The graph below shows the relationship between materown2oiv4,l+ 3om x 9jqnal age and the incidence of non-disjunction. What relation ,2+ i9xw3oovnjom4qlship is suggested by the data in the graph?

  Which stage of meiosis is represented in the diagram below? xlt 138dbus xj2;wa+- dquo7n

  The diagram below shows chromosomes during meiosiso-l( 4gl* 3zf tp hvw+xcs6h.p.


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 ge9xtr2rjy0zz , ne which would be pry09zj ,rrt z2xesent in the nucleus of a cell as a result of each process?

  Which keyword is matched to the correct defin8gv nalci7dfa f0v8oc ;119ikition?

  Which statement(s) about mitosis b4fc;uqf1bua3 u) ei7rtf0d ) 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 bed,2ko db8pw +wlow, which letter points to a cell in anaphase?

  During which stage of mitosis does the nuclear enveb7 1pqfr0(ka(tpm1 ti me w,*ulope break down?

  Which one of the following tg hqmxj nt*/k.f8o a1 (4/vt7vzentx 7ransport proteins only carries out active transport?x7xv1nt /4 fgot(qz*7.k/ v hmn8 jate

  Which process does not happen in(* 4ck(n7ly cbhn aysk *0 empv5q8(ys the shoot apex?

  Which type/s of membnh9+d 7ool,m+w(e(+ umz phcqrane transport do/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4. Which stago fzsu1 4*hvjl/ ll)4o md31a j3kl8nqe of cell division is the l34alv *lh/3sz df 4l m1jn8j1oouqk )cell currently undergoing?

  The photomicrograph below shows a root tip meristem. Which of thno*b4ye 3ogy. e following sentences correctly defo*.y4y3 bo ngeines a meristem?

  When does the random orientation of h 9m -mz8.t:::idu3v er zhdjwwllr6)h omologous chromosome pairs occur?

  Which process does not occur durd wy3 6anp/fz3ing meiosis?

  If a cell with a diploid number of 36 undergoi dj-,3f6mfoxc1.r xyxf 5 cd8es mitosis, how many chromosomes will be present in each daught5xi8 yd31fdfx6 x,-r.cjmocf er cell after cytokinesis?

  The image shows a micrograph(uet 7 uws3m6h of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromz feq*qvv47j 4osomes 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 ig2-7ti*ucz,du9el- w-l u mge ndividual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis I there ares hhehy-n3/ h0c8snq + niz4m- 64 chromosomes. What is the haploid h8hi-4 n3eqh cz-hsm/0 ys+nn number of chromosomes?

  Which arrow is pointing te+w .;eckauk8o a chiasma?

  The diagram below represents the structure of a shoot apical*8rakcc3v 0 r)hejr )l meristem. Which row ina3vc0r*l) c)rr eh8kj the table correctly identifies the processes occuring in the structures labeled in the diagram?

  How does meiosis promote4s ,we a)bqpcm9o6: ib variation?

  Which of the following statemeb+i+fal lbg8- 1 :uygezz8,b znts is/are 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 fvz8zt 1tn/h wilf37o2rom 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 primary tumi7 2,dokusu+l ours as a resko 7sul,i+ d2uult of the movement of cells?

  How many chiasmata are pre5bcy2i7rp/a esent in the diagram?

  Which statement is a similarity between cytokinesis in animal and plant celk2nw ouuo :1.bls?

  Which stage of meiosis is mtd9 k3jhs 8,*abb4de2ce rc3katched to the correct description?

  Which statement(s) are true of mcj *aw (w3vcgu,6t;i qeiosis 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 lzh.- mm5;t/(lzbfm c first meiotic division. This results in the formation of one large cell and one sl z. l-b5c( hmt;zm/mfmall cell. What is the fate of the large cell?

  Which row correctly describes diploid and haploid cells in hukb ddx f6m6zanl x-m/fr (*1e9mans?

  The following table shows the diploid co51g+wxjnf 4f :;nbwl hromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyogram be2x opqnl4p49pius9z sdzp ).,low?

  Which of the following processev.z6 cbm k:uh8s is characteristic of the meiotic and not the mitotic cell cycl:uhcmbvk6.8z e?

