The graph below shows the relationship between maternal age and wm6khgay5e5- the incidence of non-disjunctionke-g56 5wmyah. What relationship is suggested by the data in the graph?

  Which stage of meiosis is representb(kkj;:ry7o o ed in the diagram below?

  The diagram below shows chroo.3-q(vx ofhr mosomes 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 alleles of a single gene which woubx* a4l)ebuzp(kdwiyv69;k5vt; pa. ld be present in the nucleus of.a ea tpp( b9kkl 4z;;yduv6xib5w )*v a cell as a result of each process?

  Which keyword is matched to the correc8 ,tm),kwq .c ;hj hpxiix3x7et definition?

  Which statement(s) about mitosis is/are true? te*g ,mjrxv 6+ wtd kc(xj q;vm*c445f
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, whichf;sq+)p iomv5 nb(,w r letter points to a cell in anaphase?

  During which stage of mitosis does the nuclear envelope break downjpxv o m34*8md 8uzqj/?

  Which one of the following tr(7jm aai vh,l;ansport proteins only carries out active transport?aim(lh ,jva; 7

  Which process does not happen in the shoot ape vttw:(icx4: wgwxbwi6qz 2ww 488t:fx?

  Which type/s of membrane transport do/does not requirz3haaqo0sf2tec0evja i:m( 2/ a4fe* e energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4. Which st)u3h/du6 be4l wb6jyqa.t0opage of cell division is the cell currently undergohb e .ad6)q0lo6t 4ju/3wy pubing?

  The photomicrograph below shows a root tip meristem. Which of the following segr9h2kz bj5u(ntencejhbg( 95kz u2rs correctly defines a meristem?

  When does the random orientation of homologous chromosome px1pkf9gf a,u2yo 1xo8 airs occur?

  Which process does not occur d5hcg0ayz+owd ll9+ .curing meiosis?

  If a cell with a diploid number of 7 vg23ol s0hw s7go5oo36 undergoes mitosis, how many chromosomes will be present in each daughter cell aftgs0oovosg 372 5 ol7hwer cytokinesis?

  The image shows a micrograph of a c-db5 6 9myrcynell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologov h0cpi) -fr qc0j(e6zybel.4 us 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 synd ./o z:i.zzafmrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) df ,x1ax9sqw2sh zq5-a*tuet 4uring prophase I of meiosis I there are 64 chromosomes. What is the haploid nwq,htz*x2q54faxu s1sa 9 te- umber of chromosomes?

  Which arrow is pointing to a chqjrhx;fl0(c1 ld ,4vi 9uqt * n29nwpeiasma?

  The diagram below represents the structure of a shoot apical meristem. Which rowy+rc( . g4oijj in the table correctly identifies the processes occuri(r jji.gc+o y4ng in the structures labeled in the diagram?

  How does meiosis promote variatiomni0 cjwt; 46 mfw.*)fb qstb3n?

  Which of the following statements is/are correct for m(* x j2b3qli8)xf hfcbeiosis?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametes produced from two h-4ife f7gyklt-q2ylo. 9lg( vomologous 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 k1:v2v -w.,2m- xgjvgscou qgr-ro*m secondary tumours from primary tumours as a rex2ggwo *mvr u2.,-vrc1:-s g okqjvm -sult of the movement of cells?

  How many chiasmata are prixkf5 j)ys6k2qk:qme( 7 w9 izesent in the diagram?

  Which statement is a similarn.(wll znj9etx3-(w iity between cytokinesis in animal and plant cells?

  Which stage of meiosis is matched to the correct d-w suzw).0a,cgxe4 zaescription?

  Which statement(s) are true of meiosiiny *o w,0r w.tb14yym0fvv7 is 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 first meiotic division. This 9/hh0v9x prpvresults in the forma990 h/ ppxhvvrtion of one large cell and one small cell. What is the fate of the large cell?

  Which row correctly describes diploid and bs6hghlopj s6- pg1 6*haploid cells in humans?

  The following table shows the diploid chromosome number jy1h2zzgp+jk)(zpo 3 of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the kar84* n2;zgzff6 pjrnmp6cco3yz (y ,4m qkd iz5yogram below?

  Which of the following processes is characteristic of the meiotic and no gzy3ifsarr(.w0: pw.t the mitotiws:(p3ayfi rz.0.gwr c cell cycle?

