SOAL FORMATIF FKUI 2010 Elemen yang selalu terdapat dalam

SOAL FORMATIF FKUI 2010
1. Elemen yang selalu terdapat dalam protein adalah C, H, O, N.
Analisis unsur : selalu mengandung C,H,O,N,S
Mengapa selalu mengandung S??
kalo C,H,O,N si masuk akal juga….
H
|
COOH-C-NH
|
R
Jawaban : SALAH
2. Protein adalah homoppoimer dari asam amino
Definisi dari protein:
Definisi KIMIA:
•
Protein adalah heteropolimer dari asam-asam amino yang terikat satu sama lain dengan
ikatan peptida
Definisi BIOLOGIS:

Definisi biologis : Protein adalah senyawa yang merupakan hasil ekspresi informasi yang
terkandung dalam gen
Definisi BIOKIMIA:

Definisi Biokimia : Protein adalah heterobiopolimer , dibuat oleh sel sebagai hasil ekspresi
informasi dalam gen, tersusun dari asam-asam amino yang terikat satu sama lain oleh ikatan
peptida
3. Asam  amino butirat adalah asam amino yang menyusun
protein.
4. Asam aspartat adalah asam amino esensial.
Asam amino essensial:
Valiant-Pheny-Try-His-Theory-of-Meteor-Lysis-using-Selenoida-Iso-Leusine

