The graph below shows the relations.8+ qo hrslke6e zj/:xhip between maternal age and the incidence of non-disjunction. What relationship is suggezxe. l8s kh o/e:jq6r+sted by the data in the graph?

  Which stage of meiosis is represented in the diagram be me5friwa u)bna te:(,4v/s 7clow?

  The diagram below shows chromosomes during:lx*xugjz g-mya9z( 3 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 at4 . bhe/)ptpls9v sk, single gene which would be present in the nucleus of a cell as 4e.9t p,ts) hsbpkl/ va result of each process?

  Which keyword is matched to the /wjve;b )hpsk7xa:y; correct definition?

  Which statement(s) about mitoy(y(36, esqep -d 9nnyj jnc5lsis 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 letter points tobdkl4 t hb-(fk t80h54lqxw x1 a cell in anaphase?

  During which stage ofpb+g na4cpq +v.w8 *av mitosis does the nuclear envelope break down?

  Which one of the following transport proteins only carries ouq*uw2 ) 9x ;d9yskx3 j*bzb3newym7tpt active transport?xnj ;uz9bb7p*3t ky9w*d)wsx32mqe y

  Which process does not happen in the shoot .ry n b ;8v-zjo1o7dnsapex?

  Which type/s of membrane transport do/does not require energy cmntl/7iw ihs3*a /:pexpenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a yhdr3/t(jn- ucell with a diploid number of 4. Which stage of cell division is the cell currently undergoir /t(u-ydnh3j ng?

  The photomicrograph below shows a root w06 s iu7,ls, j2 gkxw .cp*vnex4*m.k.wculqtip meristem. Which of the following sentences correctly definesujk*w w..ge* p k4illqx2c7u6c,svn.xm ,0sw a meristem?

  When does the random orientation 37zafq3u ymg *h+)k: rzy5ygo of homologous chromosome pairs occur?

  Which process does not occur durin93ungi yw,d0 ng meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, how many c-zvpxsc1 dii,+5p yg -hromosomes will bpxsyi,gip v15zc+ d--e present in each daughter cell after cytokinesis?

  The image shows a micrograph c5nbdiy 5 bo)8;u1rvawfz4z,of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about h:fv q9ng k1t4x4e j1efomologous 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 syndrz6y0zd 1uz) bj0zjdj ;ome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase6/pvkf-jiub+slv *4d* a+a o j I of meiosis I there are 64 chromosomes. What is the haploid number of chromosod fp*sl 6*bavou4++-/jkajvi mes?

  Which arrow is pointingy-xiu-u nc8dp+kj.1 f to a chiasma?

  The diagram below represents the structure of a shoot apical j;xgq :kcgq 3/meristem. Which row :;3 qxkgj gq/cin the table correctly identifies the processes occuring in the structures labeled in the diagram?

  How does meiosis promote variatibwdpl.+p*1x 40nxa oaon?

  Which of the following statements is/are cb2v- tz63osnk orrect for meiosis?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametiro6ipc e*: y9w:zf;wh, hv+oes 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 formation of secondary tumours from prl y+qrtbo6hg g/12fe4-t l4u a,(mfr eimary tumours as a result of the m/4l,rtg ab6-2my4utf o (lre1gh+qefovement of cells?

  How many chiasmata are o+ irmp 6y:o4, zqy7sqpresent in the diagram?

  Which statement is a similarity +l0r)lw+fo* lam-s roe8l hk (between cytokinesis in animal and plant cells?

  Which stage of meiosis is matched to p3r 2 .czpi2f)/q3sinkiu 6onthe correct description?

  Which statement(s) are true of meiosis Iy po31zqez+a 33ke s+mhrc8,h 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 55 r*g4b;g thso-oopcfirst meiotic division. This results in the formation of one large cell and one small cell. Whaotor5hs -4gp*ogb5; ct is the fate of the large cell?

  Which row correctly descri a nir7:4ui,wdlivs.dn m*0h .bes diploid and haploid cells in humans?

  The following table shows the diploid chromosome number of a range of speciezf4wdzv5jf cqf +,d; 0s.


Which of these statements is correct?

  What conclusion can be drawkkzl3 j d(r(0in from the karyogram below?

