The graph below shows the relationship between maternal ageqlws y; l8)dyiwf /j0* and the incidence of non-disjunction. What relationship is suggested by the data inj )8; syyiw0*wlqfld/ the graph?

  Which stage of meiosis is represented in the dieu/- m.u l7klus j3ix /sn/ol.agram below?

  The diagram below show(l2 vzs *-8se 6o mqbfwnn.o*0 7rpnfys 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 v8sa :cj ynv.c e -3he9v1p,vuthe number of alleles of a single gene which would be present in the nucs9ejc: pv8 ,v-n.yu3vv1 ah celeus of a cell as a result of each process?

  Which keyword is matched to the correct x3/2f7 qryaji fmi)wr:+ac w- definition?

  Which statement(s) about mitosis is/are t;z6m8 - cev.qmu yiy)lrue?
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 xgb- :wm4 xc7fcell in anaphase?

  During which stage of mitos 5ty6rwr sz6ovl66,xyis does the nuclear envelope break down?

  Which one of the following transport proteins only carrieg*o+ai1p bpt+ n.1b a/bynh k:s out active transport?g1b+1 p /oa.ha +k* ynpn:bbit

  Which process does not happen in the shoot apex(2d17 ei39egsx;u0mopm 4 bkxv zf,ag?

  Which type/s of membrane transport do/does not require energy expenditure? ,)vzudujthia,h1j -9 :x4xd o
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4.bt;j2j1pf+: f,ued3u.b gf lk Which stage of cell division is the cell3l;,t j1.kuf+jb fe bg2u df:p currently undergoing?

  The photomicrograph below shows a root tip me:dz16*:y:ojkf:.b zz eb 2v o4bxzbpfristem. Which of the following sentenf z:byzz:vd:.ok2b*zf64obj 1x peb : ces correctly defines a meristem?

  When does the random orientation of homologous chromosome pairs o9a (/si: u5szal;4 l:uz viekjccur?

  Which process does not occur du+w -e ht59rk;1w ilsc a c;e6rfm.ni)gring meiosis?

  If a cell with a diploid number of 36 u0fnxj3v g.uy3ndergoes mitosis, how many chromosomes will be present in each daughte3x30 ynju gv.fr cell after cytokinesis?

  The image shows a micrograpp5 i uxx0n0,xmh of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologoysca6 :xqyg)1c 3) fpyus 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 individ7f; 8 :fyoz lbuio,5maual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis gkxi2b*p c/z+I there are 64 chromosom+kpcgx *b /zi2es. What is the haploid number of chromosomes?

  Which arrow is pointing to a chia o d-m8ibe6v(lra,a,wsma?

  The diagram below represents the structure of a shoot apical meris*)7p7*et kk xjwnbe che: ea.,m+hg 0xtem. Which row ih7te.7 +aj0pxeex,gk k )wmbch: e*n*n the table correctly identifies the processes occuring in the structures labeled in the diagram?

  How does meiosis promote variatioaboq. wmkhz3xg2(0h*js5m 8o n?

  Which of the following statements is/are correct for h*r cc4ql)7ewmeiosis?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametes x6e -kvevosn6 32 v 9gznm3ug9produced 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 formation of secb ,go6+tc8 qfgok 7ze/ondary tumours from primary tumours as a res7zq 6be+to , gfk8og/cult of the movement of cells?

  How many chiasmata are present in te67ci-l88 sf qehai9qhe diagram?

  Which statement is a similarity between cytokinesis in anima 9vyf oh(u. 6uytq6mhze*7/d zl and plant cells?

  Which stage of meiosis is maexwpmq 0(xsqx;9-lb0 8lw 6aktched to the correct description?

  Which statement(s) are true of meiosis I but not meioot-a3m xzl8h39k(j pc sis 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*g). *4jtky vrxr)j te first meiotic division. This results in the formaerryjgkv4tt.) *j x)*tion of one large cell and one small cell. What is the fate of the large cell?

  Which row correctly describes diploidym 0gk*yvje a ;h+73ly and haploid cells in humans?

  The following table shows the dipd 6u7zd f4jm(sfsg 1p6loid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from ,ae p x4 ;)qto,toc5frthe karyogram below?

  Which of the following processes is characteristic of the meiotic and not the mli gy6iyty-2)t02n rrh 1+wu di 26-i y hyrndw)y+gt21u ti0rltotic cell cycle?

