The graph below shows the relationship between mx jj 2 :1:.c71(ycewape(xw kd9ngappaternal age and the incidence of non-disjunction. Wn1wxj7k p.pc(w9j c: xda ee(:12gpyahat relationship is suggested by the data in the graph?

  Which stage of meiosis is represen3oj5 yq8q1xy/oy;z mv sypd.h7 e6 y bdkx:7n:ted in the diagram below?

  The diagram below shoi wgpx s 1+9-abw9h*udws 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 num :0syv/ v1xld.ykak*nn+tt 1eber of alleles of a single gene which would be present:xv yet11.0 nklty/anvs + kd* in the nucleus of a cell as a result of each process?

  Which keyword is matched to the correct definit o fe, z4gn:cz1b4rgh(ion?

  Which statement(s) about mitosis is/are nbvtboti2pwa;f (a 3*fd3t57 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 iydds2 zfx4 i27og1;l points to a cell in anaphase?

  During which stage of mrli)cyqn oq 1ov+( -)-vg+ nxjitosis does the nuclear envelope break down?

  Which one of the following transport prkw6qt g(y;(m4h npm a+oteins only carries out active transport?6 (y;a(q wthm pkm+g4n

  Which process does not happen in the shoot z2hz js0c +;xdhan.;n4:m-.gejwcuf apex?

  Which type/s of membrane transport do/does kr+rv vte0:.vj5u0 qvnot require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below ree*9 (n;g+dl1aj rk maapresents a cell with a diploid number of 4. Which stage of cell divik;1ej gaam9*d +na (rlsion is the cell currently undergoing?

  The photomicrograph below shows a root tip meristyz6ug )sj :akc )-,plvc*w hs93ig.hdem. Which of the following sentences correctly defines a meriste- c)6 *kh zw,als:3 )syv.chpidj9g gum?

  When does the random orientation of homologous chromosomv wdkzgv1f +e1 j)6fq9e pairs occur?

  Which process does not occur duri-o(lkn .*;fc gm02d4g uwmktwng meiosis?

  If a cell with a diploid n9gqwj,w iwqu6k) wri(tii , rc6*j 68*dhsac/umber of 36 undergoes mitosis, how many chromosomes will be present in each daughter cell after cytokinesis j ichi8/k6r)wc wd, (i*gisw,q*r9wua6qjt6?

  The image shows a mig46t 6*b xht 7 hzvm e dv2j5y(twe0qshx)5xe*crograph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) abouy6 u4 spo+p(.mfscfkq.uy9n ,t homologous chromosomes 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 syndrom7*qb 6hod*pt218*wlrk 6 ue zuacny bns-9 tm-e.

Which statement is not correct?

  In the cells of a horse (E. cab/ 2l(pquu*n zxallus) during prophase I of meiosis I there are 64 chromosomes. What is the haploid number of2lu* ux(/qpz n chromosomes?

  Which arrow is pointing to .gou9 / qn)a h.oth-wda chiasma?

  The diagram below represents the structure of a shoot apical merlo jso47 cbx:3istem. Which row in the table correctly identifies the processes occuring in thjo7l4sc b 3xo:e structures labeled in the diagram?

  How does meiosis proh/2 ( p( zg:hjaudd2 ph5 d/bszxg7s64eepj,omote variation?

  Which of the following statements is/are correct for p y;m,lp.w8an,hzlb2 meiosis?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametes:1-uz1 r7zjfll(rgzj 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 format97kop rly jl1-ion of secondary tumours from primary tumours as a result of the movement of celll 91lpok ryj-7s?

  How many chiasmata anw8*ckrk(9w4av th 5u pb,ec6re present in the diagram?

  Which statement is a similarity between cytokinesis in animal an+d /l6.g2hr ;ky5rshuj+rykgd plant cells?

  Which stage of meios/ dpef4v h+o8xis is matched to the correct description?

  Which statement(s) are t mg7 m: f)ff-qsjrn o68xd;q;fdp4+k :q-nmwx rue 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 oo,: y39u5uxfq*cww bgl cyte after the first meiotic division. This results in the formation of one large cell and one small cell. What is the fat5gfb cxwyuwu*3 9q,: le of the large cell?

  Which row correctly describes diploid and haploid cells i;fahatvxcw7:j d2d )9 n humans?

  The following table shows the diploid chromosome nml6wf6/-;wjz a+ iuzv2 t9/akl7tx m vumber of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the kary qv:4v5awwho 8ogram below?

