Dr. Kallie Mini Q2
- 1.
Which of the following statements concerning the plasmalemma is CORRECT?
- A.
Integral protein are located only on the cytosolic side of the lipid bilayer
- B.
Phospholipids are identical in composition in both the outer and inner regions of the lipid bilayer
- C.
Sphingomyelin and ethanolamine are evenly distributed throughout the lipid bilayer
- D.
Phospholipids having saturated and unsaturated fatty acids contribute to lipid asymmetry
- E.
Pheripheral proteins are only found on the cytosolic side of the lipid bilayer
Correct Answer
D. Phospholipids having saturated and unsaturated fatty acids contribute to lipid asymmetryExplanation
Lipid asymmetry refers to the uneven distribution of phospholipids in the lipid bilayer of the plasmalemma. This asymmetry is maintained by the presence of phospholipids with different fatty acid compositions, specifically saturated and unsaturated fatty acids. The presence of both types of fatty acids contributes to the asymmetry of the lipid bilayer.Rate this question:
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- 2.
Which of the following statements relating to receptor sites of the plasmalemma is CORRECT?
- A.
ACTH (adrenocorticotropic hormone) binds to receptor sites on the thyroid gland
- B.
TSH binds to the phospholipids of the lipid bilayer
- C.
The carbohydrate portion of membrane proteins act as receptor sites for ligands or hormones
- D.
TSH (thyroid stimulating hormone) binds to receptor sites on the adrenal gland
- E.
The receptor sites for ligands are located on the cytosolic side of the plasmalemma
Correct Answer
C. The carbohydrate portion of membrane proteins act as receptor sites for ligands or hormonesExplanation
The carbohydrate portion of membrane proteins act as receptor sites for ligands or hormones. This is because the carbohydrate chains attached to membrane proteins can act as recognition sites for specific molecules, allowing them to bind and initiate cellular responses. These carbohydrate chains can also contribute to the structural stability and proper folding of membrane proteins. Therefore, the statement correctly describes the role of the carbohydrate portion of membrane proteins in acting as receptor sites for ligands or hormones.Rate this question:
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- 3.
The primary function of intermediate filaments is to
- A.
Generate movement
- B.
Produce the structural core of microvilli
- C.
Provide mechanical stability
- D.
Produce the axoneme of flagella
- E.
Be involved in the movement of chromosomes
Correct Answer
C. Provide mechanical stabilityExplanation
Intermediate filaments are a type of cytoskeletal protein that provide mechanical stability to cells. They form a network of fibers that help to maintain the structural integrity of cells and tissues, especially under mechanical stress. Unlike microfilaments and microtubules, intermediate filaments are not involved in generating movement or producing specific cellular structures like microvilli or flagella. Instead, their main function is to provide support and stability, making them essential for maintaining the shape and strength of cells.Rate this question:
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- 4.
Which of the following is found primarily in the lamina densa of the basement membrane?
- A.
Type III collagen and proteoglycans
- B.
Type IV collagen and proteoglycans
- C.
Microfibrils and proteoglycans
- D.
Laminin and Fibronectin
- E.
Reticular fibers and type VII collagen
Correct Answer
B. Type IV collagen and proteoglycansExplanation
Type IV collagen and proteoglycans are found primarily in the lamina densa of the basement membrane. The lamina densa is the middle layer of the basement membrane and is responsible for providing structural support and filtration. Type IV collagen is the main structural component of the lamina densa, forming a mesh-like network that gives the basement membrane its strength. Proteoglycans, on the other hand, help to regulate the permeability and filtration properties of the basement membrane. Together, type IV collagen and proteoglycans play a crucial role in maintaining the integrity and function of the basement membrane.Rate this question:
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- 5.
Which of the following statements BEST describes pseudostratified columnar epithelium?
- A.
All cells make contact with the basal lamina
- B.
Nuclei are all located at the basal end of each cell
- C.
Cells are all the same size and columnar in shape
- D.
Columnar cells form the basal layer of cells and the intermediate layers above are composed of polyhedral cells
- E.
Basal infoldings are a prominent feature of this epithelium
Correct Answer
A. All cells make contact with the basal laminaExplanation
Pseudostratified columnar epithelium is a type of epithelial tissue where all cells make contact with the basal lamina. This means that every cell in this tissue is in direct contact with the underlying basement membrane. The nuclei of the cells may be at different heights, giving the appearance of stratification, but all cells still maintain contact with the basal lamina. This type of epithelium is commonly found in the respiratory tract, where it helps to protect and move mucus and particles out of the airways.Rate this question:
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- 6.
