prayers - Ria

A

Which of the following structures is present in a eukaryotic cell but absent in a prokaryote?
A. Histones
B. Cell wall
C. Ribosomes
D. DNA

C

Which of the following statements describe eukaryotic cells?
A. Includes bacteria, yeast fungi and plant cells
B. Contains 70s ribosomes
C. They have well defined, membrane bound organelles
D. Its ability to convert energy from outside sources into a utilizable form is what sets it apart from a prokaryotic cell

B

In eukaryotic cells, the mitochondrion has been described as the “powerhouse of the cell” as the majority of ATP is synthesized in it. In the mitochondria, ATP synthesis occurs in:
A. Outer mitochondrial membrane
B. Inner mitochondrial membrane
C. Mitosol
D. Mitochondrial DNA

D

It is the site for synthesis of steroids, lipids and proteins as well for detoxification reactions:
A. Peroxisomes
B. Golgi complex
C. Nucleus
D. Endoplasmic reticulum

D

Which of the following statements is true:
A. Lysosomes are responsible for lipid oxidation
B. Peroxisomes are mainly involved in cellular digestion and apoptosis
C. Cytosol is a metabolically inert component of the cell serving as the matrix on which other subcellular organelles are found
D. Nucleus is the site for both DNA and RNA synthesis, however, RNA processing occurs in the nucleolus

B

Which of the following statements best describe the cell membrane/plasmalemma?
A. It is a lipid bilayer that allows different ionic solutes and substances to pass across freely
B. It is made up of lipids, proteins and cholesterol that define cellular boundaries
C. It forms symmetrical structure composed of lipids and proteins forming specialized compartments
D. It is held together by covalent interactions, allowing for self-assembly and its capacity to self-seal

C

True of membrane carbohydrates:
A. Recognition and communication
B. They are located in the cytosolic side of the cell membrane for intracellular communication
C. They are always attached either to a membrane lipid or membrane protein and important for adhesion and receptor action
D. They are important in maintenance and regulation of membrane fluidity

C

The extracellular fluid of the cell:
A. Holds 2/3 of the body’s total body water
B. Rich in ions, specifically potassium and magnesium
C. Has sodium as its main cation and chloride as its major anion
D. Negatively charged relative to the intracellular environment

D

Which of the following statements is true of membrane fluidity?
A. The presence of unsaturated hydrocarbon tails increases membrane fluidity and thus increasing the membrane’s transition temperature
B. The presence of saturated hydrocarbon tails decreases the membrane fluidity hence lowering the membrane’s transition temperature
C. Decreasing the membrane’s fluidity makes the cell more permeable to water and other polar substances
D. Membrane cholesterol regulates and modulates the fluidity of the membrane

A

Which of the following statements describe membrane lipids?
A. They are amphipathic structure made up of a polar head and 2 nonpolar tails which may be saturated or unsaturated
B. The most common membrane phospholipids are glycosphingolipid
C. They spontaneously form a covalent assembly creating a sheet-like bilayer structure that act as lipid barrier
D. They serve as pumps, channels or sometimes receptor and are responsible for the dynamic events that occur in the membrane

D

These membrane structures are composed of a ceramide backbone to which a phosphatidyl choline is attached:
A. Phosphoglyceride
B. Ganglioside
C. Glycosphingolipid
D. Sphingomyelin

C

Which of the following aptly describe phosphoglycerides?
A. A membrane lipid made up of a ceramide backbone with glucose or galactose attached to it
B. A membrane lipid with ceramide backbone with oligosaccharide residues
C. A membrane lipid with a glycerol backbone with two fatty acids attached via an ester linkage and a phosphated alcohol
D. A membrane lipid with sphingosine backbone, a fatty acid and carbohydrate residue linked via an O-glycosidic bond

A

True of membrane proteins:
A. They are the major functional molecules of the cell membrane where dynamic membrane processes take place
B. Proteins acting as channels in the membrane usually require energy to be able to perform their function
C. Removal of either the integral or peripheral proteins from the cell membrane will result in disruption of the membrane structure
D. Membrane proteins acting as pumps always rely on concentration or electrochemical gradient for the cellular reactions to proceed smoothly

B

An enclosed lipid bilayer used for transport of drugs or enzymes or carriers of DNA and other materials to be delivered to a target organ:
A. Micelle
B. Liposome
C. Caveolae
D. Lipid rafts

