Intro to Metabolism

8/20/2019 Intro to Metabolism

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INTRODUCTION TO

METABOLISMDepartemen Fisiologi

Fakultas Kedokteran USU


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Metabolism

ALL CHEMICAL REACTIOS ECESSAR!

TO MAITAI LIFE Ana"oli# rea#tions $ s%nt&esis o'

larger mole#ules 'rom smaller ones

Cata"oli# rea#tions $ &%drol%sis o'#omple( stru#tures into simpler ones


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Metabolism

Cellular respiration $ 'ood 'uels are "roken

do)n )it&in #ells and some o' t&e energ%

is #aptured to produ#e AT*

En+%mes s&i't t&e &ig&,energ% p&osp&ate

groups o' AT* to ot&er mole#ulesT&ese p&osp&or%lated mole#ules are

a#ti-ated to per'orm #ellular 'un#tions


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AT* 'un#tions . /energ% #urren#%0 in meta"olism

gl%#ogen

glu#ose

La#ti# a#id 1 p%ru-i# a#id

A#et%l,CoA

Deaminated

Amino a#ids

Ot&er su"strate

CO23H2O

AT*

AM*

Energ% 'or .

45 S%nt&esis 6 gro)t&

25 Mus#ular #ontra#tion

75 8landular se#retion

95 er-e #ondu#tion

:5 A#ti-e a"sorption

;5Et#

*&osp&o#reatine

#reatine 3*O9


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Stages of Metabolism

Energy-containing nutrients are processed inthree major stages :

Digestion – breakdown of food; nutrientsare transported to tissues

Anabolism and formation of catabolicintermediates where nutrients are:Built into lipids proteins and glycogen

Broken down by catabolic pathways to pyru!icacid and acetyl "oA

#$idati!e breakdown – nutrients arecataboli%ed to carbon dio$ide water and

A&'


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Stages of

Metabolism

Figure 24!


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Absoprtive and Postabsorptive

States(etabolic controls e)uali%e bloodconcentrations of nutrients between twostates

Absorpti!e &he time during and shortly after nutrient

intake

'ostabsorpti!e &he time when the *+ tract is empty

Energy sources are supplied by the

breakdown of body reser!es


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Absorptive State ,“Fed State” : Anabolic Processes


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Absoprtive State

&he major metabolic thrust is anabolismand energy storage Amino acids become proteins

*lycerol and fatty acids are con!erted totriglycerides

*lucose is stored as glycogen

Dietary glucose is the major energy fuel

E$cess amino acids are deaminated andused for energy or stored as fat in the li!er


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,e!ersible pathways shift to anabolicprocesses


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"ri#$i%al "at&'a(s of t&e Absor%ti)e State

Figure 24*+b


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"ri#$i%al "at&'a(s of t&e Absor%ti)e State I# mus$le,

Ami#o a$i-s be$ome %rotei#

.lu$ose is $o#)erte- to gl($oge#

I# t&e li)er,

Ami#o a$i-s be$ome %rotei# or are -eami#ate- to

/eto a$i-s

.lu$ose is store- as gl($oge# or $o#)erte- to fat


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"ri#$i%al "at&'a(s of t&e Absor%ti)e State I# a-i%ose tissue,

.lu$ose a#- fats are $o#)erte- a#- store- as fat

All tissues use glu$ose to s(#t&esi0e AT"


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*osta"sorpti-e State<

/Fasted State0 . Cata"oli#


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Postabsorptive State,

&he major metabolic thrust is catabolismand replacement of fuels in the blood

'roteins are broken down to amino acids &riglycerides are turned into glycerol and

fatty acids

*lycogen becomes glucose


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*lucose is pro!ided by glycogenolysis andgluconeogenesis

atty acids and ketones are the majorenergy fuels

Amino acids are con!erted to glucose in the

li!er 'athways shift to maintain energy for

metabolism

.torage → glucose in blood → organs in

need


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"ri#$i%le "at&'a(s i# t&e "ostabsor%ti)e State

Figure 2421b


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"ri#$i%le "at&'a(s i# t&e

"ostabsor%ti)e State I# mus$le,

"rotei# is bro/e# -o'# to ami#o a$i-s

.l($oge# is $o#)erte- to AT" a#- %(ru)i$

a$i- la$ti$ a$i- i# a#aerobi$ states3

.lu$ose from t&e li)er is use- b( t&e #er)ous

s(stem to ge#erate AT"


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"ri#$i%le "at&'a(s i# t&e

"ostabsor%ti)e State

I# t&e li)er,

Ami#o a$i-s %(ru)i$ a$i- store- gl($oge# a#-

fat are $o#)erte- i#to glu$ose Fat is $o#)erte- i#to /eto a$i-s t&at are use- to

ma/e AT"

Fatt( a$i-s from a-i%ose tissue3 a#- /eto#e bo-ies from t&e li)er3 are use- i# most tissue

to ma/e AT"


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DOMINATION OF INSULIN & GLUCAGON IN

METABOLIC INTERACTION


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Regulation by other hormones

Adrenalin < Cortisol8ro)t& &ormone Testosterone T&%roid &ormones

=


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Intro to Metabolism

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