The graph below shows the r(sjm8 evw .tpf2l6xn8elationship between maternal age and the incidence of non-disjunction. What relationship is sugsxm2wen.plt8( fv86 j gested by the data in the graph?

  Which stage of meiosis is represented in the diagram below-ndb-i(2wo3x id*0 zshw 4wjd:mg7 az)wl y9e?

  The diagram below shows chromosomes g/c jgf /0op5iy6xwn: 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 of allele0m1 s,wujhl7k s of a single gene which would be present in the nucleus of a cell as a r1,j7wh l0smuk esult of each process?

  Which keyword is matchev02o+cpc a 3)gjw 2/3s,yawbc yaa 4lzd to the correct definition?

  Which statement(s) about mitosis ispyrhto *kb5gg a1vj*3-a 37bf /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 pqrdxc.y9 )yy7jj w/lh9ky f,+oints to a cell in anaphase?

  During which stage of mitob/ y;t,t/chl2;u uv svsis does the nuclear envelope break down?

  Which one of the follow8-)wjdvcu q,q9ll ns(;wfci74. bc uhing transport proteins only carries out active transport?b4h (ji8nfc,c u7lv)w dwqcsu;9 - .lq

  Which process does not o,ccvjqy2hy 5:2b/f bhappen in the shoot apex?

  Which type/s of membrane t8zmtf:vx9a 9rx y8(xoa* y2rmo+kgf1ransport do/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with ao 7wz(86qeufq diploid number of 4. Which stage of cell division is th ezquf(768owq e cell currently undergoing?

  The photomicrograph below shows a root tip meristem. Which of the following s 3vpdqu)gqtn9 x 2p3c-entxqnq9p -vt32u3pg cd)ences correctly defines a meristem?

  When does the random orientation of homologous chromosome pai 7v- xfh4l wrg2pg/nv/rs occur?

  Which process does no l4d *sn)ikt6cka 1c+bt occur during meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, how many chro pmbj6522uakbj*9a) l ae,q wlmosomes will be present in each daughter cell aj2 bplbm wua56lak*j92eqa) ,fter cytokinesis?

  The image shows a micr5x8jr+b3t xtqograph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/are not tn.1thoo:g+9)o +nxa yk+lo h;iokl /k q b8lk2rue?
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 indz v-ex ii41. yv.2n6pn, sh*f1c evzabividual with Down syndrome.

Which statement is not correct?

  In the cells of a hors n3gm6j+p ownba-ex6)3pi: x fe (E. caballus) during prophase I of meiosis I there are 64 chromosomes. What is the haploid number)enwp mogpnj i3xfx:6a3+6-b of chromosomes?

  Which arrow is pointing to axyx7 hlv),+pk) w( xqe chiasma?

  The diagram below represents the structure ofi 6y05)2jhx cph aww,j a shoot apical meristem. Which row in the table correctly identifies the processes occuring in the structures labeled in a5 0j ,h6wwhp2cjx )iythe diagram?

  How does meiosis promotm :-li a * lt,ypugz/os-zyc9/e variation?

  Which of the followin:38xz.a. 0zi 5s 4ego phbfrrkg statements 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 homologous i gkeg ++9p*lgchromosomes.


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 tumours from primary tumours7lal2e-byw ah;(m s 3nt pi.y0 as a result of the movement of cells?.i(;swyamlpt e23 0a7hb-nly

  How many chiasmata are present4tt9o 2jb6py km0,ltk in the diagram?

  Which statement is a similarity between cytokinesis in animal and 5capvl4 rvduo9 x*1sa /l.u8vplant cells?

  Which stage of meiosis is matched to the correct descriptio nkhgflyqvltl8xv + d)65* i/9 9-s5utbzt0zqn?

  Which statement(s) are true ansq3/. .a z:xi:g7m lz w vwi;.hq0ulof 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 firg6(lue:7, zi6qi w+ ons, uvpcst meiotic division. This results in the formation of one large cell and one small n p:zioisgcv6 w6uq l(u+7,,e cell. What is the fate of the large cell?

  Which row correctly describes diploid and haploid,n e-6c3*niz*sllk-(o zlelj cells in humans?

  The following table shows the diploid chromod2qe,3nzr9g kq,m:/ phztk5xsome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn froml 0yhkseu ni0q( ,d,(c the karyogram below?

  Which of the following processes is characteristic of the meiotic andpe7 etq4h7ssy dd *e-+ not the mitotic cell c-4ehq 77p e sd+seyd*tycle?

