Biology Exam Questions Flashcards by Allegra Masnata

Which of the following best describes the intermediate filaments?
A. They are the only filaments of the cytoskeleton that are not made up of proteins.
B. They are the main constituents of the cortex cellulare
C. They are always found outside the cell.
D. They help the cell to withstand mechanical stress.
E. None of the definitions is correct.

D. They help the cell to withstand mechanical stress.

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The filaments of the cytoskeleton that show “dynamic instability”:

A. scrolls continuously on themselves
B. move in the cytoplasm with a whip movement
C. change in length by means of polymerization and depolymerization.
D. tend to make the cytoplasm dynamically unstable.

C. change in length by means of polymerization and depolymerization.

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Which of these factors increases the fluidity of membranes?
A. Cholesterol
B. The ions Ca ++
C. The increase of the degree of unsaturation of fatty acids
D. long-chain fatty acids

C. The increase of the degree of unsaturation of fatty acids

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A molecule can be accumulated against their electrochemical gradient for
means of:
A. facilitated diffusion
B. Diffusion through a uni port channel
C. Active Transport

C. Active Transport

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Exocytosis is used by the cell for:
A. Secretion
B. Transport molecule in the extracellular space
C. To retrieve molecule from the extracellular space
D. To retrieve molecules from the plasma membrane

A. Secretion

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The activation of the G protein resulting in:
A. Gene Expression Changes
B. cAMP Increase
C. Generation of second messengers
D. Decreased cAMP

C. Generation of second messengers

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The receptors for the hormones:
A. They have high affinity for specific ligands
B. They are associated with G proteins
C. They are lipids
D. They are always located in the plasma membrane

A. They have high affinity for specific ligands

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During the process known as treadmilling:
A. proteins myosin induce the movement of actin filaments
B. The actin filaments of the muscle cells contract
C. New subunits are added at the positive while the negative subunit are anchored to membranes
D. The subunits are simultaneously added and removed from the filament.

C. New subunits are added at the positive while the negative subunit are anchored to membranes

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Which statement correctly describes the intermediate filaments?
A. They are the only filaments of the cytoskeleton that are not made up of proteins.
B. They are the main components of the cell cortex.
C. They are always found outside the cell.
D. They help the cell to withstand mechanical stress.

D. They help the cell to withstand mechanical stress.

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The monomeric GTPase Ran
A. Check the protein glycosylation
B. Check the directionality of traffic through the complex nuclear pore
C. Check the import of the nascent protein in the lattice
D. Check the correct protein folding.

B. Check the directionality of traffic through the complex nuclear pore

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Proteins synthesized on free ribosomes are intended to
A. nucleus, mitochondria, peroxisomes
B. Core, membrane, lysosomes
C. Golgi, mitochondria, membrane
D. nucleus, cytoplasm, membrane

D. nucleus, cytoplasm, membrane

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The interaction of the Notch receptor with its ligands
A. activates the signal transduction through a series of cuts proteolytic
B. active phosphorylation of phosphatidylinositol membrane.
C. induces autophosphorylation of the cytosolic tail
D. induces binding to a trimeric G protein

A. activates the signal transduction through a series of cuts proteolytic

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Yeast is an organism often used as a case study of the biology of eukaryotic cells, why?
A. you can separate clones
B. It is easy to grow
C. is easy to obtain the deletion of a specific gene
D. A + B + C

D. A + B + C

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Which of the following functions are carried out by the mitochondria?
A. biosynthesis of pyruvate
B. biosynthesis enzyme cofactors
C. oxidation of fatty acids
D. both B and C

D. both B and C

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The following statements about mitochondria are all false, except:
A. are present in all prokaryotic cells
B. contain substantial amounts of mioglobin
C. contain DNA and Ribosomes
D. accumulate peroxides

A. are present in all prokaryotic cells

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The protesomes:
A) They are abundant in the lumen of the reticle
B) They degrade DNA
C) are abundant in the cytoplasm
D) They degrade lipids

C) are abundant in the cytoplasm

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Rhodopsin, a key molecule in the reception of the light signal:
A) is a receptor associated G protein
B) It is a tyrosine kinase
C) He cAMP as a second messenger
D) A, B, C

A) is a receptor associated G protein

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The nucleus:
A) is surrounded by a lipid membrane continues
B) it is surrounded by the plasma membrane
C) it is surrounded by an extension of the reticulum membrane endoplasmic
D) it is the site of protein synthesis

