DNA o tai s the i st u io s fo g o th a d de elop e t i hu a s a d all li i g thi gs. Ou DNA is pa kaged i to h o oso es that o tai all of ou ge es.
I su ar
DNA sta ds for Deo ri oNu lei A id hi h is ade up of er lo g hai s of
he i al leters : Ade i e A , Gua i e G , Th i e T a d C tosi e C
DNA o tai s the i stru io s for our ge es
Ge es are the i stru io s for aki g protei s. Protei s do the ork ithi our
ells a d od
I hu a s, ost ge es are arra ged o hro oso es that are fou d i the u leus of ells.
THE GENETIC BOOK OF LIFE
I hu a s ge ei i fo aio , also k o as ou ge o e, a e des i ed as the Book of Life . This ook a e thought of as ei g ade up of t o olu es, ea h olu e of the ook is gi e to a pe so
o e of thei pa e ts Figure . .
Figure . : The hu a ge o e so ei es alled the
Book of Life
‘eadi g a pe so s ge ei ook of life Figure
. :
O e olu e of the ook is i he ited f o the othe a d the othe f o the fathe
Both olu es o tai hapte s ea h, e ui ale t to the pai s of h o oso es i hu a od ells that o tai ge ei i fo aio
The hapte s h o oso es a e ade up of a u e of e ipe pages odi g DNA o ge es a d i - et ee o - odi g pages of DNA
So e of the hapte s o tai a pages hile othe s o l ha e a fe . So e h o oso es a e la ge a d o tai a thousa ds of ge es a d o - odi g DNA
hile othe s a e u h s alle
Ge es a e se io s of DNA that ode fo the p otei s ou od eeds to fu io
I - et ee o - odi g se io s of DNA ha e a ious jo s, ot all of hi h e u de sta d
Ca eful e a i aio of the o ds ithi ge es sho s that all the o ds a e ade up of th ee lete s t iplets su h as AGT, GGT, ACT, CAA et .
The e a e fou lete s used i the ge ei ook. The a e A, T, C & G.
Just as eadi g the o ds o the page of a ook allo s a u de sta di g of the autho s essage, the od is a le to ead the t iplets i ge es to
Ou ells do t eed all the i st u io s all the i e. Pages of ou ge ei ook a e losed a d the eope ed he eeded. Ea h t pe of ell a ha e dife e t pa ts of the ge ei ook ope ed o shut e ause dife e t ells do dife e t jo s i ou od . Whi h ge es a e tu ed o o of a e i lue ed ou diet, he i al e posu e, e e ise, agei g a d essages f o othe ge es i the od .
Figure . : Ge ei ter i olog a d the Book of Life
DNA, GENES AND CH‘OMOSOMES IN THE BODY Ou odies a e ade up of illio s of ells. Ea h
ell o tai s a o plete op of a pe so 's ge ei ook of life.
Ch o oso es a e thought of as ei g ade up of st i gs of ge es DNA that odes fo p otei s ith o - odi g DNA et ee the . The h o oso es, i ludi g the ge es, a e ade up of a he i al su sta e alled DNA
Deo i oNu lei A id .
The h o oso es a e e lo g st a ds of DNA, oiled up like a all of st i g as sho i Figure
. .
Ch o oso es a e fou d i the u leus of all od ells e ept fo ed lood ells hi h ha e o
u leus a d the efo e do ot o tai
h o oso es.
A othe pla e i the ell he e DNA is fou d is i e s all o pa t e ts alled ito ho dria the e e g e t es of the ell that a e fou d s ate ed outside the u leus Figure . . The DNA i ito ho d ia is u h s alle a d has e litle o - odi g DNA.
Figure . : Chro oso es are like stri gs of ge es
Figure . : Diagra of a hu a ell
Chro oso es
The e a e h o oso es o tai ed i the u leus of od ells:
Of these, a e f o the othe 's egg a d a e f o the fathe 's spe
Whe the egg a d the spe joi togethe at the i e of o epio , the i st ell of the a is fo ed. This ell is opied to ake all of the ells of the a
The a s od ells o ha e
h o oso es, ade up of pai s, just like the pa e ts Figure . .
As e age a d g o , ou ells a e o i uall di idi g to fo e ells.
Othe DNA a iaio s a e asso iated ith a i eased ha e of a health o diio , fo e a ple dia etes o a e .
So e DNA a iaio s a ea the ge e
i st u io is i o e t so a fault p otei is ade o the o t ol s it h is ha ged. A a iaio i a ge e that eates a fault is alled a pathoge i
aria to utaio .
A DNA utaio a ause a p o le fo o e ell t pe ut ot a othe , si e ot all ells use all of the possi le p otei s.
Whe a DNA ha ge auses a fault p otei i ells that eed that p otei , it usuall esults i disease s pto s that a so ei es e
e og ised as a ge ei o diio .
Si e e ha e t o opies of ea h ge e, if o e op has a utaio a d the othe op is o ki g, the e a ot de elop a p o le s. We a e all o ith DNA utaio s a d so ei es these a e e ei ial o ause o p o le .
Whe a ge e a iaio is p ese t i egg o spe ells, it a e passed o to hild e i he ited . I othe ases, a e ge e a iaio a a ise i a egg o spe ell. This is alled a de ovo
ha ge.
The pe so a isi g f o that egg o spe ell ill e the i st i the fa il to ha e the DNA ha ge hi h a the e passed do to his o he hild e a d futu e ge e aio s.