Which of the following surface specializations is unique to the cells lining the epididymis?
- A.
Flagella
- B.
Cilia
- C.
Stereocilia
- D.
Microvilli and basal infoldings
- E.
Cilia and microvilli
Correct Answer
C. StereociliaExplanation
Stereocilia are the correct answer because they are unique to the cells lining the epididymis. Stereocilia are long, nonmotile, microvilli-like projections that are found in the epididymis and are involved in the absorption and secretion of substances. Unlike cilia, which are found in many other types of cells, stereocilia are only present in the cells lining the epididymis. Therefore, stereocilia are the surface specialization that is specific to the cells of the epididymis.Rate this question:
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- 7.
On the basal side of the cell, the cystoskeleton of the cell attaches the plasma membrane to the basal lamina via?
- A.
Cytokeratin filaments
- B.
Integrins
- C.
Actin microfilaments
- D.
Cadherins Ca++ dependent proteins
- E.
Proteoglycans
Correct Answer
B. IntegrinsExplanation
Integrins are transmembrane proteins that connect the cytoskeleton of a cell to the extracellular matrix (ECM). They play a crucial role in cell adhesion and signaling. In this case, integrins are responsible for attaching the plasma membrane to the basal lamina on the basal side of the cell. This attachment is important for maintaining the structural integrity of the cell and for facilitating communication between the cell and its surrounding environment.Rate this question:
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- 8.
Which of the following statements concerning zonula adherens is CORRECT?
- A.
Cadherins Ca++ dependent proteins on the plasma membrane bind to actin microfilaments via vinculin and alpha actinin
- B.
Tonofilaments insert on cytosolic side of the plasma membrane of each cell
- C.
An intermediate dense line of desmoglein is present in the intercellular space
- D.
The intercellular space is 30 nm or greater
- E.
The terminal web is composed only of actin microfilaments
Correct Answer
A. Cadherins Ca++ dependent proteins on the plasma membrane bind to actin microfilaments via vinculin and alpha actininExplanation
Zonula adherens is a cell junction that connects adjacent cells. Cadherins are calcium-dependent proteins that are present on the plasma membrane and play a role in cell-cell adhesion. In zonula adherens, cadherins bind to actin microfilaments through the proteins vinculin and alpha actinin. This binding helps to stabilize the junction and maintain cell-cell adhesion. Therefore, the statement that cadherins bind to actin microfilaments via vinculin and alpha actinin is correct.Rate this question:
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- 9.
Which of the following statements concerning meiosis is CORRECT?
- A.
Separation of chromatids occurs during anaphase I of meiosis I
- B.
Pairing of homologous chromosomes occurs in prophase I of meiosis I
- C.
Non disjunction can only occur in meiosis II
- D.
Crossing over of genetic material occurs in metaphase I of meiosis I
- E.
Pairing of homologous chromosomes occurs in metaphase I of meiosis I
Correct Answer
B. Pairing of homologous chromosomes occurs in prophase I of meiosis IExplanation
During prophase I of meiosis I, homologous chromosomes pair up and undergo a process called synapsis. This pairing is essential for the exchange of genetic material between the chromosomes, known as crossing over. Therefore, the statement that pairing of homologous chromosomes occurs in prophase I of meiosis I is correct.Rate this question:
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- 10.
Which of the following statements concerning gametogenesis is CORRECT?
- A.
Primary oocytes are arrested in the diplotene stage of prophase II before birth
- B.
Primary follicles are all formed at the time of birth
- C.
Primary spermatocytes are formed before birth
- D.
Follicular cells of the primordial follicles secrete oocyte maturation inhibitor
- E.
Ova are produced at the time of birth
Correct Answer
D. Follicular cells of the primordial follicles secrete oocyte maturation inhibitor -
- 11.
During the process of fertilization:
- A.
Acrosin and neuraminidase are released from the cortical granules. These enzymes digest the zona pellucida
- B.
The sperm's plasma membrane fuses with the cells of the corona radiata
- C.
The tail of the sperm drops off as the sperm touches the zona pellucida
- D.