C) it is surrounded by an extension of the reticulum membrane endoplasmic

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The endocytosis:
A) It is used by some viruses to infect cells
B) It is important in signaling pathways
C) It is not irrelevant in cancer
D) A, B, C

D) A, B, C

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Carbohydrates proteins are always exposed:
A) in the intracellular portion
B) in the extracellular portion
C) in the transmembrane portion
D) A, B, C

B) in the extracellular portion

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The movement of the bacterial flagella is regulated by:
A) microtubules
B) keratin filaments
C) centromeres
D) desmosomes

A) microtubules

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In what organelle does oxidative phosphorylation takes place?
A) phagosome
B) Golgi apparatus
C) endosome
D) mitochondrion

D) mitochondrion

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Microfilaments:
A) They are composed of tubulin
B) are composed of actin
C) are abundant in the mitochondrial matrix
D) They form the nuclear lamina

B) are composed of actin

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Which technique pressed the display of proteins?
A) Polymerase Chain Reaction
B) Northern blot
C) Southern blot
D) Western-blot

D) Western-blot

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integrins A) They are made up of seven transmembrane polypeptides B) are not associated with the cytoskeleton C) Defensive contacts between cells D) They are abundant in the nucleus

C) Defensive contacts between cells

NFkB A) It is involved in inflammation B) Cycle between the cytoplasm and the nucleus C) It is part of a complex signaling pathway D) A, B, C

D) A, B, C

What is the main function of dendritic cells? A) Secretion of antibodies B) Antigen presentation C) Phagocytosis D) Secretion of histamine

B) Antigen presentation

The Bcl-2 protein: A) Adjust the content of Ca ++ in the endoplasmic reticulum and its release B) It plays a vital role in cellular homeostasis C) Adjust the UPR - Unfoded Protein Response D) It has anti-apoptotic function

D) It has anti-apoptotic function

The cell cycle progression is controlled: A) From the G1 and G2 phase B) From the stage M C) From the S phase D) From the state G0

A) From the G1 and G2 phase

The necrosis is associated with: A) Condensation of chromatin B) fragmentation in apoptotic bodies C) Inflammation D) A, B, C

C) Inflammation

The exposure of phosphatidylserine on the outer face of the plasma membrane: A) induces endocytosis B) promotes the transcription C) And an early sign of apoptosis D) It is a signal of the start of cell division

C) And an early sign of apoptosis

The Rb protein is a classic tumor-suppressor that: A) Locks the cell cycle in G1 B) Turn the protein Ras C) It is caused by the Human Papilloma Virus D) It is a signal of the start of cell division

A) Locks the cell cycle in G1

Cyclins: A) They control the protein glycosylation B) Adjust the acrosome reaction C) are components of the cell junctions D) are enzyme complexes that undergo synthesis cycles and degradation in each cell cycle.

D) are enzyme complexes that undergo synthesis cycles and degradation in each cell cycle.

Wnt and Notch: A) They control the differentiation of intestinal stem cells B) They induce the production of Vascular Endothelial Growth Factor C) They control the growth of skeletal muscle D) Adjust the migration of stem cells

A) They control the differentiation of intestinal stem cells

The RANKL protein mediates communication between: A) B lymphocytes and T lymphocytes B) Osteoblasts and osteoclasts C) keratinocytes and basal lamina D) fibroblasts and extracellular matrix

B) Osteoblasts and osteoclasts

One of the defense mechanisms of epithelial cells of the oral cavity: A) Surfactant B) Lysozyme C) Fatty acids D) Antibodies

B) Lysozyme

During infection with pathogens such as Porphyromonas gingivalis in periodontal tissue It is observed: A) Complement activation B) Inhibition of Interleukin-8 C) Production of defensins D) A, B, C

D) A, B, C

Cytokinesis is the process by which: A) A cell moves in the extracellular matrix B) The chromosomes move along the mitotic spindle C) The cytoplasm divides after mitosis D) The scripts are proteins transported into the cytoplasm of a cell

C) The cytoplasm divides after mitosis

Which of these factors increases the rigidity of the membranes: A) The increase of the degree of unsaturation of fatty acids B) The reduction of the degree of unsaturation of fatty acids C) The presence of glycoproteins D) Gli ioni Na+