  The diagram represents a bud with a s8isx+o+s g8 mlnwx; q3hoot 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 n 1i im yyri)zy,34.vs0evqb/k;7e kethe chimpanzee (Pan troglodytes) is 48. Which row shows the correct chr0e y;i n7ivevkzi)ryb3 .1/ 4y,mk seqomosome number for different cell types and cell division stages?.

  At the end of which phase of 2q d6li7c0rtimeiosis I does crossing over occur, and what is the outcome of crossing over?2icd7t6r iq 0l

  Which of the following st0ess tm/dwib;6 6mi sg kw)4q1atements does not describe a step in the sodium-potassium pump cy6mse ) ss 4qw0w/mi1g t6ikdb;cle in the neuronal cells?

  Which row in the table below is .juncdr1;ja,z /vmqz m .ah6upqx78v o64k+atrue of meiosis?

Membrane transport is important for allowing particles qphc g w04hgtu pt/ 2ok90s3;qto move across the cell membrane and respond to c /9;hqt0 2q3twppokg 04 uhsgchanges in the chemical composition 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 hq j5(c n(ax*vn4oi5xregulated 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 conc8twx9/ c*zu q0dbuo 4jentrations of different cyclins during the cell cycle. Which cdo89w*ut/bz j 4ux0qc yclin is involved in preparing for DNA replication?

The diagram below shows chromosomes durinf63h(hmv7 p(cg avvjl(p 8,ryg 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 i*4d73. (jtt+aub(ilcnk)pq 7h ave hthe separation of homologous chromosomes?

  The mitotic index of throat tdvrye vet.b/o0 4 +a,cissues taken from 4 different patients is shown below. Which patient is most likely to have c,v/y br +vdeta 0.o4ecancerous throat tissue?

1.Draw a labelled diagram to represent the process of crossingzvmy(i4wnzn 1 siley:l )- ;.s over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal humanw.(0t(ceu cn k karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amou1ceg ao5eqe0 s7h3 6 k,x4u;nuhmprd+nt of DNA in one cell during one complete cell cycle. Each letter represents one sh aos+d6,g;u e xqkenhcm071r4uep5 3tage 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 cross ben 46.is0do4q vjcvc8atween a male cat that is homozygous for brown, long hair an84i6 n4jav0 dc c.vqosd a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic trait7t+yod /gfk1v s 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 ( e(( dv kbj)ylrdiq 9(0uy5hz-tqw2x of non-sister chromatids shown in the diagram below?(ev (xy(2r5bqk) z9j dw0tyd(uhq-li

  The photomicrograph shows a pollen grain from L. candidum (Lily). Which stageh cewq;uz4g 7i+: ofyf et:)6isv ld-irc 6;g/ of tel o6 ;7-)cf:vghews+yd cfig6i/r: 4uziq;meiosis is shown?

1.Outline the events which would lead to an individual bei:jc q5avsi1v f o3ml;)ng born with Down syndromcoiqal;5 vs 3 :)mvf1je, which is 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 indir r uk ghqzdks6lrp5h/:u4(*a/ ect way of measuring plant growth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate theh sur(/ulp 5akhrg*6:4kd q/z 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 t-::py4 cpjtf/x*ic1la v4g urwo ways in which cells can divide. The diagrams below show two cells from an organism with a diploid numbel:rp 4/p4f yxv uigc-a*t:j1c r (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 g-jw /vra+9m8grx6 lcnrowth.

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 numbe, tuh-9vkh):md,bzfb r of 8, in different stages of v:9bhfk-mb)t uh zd,,meiosis. Which row correctly names each stage?

  The micrographs show four phases of meiosis I in a plant. In what rycq8 +fu0aiwcsbr u+ 9c8y00 order do these phases occur? cq c8rf+rw ya+usiy80u9 b00 c

Mitochondria are responsible for suppx 9zlzmwa zx j9:9 zx9yw/uq+;lying metabolic energy in eukaryotic cells. In most eukaryotes, which reproduce by sexual reproduction, mitochondrial DNA (mtDNA) is inherited from only one 99 u+zxq;x/ lz x 9z9wmywz:ajof 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 y )8sn8ntf;owcells in different stages of the cell cycle in four samples of lung tissue from four patients. Which n8oys t)wf ;8ntissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complex clket n 5y/z*mk+u /37qbhii8es at different time points in the cell cycle. Which cyclin/CDK complex actzhic8m53/ulyt bk/ke7 * q+ inivates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependent Kinvrx/ outmr0.r41e q p5ase 3 (CDKN3) are highly overexpressed in cervical5o pr x4 01mq.ert/vur 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 cyclib8-tda u6isi-0ou)6xmk wwb5f 8 g f7in E the highest during the cell cycle ?