Biochem Flashcards
B-N-glycosidic bond is formed between
CYTOSINE AND RIBOSE
Which of the following groups of chemical elements are considered as trace elements?
Se, Fe, Cu, Zn
What is the buffer systems in the blood is regulated by the lungs and kidneys?
BICARBONATE BUFFER SYSTEM
Which is the true of a replicating segment of eukaryotic DNA that has three origins of replication?
THERE WILL BE 6 REPLICATION FORKS
What happens to the Carboxyl group when it donates a proton?
NEGATIVELY CHARGED
The chirality of an amino acid results from the fact that it’s a carbon
IS BONDED TO FOUR DIFFERENT CHEMICAL GROUPS
True or False (Protonated form of an amino acid)
ALL HYDROGEN IONS ARE
ATTACHED (because, hydrogen are protons)
True
Specific type of covalent bond that links several amino acids together to form peptides or proteins
PEPTIDE BOND
Of the 20 standard amino acids, only () is not optically active. The reason is that its side chain ().
GLYCINE; is a hydrogen atom
The PO4 end of the DNA is also known as
5- PRIME END
The resonance structure that can be drawn for the peptide bond indicate that the peptide bond
HAS PARTIAL DOUBLE BOND CHARACTER
Packaging site of cellular secretions:
GOLGI
Why is pKa an important property of a compound?
IT IS THE ABILITY OF A COMPOUND TO TAKE UP OR DONATE PROTONS INTO SOLUTION
It protects the separated DNA from destruction by nucleases?
SSB
When two cysteine molecules dimerize, what happens to the R groups present?
THEY REACT WITH EACH OTHER TO PRODUCE A COVALENT DISULFIDE
TRUE OR FALSE
POLYPEPTIDES CAN FORM UNLIMITED NUMBER OF CONFIGURATIONS
FALSE
Two amino acids of the standard 20 contain sulfur atoms. They are:
CYSTEINE and METHIONINE
The chromosome of a bacterium has 22 percent guanine. What is the percent composition of cytosine in this chromosome?
22
What class of lipids is usually present in biological membranes?
PHOSPHOLIPIDS
What cation serves as a co-factor and is required by the DNA polymerase for its activity?
Mg
What forms phosphodiester bonds between fragment of DNA during replication?
DNA LIGASE
Unfolding of a protein can be termed as
DENATURATION
In condensation process, how many hydrogen atoms are removed?
2
TRUE OR FALSE
SINGLE-STRANDED DNA THE TOTAL NUMBER OF PURINES IS NOT EQUAL TOTAL NUMBER OF PYRIMIDINES
TRUE
Amino acids that cannot participate in hydrogen bonding?
VALINE
TRUE OR FALSE
PEPTIDE NOMENCLATURE C-TERMINAL AMINO ACID RESIDUE KEEPS ITS FULL AMINO ACID NAME
TRUE
Amino acid containing nonpolar, aliphatic R groups
Ala, Leu and Gly
The following is made up of nucleotides?
COENZYME, CYCLIC-AMP, ATP
It is the amount of heat, per unit mass of liquid, required to raise the temperature by one degree Celsius.
SPECIFIC HEAT
What is the amino acids is the most hydrophobic in nature?
LEUCINE
Which is true about DNA denaturation?
IT OCCURS BY HEATING
If the NH2 group is oriented to the right it is a
D ISOMER
Which is an RNA sequence?
A AND U; G AND C
What type of amino acid R group is involved in Electrostatic interaction interactions that contribute to tertiary protein structure?
ACIDIC AND BASIC R GROUP
What is the correct classification of polysaccharides?
STORAGE AND STRUCTURAL
are conjugated proteins that contain carbohydrates or carbohydrate derivatives in addition to amino acids
GLYCOPROTEINS
What is the name of the organic molecule that contains a carboxyl group and amino group?
PROTEIN, AMINO ACID
What are places where protein play an important role?
ENZYME PRODUCTION
If pK1= 2.34 and pK2 = 9.60, then the isoelectric point pI is?
5.97
Proteins that are generally insoluble in water and they are involved in structural functions
FIBROUS PROTEIN
What is considered as the 21st amino acid?
