BIOCHEM - MIDTERM Flashcards
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
Which is NOT characteristic of the genetic code?
OVERLAPPING
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
Which of the following is a mismatch?
TEMPLATE – DOUBLE STRANDED DNA (ALL THROUGHOUT THE REACTION)
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
Which is NOT a modification that occurs after synthesis of a polypeptide?
ADDITION OF A 5’ CAP
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
Which statement is true?
IN EUKARYOTES, THERE IS EVIDENCE THAT RIBOSOMES ARE PRESENT IN THE NUCLEUS
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
Which is INCORRECT regarding transcription in prokaryotes?
DNA PRIMER IS USED INSTEAD OF RNA PRIMER
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
Which of the following is TRUE for 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.
The first aminoacyl-tRNA that binds the ribosome during protein synthesis in prokaryotes is:
fmet – tRNA
Which is INCORRECT concerning RNA polymerase in prokaryotes?
The sigma subunit is responsible for the termination of transcription
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
Which is INCORRECT regarding RNA synthesis in eukaryotes?
ONLY ONE RNA POLYMERASE IS INVOLVED
The -10 region of prokaryotic promoter is also known as
PRIBNOW BOX
Which of the following is TRUE regarding the polysaccharides glycogen and cellulose?
ONLY GLYCOGEN MOLECULES HAVE BRANCHING REGIONS
Which of the following statements is true about migration of biomolecules?
RATE OF MIGRATION IS DIRECTLY PROPORTIONAL TO CURRENT
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
Which of the following is true of enzymes?
They increase the rate of reaction by stabilizing the transition state
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
The following terminate protein synthesis EXCEPT
UUA
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.