Acrosin and neuraminidase are released from the acrosome. These enzymes digest the zona pellucida
- E.
The cortical granules release enzymes that digest the corona radiata cells
Correct Answer
D. Acrosin and neuraminidase are released from the acrosome. These enzymes digest the zona pellucida -
- 12.
Which of the following statements concerning the fertilization process is CORRECT?
- A.
Uncapacitated sperms can penetrate the secondary oocyte
- B.
Enzymes released from the cortical granules cause the oocyte plasma membrane and the zona pellucida to undergo a conformational change
- C.
The zygote that is produced has 1n chromosome number
- D.
Several sperms normally penetrate the secondary oocyte
- E.
Sperms become capacitated in the epididymis
Correct Answer
B. Enzymes released from the cortical granules cause the oocyte plasma membrane and the zona pellucida to undergo a conformational changeExplanation
During the fertilization process, enzymes released from the cortical granules cause the oocyte plasma membrane and the zona pellucida to undergo a conformational change. This change in the plasma membrane and zona pellucida prevents any additional sperm from penetrating the oocyte, ensuring that only one sperm is able to fertilize the egg. This process is known as the zona reaction and is necessary for successful fertilization to occur.Rate this question:
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- 13.
During the menstrual cycle
- A.
Follicle stimulating hormone causes ovulation of the secondary oocyte
- B.
A primary oocyte arrested at metaphase I of meiosis I is released at the time of ovulation
- C.
Luteinizing hormone stimulates the granulosa and theca interna layers to form the corpus luteum
- D.
Luteinizing hormone stimulates several primordial follicles to develop
- E.
Follicle stimulating hormone stimulates the corpus luteum to secrete estrogen
Correct Answer
C. Luteinizing hormone stimulates the granulosa and theca interna layers to form the corpus luteumExplanation
During the menstrual cycle, luteinizing hormone (LH) stimulates the granulosa and theca interna layers of the ovarian follicle to form the corpus luteum. The corpus luteum is a temporary endocrine structure that forms after ovulation and secretes hormones such as progesterone and estrogen. This hormone production is essential for preparing the uterus for potential implantation of a fertilized egg. Therefore, the statement that LH stimulates the granulosa and theca interna layers to form the corpus luteum is correct.Rate this question:
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- 14.
Which of the following statements concerning the menstrual cycle is CORRECT?
- A.
Human chorionic gonadotropin is secreted from the pituitary gland
- B.
Progesterone secreted from the corpus luteum inhibits the secretion of luteinizing hormone
- C.
Estrogen secreted from the corpus luteum. stimulates ovulation
- D.
Progesterone secreted from the corpus luteum inhibits the secretion of Follicle stimulating hormone
- E.
Human chorionic gonadotropin causes primordial follicles to develop
Correct Answer
B. Progesterone secreted from the corpus luteum inhibits the secretion of luteinizing hormoneExplanation
Progesterone, which is secreted from the corpus luteum, plays a role in regulating the menstrual cycle. One of its functions is to inhibit the secretion of luteinizing hormone (LH) from the pituitary gland. This is important because LH is responsible for triggering ovulation. By inhibiting LH secretion, progesterone helps to prevent further ovulation during the menstrual cycle.Rate this question:
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- 15.
- Which of the following statements concerning development of the zygote is
- A.
The inner cell mass attaches to the endometrial layer
- B.
The zygote undergoes several meiotic divisions to form the morula
- C.
The blastocyst is composed of a compacted mass of cells
- D.
The morula implants into the endometrial layer of the uterus
- E.
At around 5 6 days, the blastocyst loses its zona pellucida and implants on the endometrium as a result of the trophoblast layer
Correct Answer
E. At around 5 6 days, the blastocyst loses its zona pellucida and implants on the endometrium as a result of the trophoblast layerExplanation
The correct answer is that at around 5-6 days, the blastocyst loses its zona pellucida and implants on the endometrium as a result of the trophoblast layer. This statement accurately describes the process of implantation, which occurs during the early stages of pregnancy. The blastocyst, a hollow ball of cells, attaches to the endometrial layer of the uterus and begins to invade the tissue. This attachment is facilitated by the trophoblast layer, which helps the blastocyst to implant and establish a connection with the maternal blood supply. The loss of the zona pellucida, a protective layer surrounding the blastocyst, is necessary for this process to occur.Rate this question:
- 16.