  Which of the following processes is characteristic of the meiotic and not the0q kw gak: x.4uv4- dp9(dnmom mitotic celp4dko 0:qwxna dv.m g4ukm -9(l cycle?

  The diagram represents a bud with a shoot6nfjay g6:fv,.. p qp6(hbxjb 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 chimkxckd+ 3;urr*op6g ku p: 1qrk 2.nwl9panzee (Pan troglodytes) is 48. Which row shows the cgkrw 6+ p.rxnkpq2 9kcu1:k *ordl u3;orrect chromosome number for different cell types and cell division stages?.

  At the end of which ph9ka;qvtm cw */ase of meiosis I does crossing over occur, and what is the outcome of cross akq; mw/vtc9*ing over?

  Which of the following statements 8;5ygw1 fy h,m w/k0+ghk dlxydoes not describe a step in the sodium-potassium pump cycle in the neuronal cmw/xdf,ggh8kh+1yyly0 5 k;wells?

  Which row in the table belowx q2,bg 4vtsa ew5,v,v is true of meiosis?

Membrane transport is important for allowing particles to move across the cellm v7e9bqji( d: membrane and respond to changes in the chemical comd(i 7v j:em9qbposition 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 regulp 4yl4+0vkrod ated 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 dif.d o:sqz6p3s mferent cyclins during the cell cycle. Which cyclin isz6 sqds .p:m3o involved in preparing for DNA replication?

The diagram below shows chromosomes during meiosis. +; m7d mvuc;po+i7 cak

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 invgw)kh(xvh31t 6s bjs bs*v., uolves the separation of homologous chromosomes?

  The mitotic index of throat tissues taken from 4gg:tst7(b r4 j different patients is shown below. Which patient is most likely to have cancs4:gjr(gbt t7erous throat tissue?

1.Draw a labelled diagram to represent the protd- ubtqg+szg n4kzlk6.1 u y4l85w;pcess of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal/crl h1v 8.keb human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cell durw4d7xoj s1 sd-ing one complete cell cycle. Each letter represents one stage of th7o4 d1sjds w-xe 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 showstr4u4lp/ela3 a cross between a male cat that is homozygous for brown, t4 e/l3ra4lu plong hair and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits capjz9r0ubv)l; rvsydp 6mi:7 :n 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 f.dvc aw7k8)hw oeb,j5rom the crossing over of non-sister chromatids shown in the diagram belo,)ko 5h d. e8abjcvww7w?

  The photomicrograph shows a pollen grain from L. candidum (Lily)7x+ j7h fvtvomiy e1+/q4v gw-. Which stage of meiosis is shown? 7e+mxj+htf1v 7ovvw/ iy 4qg-

1.Outline the events which would lead to an indp 0ww7m q24rbjct+sv*ividual being born with Down syndrome, which is characterised by the presence of threqt04 wb*pc7 2+mvj wrse copies of chromosome 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indirj*)v/c3qx qa yect way of measuring 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 mitotic indc/y*qv3 jq ax)ex 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 in5pqp;5 4 wzyog which cells can divide. The diagrams below show two cells from an organism with a diploid nu5q gw;p4o y5pzmber (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 ofcnf: 2-40b ka4s s5 so ;kyck0bfi2iqt 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 number6 b;pz* jgdu7n of 8, in different stages of meiosn;zgj*d 7ub6pis. Which row correctly names each stage?

  The micrographs show four phases of meiosis I in a plant. In wvk i vqio22-3t fr+9prhat order do these phases occur? qov f3rt i i+rv2kp-92

Mitochondria are responsible for supplying+uaf iu2i2h9y 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 isy a2uh2i+ui9f 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 cells in different ekw;ul.+v t*opa 4q4gx ykh59stages of the cell cycle in four samplh 4lkyx+ ;*guk.a vtoe5qp94wes of lung tissue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominatmbb9rh:34 cdh kxm(; nt cyclin/CDK complexes at different time points in the cell cycle. Which cyclin/CDK mkrh9d h tmb:4xb;(c3complex activates DNA replication machinery?

  Studies have shown that genes sk5p ggsd7:9lt39ku0 h *xjaxtuch as Cyclin Dependent Kinase 3 (CDKN3) are highly overexpressed in ceus90tgp5h k7xk tljg 93 :xa*drvical 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 cjc8;7 nxvr ml9ycle ?