BIOLOGY Form 4 Chapter 5 Cell Division

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Chapter 5:Cell division 2014

5.1 Mitosis

The meaning and significance of mitosis Trial Kedah 2008 Trial selangor 2010

No Marking scheme Marks

(a) State three importance of mitosis to living organism 3mP1- mitosis increases the number of cells in organism (during growth process)P2- mitosis important for replacing dead / worn out / damaged cells.P3- Injured organ can be repairedP4- Some organism can regenerate lost parts of their bodies/ reproduction through MitosisP5- mitosis ensures that new cells that are formed will have exactly the same genetic information and characteristic as it parent cell.

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(b) Explain the important of the process (mitosis) to the living thing Essay & StructureF1-increase the number of cells(during growth process)P1-replacing dead cell/repair the damaged tissue/organP2-for growth/development in living organismF2-to produce genetically identical for daughter cellsP3-asexual reproduction (for unicellular organism)P4-maintain the chromosomal number (of daughter cells) any 2 F+P

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(c) Give two significant of mitosis P1-Mitosis allow a zygote to produce more cell in order to grow into a a multicellular organismP2-Mitotic cell division allows damaged cells to be repaired replaced and regeneratedP3-Mitosis is the basis for asexual reproduction in unicellular organism

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(d) Where do processes (mitosis) occur in an animal?/ Name the type of cell in human where mitosis take placeSomatic cells 1 1

(e) Give three example of cells named in (c)Muscle cellsConnective cells //blood cell/nervous cells

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Chromosomes and chromosomal number Selangor 2008


(a) Trial Johor 2011

4551/2 ®All Right Reserved SULIT

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State the chromosomal number of each daughter cell produced at the end of the division shown in diagram 312chromosomes

1 1

(b) Trial Johor 2011Based on your biological knowledge, give a reason for answerE2-During meiosis, the cell undergoes two nuclear division but the chromosomes/DNA of each chromosomes only replicates onceE3-each daughter cell receives half the number of chromosomes from the parent cellAny one E

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(c) The chromosome number in somatic cell of this organism is 12 state the chromosome number in each of the daughter cell in ZA-Six(chromosomes)R-(during meiosis) the daughter cell/ n receive half the daughter chromosome from the parent cells/2n//daughter cell haploid/n, daughter cell haploid/2n

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The cell cycle Trial Johor 2010 Trial Melaka 2009 Trial PP 2012


(a)

Name phase U and VPhase U: InterphasePhase V: Mitotic cell division/M phase 1

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(b) Phase U is further divided into three sub phases, X, Y and Z. Describe whatHappens at sub phases X, Y and Z.X : Cell synthesizes protein / new organelles formedY : DNA is synthesized / is replicated / 2 sister chromatids formedZ : Cell accumulates energy / synthesize energy / prepare forcell division

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(c) The number of chromosomes present in the nucleus of a somatic cell is 6.Diagram 2.2 shows a stage of cell division to produce gametes.Complete the diagram to show the chromosomes for a daughter cell produced


Phase V

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at the end of sub-phase Q 2

No. of chromosomes are haploid / 3 chromosomesTypes of chromosomes/ non homologousNew genetic combination any 2

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(d)

Name stage QInterphase 1 1

(e) Explain the importance of stage Q 2/State what happen in cell during U phaseF1-Replication of DNA occurs P1-to produce two genetically identical sister chromatidsF2-Synthesis ATP //accumulate energy

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Interphase

Interphase Marking scheme Marks

G1

Name phase P and state the process that occurs in this phase 2P1-G1/growth phase 1P2-synthesis of new protein /organelles occurs in the cell

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S phase Describe what happens at S phaseDNA is synthesized / is replicated / 2 sister chromatids formed 1 1

G2 Describe what happens at G2

Cell accumulates energy / synthesize energy / prepare for cell division 1 1


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The phase of mitosis in animal cells Trial Johor 2010 Trial Kedah 2008 Trial Pahang 2007

Trial PP 2012


(a) What is meant by MitosisP1-The division of cell nucleus forms two daughter cellP2-Each with same chromosome number and type of chromosome as the parent

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(b) State the type cell division involved in the cell cycle/ What type of nuclear division isMitosis/Mitotic cell division 1 1

