chapter 3 heridity and variation student's copy

7/23/2019 Chapter 3 Heridity and Variation Student's Copy

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3.1 Understanding Cell Division

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CHAPTER 3 HEREDITY AND VARIATION

3.1 Understanding Cell Division

3.2 Understanding te Prin!i"les and #e!anis$ o% Ineritan!e

3.3 Understanding &e' Deter$ination and te O!!(rren!e o% T)ins

in H($an *eings

3.+ Understanding #(tation

3., Eval(ating te E%%e!ts o% -eneti! Resear! on H($an i%e

3./ Anal0sing Variation a$ong iving Tings3. Realising te Need to Adere to a Code o% Eti!s in -eneti!

Resear!



Cell Division All living organisms undergo growth and reproduction. All organisms are made up of ____________________. These ___________________ through ______________ and ___________________________ to new cells. There are two types of cell division,

_____________ and ____________.Cro$oso$e -enes and DNA

1. a) _______________ are the basic units of _________________ that determine the ____________________________________________

b) Genes carry _______________________ from one generation to another.! Genes are located in ___________________ known as __________________

__________________ 2. __________________ are located in the _______________, carrying information that

__________________________.3. ach chromosome is made up of long molecules known as __________________

___________________________.#itosis1. _____________ is a type of cell division which occurs in _________________ . ach

cell _______________________________________________________ !. "itosis only occurs in somatic cells but not in __________________________ #. The genetic content of the new cells is ____________ as that of the parent cell.$. The new cells have the _______________________________ as the parent cell.%. The importance of mitosis includes the following&

a) _____________________________________________________________ b) _____________________________________________________________ c) ______________________________________________________________

#eoisis1. __________ is the _____________________________ that produces _________ 2. Gametes contain ______________________________________________ found in

the _____________________________ #. ________________________ in reproductive cells i.e. in the ____________ and

___________ of animals and the ________________ and ____________ of plants.$. The importance of meiosis includes the following&

a) ______________________________________________________________ ______________________________________________________________

b) ______________________________________________________________ ______________________________________________________________

c) ______________________________________________________________ ______________________________________________________________

Pro!ess o% #itosis

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Proses o% #eiosis

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E'er!ise 3.2

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#. 'a) (tate four differences between cell division through mitosis and meiosis.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

$ "arks*

The cell division that takes place in the body parts of a student is shown above. +plainhow you would build a concept based on the information above. our e+planation shouldinclude the following.

'i) -dentify two common features

___________________________________________________________________

___________________________________________________________________ 'ii) uild an initial concept

___________________________________________________________________

___________________________________________________________________ 'iii) Give one e+ample of body part that undergoes this cell division and one e+ample of

body part that does not undergo this cell division. Give reason for each e+ample.

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________ 'iv) +plain the actual concept

_____________________________________________________________________

_____________________________________________________________________

/ "arks*

3.2 Understanding te Prin!i"les and #e!anis$ o% Ineritan!e

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ach __________________ has ________________, i.e. _____________________

from the father and _________________________ from the mother. Therefore, we

____________ half of our traits from our fathers and the other half from our mothers.

Do$inant -enes and Re!essive -enes

1. _______________________ are controlled by genes that e+ist in ____________

!. __________________ are genes that ________________________ when paired

with genes that are __________________________________

#. __________________ are weaker genes which __________________________

________________________ when paired with dominant genes.

$. The table below shows some of _____________________________________

in humans.

Do$inant traits Re!essive traits

Te #e!anis$ O% Ineritan!e

1. _______________________ '10!!100$) was an Austrian scientist known as the

_________________ because he discovered the _________________________

!. ___________ refers to the ______________________ found in the genes of an

organism.

#. ____________ refers to the ______________________ which can be seen in an

organism.

$. The genotype of an organism ___________________________________ of the

organism.

%. The following illustration shows the _____________________________________

Assume that 2T 2 represents the dominant gene 'tall) and

2t 2 represents the recessive gene 'dwarf)

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E'er!ise 3.2 4 A!tivit0

Aim & To study genetically inherited traits.

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"aterial & Two plastic tokens and labeling paper.

&e!tion A

1. 3abel both sides of token 1 with letter T to represent dominant gene.

!. 3abel both sides of token ! with letter2t2 to represent recessive gene.

#. Toss the both tokens and observe combination of the letter at token surface after

falling on table and record in table below.

$. 4epeat step # as much as !% times.

&e!tion *

4epeat simulation by marking both tokens with letter T while the other side is labeled 2t2.

5iscussion:

1. 6omplete the percentage for simulation A and .

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!. 7ill in the blank with the term dominant genes and recessive genes.

'a) 4ecessive genes& Genes which only show their effects in the absence of dominant

genes .

'b) 5ominant genes& Genes which show their characteristics that they control whenpaired with a dominant gene or recessive genes

#. The mechanism of trait inheritance in "andel2s e+periment can be illustrated by using

the 8unnet s9uare. 6omplete the 8unnet (9uare for (imulation A and (imulation B.