During the 2nd week of development
- A.
The uteroplacental circulation develops within the secondary yolk sac
- B.
The primitive uteroplacental circulation is established as a result of the activity of syncytiotrophoblast cells on maternal sinusoids
- C.
The inner cell mass is composed of trophoblast and hypoblast
- D.
The bilaminar germ disc is composed of epiblast and trophoblast
- E.
The amniotic cavity lies below the hypoblast layer of cells
Correct Answer
B. The primitive uteroplacental circulation is established as a result of the activity of syncytiotrophoblast cells on maternal sinusoidsExplanation
During the 2nd week of development, the primitive uteroplacental circulation is established as a result of the activity of syncytiotrophoblast cells on maternal sinusoids. This means that the syncytiotrophoblast cells, which are part of the developing placenta, interact with the maternal sinusoids (blood vessels) to establish a circulation system that allows for the exchange of nutrients and waste products between the mother and the developing embryo. This is an important step in the development of the placenta and ensures that the growing embryo receives the necessary nutrients for its development.Rate this question:
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- 17.
Which of the following statements concerning embryonic development is CORRECT?
- A.
Placenta praevia refers to implantation of the fertilized egg in the fallopian tube
- B.
The trophoblast cells differentiates into syncytiotrophoblast and cytotrophoblast
- C.
The germ disc during the second week of development is composed of epiblast, trophoblast and mesoderm
- D.
The amnion develops around the 13th day of development and is called the secondary yolk sac
- E.
The prochordal plate develops from the epiblast layer which is columnar in shape
Correct Answer
B. The trophoblast cells differentiates into syncytiotrophoblast and cytotrophoblastExplanation
The trophoblast cells differentiate into syncytiotrophoblast and cytotrophoblast during embryonic development. This process occurs in the early stages of pregnancy and is essential for the formation of the placenta. The syncytiotrophoblast is responsible for implantation and invasion into the uterine wall, while the cytotrophoblast helps in the formation of the chorionic villi. Together, these two cell types play a crucial role in supporting the developing embryo and facilitating nutrient and waste exchange between the mother and the fetus.Rate this question:
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- 18.
Which of the following descriptions BEST suit the multilaminar primary follicle?
- A.
An oogonia surrounded by a single layer of columnar cells
- B.
A primary oocyte surrounded by a single layer of cuboidal cells
- C.
A primary oocyte surrounded by many layers of follicular or granulosa cells
- D.
A primary oocyte surrounded by a flattened layer of follicular cells
- E.
A primary oocyte surrounded by a corona radiata layer of cells
Correct Answer
C. A primary oocyte surrounded by many layers of follicular or granulosa cellsExplanation
A multilaminar primary follicle is characterized by a primary oocyte surrounded by many layers of follicular or granulosa cells. This description indicates that the follicle is in the early stage of development, with multiple layers of cells surrounding the oocyte. The presence of these layers of cells is essential for the growth and maturation of the oocyte.Rate this question:
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- 19.
- Which of the following statements concerning the mature graafian follicle is
- A.
Follicle stimulating hormone stimulates the granulosa layer to convert androstenedione to estrogen
- B.
Follicle stimulating hormone stimulates the theca interna layer to produce progesterone
- C.
The theca externa layer produces estrogen
- D.
The theca interna layer produces estrogen
- E.
Progesterone stimulates ovulation of the secondary oocyte from the graafian follicle
Correct Answer
A. Follicle stimulating hormone stimulates the granulosa layer to convert androstenedione to estrogenExplanation
The granulosa layer of the mature graafian follicle is responsible for converting androstenedione to estrogen. This process is stimulated by follicle stimulating hormone.Rate this question:
- 20.
In the absence of fertilization, the
- A.
Corpus luteum degenerates and forms scar tissue called the corpus albicans
- B.
Corpus luteum enlarges to become the corpus luteum of pregnancy
- C.
Human chorionic gonadotropin maintains the viability of the corpus luteum
- D.
Luteinizing hormone continues to stimulate the corpus luteum
- E.
The corpus luteum last for only 2 days after ovulation
Correct Answer
A. Corpus luteum degenerates and forms scar tissue called the corpus albicansExplanation
In the absence of fertilization, the corpus luteum degenerates and forms scar tissue called the corpus albicans. This is because the corpus luteum is responsible for producing hormones that support pregnancy, such as progesterone. If fertilization does not occur, there is no need for the corpus luteum to continue producing these hormones, so it begins to break down and eventually forms scar tissue. This process prepares the body for the next menstrual cycle.Rate this question:
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- 21.