C

A category of transport mechanism in which 2 different molecules are transported in or out of the cell at the same time in different directions:
A. Uniport
B. Symport
C. Antiport
D. Simple diffusion

C

Which of the following statements is true of facilitated diffusion:
A. Involves the action of protein channels and are unaffected by concentration or electrochemical gradients
B. Increasing the concentration gradient in the presence of a fixed number of carriers will hasten solute transport
C. The time it takes for the solute-carrier to interact will have an impact on facilitated diffusion
D. The permeability coefficient as well as membrane thickness will affect the rate of facilitated diffusion

A

A specific mechanism of cellular transport that requires ligand-receptor binding in a designated invaginated area in the cytosolic side of the membrane that is coated by filamentous materials resulting in a reduced uptake of fluids or unbound materials:
A. Receptor-mediated pinocytosis
B. Signal transduction
C. Exocytosis
D. Fluid-phase pinocytosis

B

True of secondary active transport:
A. Na-K-ATPase pump is a prime example
B. Relies on the concentration or electrochemical difference provided by the primary active transport
C. A transport mechanism that is dependent on the concentration difference provided by facilitated diffusion
D. Directly utilizes ATP and together with the primary active transport, further establishes electrochemical and concentration gradient across the membrane

C

Signal transmission across the membrane:
A. Requires the physical transport of the signal molecule in order to effect a response
B. Is a non-selective process mediated by a series of reactions triggered by the binding of a receptor to its ligand until a desired response is elicited
C. Involves generation of signal molecules such as calcium, diacylglycerols and cyclic nucleotides in order to effect a response
D. Transduction of relay molecules is what initiates this process

B

Which of the following statements regarding the cell membrane is correct?
A. Lipid rafts or microdomains found in the cell membrane are fixed in a designated area of the membrane to provide a more efficient mechanism of transport
B. Membrane lipid, unlike membrane proteins, may move from one layer of the membrane to the other layer
C. Lipids move in the cell membrane along its plane via lateral diffusion; such movement is not exhibited by membrane proteins
D. Neither membrane lipid nor membrane proteins can transfer from one lipid to the other, hence maintaining the membrane’s asymmetry

D

A protein rich in this amino acid increases its ability to absorb UV light:
A. glycine
B. proline
C. threonine
D. tryptophan

B

Which of the following interactions/bonds that stabilizes higher orders of protein structure drives the folding process?
A. hydrogen bonds
B. hydrophobic interactions
C. disulfide bonds
D. van der Waals forces

C

TRUE about an amino acid at its physiologic pH:
A. it carries a (-) charge on its amino group and a (-) charge on its carboxyl group
B. it carries a (+) charge on its amino group and a (+) charge on its carboxyl group
C. it carries a (+) charge on its amino group and a (-) charge on its carboxyl group
D. it carries a (-) charge on its amino group and a (+) charge on its carboxyl group

B

Which amino acid below IS NOT part of this peptide chain: REYQW
A. glutamate
B. lysine
C. arginine
D. tryptophan

B

Which of the following amino acids is found in the interior of a protein?
A. lysine
B. valine
C. serine
D. arginine

C

Which amino acid below is considered essential for the physical development of children?
A. valine
B. serine
C. arginine
D. alanine

C

What process is involved in the formation of the peptide bond?
A. esterification of two amino acids
B. enzymatic fusion of two amino acids
C. condensation of COOH of one amino acid and NH of another amino acid
D. oxidation of two SH groups from two amino acids

D

One of the following amino acids participates in enzyme modification by phosphorylation:
A. asparagine
B. arginine
C. glutamate
D. serine

A

The donut-shape of this chaperone protein provides a sheltered environment for the new polypeptide as it folds until all hydrophobic regions are buried within the interior:
A. Hsp60
B. Hsp70
C. Hsp30
D. Hsp80

C

One of the following amino acids, which when found in large amounts in proteins, increases the buffering capacity of the protein at physiologic pH:
A. tyrosine
B. glycine
C. histidine
D. lysine

D

What is the protein structure of hemoglobin?
A. primary
B. secondary
C. tertiary
D. quaternary

B

Which of the following amino acids disrupts conformation of alpha helix and produces bends?
A. valine
B. proline
C. tryptophan
D. phenylalanine

