The graph below shows the relationship between maternal age 96 qf0n:jooqxand the incidence of non-disjunction. What relationship is suggested by the data in the graph?x q0jf :onq96o

  Which stage of meiosis is represented in the diahsk+cqs8tk ). je. 4ergram below?

  The diagram below shows chromosomes d fl 1f40lrq*xhuring 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 f 5yqrt. :,fixstates the number of alleles of a single gene which would be present in the nucleus r5y f ,x:if.qtof a cell as a result of each process?

  Which keyword is matched to th0as5ayk 3 * +,v,kd4da 1 e/qnytyameme correct definition?

  Which statement(s) about mitosis is/are truw v()bc( t::+nazu.kp:f shw2xkh 9cfe?
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 letteto-0 ed8qywgr 7q xg9,r points to a cell in anaphase?

  During which stage of mitosis does the ns2jy/.y ,t qafuclear envelope break down?

  Which one of the following transport pr3towrou r usr):p.k(.oteins only carries out active transport? .wr3o.o(usk: t)pru r

  Which process does not happen in td xm7o gxr2/ v-gvjol+e5k)u*he shoot apex?

  Which type/s of membrane transport do/does not require energy expenn+hye: yc j,i::jzc6 jditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell wi:82)ebug oqe6yskmkc-je *3r th a diploid number of 4. Which stage of cell division is the cell currko c:kjrse6qmgee)by 328 u*-ently undergoing?

  The photomicrograph betlxd -8.7i6s knio dy8low shows a root tip meristem. Which of the following sentences correctly defines a mer.y 8nsl6t-7d oiidx 8kistem?

  When does the random orie id4 iyg1viz/-ntation of homologous chromosome pairs occur?

  Which process does not occur dv0wa26-def pg)jp:no.gg s a0 uring meiosis?

  If a cell with a diploid bo 3a7-ag 6ucxnumber of 36 undergoes mitosis, how many chromosomes will baob 63 a7c-gxue present in each daughter cell after cytokinesis?

  The image shows a micrograph7 b: ,bymghz+ /b 7, m/b-ejyhwzer.eb of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/are not trufy;o fg 4bv+5ve?
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 syndromfombe9 m 9a6 c-j7qg5se.

Which statement is not correct?

  In the cells of a horse (E. caballus) during pro0mvvx w5 2kaf.phase I of meiosis I there are 64 chromosomes. What is the haploid number of chromoskfa.mv v02wx5omes?

  Which arrow is pointino; etcq*(s sq,/ 4vlgcg to a chiasma?

  The diagram below represents the structure of a shoot a9rj+ef24 j+jttdylqxx+6yegwe9-:q pical meristem. Which row in the table correctly identifies the processes occuring in the structures lw d xy:je++- g924lttr9exj+fy6jqqe abeled in the diagram?

  How does meiosis promote var8:mvn jsg5/ 34pavddp x 5iwl .(mm7criation?

  Which of the following statements is/are coc,6 sja+niy* hrrect 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 ho t1dvmm4 dp/ .,6irrlxmologous 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 73klw7 i w+3ar59o ytpd a(oxyof secondary tumours from primary tumours as a result of the movement ad 5w+ply7 9 (irk7ow3xta3 yoof cells?

  How many chiasmata are za 81(z/2l yucsmzyew (e1e2vpresent in the diagram?

  Which statement is a similaritaj, y2 jy2oxy.ra b:-j,tg7tu y between cytokinesis in animal and plant cells?

  Which stage of meiosis is matched to the correct 2y9 sd (8bb z.w7hfp ixamzs9o*wnd3)description?

  Which statement(s) are true of meu xob/ a(ra* ei2-5qgbiosis 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 anv0yeg 0v- z7 c:jxv:hh oocyte after the first meiotic division. This results in the formation of one large ce7cvh:g zhe yvj:v0x-0 ll and one small cell. What is the fate of the large cell?

  Which row correctly describes diploid and hattclw4 1g28e8j.u ra tim*1uh ploid cells in humans?

  The following table shows the52u1o pbusyk2 diploid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be (to c5e;o a5 pwp)qteb7x o8:udrawn from the karyogram below?

  Which of the following processes is characteristic of the meiotic ay/d4/kp /i pphnd not the mi/p/4p iyp/hk dtotic cell cycle?