Valine

Phenylalanine

Tryptophan

Histidine

Threonine/Tyrosine

Methionine

Lysine

Selenocysteine

Isoleucine

Leucine
5. Asam amino L-sitrulin tidak pernah menyusun protein karena tidak punya kodon.
Although citrulline is not coded for by DNA directly, several proteins are known to contain
citrulline as a result of a posttranslational modification. These citrulline residues are generated by
a family of enzymes called peptidylarginine deiminases (PADs), which convert arginine into
citrulline in a process called citrullination or deimination. Proteins that normally contain
citrulline residues include myelin basic protein (MBP), filaggrin, and several histone proteins,
whereas other proteins, such as fibrin and vimentin are susceptible to citrullination during cell
death and tissue inflammation.
Patients with rheumatoid arthritis often have detectable antibodies against proteins containing
citrulline. Although the origin of this immune response is not known, detection of antibodies
reactive with citrulline (anti-citrullinated protein antibodies) containing proteins or peptides is
now becoming an important help in the diagnosis of rheumatoid arthritis.[3]
In recent studies, citrulline has been found to relax blood vessels.[4]
TRUE
6. Untuk dapat berfungsi secara maksimal, protein memerlukan pH dan suhu
tertentu.
TRUE
•
Di luar pH optimum, aktivitas biologis protein selalu <
•
Hal yang sama bagi to : to yg  protein aktif maks : to optimum. Di luar to optimum, aktivitas
biologis suatu protein selalu <
7. Struktur sekunder berupa simpai disebabkan oleh terbentuknya ikatan S-S intra
rantai polipeptida.
Heliks-@
Ikatan hidrogen (H) antara –CO- suatu ikatan peptida dengan –NH- ikatan pptd 3-4 aa ke depan atau ke
belakang  heliks-
Beta SHEET
Ikatan H antara –CO- & -NH- terbentuk antara peptida berhadapan
Lipatan/tekukan/Bending
AA PROLIN
Loop atau simpai
O/ ikatan –S-S- terbentuk sbg hsl oksidasi 2 aa sistein dlm 1 rantai protein (1 ggs –SH /sistein)
Sulur sembarang/RANDOM COIL
saling tolak antara aa dengan R bermuatan sama (sama-sama asam atau basa)
8. Umumnya protein globular adalah protein regulator.
TRUE
Protein globular umumnya berfungsi sebagai protein regulator
contoh protein globular:
enzim, transporter, caraka 1 (mediator), pertahanan, reseptor
Protein fibriller umumnya berfungsi sebagai protein structural:
keratin- dan keratin- (lembar-), kolagen, elastin, bagian molekul myosin
9. Menurut Beadle dan Tatum, 1 gen menentukan 1 enzim, atau lebih tepatnya
terdapat 1 protein.
Beadle & Tatum (1946) : mutan Neurospora crassa tidak mampu meragikan roti  cacad enzim
menyertai cacad gen  one gene one enzyme (protein)
REMEMBER THAT ENZYME IS ALWAYS A PROTEIN!!
10. Sel melaksanakan sejumlah besar jenis reaksi kiia setiap saat secara
teratur.
there are something within cell, enable a large number of chemical reactions occurred in a highly
coordinated manner, in a mild environtment condition and often produce various compounds with very
complicated structure
Enable large number of chemical reaction in a highly coordinated manner
TRUE
11. Sebagian besar enzim seperti umumnya protein berada dan berfungsi dalam sel.
Most enzyme, as most other protein, are synthesized, rest and work within a cell
TRUE
12. Enzim pencernaan adalah enzim ektrasel.
Definition of Extracellular enzyme:
An enzyme, such as a digestive enzyme, that functions outside the cell from which it originates. Also
called exoenzyme.
13. Enzim pencernaan termasuk kelas hidrolase.
TRUE
14. Asam pantotenat diperlukan sebaga prekursor koenzim A yang diperlukan enzim
untuk metabolisme asam lemak.
TRUE
Pantothenic acid, also called vitamin B5 (a B vitamin), is a water-soluble vitamin required to sustain life
(essential nutrient). Pantothenic acid is needed to form coenzyme-A (CoA), and is critical in the
metabolism and synthesis of carbohydrates, proteins, and fats. In chemical structure, it is the amide
between D-pantoate and beta-alanine. Its name is derived from the Greek pantothen (πάντοθεν)
meaning "from everywhere" and small quantities of pantothenic acid are found in nearly every food,