  The diagram represents a bud with a shoot apical meristemli c/).jwm n-r.

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) isgxqbs et d;qps6(7o53h4hk* *o ti-z p 48. Which row shows the correct chromosome number for different cell types and cell ddbg7qe k-h6ot( p h* s3xsz*;qo5p4itivision stages?.

  At the end of which phase of meiosis I does crossing ove1ki+b 6vx4))mnm o3ejgsl u)nr occur, and what is the outcome of crosi n1vmeo)6+l4ug)xj bsk3m)nsing over?

  Which of the following statements does not describe a step in the sodium-pot):luhn vyv lg*o.* o.sassium pump cycle in the neuronal**u.v: oy .lnvolhs)g cells?

  Which row in the table below is true of me1m:6ou7lqpo o iosis?

Membrane transport is important for allowing particles to move jz:cn()jx *bracross the cell membrane and respb )cxzj n*(jr:ond to changes 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 regula,xpwit z51sd76r5cu/y8gr od ct07 ngted 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 differentt+.zreo b( /lp cyclins during the cell cyopz b./tle+ (rcle. Which cyclin is involved in preparing for DNA replication?

The diagram below shows chromosomes during mei0 uss3u+wxtc5lh.vq+ lz/7 pe osis.

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 invoo.xri*9m fa7nk9 -xcpj.3b silves the separation of homologous chromosomes?

  The mitotic index of throat tissues t+p+bm (,r zo k7ldmat0aken from 4 different patients is shown below. Which patient is most likely to have cancerou(k ptl+m0+dmbaz7o,r s throat tissue?

1.Draw a labelled diagram to represent thexg4cmiqi3g4tks:sep.9uk 0 8 process of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal ddc77 6jk 30mbth 0ol/o 2qgbehuman karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cell dur0(bw;az ou )cling one complete ce) u;ab0l cowz(ll cycle. Each letter represents one stage 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 ba/fqxq - bx,.oy)jdf+etween a male cat that is homozygous for brown, long haqj+)a xf/f, .xdyb-oq ir and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normal distribu71rcd4164fitkdid5rb d 5*wneb n;v f2- zjzktion.

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 no2t vdj fz +5:/,gws*uv 8tduuvn-sister chromatids shown in the diagram bel:5+ t*g udu8zj2tfv,uv wv/s dow?

  The photomicrograph shows0sftn9 +pty:qbk x/ 70x- d1 ygomijm+ a pollen grain from L. candidum (Lily). Which stage of meiosis is show 9s7mpg -tnb0fkmyxq01xi+o /yd:+jt n?

1.Outline the events which would lead to an individual beingurp76 es z0/c pblsr+9 born with Down syndrome, which is characterised by the presence p+srz ulp r/b9ec7s60of 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 pla(bteer;49 6qoe+ ri6ltdn( ap nt growth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the effect of;e(tra(pb eo rel6nd+t q94i 6 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. Thp7 ohne/;o-hou8si 3 fla:u0i e diagrams below show two cells from an organism with a diploidi -7; lhua0sfp8hio o:3 /eoun 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 gen .ly*0adfzji *e 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 o 8k +;v llj;err2,qhostages of meiosis. Which row correct, j2;l8+lkqr rove;oh ly names each stage?

  The micrographs show four phases of meiosis I in a plant. In what *d r;l aq53ljworder do these phases occurjrqlw*ad l 5;3?

Mitochondria are resp15mqeb* 1 -eucw- lehponsible 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 nuclear DNA which is inherited from both parent -mewel- p151bu qhe*cs. 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 differentb5t ;yk kp+o-c stages of the cell cycle in four samples of lung tiss5kypotk-;c +b ue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominv9de,z z q2,sgant cyclin/CDK complexes at different time points in the g ,se,zq 2zd9vcell cycle. Which cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependen/u3wp3a/f7bsy3- eg.svl tv/ehz5tbt Kinase 3 (CDKN3) are highly ovl/3e szf/3t thpg73 w/b eu sbav.y-5verexpressed 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 cy x2+795gbxm6c yvp oedcle ?