CH 3 Heredity
August 7, 2022 | Author: Anonymous | Category: N/A
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CHAPTER 3
HEREDITY AND VARIA VARIATION TION
1. CELL DIVISION 1. The nucleus of a cell c contains ontains many small-thread small-thread like structures called chromosomes. chromosomes. 2. Chromoso Chromosomes mes are built built from mol molecul ecules es called called Deoxyr Deoxyribon ibonucle ucleic ic acids. acids. (DNA) . !ach DNA mole molecules cules cont contains ains thousand thousands s of "e "enes. nes. #.
$enes exist in %airs. & &ne ne "en "ene e is inherited from th the e father and and one one from the mother. mother. N3C!3,
C!
C45&'&,&'!
DNA
$!N!
MITOSIS & MEIOSIS i. i i. iii. ii i. i*.. i* *.
'i 'ito tosi sis s oc occu curs rs in all all som somat atic ic cell cells s ex exce ce%t %t in sex sex cell cells. s. t %roduces 2 d au au"hter cells. 'e 'eio iosi sis s occ occur urs s in in s sex ex or or"a "ans ns to %r %rod oduc uce e "am "amet etes es.. &n &ne e %are %arent nt cell cell %rodu %roduce ces s # dau dau"h "hter ter ce cells lls.. The The nu numb mber er of chrom chromoso osome mes s is ha half lf of the number in %arent cell. Th Ther ere e ar are e 2 sta" sta"es es in me meio iosi sis s call called ed meio meiosi sis+ s++ + an and d meio meiosi sis s +. +.
THE STAGES IN MITOSIS 9arent cell The chromosomes shorten fatten and become clearly *isible
Chromosome re%lication into thread 7 like structures called chromatids.
Chromosomes ali"n themsel*es at the e8uatorial %late
,ister chromatids se%arate and mo*e to the o%%osite %oles Centromeres di*ide At the same time time cell be"ins be"ins to di*ide
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The ne6 nuclear membrane is formed T6o dau"hter cells are %roduced
2 The ne6 nuclear membrane are formed T6o dau"hter cells are %roduce
THE STAGES IN MEIOSIS 9arent cell
Chromosomes in nucleus shorten and fatten
5e%lication and crossin" o*er in chromatids occur
Chromosomes are arran"ed at e8uatorial %late
Chromatids se%arate and mo*e to o%%osite %oles
2 dau"hter cells formed
Chromosomes are arran"ed at the centre of the cell
Chromatids se%arate Cell be"in to s%lit
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!ach dau"hter cell contains half the number of chromosomes of the %arent cell 20
Compare and Contrast between Mitosis and Meiosis Mitosis 1 2 ,ame :e :es s n somatic cells To %roduce ne6 cells for "ro6th and to re%lace dama"ed cells
Cell division Pod!"t N!#$e o% "o#oso#es Geneti"'ll( identi"'l Pl'"e
Meiosis 2 # 4alf the number No n sex cells
P!)ose
$ametes
Di%%een"e $et+een #itosis 'nd #eiosis
Te I#)ot'n"e o% Mitosis 'nd Meiosis MITOSIS
1.'itosis form ne6 cells for "ro6th and to re%lace a dama"ed or died cells. 2.To ensure that the number of chromosomes in dau"hter cell is identical to that of the %arent cell. MEIOSIS
1. To %roduce "ametes 6ith half the number of chromosomes of the %arent cells. 2. t allo6s a s%ecies to maintain a constant number of chromosomes in the offs%rin". . To form *ariation bet6een s%ecies. *. INHERITANCE 1. nheritance is a %rocess of of %assin" " "enetic enetic information of characteristics characterist ics or traits from offs%rin". ,!, 111 elantan 2//0
%arents to
2;
2. $enes are di*ided into 2 dominant and recessi*e recessi*e.. . 4uman bein"s ha*e +# chromosomes. This means that 6e ha*e +2+ %airs of homolo"ous chromosomes. #. Combinatio Combination n of "enes it %ossesses is called called "enoty%e. . The characteristics that can be obser*ed or determined is called %henoty%e. . A dominant "ene is a "ene 6hich can sho6 the characteristics characteris tics it controls 6hen it %airs 6ith a recessi*e "en. 0. The recessi*e "ene only sho6s its characteristic characteristics s 6hen %aired 6ith another recessi*e "ene. C''"teisti"s
Do#in'nt "''"teisti"
Re"essive "''"teisti"
Ton"ue rollin"
Ability to roll the ton"ue
nability to roll the ton"ue
!ar-lobe
9resence of ear-lobe
Absence of ear-lobe
!ye colour
ation
C D
1/. Fhere does mitosis take %laceG A ,%erm C < Anther D
'eiosis Cross-o*er
&*ary ,omatic cells
11 11..