with high amounts in whole-grain cereals, legumes, eggs, meat, and royal jelly. It is commonly found as
its alcohol analog, the provitamin panthenol, and as calcium pantothenate. Pantothenic acid is an
ingredient in some hair and skin care products
15. Enzim tidak mengubah nilai Km, enzim hanya mempercepat tercapainya bentuk
peralihan.
TRUE
 In an other words, it means that the presence of an enzyme will not, or even more exactly, will
never change the K value of any reaction
 The role of E, therefore, is to lead S to its transition form
16. Dalam bentuk peralihan, substrat berada dalam keadaan yang sangat stabil.
FALSE
Transition State & Transition Form
 To explain to problem, let we see the following spontaneous reaction :
A→B
 Indeed, the reaction occurs in the following manner :
A ⇌ A’→B
 A’ is the transition form of A with the general characteristics :
- Has a very short life (second or <<)
- Need certain energy input (despite its spontaneity)
Has a relatively unstable structure
- In this condition, A’ becomes a metastable molecule
- Like other metastable systems, a very little change can push A’ into another very stable molecule, B.
Then we find the 2nd half reaction : A’→ B.
- If we take into account the role of A’, then in the overall reaction we will eliminate the A’ from the
overall reaction, as if A’ is never exist, exactly as the ES case, therefore as the role of E itself
17. Bentuk kurva hubungan [S] dengan kerja reaksi kimia pada enzim dikenal
sebagai kurva Michaelis-Menten ditemukan dalam seluruh sistem yang mempunya
saturasi.
TRUE
v= V[S]/Km+[S] relate the concentration of substrate to rate of reaction of an enzyme, it is found in all
system which has saturation
18. Sejumlah protein termasuk enzim memerlukan Ca atau Zn untuk memantapkan
struktur 3D sehingga dapat berfungsi.
 Cofactor’s functions :
1.As an enzyme stabilizer : Ca, Zn
2.Involve in reduction-oxidation (redox) reaction. In this case, the bounded metal can accept and release
electron : Cu, Fe and Mn
3.Stabilize coenzyme or substrate : Mg
4.Make environment suitable for E:K,Na
19. Km adalah nilai K reaksi disosiasi ES, gambaran afinitas, dan juga [S] yang
menyebabkan kecepatan reaksi tepat = setengah kecepatan maksimum.
Km is where the v of the reaction is half of the V max
20. K disosiasi HbO2 > K disosiasi HbCO.
TRUE
ingat bahwa Kdis lebih kecil maka Afinitas lebih besar….
Kita ketahui bahwa afinitas HbCO lebih besar daripada HbO2 - bahayanya di lapangan parker di
tempat terutup dapat menyebabkan keracunan CO sehingga berbahaya
21. Molekul enzim "memaksa" substrat untuk teregang menjadi bentuk transisi
dalam suhu biasa.
TRUE
Salah satu spesialisasi enzim adalah dapat membentuk substratproduk dalam suatu keadaan
yang normal SUHU BIASA
22. Hb hanya akan mengikat O2 bila besi dalam hem berada sebagai Fe2+
TRUE
Hb hanya dapat mengikat O2 dalam keadaan terreduksi FE2+
Facts about Hb you would like to know::
 Memberi warna merah Hem:Fe-porfirin
 Porfirin dibntk o/ 4 cincin pirol
 Fe di tgh cincin, bntk ikatan koordinasi dg N pirol
merah pada darah o/ pigmen Hem : Fe-porfirin
23. Imunoglobulin utama dalam serum adalah IgG.
TRUE
Immunoglobulin G (IgG) is a monomeric immunoglobulin, built of two heavy chains γ and two light
chains. Each IgG has two antigen binding sites. It is the most abundant immunoglobulin and is
approximately equally distributed in blood and in tissue liquids, constituting 75% of serum
immunoglobulins in humans.[1] IgG molecules are synthesized and secreted by plasma B cells.
24. Pada sel prokariotik DNA juga dijumpai dalam mitokondria.
Does prokaryote generally have Mitochondria? I don’t think so
FALSE
25. Komponen asam nukleat adalah gugus fosfat, gula ribosa, dan basa nitrogen.
Nucleic acid is divided into two types which are: DNA and RNA…
DNA consist of Deoxyribose sugar,phosphate and nitrogen base
RNA consist of ribose sugar,phosphate and nitrogen base
FALSE
26. ATP (adenosin tri fosfat) adalah molekul nukleosida
.FALSE
ATP is a NUCLEOTIDE
Adenosine-5'-triphosphate (ATP) is a multifunctional nucleotide used in cells as a coenzyme. It is often