SELENOCYSTEINE
What liquids has the highest specific heat?
WATER
TRUE OR FALSE
THE QUARTENARY STRUCTURE IS RELATED TO THE BASIC LINEAR STRUCTURE OF A PROTEIN
FALSE
The two strands of the DNA helix are held together by
HYDROGEN BONDS BETWEEN THE BASES
What groups of chemicals can be used to denature proteins?
ALKALOIDAL REAGENTS, INORGANIC ACIDS, HEAVY METALS
Adenine forms a covalent bond with a nucleic sugar at
N9
A type of protein structure which involves the associations among the peptide chains present in a multimeric protein
QUARTERNARY
In eukaryotes, histones can bind with DNA because histones have amino acids that are
POSITIVELY CHARGED
Amino acid with hydroxyl OH group include
TYROSINE
Which of the following is not the classified form of conjugated proteins?
COMPLETE PROTEINS
It is a process of modifying the molecular structure of a protein. It involves the breaking of many of the weak linkages, or bonds (e.g., hydrogen bonds), within a protein molecule that are responsible for the highly ordered structure of the protein in its natural (native) state.
DENATURATION
It provides the OH group to which the DNA polymerase adds the new nucleotide to the growing DNA strand?
RNA PRIMER
In DNA replication, which enzyme is responsible for the elongation of the new DNA strand?
DNA POL III
TRUE OR FALSE
observed in the experiment that showed that DNA replication is semiconservative, The daughter DNAs in the first replication consisted of parent double-stranded DNA (15N strand-15N strand) and a DNA having two new strands (14N strand-14N strand).
FALSE
Defined as the amount of heat needed to turn 1g of a liquid into a vapor.
HEAT OF VAPORIZATION
Which is a pyrimidine in the DNA?
THYMINE
What is an example of Fibrous protein?
COLLAGEN
Zwitterions are?
EXIST IN A NEUTRAL pH
The monomers of nucleic acids are
NUCLEOTIDES
What introduces a swivel point in advance of the replication fork to relieve the torsional strain caused by unwinding of the DNA double helix?
TOPOISOMERASE
A buffer solution is composed of 0.25M acetic acid and 1.20M sodium acetate. What would be the pH of the solution? Select the closest value. (pka of acetic acid is 4.74)
5.00
This hormone is also called as Anti-Diuretic Hormone and contains 9 amino acid residues
VASOPRESSIN
TRUE OR FALSE
IN AN A-HELIX, ALL THE AMINO ACID R GROUPS LIE OUTSIDE THE HELIX
TRUE
TRUE OR FALSE
The following are arranged in order of molecular complexity (start from the the most complex level):
ORGANELLE > SUPRAMOLECULAR COMPLEX > BIOMOLECULES > METABOLITES > INORGANIC PRECURSORS
TRUE
The three-letter abbreviation for the amino acid asparagine is
ASN
It refers to particularly stable arrangements of amino acid residues in a protein that give rise to recurring patterns?
SECONDARY STRUCTURE
Which part of the amino acid gives it uniqueness?
SIDE CHAIN
TRUE OR FALSE
Polarity compounds are also “water-loving”
TRUE
TRUE OR FALSE (LAGGING STRAND)
THE DIRECTION OF SYNTHESIS IS TOWARD THE REPLICATION FORK
FALSE
Amino acid are ampholytes because they can function as either a(n)
ACID OR BASE
TRUE OR FALSE
EUKARYOTES REQUIRE RNA PRIMERS BUT PROKARYOTES DO NOT
FALSE
What amino acid has indole ring in its side chain?
TRYPTOPHAN
The acid component of the buffer:
ADDS MORE H+ TO THE SOLUTION, RELEASE H+
The smallest amino acid is
GLYCINE
Which pair of amino acid absorbs the UV light at 280nm?
TRP AND TYR
TRUE OR FALSE
Both a-helix and b-pleated sheet structures can be present in the same protein.
TRUE
Which base pair is not found in DNA?
ADENINE- GUANINE
TRUE OR FALSE (SIDE CHAIN OF AMINO ACID)
ARE ALWAYS CHARGED AND PRESENT IN ALL AMINO ACID
TRUE
Peptide bond is a?