A

The exact sequence of amino acids in a protein as determined in the DNA is the protein's:
A. primary structure
B. secondary structure
C. tertiary structure
D. quaternary structure

D

Which of these amino acids when not available in the diet can lead to its deficiency?
A. alanine
B. cysteine
C. methionine
D. phenylalanine

B

Which group in the chemical structure of amino acids is responsible for its function and dictates its orientation in protein structure?
A. carboxyl group
B. R group or side chain
C. amino group
D. central carbon

B

One of the following amino acids forms pyruvate upon catabolism:
A. arginine
B. alanine
C. tryptophan
D. methionine

C

The following are branched chain amino acids EXCEPT:
A. Isoleucine
B. leucine
C. lysine
D. valine

B

Prion disease is a disorder due to the alterations at these levels of protein structure:
A. primary and secondary
B. secondary and tertiary
C. tertiary and quaternary
D. primary and quaternary

A

Which of the following amino acids is both ketogenic and glucogenic since it yields both acetoacetate and pyruvate upon metabolism?
A. Tyrosine
B. Threonine
C. Leucine
D. Histidine

C

In the synthesis of collagen, which vitamin is required by prolyl and lysyl hydroxylase to produce hydroxyproline and hydroxylysine?
A. Thiamine
B. Cobalamin
C. Ascorbic acid
D. Niacin

B

Mario loves to eat huge amounts of rice. Which of the following vitamins does he need an increased intake of?
A. Riboflavin
B. Thiamine
C. Pyridoxal phosphate
D. Ascorbic acid

A

Which of the following is lost during oxidation reactions?
A. Electrons
B. Hydrogen
C. Oxygen
D. Neutrons

B

The isoalloxazine ring assists in the metabolic function of which coenzyme?
A. Thiamine pyrophosphate
B. Flavin adenine dinucleotide
C. Nicotinamide adenine dinucleotide
D. Coenzyme A

B

A coenzyme can catalyze a reaction by itself.
A. True
B. False

D

Ascorbic acid is an important coenzyme of which enzyme?
A. Thymidine kinase
B. Pyruvate dehydrogenase
C. Transketolase
D. Proline hydroxylase

C

Which of the following is true of prosthetic groups?
A. They dissociate after a reaction
B. They are not tightly-bound
C. Metalloenzyme is an example
D. They do not need a substrate

A

Which of the following coenzymes is associated with glycogen phosphorylase?
A. Pyridoxal phosphate
B. Thiamine pyrophosphate
C. Acyl carrier protein
D. Cobalamin

C

In the folate trap, which of the following amino acids accumulate?
A. Methionine
B. Cystine
C. Homocysteine
D. Betaine

A

What is the group being transferred by coenzyme A?
A. Alkyl group
B. Carbon dioxide
C. Aldehyde group
D. Oxygen

C

True of isomers:
A. Same chemical properties
B. Same physical properties
C. Same chemical composition
D. Same structure

B

Pantotheine is the functional moiety of:
A. Biotin
B. Acyl carrier protein
C. Pyridoxal phosphate
D. Flavin adenine dinucleotide

C

Luisa has skin changes, fragility of blood capillaries, tooth loss and bone fractures. What vitamin deficiency does she have?
A. Vitamin B1
B. Vitamin B6
C. Vitamin C
D. Vitamin K

B

Pantotheine is the functional moiety of:
A. Biotin
B. Acyl carrier protein
C. Pyridoxal phosphate
D. Flavin adenine dinucleotide

D

A functional deficiency of this vitamin may be due to avidin in egg whites.
A. Thiamine
B. Riboflavin
C. Cobalamin
D. Biotin

A

Which of the following coenzymes is essential in DNA synthesis?
A. Tetrahydrofolate
B. Pyridoxal phosphate
C. Carboxybiotin
D. Nicotinamide adenine dinucleotide

C

What type of anemia is secondary to vitamin B12 deficiency?
A. Microcytic anemia
B. Aplastic anemia
C. Megaloblastic anemia
D. Normoblastic anemia

C

Which of the following function in the modulation of steroid hormone action?
A. Thiamine
B. Nicotinic acid
C. Pyridoxal phosphate
D. Panthotenic acid

B

It is a glycoprotein secreted by the parietal cells of the gastric mucosa whose deficiency may lead to pernicious anemia.
A. Pepsin
B. Intrinsic factor
C. Hydrochloric acid
D. Trypsin

