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Konu 1. Canlılığın incelemesi. Biyoloji Nedir?. Canlıları inceleyen bilim dalıdır Mikroskobik seviye Makroskobik seviye Küresel seviye Yapı,fonksiyon,büyüme , evrim,dağılım, taksonomi, filogeni, çeşitlilik. 1 Biyosfer. Fig ür 1. 4. Biyolojik Organizasyon Düzeyleri. - PowerPoint PPT Presentation
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Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
PowerPoint Lectures for Biology, Seventh Edition
Neil Campbell and Jane Reece
Lectures by Chris Romero
Konu 1Konu 1
Canlılığın incelemesi
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Biyoloji Nedir?
• Canlıları inceleyen bilim dalıdır
• Mikroskobik seviye
• Makroskobik seviye
• Küresel seviye
• Yapı,fonksiyon,büyüme,evrim,dağılım, taksonomi, filogeni, çeşitlilik
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Biyolojik Organizasyon Düzeyleri
• Biyosforden - Organizmaya
Figür 1.4
1 Biyosfer
1 Ekosistem
Komünite
Populasyon
Organizmaa
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
• Organdan - Hücre - Moleküle
Cell
8 Hücre
6 Organ
7 Doku
10 Moleküller
9 Organeller
50 µm
10 µm
1 µm
Atoms
Figür 1.4
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Hücreye yakın bir bakış
• Hücre
- yaşam için gerekli olan tüm aktivitelerin gerçekleştiği, biyolojik organizasyonun en küçük seviyesi
25 µmFigür 1.9
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Hücre’nin iki önemli formu
• Tüm hücreler
– Membran tarafından çevrilmiş
– Genetik bilgi olarak DNA
• İki form hücre
– Ökaryotik
– Prokaryotik
EUKARYOTIC CELL
Membrane
Cytoplasm
Organelles
Nucleus (contains DNA) 1 µm
PROKARYOTIC CELL
DNA
(no nucleus)Membrane
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Yaşamın üç Domain’i
• Yaşam en üst seviyede 3 domain’den oluşur
– Bakteri
– Archaea
– Eukarya
Protista Bitki Mantar Hayvan
Prokaryotik canlılar
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
3 domain
Figür 1.15
100 µm
0.5 µm
4 µmBacteria are the most diverse and widespread prokaryotes and are now divided among multiple kingdoms. Each of the rod-shapedstructures in this photo is a bacterial cell.
Protists (multiple kingdoms)are unicellular eukaryotes and their relatively simple multicellular relatives.Pictured here is an assortment of protists inhabiting pond water. Scientists are currently debating how to split the protistsinto several kingdoms that better represent evolution and diversity.
Kingdom Plantae consists of multicellula eukaryotes that carry out photosynthesis, the conversion of light energy to food.
Many of the prokaryotes known as archaea live in Earth‘s extreme environments, such as salty lakes and boiling hot springs. Domain Archaea includes multiple kingdoms. The photoshows a colony composed of many cells.
Kindom Fungi is defined in part by thenutritional mode of its members, suchas this mushroom, which absorb nutrientsafter decomposing organic material.
Kindom Animalia consists of multicellular eukaryotes thatingest other organisms.
DOMAIN ARCHAEA
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
PowerPoint Lectures for Biology, Seventh Edition
Neil Campbell and Jane Reece
Lectures by Chris Romero
Konu 2Konu 2
Canlıların kimyasal içeriği
• Element• Bileşik
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Element
• Kimyasal tepkimelerle başka bileşiklere parçalanamayan maddelerdir
• 92 element
• Atomlar’dan oluşmuştur
• carbon C, hydrogen H, oxygen O ve nitrogen N bir organizmanın 96% oluşturan zorunlu elementlerdir
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Diğer elementler
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
İz element
• Çok az miktarda olsa da organizmaın ihtiyaç duyduğu element
• Fe ve Zn
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Bileşik
• Belirli bir oranda bir araya gelen iki veya daha fazla element içeren madde
• NaCl (1:1), H2O (2:1)
• Elemetlerinden farklı karakterlere sahip
Sodium Chloride Sodium Chloride
+
Sodyum Klor Sodyum klörürFigür 2.3
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Atom
• Maddenin en küçük parçası
• Her elementin belirli atom çeşidi var
NötronProtonElektron
?