(c) State one reason for your answer(refer to the question got answer there) e.g. mitosis occur in root cell /somatic cell P1-has 4 phase : prophase /metaphase/anaphase/telophaseP2-Only 2 daughter cells are formed / producedP3- Chromosome number in the daughter cells are same as parents

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(d) State two characteristic of daughter cell when parent cell undergoes P(mitosis)P1-The daughter cell has a similar number of chromosome to the parent cellP2-The daughter cell has similar genetic content to the parent cell

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(e)

In diagram 2 which chromosomes labeled A,B,C,D is homologous to chromosomes x E

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(f) Explain why root tip is used for preparing slide to shows this cell cycle2mF :Root tip is growing region/root tip has meristemP: the cell are actively dividing by mitosis

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(g)

Arrange the stages in Diagram 1 according to the correct sequence of events duringcell division.L, N, K and M 1 1

(h) State one organs where this type of cell division occursOvary//testis 1 1


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Phase Marking scheme Marks

Trial Kedah 2008 Name the stages labeled L/ What stage of nuclear division isProphase 1 1

State the characteristic of the of phase (prophase)P1-the chromosome become shorter and thickerP2-Each chromosome consists of two identical thread called chromatids

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Explain what happen at stage LP1-chromosomes thicken and shortenP2-the nucleolus and nuclear membrane disappearP3-The spindle fibres form

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Name the stages labeled N/ What stage of nuclear division isMetaphase 1 1

Explain the behavior of chromosomes during stages K and N./ Give a reason for your answerHomologous chromosomes line up / align at metaphase plate 1 1

Explain the chromosomal behavior in stage Q F-Q is metaphase E1-Chromosome align at metaphase plate/equator of the cellE2-spindle fibres fully formed E3-Attach to centromere of the chromosome Any 2

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For a plant cell where 2n=4, draw three separate diagram to show Metaphase, mitosis

D- Chromosome are line up on the spindle fibre 1 1

State the important of the chromosomal behavior in mentioned in (b) (i)P1-to ensure new cells produced are identical in chromosomal numberP2-to ensure the sister chromatids can separate /move to the opposite side

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Name the stages labeled K/ What stage of nuclear division isAnaphase 1 1

Explain the behavior of chromosomes during stages K and N.K : Sister chromatids separate and move towards the opposite poles 1 1


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Trial selango 2010

Name the stage YEarly telophase 1 1

Trial Kedah 2008 Name the stages labeled M / What stage of nuclear division isTelophase 1 1

Draw the chromosomes in daughter cell I and daughter cell II produced through mitosis

1 1

Draw a daughter cell of cell P after both cells have completed the cell division. in the boxes provided below 2

NOTE : Number of chromosome ,n = 2. 1The type (colour) of chromosomes 1

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State the number of daughter cells and number of chromosomes (i) Number of daughter cells 4

(ii) Number of chromosomes 2


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Cytokinesis


(a) Structure v is form during cytokenesis bur in animal cell, actin filament in cytoplasm contract to pull a ring of the plasma membrane inward forming a groove. Name the groove Cleavage furrow 1 1

(b) Explain the process (cytokinesis) occurs (plant cell)

F-Cytokinesis,which is the division of cytoplasm

P1-A cell plate is formed at the cell equator, that enlarged and eventually combines with the plasma membrane

P2-A new cell wall is formed

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1 2(c) Describe how cytokinesis occurs in plant and animal cells to produce two daughter cells.

F-process of cytoplasmic division

P1-begins before nucleus division is complete / during telophase to form two daughter cells

P2-in animal cells, actin filaments in the cytoplasm contracts

P3-to pull a ring of the plasma membrane inwards

P4-forming a groove called a cleavage furrow

P5-the cleavage furrow pinches at the equator of the cell and deepens progressively until two daughter cells are separated

P6-in plants cells, the membranous vesicles are formed along the equator between the two nuclei

P7-the vesicles fuse to form a cell plate

P8-the cell plate grows outwards until its edges fuse with the plasma membrane of the parents cell

P9-at the end of cytokinesis , cellulose fibres are produced by the cells to strengthen the new cell walls

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Cytokinesis takes place both in animal cell and plant cell

State two similarity and one different between the cytokinesis in animal cell and plant cell during mitosis

Similarity-F1-Both involved the division of the cytoplasm to produce two daughter cells

F2-Both produced two nuclei each with an identical chromosomes

Differences F1-Inanimal cells cytokinesis occurs ny formation of cleavage furrows/actin filament while in plant cell cytokinesis occurs by formation of cell plate

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The effect of uncontrolled mitosis Trial Melaka 2009 Trial Melaka 2008


(a) Diagram 2.1 shows the formation of tumor in lungs. Trial Kedah 2008Tumor is an abnormal mass of cells that can invade and destroy neighboring cells.

