The graph below shows the relationship between maternal age and the incidencep*3m3+wk:hegk:2xl i j2 znd+j l7dnj of non-disjunctied+j+hp3 lkkj nml:2*zwi2d j:x73gn on. What relationship is suggested by the data in the graph?

  Which stage of meiosis is represented in the e)apmy6o 6*kh1h)app /h3zpi diagram below?

  The diagram below shows chromosomes during meios o;:3 t.u)m9w x1ixgaslbqi )mis.


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 v+/lxd y3d:p kydh k 777ikk7qnumber of alleles of a single gene which would be present in the nucleus ofq7d x +i7khyplkyv dd 7/:37kk a cell as a result of each process?

  Which keyword is matched to the correct defis/o7+2 5sezxh xgi9qhrloxt 7 1lmlyo h609s.nition?

  Which statement(s) about m 23 ux-e1ae)dmzswr)titosis is/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 lettr9,vv+mz6jrymus 3ivf0wd /8er points to a cell in anaphase?

  During which stage of mitosis does the nuclpd5k *wl)0gc +5bk./mqp *msll)hgmvear envelope break down?

  Which one of the following transport proteins only carrie ,o eoc.z:t5kas out active transport?zk o5eao c,t.:

  Which process does not happen in thzw(ppg87xr 1je shoot apex?

  Which type/s of membrane transqa11zunzuu2 -vn ;u1g6 l xi5bport do/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cee/*9(u7o imh rpop 1ldll with a diploid number of 4. Which stage of cell division is the cell currently ui phu7*19 rloeom/(p dndergoing?

  The photomicrograph below shows a root tip m/30z dy rowin0eristem. Which of the following sentences correctly define0dwoy i /30rzns a meristem?

  When does the random orientation of homologous chro4 q mdr;5ejlt2mosome pairs occur?

  Which process does not occur during m aog( ;tat2eq6eiosis?

  If a cell with a diploid numbervz+t bzg1u;fn)c6e ,r of 36 undergoes mitosis, how many chromosomes will be present in each daughter; brz+n,v6t) fueg cz1 cell after cytokinesis?

  The image shows a microgr(j v:ig:od j,fa3 dyor;4m7*6 eqczn naph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/are not tru+1dbt. q+qcp -3j mqkre?
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 syndckyt, h)n* x65nciki95n a+mirome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase0omkyp u 0)y1t -0kbec I of meiosis I there are 64 chromosomes. What is the haploid number of chroc0-umyp) o 0tky0 1ekbmosomes?

  Which arrow is pointing to a c)7tpgt,m-w i+t-lj nkqf 5scq5dt96 yhiasma?

  The diagram below repreb:n c2bq* /rwv iz)5vxsents the structure of a shoot apical meristem. Which row in the table correctly identifies the procez5 )n2xibw:vcqv/ * brsses occuring in the structures labeled in the diagram?

  How does meiosis promote vari 7mibord938w bybvz9* w s61tiation?

  Which of the following statements is/ zg vq z)w:u9vxb1zd7(d3-vr hare 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 homologouepgylp4v(t) nc/ ,dj9s 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 secondary ti1csca0hbo4i mh y vw:2: y97zkano,iw j54q6 umours from primary tumours as a6i2ooca4z:wchw1s9 qi4i 0yvb 5y7j,:amnkh result of the movement of cells?

  How many chiasmata are prese s .nqg(mwri 3),t+it n,/2c;g dtsilpnt in the diagram?

  Which statement is a similarity betweo gdu 61pcs5;yey-c *s2a sgq6en cytokinesis in animal and plant cells?

  Which stage of meiosis is matched to the cq ufdtapb6g74nc(km u u6w56-orrect description?

  Which statement(s) are true of meiosis I but not meiosis II?za y0 zois+-0bs-v7 q x7qv;ow
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 oochx4lgf+l/ 494 q*gjuihcb k3syte after the first meiotic division. This results in the formag3kihxu+bh4/c4s9 lf*j qg l4tion of one large cell and one small cell. What is the fate of the large cell?

  Which row correctly describes diplo7obfp98 l0 o +qwqb*haid and haploid cells in humans?

  The following table shows the diploid chromosome number c0, kfongrq: *of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the m+.b5(k 6eg v(dzmfab karyogram below?

  Which of the following phsml5 z p+ey9+ -xar7btleo/ 2rocesses is characteristic of the meiotic and not the mitotic 7be/+-x5 szmay t9hle o2lr+p cell cycle?