  The diagram represents a bud wm .,cpyy*; g4nk2vr/qvc zs4cqwd r*:ith 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 0a+u ,uffysxh qj)/8a the chimpanzee (Pan troglodytes) is 48. Which row shows the correct chromosome number for different ceuqj, 8xfahfa+u)y0s/ ll types and cell division stages?.

  At the end of which phdm3esnokb /*: z7hb:r2gbh8:k lt9 vbase of meiosis I does crossing over occur, and what is the o zv d:7o9:b nk 8gs r:m3bbk2lhbt*/ehutcome of crossing over?

  Which of the following statements does not describe a step in the sohn amfa4zew+vv84y8-) og -x jdium-potassium pump cycle in the neuronjv 4ah-ozf 8 4ne -avw+x8gm)yal cells?

  Which row in the table below is true of meioim.(ur4i )pfrsis?

Membrane transport is important for allowing particles to move xiky;93ki(a r l;xf+ jacross the cell membrane and respond to changes in the chemical composition of the extracil (rj3;f+;kaik9y xx ellular 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 mitosii ikg95dsoh-5 s 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 uaa8 1yp .wme68(hr erv4w4 viconcentrations of different cyclins during the cell cycle. Which cyclin is involved in preparing for DNA replicatio miw1(eau8pr 4y e6v48.hwa vrn?

The diagram below sh,q5l*e f.r0t tdu v7uyows 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 involpx v1 1 a735npkhktcv1ves the separation of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 different 4fvn *t*eyl1f re,gc *patients is shown below. Which patientrf,* tecy *nl*v1e4f g is most likely to have cancerous throat tissue?

1.Draw a labelled diagram to represent the pr eknp.gb:cvmnlp 8 6 -rza5d zd+h* d(i,,hax(ocess of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abuv3nf ,.pe;5 o-jq etbnormal human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in o:k+e 8i treny5ne cell during one complete cell cycle. Each letter represents one stage of the cell cke8 y5:nt re+iycle.


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 homon s,07) o5ndctl:aitv zygous for brown,n)d 5ctiat0vo l ns:,7 long hair and a 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 x;xhv810vuv, gj c)ution.

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-sist ud+z :niki3qh8 vgn61vd/)gcer chromatids shown in the diagrhn d18+ 3g)qni6c vdiv zu:/kgam below?

  The photomicrograph shows a pollen grain from L. candidum (di:7.eg8+jg u6ht g jpLily). Which stage of meiosis is shodpgu h87+gtjg e ji:.6wn?

1.Outline the events which would lead to an individual being (txfzdtmjwmdz8a 49. i.d/ 2hborn with Down syndrome, which is characterised by the presence of three copies of chr8d fm(it. dzzth49m.j /axd2womosome 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indirect way of measuring plant )wbx9mcw 6 +gp-6pksd growth. A study was conducted on white onions (Allium cepa), under controlled conditions in a)pgxw9ps6 +d6w b-cmk lab, to 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 b6dau 5hl2by yau3h0l2 elow show two cells from an organism with a diploid 2d l2l0 6auhy5yh3abunumber (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 exppxhxs49um)2+ ;p gn jaression 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 diploid6dl3a qh km2ks/ 0;2juz.i ary number of 8, in different stages of meiosis. Which row correctur2zi 6 0kl2m hsaadq.j3/y;kly names each stage?

  The micrographs show f9zt9ctj/ xys:jd;d i8 our phases of meiosis I in a plant. In what order do these phases ociddz8jt9 stxjc9:y /;cur?

Mitochondria are responsible for supplying metabolic en -yj1fdu6qxc9 ergy 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 reproduction between two different yeast species,xcyf6qdu-9 1j 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 of the cell cycleuhk:3dfva a3 n1ly6z1**gmdg in four samples of lung tissue from four a13n*f 6*yz 3:dgvklu mgda1hpatients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at dife+ v;4lc k 2+edgw -ulme*t7uaferent time points in the cell cycle. Which cyclin/CDK complex activat twe;+e4+du-mgkl7vlcua2e* es DNA replication machinery?

  Studies have shown that genes such as Cyc):jfwh/kuf1 h-jm5slzd,t,t jm,k + s lin Dependent Kinase 3 (CDKN3) are highly overexpressed t tk,+f mwf,,k)msju1-:z/dhh sjlj5in 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 cyclinr cl3hd;zul* 9 E the highest during the cell cycle ?