called the "molecular unit of currency" of intracellular energy transfer.[1] ATP transports chemical
energy within cells for metabolism. It is produced by photophosphorylation and cellular respiration and
used by enzymes and structural proteins in many cellular processes, including biosynthetic reactions,
motility, and cell division.[2] One molecule of ATP contains three phosphate groups, and it is produced
by ATP synthase from inorganic phosphate and adenosine diphosphate (ADP) or adenosine
monophosphate (AMP). Metabolic processes that use ATP as an energy source convert it back into its
precursors. ATP is therefore continuously recycled in organisms, with the human body turning over its
own weight in ATP each day.[3]
27. Perbedaan antara DNA dan RNA adalah kemampuannya dalam mempertahankan
informasi genetik.
TRUE ?!?!?!
DNA memiliki mekanisme PROOFREADING
RNA tidak meimiliki mekanisme PROOFREADING
begitulah kelihatannya alasan yg baiknya
28. Informasi genetik di dalam molekul DNA dipindahkan ke molekul RNA pada saat
replikasi DNA.
FALSE
The genetic information is transferred to RNA molecule in the process of TRANSCRIPTION
The picture:
29. Perpindahan informasi genetik terjadi pada proses mitosis.
False
Prophase I which happened in MEIOSIS
During prophase I, DNA is exchanged between homologous chromosomes in a process called
homologous recombination. This often results in chromosomal crossover. The new combinations of DNA
created during crossover are a significant source of genetic variation, and may result in beneficial new
combinations of alleles. The paired and replicated chromosomes are called bivalents or tetrads, which
have two chromosomes and four chromatids, with one chromosome coming from each parent. At this
stage, non-sister chromatids may cross-over at points called chiasmata (plural; singular chiasma).
30. Kesalahan pada proses transkripsi gen dapat diperbaiki.
False
Look at the table, PROOFREADING
31. Kesalahan pada proses transkripsi gen dapat menyebabkan mutasi gen.
TRUE
hmmm kesalahan transkripsi Kesalahan RNA yg ditraskripsii  Protein yg ditranslasi MUTASI
32. Proses translasi terjadi di dalam ribosom.
TRUE
Lihat lagi :
33. Protein-protein mitokondria disintesis pada REK.
False
protein protein mitkondria disintesis di sitosol
34. Perubahan glukosa menjadi galaktosa adalah
contoh mutarotasi.
Mutarotation:
is the change in the optical rotation that occurs by epimerization (that is the change in the equilibrium
between two epimers, when the corresponding stereocenters interconvert). Cyclic sugars show
mutarotation as α and β anomeric forms are interconvert.[1] The optical rotation of the solution
depends on the optical rotation of each anomer and their ratio in the solution.
H
OH
C
H C OH
HO C H
O
H
C
H C OH
HO C H
H
HO
C
H C OH
HO C H
H C OH O
H C OH
H C OH O
H C
H C OH
H C
CH2OH
CH2OH
CH2OH
35. Senyawa yang mempunyai isomer optik dapat memutar bidang cahaya
terpolarisasi.
A chiral molecule is a type of molecule that lacks an internal plane of symmetry and has a nonsuperimposable mirror image. The feature that is most often the cause of chirality in molecules is the
presence of an asymmetric carbon atom.[1][2]
TRUE
36. Laktosa termasuk gula pereduksi karena tersusun dari glukosa dan galaktosa
yang terikat dengan ikatan glikosidik -1,4.
Lactose is:
•
Also called milk sugar.
Composed of galactose and glucose linked by a  -1,4-glycosidic bond
FALSE
WHY.. BECAUSE LACTOSE IS NOT A REDUCING SUGAR
Remember:
Glucose + fructose
sucrose
37. Persamaan antara amilopektin dan glikogen adalah dalam hal percabangan pada
ikatan -1,4 glikosidik.
Amylose
Amylopectin
Unbranched (spiral)
Branched
300-400 glucose
3000 glucose
Glycosidic @(1,4)
Glycosidic @(1,4) branch: @(1,6)
I2 : DEEP BLUE
I2: Purplish RED
Glycogen is similar to amylopectin but is even more branched
Function in energy storage in muscle tissue and fiber
Many branch as a quick means in putting glucose into blood
38. Bakteri yang mempunyai enzim glukosidase akan dapat mencerna
selulosa.
Cellulose
A linear polymer of approximately 2800 D-glucose units per molecule joined by -1,4- glycosidic bonds