  The diagram represents a bud with a a 0o6/guf*pv bshoot 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 chimpanzp7 mf 33 c2nvr0b sr,hk7vy.xaee (Pan troglodytes) is 48. Which row shows the correct chromosome number for different cell tya 02rp,k7h ncmrv.sx7by v3f3pes and cell division stages?.

  At the end of which phase ofe:qd7yap:3- ojm-wk h meiosis I does crossing over occur, and what is the outcome ow-7:jmeo3k- p: ha qdyf crossing over?

  Which of the following statements does not describe a step in the sodium-potassip7;0aux+ ztu 3an1ufxoog4:a-ghn3j ujkn 12um pump cycl uuo7nxzaj4a 3 gxhtfo:-g+k 2p1u103nan;uje in the neuronal cells?

  Which row in the table below is true of meiosiw80crt .+jhnos?

Membrane transport is important for allowing particles to ++2 pv *phlxtm zh)sec:oju* +gw )rx:move across the cell membrane and respond to changes in the chemical compos:*om s ) +x*ep:jhrwxuph2gcztl+ +)v ition 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 regulateqf4 5b( u8ltaeln;t g4d 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 differe b8oh/ 6u1edvxnt cyclins during the cell cycle. Whi b8vehx u16do/ch cyclin is involved in preparing for DNA replication?

The diagram below shows chromosomes during meiosis.wlbh3, 5 z:vmm )glx+csq,3 *llq l-lm

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 homolog w *aoe07tw:wpous chromosomes?

  The mitotic index of throat tissues taken from 4 different patients isznz)slb, *r3u shown below. Which patient is most likely to havznzu,3 bl) s*re cancerous throat tissue?

1.Draw a labelled diagram to repr 0;(yrb/*bcrbh w 4pt yx rpfv4f (56wecobd5:esent 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 karyotype. k0u psa107wleqi((wy


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount ofe 9r:j/:d06fjr brk+wjes3vag d)pce2*e0k t DNA in one cell during one complete cell cycle. Each letter represents one stage of rjdte 93bvgk0eafrk6/d2*ej0p:+j ce):s wrthe 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 cn7zzh iie ))idt+-f/v x*jr,k at that is homozygous for brown, long hair and a female cat tha7/itj,d *k) vrx+ hzfzi)i-net has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normal distribution. e vs3*nmwm;roqik .82jjtoi+0. /xiy

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-9:avuy5 uvrza0 5rup5 9bn 8xysister chromatids shown in the diagra:xa p5av95vyr ub8z5 yurn9 u0m below?

  The photomicrograph shows a pollen grain from L.ueejud 15+m(9 f +kxic candidum (Lily). Which stage of meiosis is show5(um eej1du +9f+icxk n?

1.Outline the events which would lead to an indivi*oy z,yu:3tazdual being born with Down syndrome, which is characterised by the presence of three copies of chromosy:, z z3a*uoytome 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indirect way of measuring plant growth. A stix+x(om*c1k ,efj1i k+;ympq h3:c itudy was conducted on white onions (Allium cepa), under i+3h,i;o ktp11x(imc *exy +mkq jf:ccontrolled conditions in a 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 waysyc9 /u/l db zzg2(vkz* in which cells can divide. The diagrams below show two cells from an or9ku2c*dbg l(y/ z/zzvganism 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 expression in stem growthpewcdxp n(r8)aw6b 1 yd:3ni) .

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 numb ykedmz:m.cq r;n85t+n8y p t6 /ta:cher of 8, in different stages of meiosis. Which row correctly names each sta:tzk yptcnc6/hemy:8 d .nt r5qa+8;mge?

  The micrographs show four phases of meiosis I vc7lrwo(:3mnbn+ek2 in a plant. In what order do these phases occulv3crme 2 +:on7nkbw (r?

Mitochondria are responsible for supplying metabolic energy in eukzkm jukj3hf g85s0 l*q s8g)m.aryotic 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 mj*gss8 )m5z0fk3j q8lu gh. knuclear 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 t/ ,h8nd -uktm t0ke;cshe cell cycle in four samples of lung tissue from four patients. Which tisdkm , huec-tn;kts08 /sue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK comple 0wvp*ufj; z5zxes at different time points in the cell cycle. zw ;*5v pzjf0uWhich cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that gen kt7w-p8r6 nules such as Cyclin Dependent Kinase 3 (CDKN3) are highl6-rpnl 8utk w7y 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 highnnxtv )cfn/7 :gat 8i6qk vs.1est during the cell cycle ?