  The diagram represents a bud with a shoot apical merk tu: mr+ky1e3 lmvw1m x2c70fistem.

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 rot: )jhk2- huyd /scqnp/b2au8w shows the correct chromosome number for different cell :2p/qnbj dsua/k- u)cthy 28h types and cell division stages?.

  At the end of which pha 9 jz yas*.re)r.t3)iazc 0ysase of meiosis I does crossing over occur, and what is the outcome of)z3)z ia * ajte9rsyc y0.r.as crossing over?

  Which of the following statements does not dehuxgslc,fr 12m .np7)i r( xa:okb55qscribe a step in the sodium-potassium pump cycle in the neuronal cells?.m) n7,kqr fruix c gas(55 bxolh:21p

  Which row in the table belkzw2uwy t( 6+vfmnzn, 85caz,ow is true of meiosis?

Membrane transport is important for allowing particles to move across the6ynmkpx, 6 h2y cell membrane and respond to changes in the chemical composi 6mykn 6ph2y,xtion 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 regulatednlgaplq1 k; i6k3s oydi1s) 6: 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 cyclins du36 k km:2zyjjering the cell cycle. Which cyclin is involved in preparing for DNA replimzkk3 j:6je2 ycation?

The diagram below shows pegli(39 x0 (s,klhb wchromosomes 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 separn d5i2fz/j* tpation of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 different patients is sk (kju)c fd o /jf ducvdqh5y.0o.t301hown below. Which patient is mo3)j0/q1 to fhc vf5kok(yjd.dduu0c. st likely to have cancerous throat tissue?

1.Draw a labelled diagram to represent the per ( rm e+86s a63pf)pzmgd8uqrocess of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal human karh:g3bgw3+u xl8 ano cac66(mhyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amounty(2ddk b +obq/va5 b7yrb10ax of DNA in one cell during one complete cell cycle. Each letter represents one stage of thed+ ko1v ab bdr b2x/50yy7qab( 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 tj8 lw2( pg,uejhat is homozygous for brown, long hair and a female cat that has black, short ha u2 glpe8,wjj(ir.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normal distribution. whno i*p8jgc u0) (agsz14xs5

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-sister chromat7 wd 4,7hmchte,vu2 +phgzs q.e3vt+ gids shown in the diuhe,h+devzg, v4wt+.c sp 732gt m7hqagram below?

  The photomicrograph shows a pollen grain -cz 0hkg:nfhkn8 n qqf01o(; pfrom L. candidum (Lily). Which stage of meiosi0hhk 1oncnk -gnq(fq :z; f80ps is shown?

1.Outline the events which would lead to an individual being born wxfl lq7,uju2ll4an*l,udm/ : ith Down syndrome, which isxjl4,fna/,l:*m u27u uqlld l 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 bb)6,fp vc x2rco6,buway of measuring plant growth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the ,p r6uv2ocbc, bb6)fxeffect 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 d lj7o* mj g7uq4 s9vtwl;*l;jhiagrams below show two cells from an organism with a diploid 77;vgqjo*j; wl*s9hllmut4j 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 growth. qn t,fp:u/x-*jsdc x,

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 stlnrmc d2 mqa4j29e)z5ages of meiosis.j5lqr2c)ma 9d2enzm 4 Which row correctly names each stage?

  The micrographs show four phases of meiosis I in a plant. In what order do )fv hc(/ -kery /sbwj0these phases occurw/e0) bck/ rshy-jv(f?

Mitochondria are resp m ao)0ubxwq /35yck5wonsible for 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 tou03waxq/mocyw ) 55bk 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 owh74 nt ;9zcc6la vfm*f the cell cycle in four samples of lung tissue from four patients. Which tissuz6wfm7vc9 a lc;htn*4e has the lowest mitotic index?

  The diagram shows thep mq: inxa:2l o3+ma:q dominant cyclin/CDK complexes at different time points in the cell cycle. Which cyclin/CDK complex activates DNA replication mxniaqma:2m pq lo:+ 3:achinery?

  Studies have shown that genes such as Cyclin Dependent Kinase 3 (CDKN3) are hic)yac1 n j)om,/zc94tpwmrn(ghly overexpressed in cervical tumour1/ ccy n4w(9omt)jcnar)z,mps.


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 dx c9q3 :od7atE the highest during the cell cycle ?