B) The reduction of the degree of unsaturation of fatty acids

As an erythrocyte maintains its cell volume? A) Using a pump Na + -K + B) Through an ABC transporter C) Using the transporter GLUT4 D) By means of a pump Ca ++ - dependent

A) Using a pump Na + -K +

The nuclear lamina has function of A) Support, chromatin organization, B) Transcriptional regulation and DNA replication C) Assembly and positioning of the core D) A, B, C

D) A, B, C

Tay Sachs disease is caused by: A) The deficiency of the enzyme phosphatidylinositol 4,5-biphosphate 5 phosphatase B) A deficiency of lysosomal enzymes required for a division of gangliosides C) A mutation in the lamina A gene D) A defect in the function of peroxisomes

B) A deficiency of lysosomal enzymes required for a division of gangliosides

Vesicular transport is involved in all the processes listed below, except: A) of solutes Pumps B) Traffic substances C) Exocytosis D) Endocytosis

A) of solutes Pumps

The mode of transmission of an endocrine signal is characterized by: A) Low affinity for its receptor B) Action at a distance of target cells C) Action on cells in direct contact with each other D) Fast Transmission

B) Action at a distance of target cells

Which of the following is the correct sequence of the stages of mitosis? A) telophase, anaphase, prophase, metaphase B) anaphase, prophase, telophase, metaphase C) prophase, anaphase, metaphase, telophase D) prophase, metaphase, anaphase, telophase

D) prophase, metaphase, anaphase, telophase

Cytokinesis is the process by which: A) A cell moves in the extracellular matrix B) The chromosomes move along the mitotic spindle C) The cytoplasm divides after mitosis D) The proteins are transported into the cytoplasm of a cell

C) The cytoplasm divides after mitosis

B) The reduction of the degree of unsaturation of fatty acids

As an erythrocyte maintains its cell volume? A) Using a pump Na + -K + B) Through an ABC transporter C) Using the transporter GLUT4 D) By means of a pump Ca ++ - dependent

A) Using a pump Na + -K +

The nuclear lamina has function of: A) Support, chromatin organization, B) Transcriptional regulation and DNA replication C) Assembly and positioning of the core D) A, B, C

D) A, B, C

The energy produced during cellular respiration can be immediately stored in: A) ATP B) Glucose C) Lipids D) Proteins

A) ATP

In what stage of mitosis the chromosomes are aligned at the equator of the cell? A) Prophase B) Metaphase C) Anafase D) Interphase

B) Metaphase

The massive caspase activation is: A) An early sign of apoptosis B) A fatal sign of apoptosis C) An early sign of necrosis D) The initial stage of phagocytosis

B) A fatal sign of apoptosis

Cytotoxic T lymphocytes kill target cells by: A) Integrins B) receptors associated with G protein C) The perforins D) The Heat Shock Proteins

C) The perforins

The cell adhesion-cell and cell-matrix is mediated by all of the following molecule, except: A) selectins B) Interleukins C) cadherins D) Members of the superfamily of immunoglouline

B) Interleukins

The channel junctions A) They allow the ion exchange and small molecule B) are present at the level of the immunological synapse C) They encourage cell-extracellular matrix contact D) Make up the emodesmosomes

A) They allow the ion exchange and small molecule

Which of the following is not a characteristic of cancer cells: A) Loss of cell cycle control B) Trapiantabilità C) Loss of contact inhibition D) A, B, C

D) A, B, C

To what type of cancer is associated with the BCRA-1 gene: A) Thyroid B) Udder C) Leukemia D) Bone

B) Udder

Which of the following is not a form of defense of the body's surface? A) Skin B) Salivary amylase C) Mucus D) microflora intestine

B) Salivary amylase

lysozyme A) It is a cytoplasmic organelle B) It is a proteolytic enzyme C) degrades the peptidoglycan cell wall D) Activates the complement

C) degrades the peptidoglycan cell wall

In an experiment, which is the function of the positive control? A) It is the substance that is to be identified B) the reference standard C) the rappresentative from a sample that definitely is a positive result D) Its inclusion in an experiment is not always necessary

C) the rappresentative from a sample that definitely is a positive result

Which of these ions is present in significantly higher concentration inside than outside the cell? A) Ca2 + B) Cl- C) H + D) K + E) Na +

D) K +

The membrane potential of a resting cell is determined primarily by the concentration gradient within the cell of _____ A) Cl- B) protein anions C) K + D) Na +