Explain the formation of tumor P1-When cell divides through uncontrolled mitosisP2- caused by severe disruptions to the mechanism that controlsthe cell cycle / give example // mutationP3- cancerous cells will be formedP4-Cancer cells compete with surrounding normal cells to obtainnutrients (and energy) for growthP5-Cancer cells will grow to form tumor, an abnormal mass ofcells // Cancerous cell undergoes mitosis to produce moreCancerous cells.P6- tumor can spread/expand and destroy neighboring cells. Any 3

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(b) Explain one activity that can cause tumor in lung. F1 : Expose to radiation/ x-ray/ exampleE1: Consist/ carry high level of energyE2: Destroy/disrupt the chromosome structureOr other suitable example

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(c) Cancer is genetic disease caused by uncontrolled mitosis. Name two chemical substances which cause a cancer P1-benzo-alpha pyreneP2-nicotine/any suitable

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(d) Name the process occurred and state a factor that causes itProcess deletion FactorF1-Rays: X-rays/gamma rays/UV rays/nuclear radiation /radioactive raysF2-chemical: benzene/formaldehyde/carbon tetrachloride/asbestos/mustard gas/ tar/pesticides

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(e) Explain how radiotherapy affected cell cycle in cancer treatment. F : Radiotherapy uses radiation / high energy raysE1 : destroy the nucleus of cancerous cellsE2 : cancerous cells die / cannot divide mitoticallyE3 : cell cycle stops

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(f) Ahmad has been exposed to gamma rays which results in the failure ofstructure R to be formedF1 : Structure X is the spindle fibreP2: If structure X fails to be formed, chromosomes cannot be pulled to the opposite poles.P3 : This causes the reproductive cells to have either extra or less number of chromosomes

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(g) Which process related to the formation of cancerous cells?

Mitosis1 1

(h) Explain how cancerous cells are formed in human body.

F: The cancer cells occur due to severe disruption of mechanism that controls the cell cycle.E: The cells divide without control and regulation to form cancerous cells// uncontrolled

division of cells forms cancerous cells

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(i) State two ways to prevent from being exposed to factor you have named in above P1-prevent form exposure to radioactive rays//use sun blockP2-Prevnet from taking food containing flavor /coloring /additive/ preservative

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Cloning Trial Johor 2010


(a) Define cloning P1-process of producing new genetically identical organism (refer to the question needed eg. Frog )P2-Through asexual reproductionP3-by stem/leaf cutting/layering/grafting/tissue culture

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(b) Explain the principles used in the cloning technique

P1 : Cloning is an asexual reproductive process of producing clones//does not involve gamete

P2 : A clone is a group of cells//organism//a population of organisms produced from a single ancestral cell.

P3 : A clones genetically identical

P4 : The technique can be used to produce high quality of organism / orchids/ oil palm / cocoa plants.

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(c) Based on Diagram 2, state the meaning of cloning.Cloning is a process to produce a new frog identical to its parent by mitosis 1 1

(d) Name the type of reproduction shown in Diagram 2.Give a reason for your answer. F-Asexual reproduction.P-The production of offspring is not involving the process of fertilization.

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(e) Describe why a mature intestinal cell is used in this experiment P1-Mature intestinal cells are able to undergo cell divisionP2-have all the necessary factors required for a complete cell division.