  The diagram represents a i6u4hy/flqfu.2q) 7k z6h d ald*rf9k bud with 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 chimpanzee (Pan troglodytes) is 48. Which row show4gv b/m(.y3hh ma v3qks the correct mq h34k (hva gv.b/ym3chromosome number for different cell types and cell division stages?.

  At the end of which phase of meiosis I does crossing o /(olm a*/f.v ur5mx.5b fijnrver occur, and what is the outcome of crossarr /b .u(* l/o.5xn5jfmmifving over?

  Which of the following statements does not describe a stnjz49x d-al5woa66i 0s ag(xvep in the sodium-potassium0n (x svx9gad4il 5z6o-w6ja a pump cycle in the neuronal cells?

  Which row in the table below,u6 t r5mvgydlly71,v is true of meiosis?

Membrane transport is important for allo:--c jcc3d sdiwing particles to move across the cell membrane and respond to changes in cj-i :d-cds c3the 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 i- g- 0vpzcg4manw4uv ,pgc08hs 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 concentrations of difu m+d 5ljw-pjiwp3 4qt 55gtf8ferent cyclins during the cell cycle. Which cyclin is involved in preparing for53m4 u5il-ftg58 tdw p+ pqjwj DNA replication?

The diagram below shows t8w9s7 z8y o2pxby t;z/q0hjmchromosomes 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 meiosise l 5do03x ijuda+nu -rzv4w29 involves the separation of homologous chromosomes?

  The mitotic index of thrr b t2 2)py q0,vidf5(gs t*mw(gz(aufoat tissues taken from 4 different patients is shown below. W vqd )2( t,(2 fg*ystumr5 wi0gzp(fabhich patient is most likely to have cancerous throat tissue?

1.Draw a labelled diagram to represelz0n y3-* n f,rcpwi7rnt 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 h):vh)2,qzs,mz hj ro xuman karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relatw7uim2m, yw6 an(rpn1ive amount of DNA in one cell during one complete cell cycle. Each letter represents one stage of thenwrm y ,uw 1m6a(n27ip 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 )i d(.epx0z mzcross between a male cat that is homozygous for brown, loizdpx. (m0 ez)ng hair and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits c m-t19(ca2 y :l714lp ewi(e yzeuelmwq+)gasan 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 chro ;/k(o f;d17(jq bjrvrq;cnovmatids shown in the diagravqjd7fvb ;jkr /;( o1(nq;oc rm below?

  The photomicrograph shows a pollen grail h0;o6f 3v- dyobev)pn from L. candidum (Lily). Which stage of meiosef3p 6; blvv0yo)h-do is is shown?

1.Outline the events which would ag(0*pk jqkn0ep1r p 0lead to an individual being born with Down syndrome, which is characterise(p 0 k1krpej0p0qag* nd 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 way of measuring pn0r) i 9lx0ubllant growth. A study was conducted on white onions (Allium cepa), under controlled c0ibl 9)u xln0ronditions 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 ways in which cells can divide. The diagrams* w6c9d)y(( zx ncxa.te vv)wc below show two cells from an orv .yec )x vc6dx*(w)wz ct9(anganism 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 ;xyf a47.rp.q6 fnlqlihd7h0yb 74d* a-cuqh gene expression 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 stlyk a.8k4 u; rjnq0dr6ages of meiosis. Which row correctly names el04;rad6jyqk8n u. rk ach stage?

  The micrographs show four phases of meiosis I in a p0fg- g i0zle9byvw*h(zrkn63xjg w 7. lant. In what order do these phases oc -g39eyirwzz0hn7 6fv0lk. (bggw *x jcur?

Mitochondria are responsible for supplying metabolic energy in eukaryotic aig+ b4)fx5yu8)uln g+a(k bgcells. 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 inheb+ gb4ka y5 uf u+()ggna)xi8lrited 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 kmoo709vmq;+j4 dd : .8az-msgd+la 5kngfbv number of cells in different stages of the cell cycle in fourd7dm og-azvmoalq+n:gvf+bs 5.m0k4 d k8j9 ; samples of lung tissue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the domint6 9yg6b-vc z rl 54rt)fnmd3nfvzi.5 ant cyclin/CDK complexes at different time points in the cell cycle. Which cyclinnvcrg9mtf534 t diyzrb.56 l-6n)f vz/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependent Kinase 4e:/e okj yn6xhc 3g28o+kih u3 (CDKN3) are highly overexpressed in cervical to 3j6e4h/geokun ixykc+:h82 umours.


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 cq h3wg l77up8ko+ta3 jycle ?