C) K +

the pancreas cells incorporate amino acids labeled with radioactive isotopes in proteins. This "marking" of newly synthesized proteins allows the researcher to monitor the localization of these molecules within the cell. In this case, you use imaging to analyze the path of an enzyme produced by pancreatic cells, What is probably most likely route taken by this enzyme? A) Golgi - ER - Lysosomes B) Core - ER - Golgi C) ER - Golgi - vesicles fuse with the plasma membrane D) ER – lysosomes - vesicles fuse with the plasma membrane

C) ER - Golgi - vesicles fuse with the plasma membrane

Cyanide binds to certain molecules involved in the production of ATP. Should one the cell must be exposed to cyanide, most of such a compound would be reflected in: A) Mitochondria B) Ribosomes C) Peroxisomes D) pattern endoplasmic

A) Mitochondria

Vinblastine is a drug currently used in chemotherapy. Given that the drug in interferes with the assembly of microtubules, its effectiveness should be put in relation to: A) Interference with the formation of the mitotic spindle B) inhibition of phosphorylation of regulatory proteins C) A block in the synthesis of cyclins D) An inhibition of DNA synthesis

A) Interference with the formation of the mitotic spindle

A given cell presents half of the DNA than other cells present in a tissue metabolically active. This cell then is in: A) G1 B) G2 C) Prophase D) Metaphase

A) G1

One of the differences between tumor cells and normal cells is that the first: A) they are not capable of synthesizing DNA B) They stop in the S phase of the cell cycle C) They continue to divide even when they are in close contact with each other D) They go to apoptosis due to inhibition by contact

C) They continue to divide even when they are in close contact with each other

The drug cytochalasin B interferes with actin function. Which of the following cell cycle aspects will be more affected by the treatment with cytochalasin B? A) of the mitotic spindle formation B) Attack of the spindle fibers to kinetochores C) Dintesi DNA D) formation of the cleavage furrow

D) formation of the cleavage furrow

Which of the following events do NOT occurs during mitosis? A) Condensation of chromosomes B) DNA replication C) Separation of sister chromatids D) Separation of the poles of the mitotic spindle

B) DNA replication

The phosphorylation cascades that involve a sequential activation of protein kinase are optimal for the signal transduction because: A) They are species-specific B) They induce always the same cellular response C) greatly amplify the initial signal D) The number of molecules involved is small and constant.

C) greatly amplify the initial signal

Which type of receptor, binding a specific signal sequence, directly causes a variation of the ion concentration on the opposite side of the membrane? A) A tyrosine kinase receptor B) A G-protein coupled receptor C) A voltage-dependent ion channel D) A dimer of phosphorylated tyrosine kinase

C) A voltage-dependent ion channel

The activation of tyrosine kinase receptors is characterized by: A) Dimerization and phosphorylation B) Binding of IP3 C) A phosphorylation cascade D) Hydrolysis of GTP

A) Dimerization and phosphorylation

The fat-soluble signaling molecules, such as testosterone, crossing the membrane of all cells, but they work only on specific target cells. Because? A) The intracellular receptors are present only on the target cells B) The majority of the cells is devoid of chromosome Y C) Only the target cells possess the cytosolic enzymes that transduce the testosterone signal D) Testosterone is able to start the cascade that the activation of the transcription factor only in the target cells

A) The intracellular receptors are present only on the target cells

Consider the following route: Adrenaline> receptor associated protein G> G protein> adenylate cyclase> cAMP. Which is the second messenger? A) cAMP B) Protein G C) GTP D) Adenylate cyclase

A) cAMP

Apoptosis involves all except the following events: A) DNA Fragmentation B) intracellular signaling C) Activation of intracellular enzymes D) Cell lysis

D) Cell lysis

Difference between cell membranes in an eukaryotic cell? A) Phospholipids are only found in some membranes B) Each has specific membrane proteins C) Only some membranes are made up of amphipathic molecules D) In some membranes the surfaces exposed to the cytoplasm are hydrophobic, while in others are hydrophilic.