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(f) Based on Diagram 2, name the species of frog that will be produced at the endof the experimentSpecies Y 1 1

(g) Explain your answer in (g) (i).The nucleus of the frog is obtained from species Y. 1 1

(h) Describe a cloning technique in a production of dairy cow.F1-Somatic cells from the cow are extracted from the mammary glands/any somatic tissue and placed in culture medium(low nutrient)F2-An egg cell is extracted from the ovary of female cow/surrogate motherF3-The nucleus of egg cell is then sucked out/removedF4-The nucleus of somatic cell fused into the anucleated/ egg cell without nucleusF5-Stimulating them with electric pulseF6-The fused cell/ new cell divides repeatly by mitosis ( in the medium) to form an embryoF7-Th embryo is then implanted into surrogate mother/female cowF8-The embryo develop into a new individual and born as a cloned animal MAX 7

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Tissue culture


(a) Trial melaka2007 essayExplain how the plant being cloned Technique-tissue cultureP1-Small pieces of tissue of (explants) Taken form sterilized parent plantP2-The explants are then placed inside a test tube containing nutrient and growth hormonesP3-Plant divide by mitosis to form a callus(undifferentiated mass of tissues)Cells in the callus develop into embryo and later into plantletP5-The rooted plantlets are then transferred to the soil and kept in controlled environment until they grow into adult plantsP6-From one original plant , hundreds of genetically plants could be produced

Skill of application Q1-Must have P2&P4&P5

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(b) Diagram 6.3 shows an experiment to show the different between two ginger plants which is obtained from tissue culture and are planted in two different environment

Explain the role of tissue culture in this experiment 2F1-Plantlets from tissue culture have the same genetic material P1-This is to show /ensure/proof the different of the plants in Set A and Set B are caused by abiotic factors

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A piece tissue is taken from the parent plant

Plantlet is planted in the open ground (loam soil),spaced 30 cm apart and exposed to bright sunlight. the plantlet is watered on alternative days

Plantlet is planted in flower pots (sandy loam soil), spaced 10 cm apart and place under the tree shade. The plantlet is watered on alternate days

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(c)

Diagram 6.1 is a new variety of vegetable which has a great commercial valueDiagram 6.2 is the original parent of the plant Based on the above diagram and with your biological knowledge, explain how a farmer can propagate this variety to give a large scale of yield and at the same tome maintain its quantity 6P1-the technique used is issue culture techniqueP2-A piece of tissue / explants is taken from the young part of the parent plant eg. Root and cut into smaller piecesP3-The tissue are sterilized (with dilute sodium hypochlorite solution o prevent the growth of pathogens /bacteria/fungusP4-Each pieces of sterilized tissue ia placed onto a growth medium / gel containing nutrient (eg. Glucose, amino acids, mineral etc.) And hormone/ auxin with optimum pH levelP5-The apparatus and culture, medium used must be in sterile condition and keep under the suitable temperature/30oC-35oCP6-the tissue cells then divide repeatedly by mitosis to produce mass of undifferentiated cell/callusP7-After several weeks, callus differentiated to produce shoots and roots /organogenesisP8-once the roots grow , the plantlets/ little plant removed and transferred t the soil for growth into the adult plant P9-the plantlets produce this way are genetically identical and known as clonesP10-Therefore, all adults’ plans that develops from them fruits

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Advantage of cloning Trial Johor 2010 Trial Melaka 2009


(a) State one advantage of cloningAdvantageP1-large number of offspring can be produceP2-in a short timeP3-All the good characteristic of parent can be maintained in offspring

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(b) A farmer wants to breed a good variety of banana plants for commercial production. Suggest a suitable method to be used and explain how the method named can increase the crop yield. 3T : Tissue culture / CloningE1 : Large numbers of clones can be producedE2 : Within a short period of time / any time

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E3 : Clones inherited good characteristics/ resistance to diseases/ fast growth rate / large fruit / good genetic traits

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(c) A farmer wants to breed a good variety of pineapple plants for commercial productionSuggest a suitable method to be used which is involved the cell cycle in diagram 2.1cloningExplain how the method named can increase the crop yieldF-large numbers of clones can be producedE1-Within a short period of time / any time E2-clones inherited good characteristic

E3-example on good characteristic /resistance to disease /fast growth rate/large fruit ANY 2

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Disadvantage of cloning Trail Johor 2010 Trial Melaka 2009


(a) State one disadvantage of cloningDisadvantageP3-The offspring produced do not show any genetic variationP4-the offspring produced have same level of resistant to certain disease/pestsP5-All the offspring can be destroyed by a disease if they do now have the resistance

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(b) State a problem that can occur when using this method(cloning)Clones can be destroyed completely if they do not have the resistance to new diseases / pest.//No variation

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5.2 Meiosis

The significant of meiosis


(a) State the importance of processes P and Q.

