The graph below shows the relationship between matdh8qv h; * sg:5 oz ofp+9qig.z1rc:drernal age and the incidence of non-disjunction. What relationship is suggested by the data in the graph? *hq.h 9odrfdg ropzq5z:;:i+ cvg 8s1

  Which stage of meiosis is represented in the diagram belop/wi+rv2(vxab )q mk qk77/:7a mhlvww?

  The diagram below shows chromos0om 097nbip ja5kc 0bw1ey;sn omes 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 single5c/.h (xkllt y gene which would be present in the nucleus of a cell as y xc/l.h5t(kla result of each process?

  Which keyword is matched to the correct o*x3opje ca) :definition?

  Which statement(s) about mitoi :k0prcbec6h,;oyi a.rr+1 fsis 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 to a cell in anahp/ ly6 e 6:nq:dopvi3 (pqe9vdmns4 )phase?

  During which stage of mitosis p:x17 m18ton qw0z caqi4d 2bfdoes the nuclear envelope break down?

  Which one of the following transport proteins only carries vt,4l aj3+2 1 8a6uvrcohjxyo out active transport?vjt8aj, h2 y1acx 43lu6o ovr+

  Which process does not happen in the shoot j;6fnkebp*-w5.dm zoapex?

  Which type/s of membrane transport do/does not require energy expene9 ry2 n):,v*lczpjwpg: hpn6diture?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4. Which stagrlb68p .tvd7x e of cell division is the cell ctdx. rbv 8lp67urrently undergoing?

  The photomicrograph below showsyw3o(h1o( 6aj:/: rwegvxe kt a root tip meristem. Which of the following sentences corr:1j h wv /ayto(e3gkwe6x (:orectly defines a meristem?

  When does the random orientation of homologous chromosome pairjb608mv lmij ;s occur?

  Which process does not occ.7e q3m sdjpl/ur during meiosis?

  If a cell with a diploid numb9u/.lqae2 tn3 yleo0 per of 36 undergoes mitosis, how many chromosomes will be present in each dalpq/e 32.en9o 0laytu ughter cell after cytokinesis?

  The image shows a micrograph of a m d sul icc/*d (s/tbn5t4dl14cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromooq/fvm 8ck r8ll (dh ( h*hhk(4v6p,glsomes 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 t l(stah4l;2k*hdq r )ii19wxindividual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis I tlo oa/2 un,go:here are 64 chromosomes. What is to,2goo u/anl: he haploid number of chromosomes?

  Which arrow is pointing to a 2wxz)hpde*0() ap r*7 vcfd wuchiasma?

  The diagram below represents tvbq 4rh7z6zhii-, u mes 3*hf1he structure of a shoot apical meristem. Which row in the table correctly identifies the processes occuring in the structures labeled4f*vi31 zz- e6bhhsim,ru hq7 in the diagram?

  How does meiosis promote variai5a k p. uupo4*syql;h3wp;: otion?

  Which of the following statements is/o :o ue2qwmd-v1+r1ep mf(gl7x/ mzr1are 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 homologous2+ml:w 4xm .mfmj;gfv 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 secon k-i dfisub3. sp1w2-kibkb)7dary tumours from primary tumours as a re3i)b-s bp biks1i-d .kkw2f7usult of the movement of cells?

  How many chiasmata are present in the diagrs 4)p :5(5zm7 jublqgref8pmpiamg, 6am?

  Which statement is a similarity between cytokinesis in animtk+*d vu f7 3:lfim)jval and plant cells?

  Which stage of meiosis is match tgh5c)*wrt-or,8jn wed to the correct description?

  Which statement(s) are true of meiosis I but not meiosis Ii (z bv j2k7(nayc(zm6wi gjxt lm0:06I?
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 fic2xl ,/7 oz.kqlxx9m.sxwod ) rst meiotic division. This results in the formation of one large cell and one small cell. What is the fate of the la.z7kdm lxc o.sl, wqxxo92 /)xrge cell?

  Which row correctly describes diploid and haploid ;fqhu 5j rs,o7*wr*rzcells in humans?

  The following table shows f,u./ 1tvx p+rhreu 3rthe diploid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be draw(ktplt) 0x5oi n from the karyogram below?

  Which of the following processes is characteristic of the meiotic andjygwo j63(*)phbr5f2*s euen not the mitotic cell c es(6bp523n jg)y*jf w*ro ehuycle?

  The diagram represents a bu3 24 o3w/;es1kjalm c psexbx hh9*zf7d 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 chimp) q-gf+mqbvyvc d+65tanzee (Pan troglodytes) is 48. Which row shows the correct chromosome number for different vb++5-m q fqvy)cdtg6 cell types and cell division stages?.