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Kimyasal Bağ
• Kovalent
• İyonik
• Zayıf Kimyasal Bağlar
• Hidrojen bağı
kuvvetli
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Kovalent Bağ
Name(molecularformula)
Electron-shell
diagram
Structuralformula
Space-fillingmodel
(c)
Methane (CH4). Four hydrogen atoms can satisfy the valence ofone carbonatom, formingmethane.
Water (H2O). Two hydrogenatoms and one oxygen atom arejoined by covalent bonds to produce a molecule of water.
(d)
HO
H
H H
H
H
C
Figür 2.12
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Iyonik Bağ
• Atomlar arasında elektron transferi
Cl–
Chloride ion(an anion)
–
The lone valence electron of a sodiumatom is transferred to join the 7 valenceelectrons of a chlorine atom.
1 Each resulting ion has a completedvalence shell. An ionic bond can formbetween the oppositely charged ions.
2
Na NaCl Cl
+
NaSodium atom
(an unchargedatom)
ClChlorine atom(an uncharged
atom)
Na+
Sodium on(a cation)
Sodium chloride (NaCl)
Figür 2.15
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Hidrojen Bağı (Zayıf)
Water(H2O)
Ammonia(NH3)
OH
H
+
–
N
HH H
A hydrogenbond results from the attraction between thepartial positive charge on the hydrogen atom of water and the partial negative charge on the nitrogen atom of ammonia.+ +
Figür 2.16
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
PowerPoint Lectures for Biology, Seventh Edition
Neil Campbell and Jane Reece
Lectures by Chris Romero
Konu 3Konu 3
Biyolojik Moleküllerin yapısı
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings20
Makromoleküller
– Küçük moleküllerden oluşan büyük moleküller
– Yapısal olarak kompleks
– Kovalent bağ
Figür 5.1
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings21
Makromoleküller
•Çoğu Makromolekül monomerlerden oluşmuş polimerlerdir
• Dört önemli organik molekül (ilk 3 polimerdir)
– Karbohidrat
– Protein
– Nucleik asid
– Lipid
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings22
• Polimer
– Monomer olarak bilinen ve tekrarlanan birimlerin bir araya gelmesi
– Her monomer kendine özgü polimeri oluşturur
– Örn: amino acidler proteinlerin monomeri
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings23
Polimerlerin oluşumu ve parçalanması
• Monomerler dehidrasyon tepkimesi ile daha büyük molekülleri oluşturur
• H2O çıkışı
• Hidroksil (-OH) ve Hidrojen (-H) grubu
Dehydration reaction in the synthesis of a polymer
HO H1 2 3 HO
HO H1 2 3 4
H
H2O
Short polymer Unlinked monomer
Longer polymer
Dehydration removes a watermolecule, forming a new bond
Figür 5.2a
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings24
Polimerlerin oluşumu ve parçalanması
• Polimerler monomerlerine ortama H2O ilavesi ile (Hidroliz) parçalanabilir
• -H bir monomere, -OH diğer monomere
Hydrolysis of a polymer
HO 1 2 3 H
HO H1 2 3 4
H2O
HHO
Hydrolysis adds a watermolecule, breaking a bond
Figür 5.2b
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings25
Karbohidratlar
• Şeker ve bunların polimerlerini (nişasta, selüloz) içerir
• Monosakkaritler en basit şeker
• İki mososakkarit+kovalent bağ= Disakkarit
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings26
• Örnek monosakkaritlerTriose sugars
(C3H6O3)Pentose sugars
(C5H10O5)Hexose sugars
(C6H12O6)
H C OH
H C OH
H C OH
H C OH
H C OH
H C OH
HO C H
H C OH
H C OH
H C OH
H C OH
HO C H
HO C H
H C OH
H C OH
H C OH
H C OH
H C OH
H C OH
H C OH
H C OH
H C OH
C OC O
H C OH
H C OH
H C OH
HO C H
H C OH
C O
H
H
H
H H H
H
H H H H
H
H H
C C C COOOO
Ald
oses
Glyceraldehyde
RiboseGlucose Galactose
Dihydroxyacetone
Ribulose
Keto
ses
FructoseFigür5.3
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings27
• Monosakkaritler
– Doğrusal (linear)
– Halkasal (ring)H
H C OH
HO C H
H C OH
H C OH
H C
O
C
H
1
2
3
4
5
6
H
OH
4C
6CH2OH 6CH2OH
5C
HOH
C
H OH
H
2 C
1C
H
O
H
OH
4C
5C
3 C
H
HOH
OH
H
2C
1 C
OH
H
CH2OH
H
H
OHHO
H
OH
OH
H5
3 2
4
(a) Linear and ring forms. Chemical equilibrium between the linear and ring structures greatly favors the formation of rings. To form the glucose ring,
carbon 1 bonds to the oxygen attached to carbon 5.
