divfd ,-br;+z-4gjflm xwision. This results in the formation of one large cell and onel-fb f-mzjw+drg4; ,x small cell. What is the fate of the large cell?

  Which row correctly describes diploid and haploid 4uhb+o 8hjxo3 cells in humans?

  The following table shows the diploid chromosome nuap8.;+ nfe7+tzp3h kg4bxcm y mber of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyogram b9hx o.ub6.iomelow?

  Which of the following processes is characteristic of the meiotic an:obe6/z e- qmru).wykd not the mitotic celyeq: o.urw) z6- e/mkbl cycle?

  The diagram represents a bud with a shoot apt/trr9g zo ux;6jog yq*:, an5ical 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 ch1eq6v* r rcdkc tpb((n;4jfz:impanzee (Pan troglodytes) is 48. Which row shows the correct chromosome number for different cell types and cfck4qvbz d p j*rent(1r(:6; cell division stages?.

  At the end of which phase of meiosis I does crossing over occur, and what is ti2y ho- (ppj8she outcome of crossing o2yip8os(jph- ver?

  Which of the following statements does not describe a step in the :e(u8hc 6k ewz;ogu8ksodium-potassiu8w86 o;hekgu :ku( zecm pump cycle in the neuronal cells?

  Which row in the table below is true of meiog mx *7l5 jrf93be/lmpsis?

Membrane transport is important f0/v,ffkl1oo nor allowing particles to move across the cell membrane and respond to changes in the chemical composivon1off,l 0 k/tion 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/0cmsa ;bs,r1ox/ ap y is regulated 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 the concentrations of different cy 7f,fnc di58 5gzlpw+z q0)/: zgyeyqcclins during the cell cycle. Which cyclin is involved in preparing for7f8n:d 0z/q5glf ,zzqciy )+gwp 5eyc DNA replication?

The diagram below sho-jbwu te 0k8dp96fd-ows 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 separation of homologou).oqwl;z x 9cjs chromosomes?

  The mitotic index of throat tissues taken from rc p.u; ve0d p*t)3vtw4 different patients is shown below. Which patient is most like tpd.p)v*vw;tcr 30euly to have cancerous throat tissue?

1.Draw a labelled diagram to represenmi-x u)0st gyrj/*0ux t 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 huml5igj/gu dft*hq.:s* an karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one ce: slf-5mqh(y f,bdqo0ll during one complete cell cycle. Each letter represent o:f,sf5mqb-yq0(dlhs 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 sho6tmbxtbb 2c4v,(:mw 34azd el42y nc ows a cross between a male cat that is homozygous for brown, long hair and a female cat th442,c3weatvdxb(tcm 2nz o4:y6b l mbat has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits ca3skjt-* )c)b;wl(jdg mk4nvpn 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 gxt0 ) mq5vs). psl)rqover of non-sister chromatids shown in5.)lmxqg)r)vs psq0 t the diagram below?

  The photomicrograph shows a pollen grain from L. candidum 4zk/ 5oitrsu4xlm 7; u(Lily). Which stage of meiosis is shou4sm5k 7tzrl xi4;u/own?

1.Outline the events which would lead to an individual bega;;-2g/ sl/so* uhd qkbaxf(ing born with Down syndrome, which is characterised by the presence of three copies of ;/2d *a(lkb gxf ah;uo sq/-sgchromosome 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indirect way of measuring plant gx4( xoe zhye-8vok3jdg(,nx1g da,r ; rowth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, t haz;yxexkd 4j(xev1ogg no,-d3r(8,o 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 belowacf z xbt20m5j0gv/2t show two cells from ant5j0x2ta zg2f 0cvm/b 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 t k4 vnrrlbe 6)f.u *-fhpx3 7l)jvo,agene 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 diploid number of 8, incldncf-e 2lgr .8 38dvpr66zk different stages of meipg-3lr.l 8v dc kr626 decf8nzosis. Which row correctly names each stage?

  The micrographs show four phases of meiosis I in a plant. In what order r/wq,h75u7x m ags2evdo these pha7wrh a gs/v 2uq5,mx7eses occur?

Mitochondria are responsible for supplying metabolic energy in eukary*qqf tq/d2 x14vhtei0yqb)*u otic 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 reproduction between two different yeast species, could be influenced by the pt tdehyqq* 420u vixb1qq/*)farent’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 cj j(k s72peupj2 zpb3.ells in different stages of the cell cycle in four samples of lung tissue from four patients. Which tissue has the lowest 7epjjup2sp(.k 23b jzmitotic index?

  The diagram shows the domina*v-k wg8 7i2n ozz/ 4kqyggo9gnt cyclin/CDK complexes at different time points in the cell cycle gg*2k7v oio 8gz9 4nzqgk/y-w. Which cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependent K /8mkrg /q*rcmr-*b kfinase 3 (CDKN3) are highlyf* rrq r*m/bm k-cg8k/ overexpressed 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 duc/ i4 emy5oxfa+;sv z:2xsg x2ring the cell cycle ?