P : To produce haploid gamete cell1 1

(b) Name two cells produced through meiosis in humansP1- ovum / egg cellP2- sperm / spermatids

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(c) Where do processes P (meiosis) occur in an animal?P: In reproductive organ// ovary// testis

The necessity for the production of haploid gametes the type of cells that undergoes meiosis


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(a) Trial Kedah 2012 Trial Pahang 2008 Trial PP 2012 Trial SBP 2012

Based on diagram 3.1, name the type of cell division / What type of nuclear division isMeiosis 1 1

(b) State your reason P1-The crossing over process occur during prophaseP2-The tetrad(sister chromatids) are formed

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(c)

(a) Name the structure labeled P, Q and membrane V. P : Centriole Q : Chromatid Membrane V : nuclear membrane

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(d) State the function of centromereHold two sister chromatid together

(e) What happen to the homologous chromosomes in (i)First cytoplasmic divisionThe homologous chromosomes separate in opposite direction(ii)Second cytoplasmic divisionThe chromatids separate into two to form a haploid form

The stage of meiosis I Trial Pahang 2008 Trial PP 2012 Trial SBP 2012 Trial selangor 2010


Prophase I

Trial Johor 2011

Name stage X/ Name phase XProphase I 1 1

Explain one important event that takes place using stage X(Prophase I) / Explain the chromosome behaviour during this phase F1-crossing overE1-An exchange of segment of DNA between non-sister chromatids of homologous chromosomesE2-which result in new combination of genes on a chromosomes AN Y 2

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Explain how the chromosome behavior contributes to the survival of animal


Membrane V

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Trial Kedah 2012Trial Selangor 2010

species P1-(crossing over) cause variation to occur among animal speciesP2-this will enhance the ability to adapt in different environment

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State the event that occur during stage X in diagram 3.1Crossing over 1 1

Explain one important event in stage X ( crossing over) P1-(the crossing over results) exchange of genetic material between non-sister chromatids of a bivalentP2-result in the new combination of alleles on a chromosome//cause variation

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Explain the process /chromosome behavior that occur in stage X Essay & StructureP1-Chromosome become shorter thickerP2-Homologous chromosome (come together) to form bivalentP3-through a process synapsis (sometimes no marks given)P4-Non sister chromatids exchange segment of DNA/genetic material//P5-through Crossing overP5-nucleus membrane disappearsP6- Spindle fibres form

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Metaphase I

Trial Johor 2011Trial Kedah 2012

Name stage /phase Y// Describe the behavior of chromosomes in X and YMetaphase I 1 1

Explain the chromosomal behavior during phase TP1-Homologous chromosomes are arranged in lineP2-at the metaphase plate//cell equator

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Explain events during metaphase I which contribute to variation in organism P1-Independent assortment of chromosomesP2-which are randomly arranged during metaphase I, produce different haploid gametes

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Draw the chromosome behaviour in stage Y L-Location of homologous chromosomesP-correct pairing

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For a plant cell where 2n=4, draw three separate diagram to show Metaphase I, meiosis, and

Cell wall-1homologous chromosome line uo at metaphase plate -1

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Anaphase I Describe the chromosomes behavior in stage R P1-Homologous chromosomesP2-move to opposite poles

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State one significance of the movement of the chromosomes in Cell B.


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When homologous chromosomes separate and move to opposites poles of Cell B, the chromosome number is halved.

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Explain the process that occurs in stageStage S: Telophase 1

P1- chromosome arrive at the poles

P2-spindle fibre disappears

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The stage or meiosis II Trial selangor 2010


Prophase II Draw the chromosome behavior in stages D and E in the space providedD :Chromosome are in prophase II 1 1

Anaphase II For a plant cell where 2n=4, draw three separate diagram to show Metaphase, meiosis in three different cells of the same plant. 1

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Telophase IITrial Kedah 2012Trial Melaka 2008Selangor 2008

State the occurrence at Telophase IIP1-four daughter cells formedP2-each daughter cell has two chromosome/haploid/n

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Trial Johor 2011


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Based on diagram 3, draw one of the cell daughter cells produced at the end of the division

Any one daughter cell with the correct combination of chromosomesCorrect drawing of chromosomes (number and combination)-D1Correct drawing of the cell (chromosomes are enclosed in a nuclear-D2