6ombination& Genotype Tt 1:: ;

-f <T= represents gene for tall and <t= represents for dwarf,

4atio of phenotype tall to dwarf is # & 1

6onclusion & The characteristics of offspring depend on parent genes.

3.3 Understanding &e' Deter$ination and te O!!(rren!e o% T)ins in

H($an *eings

&e' Deter$ination and O!!(rren!e o% T)ins

>ho determines the _________________ ? -s it the mother or the father? -f you are a ____________ you have inherited the ________________ from your father. -f you are a

__________ you have inherited the ________________ from your father.

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&e' Cro$oso$es

1. @uman ___________ have __________________ or _____________________

!. __________________ of the chromosomes are _______________ while two are

____________________ #. __________ have ________________________________________________ the

_________________ and the ________________________

$. ________________ only have one type of se+ chromosomes& the __________

_________ . The ______________________ can be written as _______________

%.The __________________________ can be written as _________________

&e' Deter$ination #e!anis$

The ________________________ is determined by the _____________________

5uring the _ ________________________ the ___________________ is

_____________ by a 5555555555555 carrying the ____________________ then a

______________ will be born. -f the __________ is ___________ by a ____________

carrying the _____________________ then a ____________ will be born.

The _________________ of getting a son or a daughter is the same that is _______

&e' Deter$ination and O!!(rren!e o% T)ins

There are two types of twins, ______________________________________________

Identi!al t)ins non6identi!al t)ins

1. A woman usually produces ________

in one ___________________ >henthe ovum is __________________ by

__________ a _________ is _______

1. The ovaries produce _________ at the

same time and the ova are _______by _____________________

!. The __________ are ___________

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!. The ygote then _______________

_____________________ which start

to develop.

#. oth ygotes develop and become

identi!al t)ins.

$. The characteristics of identical twins

include the following&

7a they ______________________

'b) they are of the ______________

7! they have the ______________

__________________________

_____ on the________ with

___________________.

#. oth ygotes develop to form two

embryos and grow into two

_____________________________

$. The characteristics of nonidentical

twins include the following&

'a) they have __________________

'b) their ________ can be the ______

or ______________

'c) they have ___________________

___________________________

E'er!ises 3.3

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12

1.

2.



3.+

Understanding #(tation

>e know that every human being has $/ chromosomes. 5uring the process of meiosis or

mitosis some chromosomes may _____________________ or there may be some changes

in the structure or number of chromosomes. This results in _______________

_________________________ or the ____________________ of the organism. 6hanges

that occur spontaneously in the structure of the genes or chromosomes of an organism are

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known as _________________ . There are two types of mutations, i.e.

__________________ and __________________________________

Cro$oso$e #(tation

1. 6hromosome mutation occurs ____________________________________________ ______________________________________________________

!. (tructural changes in chromosomes include&

'a

)

deletion

'b

)

inversion

'c) duplication

#. 6hanges in the number of chromosomes causes...

'a) __________________

- __________________________________

- __________________________________

mental defects and heart problems small sloping eye, protruding tongue, flat and

rounded face

also known as ______________________

'b) ____________________

-

-

-

-

'c) _____________________

-

-

-

-

-ene #(tation

1. Gene mutation refers to _______________________________________________

_______________________________________

!. Gene mutation is difficult to detect in the early stages because physical changes cannotbe seen clearly.

#. Gene mutation causes the following heredity traits.

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'a) 6olourblindness

'b) Albinism

'c) (ickle cell anaemia

'd) @aemophilia

$. "utations rarely occur naturally because the ______________________________ of

mutations can be __________________________________________________

7actors or agents which cause mutations are known as _______________

8a!tors tat Ca(se #(tation

1. "utagens that have been identified to cause mutations are ___________________

____________________

!. +amples of radioactive radiation _______________________________________

the higher the dose of radiation is. the higher the rate of mutation will be.

#. 6hemical mutagens include ___________________________________________

_________________________________________ These substances are capable of

changing the structure of genes and chromosomes.

Advantages and Disadvantages o% #(tations

1. "utations have caused changes in the structure of proteins in the chromosomes.

Therefore, the chromosomes may not function properly.

!. "utations can bring positive or negative effects to all living things.

#. The following are some positive effects of mutations&

a) ___________________________________

b) ___________________________________

c) ___________________________________ An e+ample of a new rice species is "41!#. This rice species is ______________

___________________ resulting in ____________________________________

$. The following are some negative effects of mutations&

a) ______________________________________

b) ______________________________________

c) ______________________________________

3., Eval(ating te E%%e!ts o% -eneti! Resear! on H($an i%e

___________________ is a ____________________ of genes, their functions, thecharacters that they control and the diseases brought by them. Genetic research has given

________________ to humans, in particular in the fields of ____________ and __________

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Contri9(tions o% -eneti! Resear!

1. -n "alaysia, agencies such as the

_____________________________________________ _________ '"A45-) have

conducted _____________________ to produce new varieties of paddy, chillies, papayasand durians which are of high 9uality.