  Which of the following processes is characteristic of the me*v45fo)4b1h iqxgmz aiotic and not the mitotic cell cycle?qb)a gomh 4x4 *vzfi15

  The diagram represents a bud with i, fpoq /pwt1hl wh(( ;w,.)0oj ggjnfvqh/l.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 cod 6bubb8gr-*himpanzee (Pan troglodytes) is 48. Which row shows the correct chromosome number for differen6 ro-dgubb8b*t cell types and cell division stages?.

  At the end of which phase of meiosis I does crossing over occur, a u+hm7:xt a,vfnd what is the outcomvht m7xu+ f:,ae of crossing over?

  Which of the following stateme)aj y/ gy+fu8qnts does not describe a step in the sodium-potassium pump cycle in tajuq/y)8ygf +he neuronal cells?

  Which row in the tabz y(9) n, s77lc+ pqqo6uve,azwh7agk le below is true of meiosis?

Membrane transport is imc7ut), zr :gzjportant for allowing particles to move across the cell membrane and respond to changes in the chemical composition of the extracellularct ,)zg:zj u7r 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 r9mp *ai,mob;6wusn, 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 dt ph8c*+ /l:e5n id0y(zlxhzaifferent cyclins during the cell cycle. Which 5e/*l (+0y l8:dchhpxa i tznzcyclin is involved in preparing for DNA replication?

The diagram below shows v38 :q1n yd d0l;pysrkk7cl6m 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 involve eyyh.my4py/ n;0 g 7q xyfd7r-j35qlcs the separation of homologous chromosomes?

  The mitotic index of throat tissues:(2qjj* ojso j taken from 4 different patients is shown below. Which patient is most likely to has2(*q jjo:jjo ve cancerous throat tissue?

1.Draw a labelled diagnlw sv4:vohp;,ff;u q: 7i34bp8hgs nram 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 human k phzrcp e7p)s32rja( :aryotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cell during one comp frk rvc(t86rfsk *g76lete cell cycle. Each letter represents one stage of the fr7g*(6skc8rk frvt6 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 that is homozygous for browgr1y ca;;f0fy ;ynm.,r tqww,n, long hair and a female cat that has black, sh0fw;rq,nctmw .;; ygy y,rfa1ort hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic tr onir6 d:h* ; 7tjd)cotxftsqw9:6yp3aits can 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 over of non-sister j;0c e2tecd,u8q v fylp8ay-+ chromatids shown in t2cvt+l,e;eap0d j8 y c-u qy8fhe diagram below?

  The photomicrograph shows a pollen )hz,x.+ mgd:bs;,xxx1 ,xpeko ix+ b egrain from L. candidum (Lily). Which stage of meiosi1,xmi;+xseg.z ,p, e xx+xdk) hx:bobs is shown?

1.Outline the events which would lead to an individual being born with Down sygqf9 x8*xt 2cvndrome, which is characterised by the presence of three copigc*vx2 xf 8qt9es of chromosome 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indirect way of mea/u d j (ol0vu*4zd*fnxsuring plant growth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the effect of soil pH on the midu/ 4 zon(uvdx0 ljf**totic 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 ar wnwrg51.(vp ce two ways in which cells can divide. The diagrams below show two r1g5w w(cnvp .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 expressiond2./way ahr vp+za jn maks2,65/ct-t 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, in different r;jm2qd8d up9st+ww ;stages of meiosis. Which row correctly nawqdu ;p+9ds;t w28 jrmmes each stage?

  The micrographs show four phases of meiosis I in a plant. In8+natly4cws jf,7dn2 a l-xo* q0w(ty what order do these phases o2tol (yncx- dw+f* lsaq,at0wy74 8jnccur?

Mitochondria are responsibl94 )kiezwzk5(3hd vth2 -aeboe 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 to e h-9tzo(4hkv) 2z3we 5abi dknuclear 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 of the cell cycl9.b-(raty f0go/ bjx-phn e) 4hnna 0oe in four samples of lung tissue from four patients. Which tissue has the lowes ha-jy4/9nxfb nbot.gn(0-hraep)o 0t mitotic index?

  The diagram shows the dominant cyclin/CDK complexeszcs7 3 samq*5rhpy8y.l 05kf l at different time points in the cell cycle. Which cyclin/CDK complex actks7m0ly3sz.5 5 acl 8r pyf*hqivates DNA replication machinery?

  Studies have shown that genes such as 3o *ek /pjsq1dtx-/ey Cyclin Dependent Kinase 3 (CDKN3) are higho e t3/sqdk-e1/y* pjxly 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 during the cell cycle *9ludne ucvl +kbkkht1 t9 n-7b:0 1+ g.bwiqm?