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Draw the possible chromatids that occur after the non disjunction in diagram 3.1

D:all correct the number of sister chromatids formedS:al correct the sequence of sister chromatids formed

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Draw a daughter cell of cell P and Q after both cells have completed the cellDivision. in the boxes provided below


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NOTE: Number of chromosome, 2n = 4. The type (color) of chromosomes

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The different between meiosis I and meiosis II


(a) Trial Johor 2011 Selangor 2008Based on diagram 3, state two different between the chromosomal behaviour in stage X and Y

Prophase I Metaphase I

D1-Homologous chromosomes are arranged randomly

Homologous chromosomes are arranged on the metaphase/equator plate

D2-The centromeres of the chromosomes are not hold by/attached to any spindle fibre.

The centromeres of chromosomes are hold by/attached to the spindle fibre

D3-(the homologous chromosomes paired and) crossing over take place

(the homologous chromosomes paired and) crossing over does not take place

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(b) Meiosis consists of two spate division; meiosis I and meiosis II .there are a lot of different between both division .Give two differences between prophase I and Prophase II

Prophase Prophase II

P1- There is no synapsis occurs Synapsis occurs between homologous chromosomes

P2- The chromosome do not crossing over Corssing over occurs between homologous chromosomes

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(c) State the different between meiosis I and meiosis II based on stage P, Q, R dan S.

Stage Meiosis I Meiosis II


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Prophase

P

Homologous chromosome come

together form bivalent through

synapsis.There is crossing over

chromosome locate at random no

crossing over

Metaphase

Q

Pairs of homologous chromosome

arrange at metaphase plate

chromosome arrange at metaphase

plate in a straight line

Anaphase

R

Homologous chromosome move

towards opposite poles

Chromatid move to opposite poles

Telophase Chromosome arrive at the poles Chromatid arrive at poles

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The differences and similarity between mitosis and meiosis Trial Melaka 2008 Kelantan 2008

No

Marking scheme

Marks

(a)

Trial Melaka 2008

Diagram 3.1 shows cell P and cell Q undergoes one of the stages for two types of

cell division

(a) (i) State the type of cell division shown in diagram 3.1

P : Meiosis

Q : Mitosis


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(b)


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According to the stage metaphase anaphase telophase in the cell division , differentiate the event happening during mitosis and meiosis

Stage Mitosis Meiosis

Metaphase D1-homologous chromosome are arranged in linear sequence /randomly at the mata phase plate

D2-homologous chromosome line up side by side at the metaphase plate

Anaphase D3-seperation f sister chromatids to the opposite pole// the centromere of each chromosome divide into two and allows sister chromtids to move to opposite pole

D4-seperation of homologous chromosomes to the opposite pole//sister chromatids still remain attached to each other during movement to the opposite pole

Telopase D5-two daughter nuclei are formedD6-Diploid (2n) number of chromosome is remainD6-daughter cells are genetically identical to each other and to the parent cell

D7-Four daughter nuclei are formed D8-diploid (2n) number of chromosomes is reduced to haploidD9-daughter cells are differ from the parent and from each other// variation occurs among daughter clls

1m each= max 4 marks

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(c)

State a function of the two cell divisions mentioned in (a)(i).

P : Meiosis is important in producing gametes

Q : Mitosis is important in replacing dead //

damaged cells // asexual reproduction //

increasing the number of cells (growth)

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State one differences between process P (meiosis) and Q (mitosis).

P1- crossing over occur in P but not in Q

P2-Process P produces 4 daughter cells whereas process Q produces 2 daughter cells.

P3-Daughter cells produced in P have variation whereas daughter cells produced in Q are identical to parent cell. Any two

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State the different processes U (Meiosis) and V (Mitosis) 2P1-Number of chromosome of daughter cells is halved in U compared to process V which has 4P2-crossing over occurred in process U but in V, the daughter cells are genetically identical P3-Daughter cells are variant in process U but in V , the daughter cells are genetically identical ANY 2

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2

(b)

Diagram: 4

Exp: 6 =

Max: 10

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Anaphase Anaphase I

chromatid move to the opposite pole homologous chromosome will move to the

opposite

Telophase Telophase I

Each daughter cell has the same number

of chromosome

Each daughter cell has half number

2 daughter cell that is 2n 4 daughter cell that is n

only one division two times division

does not cause genetic variation cause genetic variation

Explain the differences between mitosis and meiosis, by using appropriate diagram