!. The following are some successful genetic research results&

b) 8apaya ksotika "alaysia ____________________________________________

c) 8addy "40$ ____________________________________________________

d) 6hillies "6 11 dan 1! _______________________________________

e) 5urian 5!$, 5BB. 51:: _________________________________

-eneti! Resear! in #edi!ine1. -n medicine, genetic research can help humans ___________________________ and

_____________________________________ 2. __________________ has led to the ____________________________________

such as 5own2s syndrome, haemophilia and albinism, and the_________ of genetic

diseases.

3. The __________ is a ________________________________________________

_______

$. -eneti! engineering with

__________________________________________________

______________________________________________________________________

_____________________________________ This can be used to treat cancer,

haemophilia, thalassemia and other diseases.5. -ene tests to detect

______________________________________________________

____________________________________________________ /. ___________________________________ involves the ___________________________ _________________________________________________________________________ ___________________________________________________________________________

Genetic Resear! in Agri!(lt(re1. Genetic research in agriculture has brought a lot of benefits to us.

!. The following are the benefits of genetic research&a) 8lants which are _______________________________________________________ b) 8lants can ____________________________________________________________ c) The production of _____________ allows the production of 9uality plants. Cuality crops

with _____________________________________________________________ #. Genetic engineering carried out on animals has brought the following benefits.

a) Darious _______________________________ to prevent diseases such as hepatitis .-nterferon, growth hormones and enymes have also been produced.

b) Animal products of a better 9uality have been produced in _______________ such as _________________________________

c) _____________________ have been produced so as not to depend on animals sources.

The chart below shows the advantages and disadvantages of genetic research.

Advantages Disadvantages

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Cro"s and ivesto!: *reeding1. (elective breeding is _____________________________________________________

______________________________________________________________________

______________________________________________________________________ _

!. -n the process of breeding, _________________________________________________ __________________________ while the less beneficial traits are removed.

#. This can improve the 9uality of crops and livestock such as their sie, weight, yield andproduce crops which can ___________________________________

$. 6rops such as wheat, corn, rice, and barley have _______________________________

______________________________________________________________________ _

%. -n livestock selective cattle breeding has produced the high 9uality "afriwal cow whichcan produce a lot of milk and meat.

-eneti! Resear! and teir I$"a!t1. ____________________ ("7 is the result of genetic modification of plants or livestock

carried out by adding genes to the genotype to improve the 9uality yield productionresistance so that the plants can ____________________________________________

!. The high yield from the genetically modified crop may be needed __________________ _____________________ but the seeds and fruits may cause genetic pollution.

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#. Genetically modified foods containing genes which are ___________________________

___________________________________________________ >hen humans eat thesefoods, the bacteria in these foods will be difficult to be eliminated from the body becausethey are resistant to antibiotics.

3./ Anal0sing Variation a$ong iving Tings

Variation in H($ans1. Dariation refers to _______________________________________________________ __________________________________________________________ -ndividuals of

the same species in a population are indeed different from one another.!. These differences are caused by ___________________________________________ #. Dariation occurs during ___________________________________________________ ______________________________________________________________________

$. There are two types of variation& ____________________________________________ %. The differences between continuous and discontinuous variation are shown in the tablebelow.

Contin(o(s Variation As"e!t Dis!ontin(o(s Variation

De%inition

E'a$"le

Ca(ses

Can 9e

inerited

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Te res(lting

gra"

E'er!ises 3./ 4 &e!tion A

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20

1.



21

2.



3. Realising te Need to Adere to a Code o% Eti!s in -eneti! Resear!

Genetic research has made many contributions to the fields of _______________________

________________________ 4esearchers ______________________________________

so as not to give rise to various problems in scientific research. Although the techni9ues,procedures and skills used in the field of genetic research are very useful but they must _________________________________________________________________________ _

A9(se o% -eneti! Resear! is Treating H($ans

1. -f human cloning is allowed freely without control it will ___________________________

_______________________________________

!. Genetic research may be used for _____________________________ , but it should not

be used for destroying human lives.

#. "isuse of genetic skills in __________________________________________________

______________________________________________________________________ _

$. -f dangerous animals are produced through genetic engineering, the animals are likely ______________________________________________________________________

%. The process of cloning cells 'stem cells) may be unethical because after clonings, ______________________________________________________________________

______________________________________________________________________

Te I$"ortan!e o% Esta9lising and Co$"l0ing )it Eti!s in &!ienti%i! Resear! %orte *ene%it o% #an:ind

1. (cientific research should sincerely be carried out for the benefit of mankind and not forthe ___________________________________________________

!. To prevent abuse of genetic knowledge in scientific research, a code of ethics and moralvalues must be established and adhered to by all researchers.

#. The security and dignity of all living things must be respected in this code of ethics.

$. The code of ethics should indicate the following.

a) __________________________________________________________

b) The use of human cells in genetic research is for ___________________________

c) Genetically modified 'G") crops ______________________: -f they are dangerous,they must be destroyed and strictly prohibited.

%. All results of scientific research, whether successful or unsuccessful, must be ____________________________________________________

/. An _____________________________________________________ to monitor andensure that all parties abide by the rules and code of ethics for scientific research.

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E'er!ises 3. 4 &e!tion C

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chapter 3 heridity and variation student's copy

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