COVALENT BOND
RESULTS IN HYDROPHILIC EXTERIOR
PROTEIN FOLDING
TRUE OR FALSE
Proteins with different functions usually differ significantly in their amino acid composition
TRUE
A branch of science that describes the molecular nature of life processes.
BIOCHEMISTRY
Amino acids are building blocks of
PROTEIN AND POLYPEPTIDES
The peptide bond in proteins is
PLANAR, USUALLY FOUND IN TRANS CONFORMATION
The site of formation of new DNA is called
REPLICATION FORK
Derivatives of purines and pyrimidines that have a sugar linked to a ring nitrogen
NUCLEOSIDES
What amino acids is the uncharged derivative of an acidic amino acid?
GLUTAMINE
Specific type of covalent bond that links several monosaccharides together to form carbohydrates.
GLYCOSIDIC BOND
This is an important small organic biochemical compound that supplies energy to numerous chemical reactions.
ATP
TRUE OR FALSE
required in DNA synthesis: dUTP
FALSE
Ten base pairs per complete turn of the helix is a characteristic of
B-DNA
The alpha helix is an example of which of the following structural properties of proteins?
SECONDARY
Command center of the cell:
NUCLEUS
TRUE OR FALSE
the sugar in DNA: LACKS O AT C1-PRIME
FALSE
What happens if the pH of the solution is greater than the pKa of the amino acid?
AMINO ACID WILL BE DEPROTONATED
Arrange the following in order of molecular complexity (start from the simplest level):
METABOLITES > MONOSACCHARIDES > RIBOSOMAL COMPLEX > CELL
TRUE OR FALSE
THE TWO COILED STRANDS OF DNA RUN IN PARALLEL DIRECTIONS
FALSE
Which of the following is not a pentose?
FRUCTOSE
A Polysaccharide which is often called animal starch is
GLYCOGEN
Interconversion of α form to β form
MUTAROTATION
TRUE OR FALSE
characteristic of the genetic code: OVERLAPPING
FALSE
What causes formation of highly reactive free radicals in the DNA?
X-RAY
The removal of incorrect nucleotides immediately after they are added to the growing DNA during replication is known as
PROOFREADING
How many possible codons code for amino acids?
61
In DNA extraction, which of the following chemicals dissolve the membrane components of the cell?
DETERGENTS
What strand of the DNA has the gene base sequence that specifies the amino acid sequence of a protein?
SENSE STRAND
With regards to the Michaelis-Menten equation, a molecule that has the effect of increasing the Vmax start text, end text, start subscript, m, a, x, end subscript of a reaction upon binding to an enzyme would be called what?
ACTIVATOR
What repair mechanism involves photolyase, which removes the covalent bond between pyrimidine dimmers?
LIGHT REPAIR
What is the linkage that is formed when two monosaccharides react to form a disaccharide?
GLYCOSIDIC LINKAGE (because,
monosaccharides)
What repair mechanism must recognize the methylated DNA strand to properly repair an error in DNA base pairing?
MISMATCH REPAIR
In DNA extraction, addition of lysis solution will:
ELIMINATE PROTEINS AND LIPIDS
These sugars cannot be hydrolyzed into simpler carbohydrates
MONOSACCHARIDES
What feature does a carbohydrate possessed that generates stereoisomerism?
PRESENCE OF CHIRAL CENTER
RNA splicing is involved in
REMOVAL OF INTRONS IN THE PRIMARY TRANSCRIPT
TRUE OR FALSE
TEMPLATE – DOUBLE STRANDED DNA (ALL THROUGHOUT THE REACTION)
FALSE
Which of the following compounds IS NOT considered as an irreversible inhibitor?
METHOTREXATE
Primer used for the process of polymerase chain reaction are ()
SINGLE STRANDED DNA OLIGONUCLEOTIDE
A solution that contains DNA fragments of known lengths in base pairs.
DNA LADDER
The DNA or RNA used in a PCR reaction serves as the:
TEMPLATE
What sugar is the major metabolic fuel of mammals?
GLUCOSE
What is the major difference between glucose and fructose?
TYPE OF CARBONYL FUNCTIONAL GROUP
What are the two different glucose- containing polysaccharides can be isolated from starch?