Mitosis Meiosis

Prophase Prophase I

location of chromosome is at random homologous chromosome synapsis

no crossing over/ no chiasmata crossing over/ chiasmata

Metaphase Metaphase I

chromosome are arrange at the middle of cell

homologous chromosome are arrange at the middle of cell

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The important of meiotic cell division



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(a)

Explain why the sperm has 24 chromosomesP1-Homologous chromosome fail to separate equally(during anaphase I)P2-due to exposure to mutagen //any example of mutagen

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(b) Explain the genetic disease faced by offspring PP1-offspring has 47 chromosomeP2-Down syndromeP3-Chromosome number 21 has three chromosomeP4-Has short tongue/broad face//any suitable characteristic any 2

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(c) Trial melaka2007

Explain the importance of meiosis in maintaining the number of chromosomes in human in diagram 7.1 The important of cell division P1-Meiosis is the process of cell division that reduces the number of chromosomes in new cells //meiosis halved the number of chromosomes in the parent cellP2-Meiosis produce haploid reproductive cell or gameteP3-each gamete receive one chromosomes from every pairs of homologous chromosomes P4-the gamete contain only 23 chromosomes/haploid number of chromosomes P5-sexual reproduction involved the fusion of two haploid gamete during the fertilizationP6-this result in the formation of a diploid zygote with 46 chromosomes (similar number of chromosomes with parent)

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(d) Explain briefly how meiosis involved in genetic variation.F1 - crossing over during prophase I of meiosisE1 – non sister chromatids of homologous chromosome break at the chiasmaE2 – segments of the chromatids exchange placesE3 – segment of the marternal chromatids become attached to the paternal chromatidsE4 – new combinations of genes are produced on these chromatids F2 – independent assortment of chromosomeE1 – at metaphase I the homologous pairs of chromosomes arranged on the metaphase plate at randomE2 – each homologous pair of chromosomes is positioned relative to the poles of the cell independent of other pairs E3 – there is independent assortment of maternal and paternal chromosomes into daughter cellsE4 – result in a variety of gametes each with different combinations of maternal and paternal chromosome

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Juvenile (2n)

Mitosis differentiate and growth

Fusion to form zygote

Zygote (2n)

MeiosisSperm (n)

Meiosis

Adults (2n)

Haploid stages diploid stages

Mitosis, differentiation and growth

Egg (n)

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5.3 Appreciating the movement of chromosome during mitosis and meiosis Trial Kedah 2012


(a) Trial Johor 2011Explain what will happen in human if the chromosomes fail to separate during stage Y 2E1-One of the daughter cells produced might contain one extra chromosomes/one lesser chromosomeE2-During fertilization , if the cell with an extra /lesser chromosome fuses with an normal sperm the zygote shall contain one extra/47//one lesser/45 chromosomesE3-producing down/klinefelter’s//turner’s syndrome baby/offspring ANY two

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(b) Name the disorder that may occur when normal gamete fertilize with the no disjunction affecting human chromosomes 21that occur as in diagram 3..2Down syndrome 1 1

(c) This child is suffering from a type of genetic disorder/ he has a moon face , slated eye, a short neck and protruding tongue/ Uncontrolled meiosis leads to gamete produced both abnormal number of chromosomes .Name one disease caused by uncontrolled meiosis 1Down syndrome /turner syndrome /klinefelter

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(d) Based on the information above , name the type of genetic disorder shown by the childDown’s syndrome 1 1

(e) The ovum in diagram 22 carrier 24 chromosomes. Which chromosomes has an extra copy Chromosomes number 21Explain how the abnormal chromosomal number in the ovum can cause the genetic disorder mentioned in

P1-Chromosomes number 21 fails to separate during anaphase I//non –disjunction of chromosomes number 21 during anaphase IP2-When fertilization occurs, 24 chromosomes in the ovum will fused with 23 chromosomes in the sperm P3-produce zygote with 47 chromosomes // trisomy 21

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BIOLOGY Form 4 Chapter 5 Cell Division

Documents

cell division2014

type of cell

daughter cell haploid2n

daughter cell producedat

daughter cell n

stage of cell division

cell cycle trial johor

chromosomal number of