  At the end of which phase of meiosis I does croj83x dmfdzz7 z9err*2ssing over occur, and what is the outcome of crjzm e2zf z897drx3dr* ossing over?

  Which of the following statements does not describe a step in tl,bv67xlf5gy48f s-+ itm f cn8mbgo5 he sodium-potassium pump cycle i-vymb b476+f8mf l isnx5 ,o8clg ftg5n the neuronal cells?

  Which row in the table below is true of meihu az1/bc pc(l5 +7ftb d(-doposis?

Membrane transport is important for allowing parttjn0u61p e2dkxl6 xyyx:4 gvfd9 u46 yicles to move across the cell membrane and respond to changes in ty xf0 yx 4vj 4t6k:n9xdep6uu1l 6g2ydhe 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.qqbg-dr3 v k-fab3ls8wr+6-e. psev 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 different cyclinsro0j7f 45efprb a e29etzd15q during the cell cycle. Which cyclin is involved ep0 o aefr9tfq j 41e7zdr5b52in preparing for DNA replication?

The diagram below shows chromosomes durin58/n/0p7ndjnb g znvzw m 6(zcg 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 the separation of homologous ch qlf(awdibn4cyqr 6,4u 20w2iromosomes?

  The mitotic index of throat tissues taken from 4 different patients is shown b mo na,rn24)vv*,x g b*;elvtkdvk;t,elow. Which pat*)n b,*o4d nxrvkamg;k,evl;v, tt 2v ient is most likely to have cancerous throat tissue?

1.Draw a labelled diagram to represent the process of crossing2j ne7ubdzj6s0) /a9fzn p re5 over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal h aa.xrz- ;)ionuman karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the rela9tnvk;4 ph)vxra)dm + )gxn 8otive amount of DNA in one cell during one complete cell cycle. Each letter represents one staxgo n8+mnp kx hvv;4atd )r)9)ge 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 be iwy z)cw*hd t4i 2w/0syxw-4vtween a male cat that is homozygous for brown, long hair and a female cat that has black, short 42swid 4)w/ wi*z chyx-wvy0thair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normal distribu+ 7hoasz re+w*tion.

2.Outline the differences and similarities between homologous chromosomes.

3.Explain why expected and observed Mendelian ratios may differ.

  Which gamete can resulte5ixnd p*wg4- from the crossing over of non-sister chromatids shown in the diagram below?ed *4-wn xgpi5

  The photomicrograph shows a pollen grain fy6sazw1nay,r:: y ab 74mff2kto8: xfrom L. candidum (Lily). Which stage of meiosis is4fy6fbfwz y :xa na tamy72:o1k:s,r 8 shown?

1.Outline the events which would lead to an individual2p x9z7 fczb8h being born with Down syndrome, which is characterised by the pxz zc28bf9h7presence 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 plant growth. dkgm)hp *a/cc r pfw ,s)f80,lA study was conducted on white onions (A,*0cphd s,/c)lpwkfm8)ag fr llium cepa), under controlled 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 ways in which cells can divide. The diagrams h2+wk,b tma0ii4k 5oc below show two cells from an organism with a diploid n oi,aki b0mk5wh 24t+cumber (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,k1sr+w )yu yn 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 5f,ytzhy0tx(a d40u:a t;fwno-n hd6 stages of meiosis. Which row correctly names eacd; ynhht:naoffdx64uw,5t- 0ta0 (yz h stage?

  The micrographs show four phases of meiosis I in a plant. In what order2ud0n;ms.pe- bj7e 9z/*bwh oo oq4 us do these pje p/*onz4sm; 7 hb29uqbwsd0oo. eu-hases occur?

Mitochondria are responsible for sue+o+m/ jo4e 1dck*q o l2fj0irpplying 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 ie moqdcrlj0/ 2++4fo*1ojeknuclear 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 difcn7p--o,a( 2u rx ppweferent stages of the cell cycle in four samples of lung tis (,cp-wup- rep o2x7nasue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at different ti0ornani0*qmag /61f ome points in the cell cycle. Which cyclin/CDK complex ac*06no01q / iagnrfomativates DNA replication machinery?

  Studies have shown that genes such as C+ ob4qe7n cmeb+:4b2lpxed k;yclin Dependent Kinase 3 (CDKN3) are highly overexpressed in cervicc+:eopend;7q4l b 2xb4+kmb eal 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 durinufi;oj ux*b smw*z+s(1 ra1(rg the cell cycle ?