OH3
O H OO
6
1
Figür 5.4
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings28
• Disakkaritler
– İki monosakkarit
– Glikozidik bağ
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings29
Dehydration reaction in the synthesis of
maltose. The bonding of two glucose units forms maltose. The glycosidic link joins
the number 1 carbon of one glucose to the
number 4 carbon of the second glucose. Joining the glucose
monomers in a different way would result in a different
disaccharide.
Dehydration reaction in the synthesis of sucrose. Sucrose is
a disaccharide formed from glucose and fructose.
Notice that fructose,though a hexose like
glucose, forms a five-sided ring.
(a)
(b)
H
HO
H
HOH H
OH
O H
OH
CH2OH
H
HO
H
HOH
H
OH
O H
OH
CH2OH
H
O
H
HOH H
OH
O H
OH
CH2OH
H
H2O
H2O
H
H
O
H
HOH
OH
O H
CH2OH
CH2OH HO
OHH
CH2OH
HOH
H
H
HO
OHH
CH2OH
HOH H
O
O H
OHH
CH2OH
HOH H
O
HOH
CH2OH
H HO
O
CH2OH
H
H
OH
O
O
1 2
1 41– 4
glycosidiclinkage
1–2glycosidic
linkage
Glucose
Glucose Glucose
Fructose
Maltose
Sucrose
OH
H
H
Figür 5.5
Maltoz &Sükroz
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings30
• Polisakkaritler
– Şeker polimeri
– Organizmada çeşitli rol
• Depo polisakkaritleri
• Yapısal polisakkaritler
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings31
Depo polisakkaritleri
• Nişasta
– Glikoz monomerlerinden oluşan polimer
– Bitkilerde glikozun depo edilmesini sağlar
– Plastid
Chloroplast Starch
Amylose Amylopectin
1 m
(a) Starch: a plant polysaccharideFigure 5.6
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings32
• Glikojen
– Glikoz monomerlerini içerir
– Hayvanlarda ana depo maddesi, dallanma Mitochondria Giycogen
granules
0.5 m
(b) Glycogen: an animal polysaccharide
Glycogen
Figure 5.6
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings33
Yapısal Polisakkaritler
• Selüloz
– Glikoz polimeri
– Bitki hücreleri
– Nişastadan farkı?? (-OH)
– Doğrusal, dallanmaz
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings34
Selüloz&Nişasta
(c) Cellulose: 1– 4 linkage of glucose monomers
H O
O
CH2OH
HOH H
H
OH
OHH
H
HO
4
C
C
C
C
C
C
H
H
H
HO
OH
H
OH
OH
OH
H
O
CH2OH
HH
H
OH
OHH
H
HO
4 OH
CH2OHO
OH
OH
HO41
O
CH2OH
O
OH
OH
O
CH2OH
O
OH
OH
CH2OH
O
OH
OH
O O
CH2OHO
OH
OH
HO4
O1
OH
O
OH OHO
CH2OHO
OH
O OH
O
OH
OH
(a) and glucose ring structures
(b) Starch: 1– 4 linkage of glucose monomers
1
glucose glucose
CH2OH CH2OH
1 4 41 1
Figure 5.7 A–C
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings35
Plant cells
0.5 m
Cell walls
Cellulose microfibrils in a plant cell wall
Microfibril
CH2OH
CH2OH
OH
OH
OO
OHO
CH2OHO
OOH
OCH2OH OH
OH OHO
O
CH2OH
OO
OH
CH2OH
OO
OH
O
O
CH2OHOH
CH2OHOH
OOH OH OH OH
O
OH OH
CH2OH
CH2OH
OHO
OH CH2OH
OO
OH CH2OH
OH
Glucose monomer
O
O
O
O
O
O
Parallel cellulose molecules areheld together by hydrogenbonds between hydroxyl
groups attached to carbonatoms 3 and 6.
About 80 cellulosemolecules associate
to form a microfibril, themain architectural unitof the plant cell wall.
A cellulose moleculeis an unbranched glucose polymer.