AMYLOSE; AMYLOPECTIN
The monosaccharide units are linked by α 1- 4 glycosidic linkage in
MALTOSE
Which of the following describes the relationship between the linear forms of D- glucose and D-galactose that differ only in stereochemical configuration at the fourth carbon?
THEY ARE EPIMERS
TRUE OR FALSE
modification that occurs after synthesis of a polypeptide: ADDITION OF A 5’ CAP
FALSE
What enzyme classes catalyze reactions in which two molecules become dissociated from each other?
HYDROLASE
Which of the statements regarding enzymes is UNACCEPTABLE?
ENZYME ACTIVITY CANNOT BE REGULATED
It is the simplest sugar
DEHYDROXYACETONE
What RNA is NOT involved in the translation process?
snRNA
The genetic code is found in
mRNA
In RNA synthesis, the DNA template must be separated. Which of the following separates the DNA strands?
SIGMA SUBUNIT OF RNA POLYMERASE
In a cyclic structure, this linkage is formed by reacting the aldehyde group and a hydroxyl group
HEMIACETAL
The anticodon is found in
tRNA
TRUE OR FALSE
IN EUKARYOTES, THERE IS EVIDENCE THAT RIBOSOMES ARE PRESENT IN THE NUCLEUS
TRUE
Penicillin is an example of what type of enzyme inhibitor?
IRREVERSIBLE
What stains can be used to visualize DNA gel electrophoresis band?
ANY FLUORESCENT DYE THAT HAS AFFINITY WITH DNA
What eliminates protein in the sample during DNA extraction?
PROTEINASE K
TRUE OR FALSE
transcription in prokaryotes: DNA PRIMER IS USED INSTEAD OF RNA PRIMER
FALSE
The part of the enzyme where the substrate binds is called the:
ACTIVE SITE
When DNA copies are multiplied at a rapid rate, this is referred to as () amplification.
EXPONENTIAL
An amylose polymer and a glycogen polymer, each containing 100 monosaccharide subunits, are cleaved completely by an enzyme. How many individual glucose molecules are created during this process?
200
TRUE OR FALSE
D- and L- isomerism: The orientation of the -OH groups at the highest numbered chiral determines whether the sugar belongs to the D or L series
TRUE
The first aminoacyl-tRNA that binds the ribosome during protein synthesis in prokaryotes is:
fmet – tRNA
TRUE OR FALSE
RNA polymerase in prokaryotes: The sigma subunit is responsible for the termination of transcription
FALSE
What enzyme activates amino acids prior to protein synthesis?
AMINO ACYL – tRNAsynthetase
It is a protein molecule that has one or more carbohydrate units covalently bonded to it
GLYCOPROTEIN
What enzyme classes catalyze reactions in which two molecules are covalently connected to each other?
LIGASE
TRUE OR FALSE
RNA synthesis in eukaryotes: ONLY ONE RNA POLYMERASE IS INVOLVED
FALSE
The -10 region of prokaryotic promoter is also known as
PRIBNOW BOX
TRUE OR FALSE
polysaccharides glycogen and cellulose: ONLY GLYCOGEN MOLECULES HAVE BRANCHING REGIONS
TRUE
TRUE OR FALSE
migration of biomolecules: RATE OF MIGRATION IS DIRECTLY PROPORTIONAL TO CURRENT
TRUE
Termination of transcription is facilitated by
RHO PROTEIN
The relationship between an enzyme and a substrate molecule can best be described as:
A TEMPORARY ASSOCIATION
Which carries the amino-acid to the ribosomes during protein synthesis?
tRNA
The basic steps in protein synthesis are the same for both prokaryote and eukaryote. One difference is
THE FORMATION OF POLYSOMES
An equipment used in PCR that is programmed to shift the levels of temperature giving way to the three stages of PCR cycles:
THERMAL CYCLER
What name is given to any (organic or inorganic) nonprotein portion of an enzyme?
COFACTOR
What cannot be oxidized by Benedict’s and Fehling’s reagents?