B) Each has specific membrane proteins

According to the fluid mosaic model of membrane structure, the proteins membrane are primarily: A) Distributed in a continuous layer over the internal and the external surface of the the membrane B) Confined in the hydrophobic core of the membrane C) Immersed in the lipid bilayer D) Free to leave the membrane and surrounding solution

C) Immersed in the lipid bilayer

Which of the following factors tends to increase membrane fluidity? A) A greater amount of unsaturated phospholipids B) A greater amount of saturated phospholipids C) A lower temperature D) A greater quantity of large glycolipids

A) A greater amount of unsaturated phospholipids

Which of the following processes include others? A) The osmosis B) The diffusion through a membrane C) The passive transport D) The transport of an ion according electrochemical gradient

C) The passive transport

Homologous chromosomes migrate to oposti poles of a dividing cell in the course of: A) Mitosis B) Meiosis I C) meiosis II D) fertilization

B) Meiosis I

Meiosis II is similar to mitosis because: A) The sister chromatids separate during anaphase B) The DNA is duplicated before division C) The daughter cells are diploidi D) The number of chromosomes is reduced

A) The sister chromatids separate during anaphase

If the DNA content of a diploid cell in G1 phase cell cycle was equal to dl x, the DNA content of the same cell during metaphase of meiosis I would be: A) 0.25x B) x C) 2x D) 4x

B) x

Cell differentiation always involves: A) The production of tissue-specific proteins B) The movement of cells C) The selective loss of certain genes within the genome D) The cell sensitivity to environmental stimuli

A) The production of tissue-specific proteins

Which of the following events is an example of post-transcriptional control gene expression? A) The addition of methyl groups to cytosine of the DNA B) The binding of transcription factors to the promoter C) The folding of the DNA to form heterochromatin D) The removal of introns and the splicing of exons

D) The removal of introns and the splicing of exons

Within a cell the amount of protein produced by a specific mRNA molecule It depends in part: A) From the level of DNA methylation B) From the mRNA degradation rate C) From the number of introns present in the mRNA D) The type of ribosomes in the cytoplasm

B) From the mRNA degradation rate

Which of the following events is repeated the same number of times in spermatogenesis and In oogenesis? A) Interruption of meiotic divisions B) Production of functional gametes during meiosis C) meiotic divisions needed to produce each gamete D) Production of different cell types during meiosis

C) meiotic divisions needed to produce each gamete

Which of the following statements related to human reproduction is false? A) The fertilization occurs inside the fallopian tube B) An oocyte completes meiosis only after a sperm has penetrated theinside C) The initial stages of spermatogenesis occur in the area closest to the lumen in seminiferous tubule D) The effective hormonal contraceptives are only available for women.

D) The effective hormonal contraceptives are only available for women.

A pathologist examining a skin sample from a patient with malignant melanoma, It notes that the majority of cells have large nucleoli. This his observation It suggests that the cells are producing large quantities of: A) Golgi Apparatus B) the newly synthesized DNA C) Ribosomes D) Surface Receptors

C) Ribosomes

Many proteins undergo modifications during and / or after translation. ATP-dependent ubiquitination of proteins is a signal for: A) The addition of an oligosaccharide to the extreme N-terminal of the protein B) The recycling of the protein from the cis-Golgi to the endoplasmic reticulum to allow the ripiegamento corretto correct folding C) The addressing of the protein to the proteasome for its degradation D) The translocation of the protein into the nucleus.

C) The addressing of the protein to the proteasome for its degradation

When the cells progress through the cell cycle division, they are subjected to control mechanisms that ensure the fidelity of the process. A critical checkpoint check the occurrence of any damage to the DNA, such as those induced by radiation UV. Which of the following proteins is involved in cell cycle arrest following Detection of DNA damage? A) CDK2 B) Cyclin A C) Cyclin D D) p53

D) p53

Hormones interact with specific intracellular receptors, and this regulates interaction: A) The DNA replication B) The transcription of specific genes C) The translation of specific RNAs D) The post-translational processing of specific proteins

B) The transcription of specific genes

Some pathogens have targeted members of the routes of transmission of the intracellular signal. For example, Vibrio cholerae, the etiological agent of cholera, cause profuse diarrhea interfering with a route of intracellular signal transmission. In fact, a cholera toxin gets inside the intestinal cells and change the protein molecules chemically G. Once changed, the G protein can no longer hydrolyze GTP to GDP. What you are expected to comply within a gut cell of an individual with cholera? A) The activated G protein remains active and persistently adenylate cyclase B) The G protein is activated and can not activate the adenylate cyclase C) The subunit of the G protein do not separate D) The receptor associated G protein that is found in the membrane remains activated

A) The activated G protein remains active and persistently adenylate cyclase

Biology Exam Questions Flashcards

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