OH
OH
O
OOH
Cellulosemolecules
Figure 5.8
Bitki hücre duvarında dayanıklılığı sağlayan yapı
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings36
• Selülozu sindirmek zordur
– İnek’lerin midelerinde bu işlemi kolaylaştıracak mikroplar bulunur
Figure 5.9
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings37
• Kitin (diğer önemli polisakkarit)
– Eklem bacaklıların dış iskeleti
– Ameliyat ipi
– Azot yan grubu
(a) The structure of the chitin monomer.
O
CH2OH
OHHH OH
H
NH
CCH3
O
H
H
(b) Chitin forms the exoskeleton of arthropods. This cicada is molting, shedding its old exoskeleton and emergingin adult form.
(c) Chitin is used to make a strong and flexible surgical
thread that decomposes after the wound or incision heals.
OH
Figure 5.9 A–C
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings38
Lipidler
• Hidrofobik
• Polimer içermeyen büyük biyolojik molekül
• Yağ
• Fosfolipit
• Steroid
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings39
Yağlar
– İki tip küçük molekül, bir gliserol ve genelde üç yağ asidi
– Ester bağı
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings40
• Doymuş yağ asitleri
– mümkün olan maksimum hidrojen
– çift bağ yok
(a) Saturated fat and fatty acid
Stearic acid
Figure 5.11
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings41
• Doymamış yağ asidi
– Bir veya birden fazla çift bağ
– Çift bağ olan herbir karbonda bir hidrojen eksik
(b) Unsaturated fat and fatty acidcis double bondcauses bending
Oleic acid
Figure 5.11
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings42
• Fosfolipidler
– Sadece iki yağ asidi
– Üçüncü yağ asidi yerine fosfat bulunur
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings43
• Fosfolipitlerin yapısı
– Sulu ortamda oluşan hücre membranındaki çift tabakalı yapı
Hydrophilichead
WATER
WATER
Hydrophobictail
Figür 5.13
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings44
Steroidler
• Birbirleriyle kaynaşmış dört adet halka içeren karbon iskeleti
– Kolestrol
– Eşey hormonları
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings45
• Kolestrol
– hücre membranında bulunur
– bazı hormonların öncüsüdür
HO
CH3
CH3
H3C CH3
CH3
Figür 5.14
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings46
Proteinler
• Proteinler çeşitli fonksiyonlara neden olan farklı yapılara sahiptir
• Enzim
• Hücrelerde çeşitli görev
• Monomer; amino asit
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings47
• Protein görevlerine genel bakış
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings48
• Enzimler
– Katalist (kimysal reaksiyonları hızlandırıcı) olarak görev yapan proteinler
Substrate(sucrose)
Enzyme (sucrase)
Glucose
OH
H O
H2O
Fructose
3 Substrate is convertedto products.
1 Active site is available for a molecule of substrate, the
reactant on which the enzyme acts.
Substrate binds toenzyme.
22
4 Products are released.Figure 5.15
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings49
Polipeptid
• Polipeptid
– a.a oluşmuş polimer (zincir)
• protein
– Bir veya birden fazla polipeptid içerebilir
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings50
• Amino acid
– Karboksil (C terminal) ve amino (N terminal) grupları içeren organik molekül
– R grup (yan zincir) farklı a.a.’leri oluşturur
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings51
Yirmi Amino Asid
• 20 different amino acids make up proteins
O
O–
H
H3N+ C C
O
O–
H
CH3
H3N+ C
H
C
O
O–
CH3 CH3
CH3
C C
O
O–
H
H3N+
CH
CH3
CH2
C
H
H3N+
CH3CH3
CH2
CH
C
H
H3N+
C
CH3
CH2
CH2
CH3N+
H
C
O
O–
CH2
CH3N+
H
C
O
O–
CH2
NH
H
C
O
O–
H3N+ C
CH2
H2C
H2N C
CH2
H
C
Nonpolar
Glycine (Gly) Alanine (Ala) Valine (Val) Leucine (Leu) Isoleucine (Ile)
Methionine (Met) Phenylalanine (Phe)