A

Which of the following enzymes converts methyltetrahydrofolate to tetrahydrofolate?
A. Methionine synthase
B. Methyltetrahydrofolate reductase
C. Cystathionine-B-synthase
D. Dihydrofolate reductase

B

What is the metal ion, which, together with vitamin C, aids in the formation of carnitine?
A. Mg
B. Fe
C. Zn
D. Cu

D

A hypothetical drug was added to an enzyme with substrate mixture which resulted in lowering of Vmax. If the substrate concentration needed to achieve half-Vmax is: 10 mM (without drug X), and 10 mM as well (with drug X). What type of inhibitor is drug X?
A. Competitive
B. Uncompetitive
C. Irreversible
D. Noncompetitive

A

Refers to the protein part of holoenzyme:
A. Apoenzyme
B. Cosubstrate
C. Cofactor
D. Prosthetic group

A

Incorrect about enzymes:
A. All are made up of proteins
B. Increases the reaction velocity
C. Lowers activation energy
D. Delta G is unaffected

C

Enzymes speed up the rate of chemical reactions by lowering:
A. Gibbs free energy
B. Entropy
C. Transition state energy
D. Enthalpy

A

To check for vitamin B1 deficiency, you ordered transketolase enzyme activation assay. Rationale:
A. (+) vitamin-derived cofactor to incubation converts previously inactive apoenzyme into active holoenzyme
B. (+) vitamin-derived cofactor to incubation converts previously inactive holoenzyme into active apoenzyme
C. (+) vitamin-derived cofactor to incubation converts previously active holoenzyme into inactive apoenzyme
D. (+) vitamin-derived cofactor to incubation converts previously active apoenzyme into inactive holoenzyme

C

Sucrase catalyzes the cleavage of glycosidic bonds using a water molecule. This is an example of enzyme class:
A. 1
B. 2
C. 3
D. 4

A

Epimerases, cis-trans isomerases belong to class:
A. 5
B. 4
C. 3
D. 2

A

Select the INCORRECT statement:
A. Competitive inhibitors increase affinity of substrate towards the enzyme
B. Noncompetitive inhibitors bear little or no structural resemblance to the substrate
C. Lineweaver-Burk & Dixon plots are linear representations of enzyme kinetics, derived from rearranged Michaelis-Menten equation
D. Plot of 1/V vs. 1/[S] is used for evaluating type of inhibition
Answer: A. Competitive inhibitors increase affinity of substrate towards the enzyme

C

True about the Michaelis constant Km:
A. Substrate concentration at Vmax
B. Velocity at half the substrate concentration
C. Substrate concentration at half Vmax
D. Velocity at full substrate concentration

B

Enzyme irreversibly blocked by Aspirin:
A. Lipoxygenase
B. Cyclooxygenase
C. Thromboxane synthase
D. Phospholipase A2

D

True about the inhibition type employed by NSAIDs on COX:
A. NSAIDs target the substrate binding site
B. Vmax unchanged
C. Apparent Km increased
D. All of these

D

What is the optimum temperature range for most human enzymes?
A. 40–55 °C
B. 20–25 °C
C. 0–10 °C
D. 35–40 °C

B

Enzyme activity factor that has a linear plot with a positive slope:
A. Substrate concentration
B. Enzyme concentration
C. Temperature
D. pH

A

Enzyme activity factor that has a hyperbolic plot:
A. Substrate concentration
B. Enzyme concentration
C. Temperature
D. pH

A

In a Lineweaver-Burk plot, what is the Km if the x-intercept is -3, and the y-intercept is 7?
A. 1/3
B. 1/7
C. -1/3
D. 3

B

In a Lineweaver-Burk plot, what is the Vmax if the x-intercept is -3, and the y-intercept is 7?
A. 1/3
B. 1/7
C. -1/3
D. 3

D

A patient was given probenecid, an uncompetitive inhibitor. Lineweaver-Burk plot will then show:
A. 2 vertical lines
B. 2 lines intersecting at the Y-axis
C. 2 lines intersecting at the X-axis
D. 2 parallel lines

A

PFK-1 is activated by dephosphorylation. What is the type of enzyme regulation employed?
A. Covalent modification
B. Feedback inhibition
C. Allosteric regulation
D. Induction, repression