SUCROSE
TRUE OR FALSE
enzymes increase the rate of reaction by stabilizing the transition state
TRUE
They are sugars in which the terminal carbon’s hydroxyl group has been oxidized to a carboxylic acid
URONIC ACID
The eukaryote small ribosomal subunit is
40S
A PCR reaction that continues for 30 cycles will produce approximately how many PCR products from a single template DNA molecule?
APPROXIMATELY 1 BILLION
Temperature level required for elongation step of PCR: Choose the closest range.
70-75° C
For each generation of each cell, how many rounds of replication occur?
ONE
At least how many cycles of PCR are needed to produce an adequate amount of DNA strands?
30
It is a polysaccharide in which only one type of monosaccharide monomer is present
HOMOPOLYSACCHARIDE
What structural feature distinguishes an aldose and a ketose?
AN ALDOSE POSSESS AN ALDEHYDE GROUP, AND A KETOSE POSSESS A KETONE GROUP
The initiating codon in for most translation processes is
AUG
What compounds is a COMPETITIVE INHIBITOR to dihydrofolate reductase?
METHOTREXATE
Carbohydrates is made up of different components such as
CARBON, HYDROGEN AND OXYGEN
What is the effect of UVL in the DNA?
IT WILL CAUSE PYRIMIDINE DIMER FUNCTION
At the initiation stage of protein synthesis, fmet-tRNA binds to this site of the big ribosomal subunit
p
In prokaryotes, the small ribosomal subunit uses this as a guide to find the first codon to be translated
SHINE DALGARNO SEQUENCE
What is meant when it is said that carbohydrates are optically active compounds?
A SOLUTION OF CARBOHYDRATE WILL ROTATE THE PLANE OF POLARIZED LIGHT
S-Adenosyl methionine (SAM) is a molecule utilized in various metabolic pathways to transfer methyl groups from SAM to an acceptor. What is the proper designation of the complex of SAM and its enzyme together?
HOLOENZYME
The big subunit of the prokaryotic ribosome is
50S
In sequential order, what are the three steps of PCR?
DENATURE DNA, ANNEAL PRIMERS, EXTEND PRIMER/ DNA
The transition state of a catalyzed reaction is
LOWER IN ENERGY THAN THAT OF AN UNCATALYZED REACTION
What sugar rotates at +66.5°?
SUCROSE
TRUE OR FALSE
following terminate protein synthesis: UUA
FALSE
Prior to a marathon run, an athlete consumes a large amount of complex carbohydrates to do what is known as “carbohydrate loading”. What happens in the body to the glucose molecules present in these complex carbohydrates? (additional 30s)
The complex carbohydrates are broken down to glucose and any excess glucose, not used for immediate energy, is stored in the form of glycogen, which can be used later as a source of stored energy.
What enzyme is directly responsible in ATP production during chemiosmosis?
ATP SYNTHASE
What is the process that releases energy?
CATABOLISM
The main function of this compound is the transfer of long-chain fatty acids to mitochondria for subsequent β-oxidation.
CARNITINE
Vitamin B2 is also known as
RIBOFLAVIN
What is associated with a negative nitrogen balance?
STARVATION
In a eukaryotic cell, glycolysis takes place in the:
CYTOPLASM
What is the effect of Vitamin D to blood calcium levels?
IT INCREASES BLOOD CALCIUM
This is the active form of Vitamin D:
1,25 – DIHYDROXYVITAMIN D
What is the chemical structure of a biological wax?
A MONOESTER FROM LONG CHAIN ALCOHOL AND LONG CHAIN CARBOXYLIC ACID
Arrange the following steps of beta- oxidation in the correct order:
I. hydration across the double bond to put a hydroxyl group on carbon 3 in the L configuration;
II. thiolytic cleavage to release acetyl-CoA and a fatty acid two carbons shorter than the starting one.
III. dehydrogenation to create FADH2FADH2 and a fatty acyl group with a double bond in the trans configuration;
IV. Oxidation of the hydroxyl group to make a ketone;
III > I > IV > II
What is needed from the Krebs Cycle in order for the Electron Transport Chain to occur?
FADH2/ NADH
Creatures utilizing inorganic compounds as electron/ hydrogen donors
LITHOTROPHS
Creatures that use organic compound as electron/hydrogendonors
ORGANOTROPHS
NOT produced in pentose phosphate pathway?