The dia"ram belo6 sho6s cell di*ision in an animal cell.
Fhich of the follo6in" follo6in" statement is correct about the cell di*isionG
12.
A < C D The
Cell di*ides once only =our identical cells are %roduced 4a*e the same kind of chromosomes ,imilar number of chromosomes chromosomes as %arent cell dia"ram dia"ram belo6 belo6 sho6s sho6s four four sta"es sta"es of meiosis.
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#
Fhich of the follo6in" follo6in" sho6s the correct se8uenceG
A <
1.
9 95, 5,I I 5,9I
C D
I,9 I, 95 5 I59,
Fhich of the follo6in" follo6in" statements is true about mitosisG A < C D
&ccurs in o*ary 9roduces "ametes 9roduces t6o dau"hter nuclei Chromosomes Chromosomes number is hal*ed
1#.
Fhat are dominant "enesG
A < C D
1.
Fhen can the recessi*e "enes be ex%ressed fullyG
A < C D
Cannot re%roduce themsel*es =ully ex%ress their characteristics characteristics Do not ex%ress their characteristics characteristics 'ulti%ly to %roduce more dau"hter cells
Dominant "enes are absent Dominant Dominant "enes are %resent man 6ho has the ability to roll his ton"ue has "ene Aa and marries ,iti 6ho has the same ability and has "ene Aa too. Fhat is the %ercenta"e of ha*in" ha*in" children that are not able to roll t ton"ueG
A <
1//K 0K
C D
/K 2K
21. The dia"ram dia"ram sho6s sex determination determination in human human
9arent
$amete
&ffs%rin"
##:
9
##
x
22:
I
##
22
22
##:
##:
Fhich of the follo6in" follo6in" chromosomes chromosomes are found in "amete 9 and offs%rin" I G
A < C D
9 22: 22 22: 22
I 22 ## ## ##:
22
Fhat is the chromosome in a normal human e"" cell cell G
A 22 < 2:
C 22: D 2
2. The dia"ram sho6s a first "eneration of cross breedin" of of t6o flo6ers 9arents red flo6er x 6hite flo6er ,!, 111 elantan 2//0
=irst $eneration
red flo6er
red flo6er
6hite flo6er
5 re%resents the dominant "enes for red flo6er
rFhat re%resent s the recessi*e for 6hite flo6er are the "enes for the "enes %arentsG
A < C D
'ale 55 55 5r rr
6hite flo6er
=emale 5r rr rr 5r
2#. =arid 6ho is able to roll his ton"ue has has the "enoty%e "enoty%e $". $". 4e married married ,ara 6ho is also able to roll her ton"ue and has the "enoty%e $". Fhat %ercenta"e of their children 6ill be able to roll their ton"uesG
A <
2K /K
C D
0K 1//K
2. Fhat determines determines the "ender "ender of a baby baby G
A < C D
Chromosomes in the o*um Ty%e of sex chromosomes in the s%erm Number of chromosomes in the s%erm Number of chromosomes in the o*um
2. Fhich of the follo6in" is the correct "enoty%eG "enoty%eG A <
'ale :
=emale :
C D
: :
: :
20. Fhat is the %ercenta"e %robability that a cou%le 6 6ill ill ha*e a baby "irlG
A 2K
< /K
C
0K
D 1//K
2;. Fhat is the chromosome chromosome number of a female foetusG
A 22 < 22:
C ## D ##:
2. 4o6 are identical t6ins formedG
A
T6o o*a fertili>ed by t6o different s%erms
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0
< C D
&ne o*um fertili>ed by t6o different s%erms T6o o*a fertili>ed by one s%erm before s%littin" into t6o &ne o*um fertili>ed by one s%erm before s%littin" into t6o
/. Fhy can non-identical non-identic al t6ins be of different sexes G A
They arise from the same same >y"ote
< C D
The s%erm fertili>es t6ot6o different o*ao*a T6o same different s%erms fertili>e different T6o different s%erms fertili>e the same o*um
1.
Fhich of the follo6in" describes ,iamese t6insG
A < C D
2.