C
O
O–
Tryptophan (Trp) Proline (Pro)
H3C
Figure 5.16
S
O
O–
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings52
O–
OH
CH2
C C
H
H3N+
O
O–
H3N+
OH CH3
CH
C C
HO–
O
SH
CH2
C
H
H3N+ C
O
O–
H3N+
C C
CH2
OH
H H H
H3N+
NH2
CH2
OC
C CO
O–
NH2 O
C
CH2
CH2
C CH3N
+
O
O–
O
Polar
Electricallycharged
–O O
C
CH2
C CH3N
+
H
O
O–
O– O
C
CH2
C CH3N
+
H
O
O–
CH2
CH2
CH2
CH2
NH3+
CH2
C CH3N
+
H
O
O–
NH2
C NH2+
CH2
CH2
CH2
C CH3N
+
H
O
O–
CH2
NH+
NHCH2
C CH3N
+
H
O
O–
Serine (Ser) Threonine (Thr)Cysteine
(Cys)Tyrosine
(Tyr)Asparagine
(Asn)Glutamine
(Gln)
Acidic Basic
Aspartic acid (Asp)
Glutamic acid (Glu)
Lysine (Lys) Arginine (Arg) Histidine (His)
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings53
Amino Asid Polimerleri
• Amino asidler
– Peptid bağlarıyla bağlanırlar
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings54
Protein konformasyonu ve Fonksiyonu
• Bir protein’in spesifik konformasyonu (şekil) onun ne işe yarayacığına (fonksiyon) karar verir
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings55
Protein yapısındaki dört seviye
• Birincil yapı
(Primary structure)
– a.a.’lerin polipeptid yapısında oluşturduğu eşsiz (spesifik) düzenlenme
Figure 5.20–
Amino acid
subunits
+H3NAmino
end
oCarboxyl end
oc
GlyProThrGlyThr
Gly
GluSeuLysCysProLeu
MetVal
Lys
ValLeu
AspAlaValArgGly
SerPro
Ala
Gly
lle
SerProPheHisGluHis
Ala
GluValValPheThrAla
Asn
AspSer
GlyProArg
ArgTyrThr
lleAla
Ala
Leu
LeuSer
ProTyrSerTyrSerThr
Thr
Ala
ValVal
ThrAsnProLysGlu
ThrLys
SerTyrTrpLysAlaLeu
GluLleAsp
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings56
O C helix
pleated sheetAmino acid
subunitsNCH
C
O
C N
H
CO H
R
C NH
C
O H
C
R
N
HH
R C
O
R
C
H
NH
C
O H
NCO
R
C
H
NH
H
C
R
C
O
C
O
C
NH
H
R
C
C
ON
HH
C
R
C
O
NH
R
C
H C
ON
HH
C
R
C
O
NH
R
C
H C
ON
HH
C
R
C
O
N H
H C R
N HO
O C N
C
RC
H O
CHR
N HO C
RC
H
N H
O CH C R
N H
CC
N
R
H
O C
H C R
N H
O C
RC
H
H
C
RN
H
CO
C
NH
R
C
H C
O
N
H
C
• İkincil yapı (Secondary structure)
– Polipeptid’de tekrar eden katlanma yada kıvrılmalar
– helix ve pilili tabaka
H H
Figure 5.20
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings57
• Üçüncül yapı (Tertiary structure)
– Polipeptidin üç boyutlu yapısı
– a.a’lerin ve R gruplarının etkileşimi
CH2CH
OH
O
CHO
CH2
CH2 NH3+ C-O CH2
O
CH2SSCH2
CH
CH3
CH3
H3C
H3C
Hydrophobic interactions
and van der Waals
interactions Polypeptide
backbone
Hyrdogenbond
Ionic bond
CH2
Disulfide bridge
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings58
• Dördüncül yapı (Quaternary structure)
– Proteini oluşturan iki veya daha fazla polipeptid’in oluşturduğu yapı
Polypeptide
chain
Collagen
Chains
ChainsHemoglobin
IronHeme
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings59
Protein yapısına genel bakış
+H3NAmino end
Amino acidsubunits
helix
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings60
Orak-hücre hastalığı: proteinin birincil yapısında olan basit bir değişim
• Orak-hücre hastalığı
– Hemoglabin proteininde bulunan bir a.a’in değişimi
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Fibers of abnormal
hemoglobin deform cell into
sickle shape.
Primary structure
Secondaryand tertiary
structures
Quaternary structure
Function
Red bloodcell shape
Hemoglobin A
Molecules donot associate
with oneanother, each
carries oxygen.Normal cells
arefull of
individualhemoglobinmolecules,
eachcarrying oxygen
10 m 10 m
Primary structure
Secondaryand tertiary
structures
Quaternary structure
Function
Red bloodcell shape
Hemoglobin SMolecules
interact with one another tocrystallize into
a fiber, capacity to
carry oxygen is greatly
reduced.
subunit subunit
1 2 3 4 5 6 7 3 4 5 6 721
Normal hemoglobin
Sickle-cell hemoglobin
. . .. . .