GLUCOSE – 6 – P
Which of the following amino acids DO NOT participate in the synthesis of glucose?
K, L
The only membrane bound enzyme in the citric acid cycle is ()
SUCCINATE DEHYDROGENASE
Movement across the membrane is against the concentration gradient
ACTIVE TRANSPORT
Match the following high-energy yield molecules with the number of equivalent ATPs as they travel along electron transport chain.
-FADH2 → 1.5-2.0 ATPs
-NADH → 2.5-3.0 ATPs
NADPH is used by most cells as
A REDUCING AGENT IN DETOXIFICATION REACTIONS
What happens during the first step of beta- oxidation?
FORMATION OF FATTY ACYL – CoA
Which high energy intermediate can generate more ATP through the electron transport chain?
NADH
The conversion to active form of Vitamin D happens in what organ?
KIDNEYS
In Anabolism, larger molecules are () from smaller ones, requiring input of energy.
SYNTHESIZED
What is the relationship between carbon chain length and melting point for fatty acids?
AS A CARBON CHAIN LEGTH INCREASES, MELTING POINT INCREASES
Where does the electron transport chain happen?
MITONCHONDRIAL MATRIX
vitamin K-dependent proteins have anticoagulation/ anti-clotting effect?
PROTEIN S
In fatty acid synthesis, acetyl-CoA must be converted into this compound in order to get to the cytoplasm (from the mitochondrion). This compound is:
CITRATE
What membrane lipids does not contain a head and two tails structure?
CHOLESTEROL
Which portion of aerobic respiration results in the greatest amount of ATP production?
OXIDATIVE PHOSPHORYLATION
Where is beta oxidation taking place in mammals?
MITOCHONDRIA
The totality of an organism’s chemical reactions is called:
METABOLISM
It is a process wherein carbon-carbon double bonds are broken down thus producing short chain aldehyde and carboxylic acid products
OXIDATION
What products of Krebs’s Cycle are essential for oxidative phosphorylation?
NADH AND FADH2
Which of the following is NOT a characteristic of Vitamin C?
FACILITATES DEGRADATION OF COLLAGEN
TRUE OR FALSE
LOW DENSITY LIPOPROTEIN CONTRIBUTES TO REDUCED BLOOD CHOLESTEROL LEVELS
FALSE
Beta oxidation, the process by which fatty acids are broken down for energy production, takes place where?
MITOCHONDRIA ONLY
Gluconeogenesis involves the conversion of
PYRUVATE TO GLUCOSE
Lysine and threonine are amino acids that can be degraded directly into Acetyl- CoAwhich is used to synthesize fatty acids and ketoacids. These amino acids are characterized as:
KETOGENIC AMINO ACIDS
ARE MORE STABLE THAN WATER – SOLUBLE VITAMINS
Fat-soluble vitamins
TRUE OR FALSE
SPHINGOPHOSPHOLIPIDS’ CARBON CHAIN CONTAIN 20 CARBON ATOMS
FALSE
Sphingosine plus fatty acid is known as
CERAMIDE
CAN BE FOUND IN CITRUS FRUITS
Water-soluble vitamins
What is the major lipid-soluble antioxidant?
VITAMIN E
Sphingoglycolipid is made up of
SPHINGOSINE, FATTY ACID AND MONOSACCHARIDE
This means that the intake of nitrogen into the body is greater than the loss of nitrogen from the body, so there is an increase in the total body pool of protein.
POSITIVE NITROGEN BALANCE
TRUE OR FASLE
SATURATED FATTY ACID ARE STRAIGHT CHAIN; SOLID AT ROOM TEMPERATURE; HIGH MELTING POINT
TRUE
What is the product of electron transport chain mechanism?
WATER
What is the final product of beta-oxidation of fatty acids?
ACETYL COA
What type of metabolism is demonstrated in the reaction below? single protein strand –> many amino acids
CATABOLISM
Correctly classify the following amino acids according to their role in gluconeogenesis(glucogenic) and ketogenesis (ketogenic).
-glycine → glucogenic only
-lysine → ketogenic only
-phenylalanine → both glucogenic and ketogenic