Which of the following statements concerning the growing (developing) follicles is CORRECT?
- A.
Estrogens from the granulosa cells stimulates proliferation and regeneration of the endometrial lining
- B.
Androstenedione stimulates the endometrial glands to secrete glycolipids
- C.
Follicle stimulating hormone stimulates regeneration and proliferation of the endometrial lining
- D.
The corpus luteum enhances development of the follicles
- E.
Luteinizing hormone causes growing follicles to become atretic
Correct Answer
A. Estrogens from the granulosa cells stimulates proliferation and regeneration of the endometrial liningExplanation
Estrogens produced by the granulosa cells within the growing follicles stimulate the proliferation and regeneration of the endometrial lining. This is because estrogens play a crucial role in preparing the uterus for implantation and maintaining the endometrial lining during the menstrual cycle. They promote the growth and development of the endometrium, ensuring it is receptive to a fertilized egg.Rate this question:
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- 22.
Which of the following cell types differentiates into macrophages?
- A.
Neutrophil
- B.
Fibroblast
- C.
Chondroblast cell
- D.
Plasma cell
- E.
Monocyte
Correct Answer
E. MonocyteExplanation
Monocytes are a type of white blood cell that can differentiate into macrophages. Macrophages play a crucial role in the immune system by engulfing and digesting pathogens, dead cells, and other debris. Monocytes are produced in the bone marrow and circulate in the bloodstream. When they migrate to tissues, they transform into macrophages. Therefore, monocytes are the correct answer as they have the ability to differentiate into macrophages.Rate this question:
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- 23.
Which of the following statements concerning loose areolar connective tissue is NOT CORRECT?
- A.
It is composed of a dense arrangement of collagen fibers
- B.
It has lots of ground substance
- C.
It is composed of a great abundance of different cell types
- D.
It is found around glandular units
- E.
It is found surrounding small blood vessels
Correct Answer
A. It is composed of a dense arrangement of collagen fibersExplanation
Loose areolar connective tissue is not composed of a dense arrangement of collagen fibers. Instead, it has a loose arrangement of collagen fibers, which allows for flexibility and movement. This tissue type is characterized by its abundance of ground substance and various cell types. It is found surrounding glandular units and small blood vessels.Rate this question:
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- 24.
In the biosynthesis of collagen
- A.
The signal peptides of the procollagen molecule is removed in the Golgi complex
- B.
Specific proteases (procollagen peptidase) remove the registration peptides within the cytosol
- C.
Procollagen molecules are soluble due to the registration peptides
- D.
Glycosylation of specific proline occurs before hydroxylation
- E.
Polypeptide alpha chains are formed on SER
Correct Answer
C. Procollagen molecules are soluble due to the registration peptidesExplanation
The registration peptides in procollagen molecules make them soluble.Rate this question:
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- 25.
In certain pathological conditions, the amount of tissue fluid may increase thus causing edema. This condition may be BEST characterized by
- A.
Lack of plasma proteins due to protein deficiency
- B.
Lack of proteoglycans
- C.
Deficiency of glycosaminoglycans
- D.
Over production of collagen fibers
- E.
Constriction of the arterioles
Correct Answer
A. Lack of plasma proteins due to protein deficiencyExplanation
Edema is the accumulation of excess fluid in the tissues, leading to swelling. One of the main causes of edema is a lack of plasma proteins due to protein deficiency. Plasma proteins, such as albumin, help maintain the balance of fluid in the blood vessels. When there is a deficiency of these proteins, fluid can leak out of the blood vessels and into the surrounding tissues, causing edema. Therefore, the lack of plasma proteins due to protein deficiency is the best characterization for this condition.Rate this question:
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- 26.
Which of the following statements regarding proteoglycans in ground substance is CORRECT?
- A.
The glycosaminoglycans of proteoglycans have a high negative charge that attracts cations (such as Na+) and binds to water molecules
- B.
The glycosaminoglycans make up about 20% of the proteoglycan molecule
- C.
The glycosaminoglycans are called perlacans
- D.
Proteoglycans contain branched chain polysaccharides
- E.