Humans and other animals cannot use cellulose as food because we lack β -glucosidases, the
enzymes that catalyze the hydrolysis of β-glysodic bonds. We only have -glucosidases, hence
are limited to starch and glycogen with their -glycosidic bonds.

Many bacteria, however possess β -glucosidases and can digest cellulose. Animals such as the
termite and ruminants (horses and cows) can digest cellulose because their digestive systems
contain such bacteria.
REMEMBER
Chitin

The major structural component of the exoskeletons of invertebrates, such as insects and
crustaceans; also occurs in cell walls of algae and fungi

Composed of units of N-acetyl--D-glucosamine joined by -1,4-glycosidic bonds
39. Semakin panjang rantai karbon pada asam lemak maka kelarutannya semakin
tinggi.
Physical properties
of fatty acids
Chain larger Sollubility lower Melting point higher
40. Lemak adalah trigliserida yang berbentuk padat pada suhu ruang.
41. Asam lemak berbentuk cis lebih berbahaya dibandingkan bentuk trans.
Hmmmm…:)
The naturally occurring fat is the CIS the changing to trans is to extend shelf life
Look at the explanation:
•
Hydrogenation of vegetable oils converts some of unsaturated bonds to saturated, trans
conformation.
•
Trans fatty acids extend shelf life, improve margarine, shortening.
Diet high in trans fatty acids risks heart disease, cancer
42. Salah satu sifat penting fosfolipid adalah sebagai zat pengemulsi.
•
Glycerol esterified to 2 fatty acids.
•
Third position is phosphate
•
Other end of phosphate can combine with other molecules to form various derivatives
•
Amphipathic –emulsifying agents
•
Production of cell membrane
43. Kolesterol adalah prekursor garam empedu.
Cholesterol
-important constituent of cell membranes
-has a rigid ring system and a short branched hydrocarbon tail.
Precursor to Bile Acids:
- Act as detergents to
dissolve dietary fats
- Fats can be broken better by enzymes
Keeps the lipids in membrane from aggregrating: Keeps the membrane intact as a bilayer
44. Struktur primer pada DNA adalah rangkaian gula dan fosfat.
Primary structure : PHOSPATE
Secondary structure : SUGAR-PHOSPATE BACKBONE
TERTIARY STRUCTURE: Hidrogen BOND
45. Nukleotida adalah gabungan gula dan basa nitrogen, sedangkan nukelosida
adalah gabungan gula, basa, dan fosfat.
Nukleotida : Gula+Fosfat+Nitrogen
Nukleosida:Gula+Fosfat
NITROGEN GA TERMASUK YA DI NUKELOSIDA!!!!
46. Interaksi spesifik adalah terjadinya ikatan Hidrogen antara asam amino (yang
berasal dari rantai samping protein) dengan basa nitrogen (yang berasal dari
DNA) pada minor groove.
Two types of interaction of DNA:
1. Specific interaction
The formation of hydrogen bond between amino acid side chain and bases in the major groove
2. Non specific interaction
The formation of ionic or hydrogen bonds with the phosphate residues in the ribose-phosphate
backbone of the DNA
47. Polimorfisme pada DNA terjadi karena konformasi gula dan orientasi basa
relatif terhadap gula.
There are three natural forms of DNA (A, B and Z). The origin of these different forms are related to the
conformation of the sugar (C2'-endo / C3'-endo) and the orientation of the base relative to the sugar
(syn/anti).
48. Struktur double helix DNA terutama distabilkan oleh ikatan hidrogen antara
basa nitrogen dengan fosfat.
The double helix structure is mainly stabilized by hydrogen bonds between bases pairs. Since the
hydrophobic bases are stacked inside and the hydrophilic ribose-phosphate chains are on the outside,
Van der Waals forces and hydrophobic interactions are also deeply involved in the stabilization of the
double helix
49. DNA ditranslasi dalam bentuk mRNA yang kemudian ditranskripsi menjadi
protein.
FALSE
DNA DITRANSKIRPSI MENJADI MRNA DITRANSLASI JADI PROTEIN
50. Operon Lac akan bekerja pada kondisi konsentrasi glukosa rendah dan laktosa
tersedia
51. Allolaktosa sebagai inducer akan berikatan pada suatu reseptor
52. Suatu operon terdiri dari 3 elemen, yaitu gen regulator, promotor, dan
operator.
 REGULATORY GENE
 OPERON :
The gene cluster and promoter,
plus additional sequences
that function together in regulation
•
Promotor
•
Operator
•
Structural Gene
53. Regulasi terhadap gen melalui atenuasi adalah khas untuk sel prokariotik.
Attenuation regulates the termination of transcription as a function
of tryptophan concentration.
-At low levels of trp full length mRNA is made, at high levels