Figure 5.21
Exposed hydrophobic
region
Val ThrHis Leu Pro Glul Glu Val His Leu Thr Pro Val Glu
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Protein konformasyunu etkileyen faktörler
• Proteinin bulunduğu fiziksel ve kimyasal çevrenin durumu
• sıcaklık, pH, tuz (denatürasyon)
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• Denatürasyon; potein’in doğal yapısını kaybetmesi
Denaturation
Renaturation
Denatured protein
Normal protein
Figure 5.22
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Protein-katlanma Problemleri
• Çoğu proteinler
– Kararlı yapıya ulaşmadan önce birkaç ara basamaktan geçerler
– Denatüre olmuş protein aktif olarak görev yapamaz
– Sıcaklık ve pH’ta ani değişimler denatürasyona sebeb olur
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Şaperoninler
Proteinlerin düzgün katlanması için gerekli olan protein molekülleri
Hollowcylinder
Cap
Chaperonin(fully assembled)
Steps of ChaperoninAction:
An unfolded poly- peptide enters the
cylinder from one end.
The cap attaches, causing the cylinder to
change shape insuch a way that it creates a hydrophilic environment for
the folding of the polypeptide.
The cap comesoff, and the
properlyfolded protein is
released.
Correctlyfolded
proteinPolypeptide
2
1
3
Figure 5.23
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Nucleik Asid
• Nucleik acidler kalıtımsal bilgiyi taşır ve transfer eder
• Gen
– Kalıtımsal yapının ana ünitesi
– Polipeptidlerdeki a.a’leri belirler
– Nükleik asitlerden oluşur
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Nukleik Asidlerin rolü
• İki nükleik asit
– Deoxyribonucleic acid (DNA)
– Ribonucleic acid (RNA)
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Deoksiribonükleik asid
• DNA
– Genetik materyal
– Kendini replike edebilir
– Spesif proteinlerin sentezi için gerekli bilgileri taşır (RNA sentezi)
– Hücrelerin çekirdeğinde
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DNA görevleri
– RNA sentezi (transkripsiyon)
– RNA’dan protein sentezi (translasyon)
1
2
3
Synthesis of mRNA in the nucleus
Movement of mRNA into cytoplasm
via nuclear pore
Synthesisof protein
NUCLEUSCYTOPLASM
DNA
mRNA
Ribosome
AminoacidsPolypeptide
mRNA
Figure 5.25
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Nucleik Acid yapısı
• Nucleic acid
– Polinükleotid denilen polimerler halinde bulunur
(a) Polynucleotide, or nucleic acid
3’C
5’ end
5’C
3’C
5’C
3’ endOH
Figure 5.26
O
O
O
O
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• nükleotid
– Polinükleotid monomeri
– Şeker + fosfat + azot içeren baz
– Fosfodiester bağıNitrogenous
base
Nucleoside
O
O
O
O P CH2
5’C
3’CPhosphate
group Pentosesugar
(b) NucleotideFigure 5.26
O
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Nükleozid
(c) Nükleozid kısımlarıFigure 5.26
CHCH
Uracil (in RNA)U
Ribose (in RNA)
Nitrogenous bases Pyrimidines
CN
NC
OH
NH2
CHCH
OC
NH
CH
HNC
O
CCH3
N
HNC
C
HO
O
CytosineC
Thymine (in DNA)T
NHC
N C
CN
C
CH
N
NH2 O
N
HCNHH
CC
N
NH
CNH2
AdenineA
GuanineG
Purines
OHOCH2
H
H H
OH
H
OHOCH2
H
H H
OH
H
Pentose sugars
Deoxyribose (in DNA) Ribose (in RNA)OHOH
CH
CH
Uracil (in RNA)U
4’
5”
3’
OH H2’
1’
5”
4’
3’ 2’
1’
Fosfat içermeyen nükleotid kısmıdır
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Nükleotid Polimerleri
• Nükleotid polimerleri
– bir nükleotidin (şekerinin) 3´ karbonundaki -OH ile diğer nükleotidin 5´ karbonunda bulunan fosfat arasında oluşan fosfodiester bağı ile bağlanan nukleotidler
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• DNA double helix (çift sarmal)
– iki antiparalel nükleotid dizisi3’ end
Sugar-phosphatebackbone
Base pair (joined byhydrogen bonding)
Old strands
Nucleotideabout to be added to a new strand
A
3’ end
3’ end
5’ end
Newstrands
3’ end
5’ end
5’ end
Figure 5.27
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