T6o T6o children children are identical identical t6ins. t6ins. Fhich of the follo6in" follo6in" characteristic characteristic is not not common bet6een themG A <
.
y"otes . L 1 'arkM
2. Dia"ram sho6s sho6s the cross-breedi cross-breedin" n" of %ea %l %lants. ants. T re%resents the dominant "enes 6hile t re%resents the recessi*e "ene.
9arent
Ta Tallll %lant
x
,hort %lant
$enoty%e
Gamete
$enoty%e
Tt Tt
9henoty%e 9heno ty%e
Ta Tallll
Ta Tallll
Ta Tallll
Ta Tallll
DA$5A' (a)
Fhat is meant by "eneG
. L 1 'arkM (b) The abo*e %ea %ea %lant ha*e a %air %air of Tt "enes "enes 6hich sho6 the tall trait. !x%lain !x%lain this. . L 1 'arkM (c)
.
Com%lete the abo*e fi"ure by 6ritin" the %ossible "enoty%es of the %arent "amete and offs%rin" L2 'arksM The bar chart chart belo6 belo6 sho6s the result result of of a study in in a "rou% of students. students. Number2. of students
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##
;/ /
#/
2/
5oll ton"ue
able
unable
(a) Calculate the the %ercenta"e %ercenta"e of students 6ho are able able to roll roll their ton"ues. ton"ues.
. L 1 'arkM (b) i) Fhat are the the characteristics characteristics sho6n by the "ra%h abo*eG . . L 1 'arkM ii) Fhat is is the ty%e of *ariation in this situationG . L 1 'arkM (c) i) s ? the %resence or absence absence of ear lobes@ the same ty%e of *ariation as (b)iiG (b)iiG . L 1 'arkM
ii) $i*e reasons for your ans6er in (c) i. . . L1 'arkM
#
(a) Fhat does cell di*ision refers toG
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#
(b)
. . L 1 'arkM Fhat is meiosisG .
(c)
. L 1 'arkM Com%are the number of chromosomes in the dau"hter cells and in the %arent cell
(d)
L 1 'arkM ,tate t6o im%ortance of meiosis in or"anisms
i)
ii)
. .
L2 'arksM
. (a) Fhat is mutationG ,!, 111 elantan 2//0
#
L 1 'arkM
(b) ,tate t6o ty%es of mutation and ex%lain each of them
1.
.. ..
2.
... ... L2 'arksM
(c) $i*e t6o exam%les of conse8uences of each mutation named in (b)
1.
2. L2 'arksM
(d) i) Fhat is linefelter@s syndromeG . L 1 'arkM
ii) Fhat is is the cause of linefelter@s linefelter@s syndromeG
. L 1 'arkM
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#0
SECTION C
1.
No t6o indi*iduals are alike. !*ery %erson is uni8ue in himself
(a) !xamine the abo*e abo*e statement then su""est su""est a suitable suitable hy%othesis hy%othesis for an in*esti"ation in*esti"atio n to determine the 6ei"ht of forty students (boys and "irls) 6ho are all 1; years of a"e. L1 'arkM (b) Describe an an ex%eriment ex%eriment that could be carried in the classroom classroom to *erify *erify your hy%othesis. :our :our descri%tion should include the follo6in"B (i) Aim of the in*esti"ation L1 'arkM (ii) dentification dentification of *ariables L'arksM (iii) ist of a%%aratus L1 'arkM (i* Tabulation of data L1 'arkM (*) Conclusion Conclusion L1 'arkM
2. ,tudy the statement belo6
The len"th of lea*es is a ty%e of continuous *ariation
(a) ,u""est a suitable hy%othesis hy%othesis to in*esti"ate this statement. (b) Desi"n an ex%eriment ex%eriment to test your your hy%othesis thi this s statement (i) Aim of the ex%eriment (ii) dentification of *ariables *ariables (iii) ist of materials and a%%aratus (i*) 'ethod (*) 5ecordin" and analy>in" (*i) Conclusion
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L1 'arkM
L1 'arkM L2 'arksM L1 'arkM L 'arksM L1 'arkM L1 'arkM
#;
.
(a) ,tate four differences differences bet6een cell di*ision throu"h mitosis and meiosis. L# 'arksM
(b)
4air
,kin
Cell di*ision
i*er
5ed blood cell
The cell di*ision that takes %lace in the body %arts of a student is sho6n abo*e. !x%lain ho6 you 6ould build a conce%t based on the information abo*e. :our ex%lanation should include the follo6in". (i) dentify t6o common features (ii)
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