transcription of the trp operon is prematurely halted.
-Attenuation works by coupling transcription to translation.
-Prokaryotic mRNA does not require processing and since
prokaryotes have no nucleus translation of mRNA can start
before transcription is complete.
-Consequently regulation of gene expression via attenuation is
unique to prokaryotes.
54. Operon arabinosa terhambat pada kondisi tanpa arabinosa.
Activation
If arabinose is present, it builds a complex: AraC + arabinose
This complex is needed for RNA polymerase to bind to the promoter and transcribe the ara
operon. Also for activation the binding of another structure to araI is needed: CAP + cyclic AMP
So the activation depends on the presence of arabinose and cAMP.
Repression
If arabinose is absent, the AraC protein assumes a different conformation. In this conformation
the AraC protein binds to the araI DNA region as well as to the ara0 DNA region. This causes
the DNA to form a loop, preventing transcription of the downstream ara operon elements.
Sequence of the Operon:
araC : araO : araI : araB : araA : araD
55. Selama siklus litik, DNA virus berintegrasi pada situs spesifik pada
kromosom sel hospes.
FALSE
56. Dalam kondisi pertumbuhan yang menguntungkan, protein cro akan terakumulasi
yang memungkinkan sikluls litik terjadi.
•
If the growth conditions are very favorable, the intracellular levels of the proteases are high
–
The cII protein tends to be degraded
•
–
•
Therefore, PRE cannot be activated and the l repressor is not made
Instead, the cro protein slowly accumulates to high levels
•
The binding of the cro protein to OR prevents transcription of the l repressor
from PRM
•
At the same time, the cro protein allows the lytic cycle to proceed
Thus, environmental conditions that are favorable for growth promote the lytic cycle
–
This makes sense because a sufficient supply of nutrients is necessary to synthesize new
bacteriophages
57. Sigma subunit berikatan dengan DNA polimerase untuk menolong DNA polimerase
menemukan promotor.
A sigma factor (σ factor) is a prokaryotic transcription initiation factor that enables specific binding of
RNA polymerase to gene promoters. Different sigma factors are activated in response to different
environmental conditions. Every molecule of RNA polymerase contains exactly one sigma factor subunit,
which in the model bacterium Escherichia coli is one of those listed below. E. coli has at least eight sigma
factors; the number of sigma factors varies between bacterial species. Sigma factors are distinguished by
their characteristic molecular weights. For example, σ70 refers to the sigma factor with a molecular
weight of 70 kDa.
58. Fisika molekuler adalah aplikasi hukum-hukum Fisika dasar yang mengatur
struktur dan sifat-sifat molekul.
TRUE
59. Elektroforesis dapat digunakan untuk mengukur pemisahan molekul.
TRUE
60. Hibridisasi DNA dapat digunakan untuk menentukan identifikasi biomol.
ybridization is the process of establishing a non-covalent, sequence-specific interaction between two or
more complementary strands of nucleic acids into a single hybrid, which in the case of two strands is
referred to as a duplex. Oligonucleotides, DNA, or RNA will bind to their complement under normal
conditions, so two perfectly complementary strands will bind to each other readily. In order to reduce
the diversity and obtain the most energetically preferred hybrids, a technique called annealing is used in
the laboratory practice. However, due to the different molecular geometries of the nucleotides, a single
inconsistency between the two strands will make binding between them less energetically favorable.
Measuring the effects of base incompatibility by quantifying the rate at which two strands anneal can
provide information as to the similarity in base sequence between the two strands being annealed. The
hybrids may be dissociated by thermal denaturation also referred to as melting. Here, the solution of
hybrids is heated to break the hydrogen bonds between nucleic bases, after which the two strands
separate. In the absence of external negative factors, the processes of hybridization and melting may be
repeated in succession indefinitely long, which lays the ground for polymerase chain reaction. Most
commonly, the pairs of nucleic bases A=T and G≡C are formed, of which the latter is more stable.