Hyaluronic acid is a typical proteoglycan molecule that binds to heparan sulfate and chondroitin sulfate
Correct Answer
A. The glycosaminoglycans of proteoglycans have a high negative charge that attracts cations (such as Na+) and binds to water moleculesExplanation
Proteoglycans are composed of a core protein with attached glycosaminoglycan (GAG) chains. GAGs have a high negative charge due to the presence of sulfate or carboxyl groups. This negative charge attracts cations like sodium (Na+) and binds to water molecules, creating a hydrated gel-like substance in the extracellular matrix. This property allows proteoglycans to provide resistance to compression and act as a lubricant in tissues. Therefore, the statement that the glycosaminoglycans of proteoglycans have a high negative charge that attracts cations and binds to water molecules is correct.Rate this question:
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- 27.
Which of the following statements regarding an allergic reaction to bee venom is CORRECT?
- A.
A second exposure to the same venom causes the antigen to first bind to macrophage
- B.
Macrophages release histamine, heparin and leukotrienes
- C.
The antigen (bee venom) first binds to the IgM of mast cells
- D.
IgE production from plasma cells binds to the plasma membrane of mast cells
- E.
During the 2nd exposure to the antigen, mast cells are converted to macrophages
Correct Answer
D. IgE production from plasma cells binds to the plasma membrane of mast cellsExplanation
During an allergic reaction to bee venom, the correct statement is that IgE production from plasma cells binds to the plasma membrane of mast cells. This binding triggers the release of histamine, heparin, and leukotrienes from mast cells, causing the allergic symptoms. The other statements are incorrect as they do not accurately describe the sequence of events in an allergic reaction to bee venom.Rate this question:
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- 28.
In which part of collagen biosynthesis does vitamin C influence?
- A.
Packaging of procollagen in the Golgi complex
- B.
Formation of polypeptides in the RER
- C.
Glycosylation of specific hydroxylysine residues in the RER
- D.
Removal of registration peptides
- E.
Hydroxylation of specific proline and lysine residues in the RER
Correct Answer
E. Hydroxylation of specific proline and lysine residues in the RERExplanation
Vitamin C influences the hydroxylation of specific proline and lysine residues in the RER during collagen biosynthesis. Hydroxylation of these residues is essential for the proper formation and stability of collagen molecules. Vitamin C acts as a cofactor for the enzymes involved in the hydroxylation process, specifically prolyl hydroxylase and lysyl hydroxylase. Without sufficient vitamin C, the hydroxylation process is impaired, leading to defective collagen synthesis and various connective tissue disorders, such as scurvy.Rate this question:
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- 29.
Which of the following statements concerning the plasma membrane is INCORRECT?
- A.
The phospholipids are amphipathic molecules
- B.
The proteins can only be associated with the membrane as peripheral proteins
- C.
The membrane exists as a bilayer structure, with phospholipids on both the interior and exterior surfaces
- D.
It is composed of phospholipids and proteins
- E.
Fluidity of the membrane is controlled by the combination of unsaturated fatty acids in the phospholipids and cholesterol molecules in the membrane
Correct Answer
B. The proteins can only be associated with the membrane as peripheral proteinsExplanation
The statement that proteins can only be associated with the membrane as peripheral proteins is incorrect. Proteins can be associated with the plasma membrane in multiple ways, including as integral proteins that span the entire membrane or as peripheral proteins that are loosely attached to the membrane surface.Rate this question:
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- 30.
Which one of the following statements concerning the eukaryotic cell is INCORRECT?
- A.
While certain types of cells possess their own unique forms of intermediate filament proteins, they all possess lamins A, B, and C
- B.
“Dynamic instability” is a property of microtubules
- C.
Lacking a nucleus, eukaryotic cells have their DNA scattered throughout the cell
- D.
Thin filaments are used by the cell for locomotion
- E.
Electron microscopists distinguish smooth endoplasmic reticulum from rough endoplasmic reticulum by the presence of ribosomes
Correct Answer
C. Lacking a nucleus, eukaryotic cells have their DNA scattered throughout the cell -
- 31.
Which of these distinguishing features of the stages of mitosis is INCORRECT?
- A.
Anaphase - separation of the chromatids from chromosomes
- B.
Prophase - duplication of the centrioles
- C.
Prometaphase - breakdown of the nuclear envelope
- D.
