79859310 Chapter 3 Heredity and Variation

8/12/2019 79859310 Chapter 3 Heredity and Variation

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Name: Class: .Chapter 3Exercise 1Learning Area: Heredity and VariationLearning O!ecti"e: #nderstanding cell di"ision

1. $he diagram elo% sho%s the process o& mitosis. 'ill in the lan(s %ith the %ords gi"en.

)eplication align n*cle*s memrane di"ide t%oshorten thic(en Chromatid same separate mo"e

Stages of mitosis Simple explanation

+ Chromosomes in the n*cle*s . ,

and are more "isile.

+ o& chromosomes occ*r.

+ Each strand o& chromosome is called a .

+ Chromosomes ......................... themsel"es in the centre o&the cell.

+ $he .. disappears.

+ Chromatids and to the opposite ends o& the cell.+ At the same time, the cell starts to ..

+ $he n*cle*s memrane &orms again.+ da*ghter cells are &ormed.+ Each progeny cell has the . n*mer o&chromosomes as the parent cell.

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-. Arrange the diagram in the correct se*ence:

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P Q R

W X

S

T U V


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Name: Class: .Chapter 3Exercise -Learning Area: Heredity and VariationLearning O!ecti"e: #nderstanding cell di"ision

1. $ic( /0 &or the correct statement and /2 &or the %rong statements ao*t mitosis.

/i $%o da*ghter cells are &ormed in mitosis. / /ii n mitosis, cytoplasm di"ides once. /

/iii 4itosis is important &or prod*cing ne% cells to replace the old or damaged cells. /

/i" 4itosis ca*se genetic "ariation. /

/" $he n*mer o& chromosomes in the da*ghter cell is hal& the n*mer o& chromosomes inthe parent cell. /

/"i $he parent cell and the da*ghter cell ha"e the same genetic content. /

/"ii Crossing5o"er does not ta(e place in mitosis. /

/"iii 4itosis occ*rs in somatic cells. /

-. $ic( /0 &or the correct statement and /2 &or the %rong statements ao*t meiosis.

/i 'o*r da*ghter cells are &ormed in meiosis. /

/ii n meiosis, the n*mer o& chromosomes in each da*ghter cell is the same as in the parentcell. /

/iii 4eiosis is important to organisms that reprod*ce sex*ally eca*se it prod*ces gametes. /

/i" 4eiosis ca*se genetic "ariation. /

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Score: ./27 x 100 = %


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3. Compare the processes o& meiosis and mitosis.

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MEIOSIS MITOSIS

SIMILAI!I"S

/i../ii../iii..

#I$$"

"&"S

..

N*mer o&di"isions .

..

N*mer o& da*ghtercells prod*ced ..

..

N*mer o&chromosomes in

da*ghter cell comparedto parent cell

.

.

Comination o&chromosomes in

da*ghter cell comparedto parent cell

..

.

Crossingo"er ..

..

6enetic"ariation ..


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Name: Class: ..Chapter 3Exercise 3Learning Area: Heredity and VariationLearning O!ecti"e: #nderstanding the principles and mechanism o& inheritance.

1. Complete the tale %ith the correct de&inition.

!"MS #"$II!I'S

7escries the characteristics traits o& an organism, incl*ding thephysical and the physiological

Organism %hich has t%o identical genes. Example: $$ or tt.

Composition o& gene in an organism

. $hread5li(e str*ct*re present in the n*cle*s o& a cell

..A gene %hich is %ea( and its e&&ect can e mas(ed y adominant gene

.An organism %hich has one dominant gene and one recessi"egene &or a certain characteristic. Example: 8 / 8 9 dominant gene&or lac( &*r , 9 recessi"e gene &or %hite &*r

#nit carrying a characteristic trait %hich exists in pairs in a

chromosome.

.Organism %hich has t%o di&&erent memers o& the same gene.Example: $t.

.Exchange o& genes %hen t%o chromatids cross gi"ing rise togenetic "ariation.

.. A gene %hich mas(s the e&&ect o& a %ea(er gene

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henotype Chromosomes Crossing o"er 7ominant gene 6ene 6enotype Hetero;ygote Homo;ygote Hyrid )ecessi"e gene

Score: ./2( x 100 = %


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-. A man %ith lac( hair /8 marries a %oman %ith londe hair /.Complete a schematic diagram to sho% the cross et%een a men %ho is hetero;ygo*s &or lac( hair

/8 and a %oman %ith londe hair /

8 : 6ene carrying lac( hair trait /dominant : 6ene carrying londe hair trait /recessi"e

'ather 4otherarent

4eiosis

6amete

'ertilisation

O&&spring genotype

O&&spring phenotype

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8


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8ased on the schematic diagram, determine the phenotype ratio o& their o&&spring

.

Name: . Class: Chapter 3Exercise

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79859310 Chapter 3 Heredity and Variation