A

LDH-5 level is elevated in injury to the:
A. Liver
B. Heart
C. Erythrocyte
D. Skeletal myocyte

D

Which of the following moves fastest or has the highest electrophoretic mobility?
A. CK-4
B. CK-3
C. CK-2
D. CK-1

B

They are "traffic police" of the cell and are important in sorting of many of the membrane components and proteins, directing these proteins to their destinations:

A. Endoplasmic reticulum
B. Golgi apparatus
C. Lysosomes
D. Peroxisomes

A

They consist of intricate lattice of threadlike structure and hold important roles in cell division, and cell movement:

A. Cytoskeleton
B. Cytoplasm
C. Endoplasmic reticulum
D. Plasma membrane

D

Which of the following is the site for citric acid cycle?

A. Cytosol
B. Outer mitochondrial membrane
C. Inner mitochondrial membrane
D. Mitochondrial matrix

B

The site in which the electron transport chain is located is in the:

A. Mitochondrial matrix
B. Inner mitochondrial membrane
C. Outer mitochondrial membrane
D. Cytosol

B

In which of the following does synthesis of RNA and DNA occur:

A. Golgi bodies
B. Nucleus
C. Ribosome
D. Rough endoplasmic reticulum

A

The common features of cell membrane includes:

A. Amphipathic in nature
B. Highly impermeable
C. Held together by covalent interactions
D. Symmetric distribution of components

C

True of the intracellular fluid:

A. Holds 1/3 of the body's total body water
B. Further divided into plasma and interstitium
C. Rich in ions, specifically potassium and magnesium
D. Sodium is its main cation and chloride, its major anion

B

Which of the following statements is true of membrane lipids:

A. Hydrophilic structures
B. Includes phospholipids, glycosphingolipids and cholesterol
C. Permeable to water soluble substances
D. Form into bilayers by covalent interactions

C

The more common form of phospholipid in the cell membrane is:

A. Ceramide
B. Cholesterol
C. Phosphoglyceride
D. Sphingomyelin

A

True of membrane fluidity:

A. Membrane cholesterol regulates and modulates the fluidity of the membrane
B. Saturated hydrocarbon tails increase membrane fluidity
C. The lower the membrane's fluidity the higher is its permeability to water and other polar substances
D. Unsaturated hydrocarbon tails decrease membrane fluidity

C

True of membrane carbohydrates:

A. They exist as independent component of the cell membrane
B. They are located in the cytosolic side of the cell membrane
C. They are always attached either to lipid or protein
D. They are important regulators of membrane fluidity

D

These are specialized area in the exoplasmic side of the membrane enriched with cholesterol and sphingolipids and appear to be involved in signal transduction:

A. Aquaporin
B. Tight junctions
C. Liposomes
D. Lipid rafts

C

It is a membrane lipid with a glycerol backbone with two fatty acids attached via an ester linkage and a phosphated alcohol:

A. Ganglioside
B. Glycosphingolipid
C. Phosphoglyceride
D. Sphingomyelin

B

An enclosed lipid bilayer acting as important carriers of DNA and other materials to be delivered to a target organ:

A. Caveolae
B. Liposome
C. Lipid raft
D. Micelle

C

Which of the following is a characteristic of membrane channels?

A. Involves binding of solute and conformational changes
B. Has a role both in passive and active transport
C. Transport is faster than via protein transporters
D. Transport requires expenditure of ATP

B

This is a category of transport mechanism in which 2 different molecules are transported in or out of the cell at the same time in the same direction:

A. Antiport
B. Symport
C. Simple diffusion
D. Uniport

D

It involves generation of signal molecules such as calcium, diacylglycerols and cyclic nucleotides in order to effect a response:

A. Active transport
B. Facilitated diffusion
C. Simple diffusion
D. Signal transmission

D

The exchange of gases (oxygen and carbon dioxide) that occurs in the lungs is an example of:

A. Active transport
B. Secondary active transport
C. Signal transduction
D. Simple diffusion

C

This transport mechanism relies on the concentration or electrochemical difference provided by the primary active transport:

A. Exocytosis
B. Receptor mediated pinocytosis
C. Secondary active transport
D. Signal transduction

A

The interaction of LDL to lysosome is an example of:

A. Absorptive pinocytosis
B. Fluid phase pinocytosis
C. Signal transduction
D. Primary active transport