Telophase - reformation of the nuclear envelope
- E.
Metaphase - alignment of the chromosomes
Correct Answer
B. Prophase - duplication of the centriolesExplanation
Prophase is the stage of mitosis where the chromosomes condense and become visible. It is also during prophase that the nuclear envelope breaks down. However, the duplication of the centrioles actually occurs during the previous stage, called interphase, and not during prophase. Therefore, the statement that "Prophase - duplication of the centrioles" is incorrect.Rate this question:
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- 32.
Which of the following statements is INCORRECT?
- A.
Taxol inhibits the removal of tubulin dimers from microtubules
- B.
Dynein motors move toward the minus end of microtubules
- C.
Spindle fibers run between the centrioles of a mitotic cell
- D.
Kinesin- like motors act to push adjacent spindle fibers apart
- E.
The kinetochore is involved in the addition of tubulin dimers during anaphase
Correct Answer
E. The kinetochore is involved in the addition of tubulin dimers during anaphaseExplanation
The kinetochore is not involved in the addition of tubulin dimers during anaphase. The kinetochore is a protein structure located on the centromere of a chromosome and is responsible for attaching the chromosome to the spindle fibers during cell division. It helps in the movement of chromosomes during mitosis and meiosis, but it does not play a role in the addition of tubulin dimers to microtubules during anaphase.Rate this question:
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- 33.
Cells having basal infoldings are characteristic of
- A.
Ion transport
- B.
Mucus secretion at the apical end of the cell
- C.
Cells having lots of desmosomes
- D.
Cells lacking mitochondria on the basal side
- E.
Cells lacking endoplasmic reticulum on the basal side
Correct Answer
A. Ion transportExplanation
Cells having basal infoldings are characteristic of ion transport. Basal infoldings are specialized membrane structures that increase the surface area of the cell, allowing for more ion channels and transporters to be present. This enables the cell to efficiently transport ions across the membrane. Therefore, the presence of basal infoldings is indicative of a cell's ability to perform ion transport.Rate this question:
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- 34.
Microvilli are structures that
- A.
Have a core of actin microfilaments
- B.
Are involved in the movement of materials over the cell surface
- C.
Have a core of microtubules
- D.
Are involved in cellular movement
- E.
Utilize the sliding filament mechanism for movement
Correct Answer
A. Have a core of actin microfilamentsExplanation
Microvilli are finger-like projections found on the surface of certain cells, such as the cells lining the small intestine. These structures have a core of actin microfilaments, which provide support and stability. They are involved in the movement of materials over the cell surface, such as the absorption of nutrients in the small intestine. The actin microfilaments within microvilli can also undergo contraction, allowing for movement and changes in shape of the microvilli. Therefore, the correct answer is that microvilli have a core of actin microfilaments.Rate this question:
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- 35.
Which of the following features is NOT a characteristic of epithelia?
- A.
Epithelia display lateral communications
- B.
Epithelia display avascularity
- C.
Epithelia display polarity
- D.
Epithelia are normally separated by large (2 microns) intercellular spaces
- E.
A basal lamina is produced by the basal cells of epithelia
Correct Answer
D. Epithelia are normally separated by large (2 microns) intercellular spacesExplanation
Epithelia are NOT normally separated by large (2 microns) intercellular spaces. Epithelial cells are tightly packed and form continuous sheets, with minimal space between them. This close arrangement allows epithelia to function as barriers and selectively regulate the movement of substances.Rate this question:
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- 36.
Pemphigus vulgaris is an autoimmune disease. Which of the following components of the cell is affected by this disease?
- A.
The desmoglein of macula adherens
- B.
Actin microfilaments of zonula adherens
- C.
Ca++ dependent cadherins of both zonula adherens and macula adherens
- D.
The tonofilaments of macula adherens
- E.
Fibronectin in the intercellular space
Correct Answer
A. The desmoglein of macula adherensExplanation
Pemphigus vulgaris is an autoimmune disease that affects the desmoglein of macula adherens. Desmogleins are a type of cadherin protein that are important for cell adhesion in the epidermis. In pemphigus vulgaris, autoantibodies are produced against desmogleins, leading to the breakdown of cell adhesion and the formation of blisters in the skin and mucous membranes. This is why the desmoglein of macula adherens is affected in this disease.Rate this question:
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- 37.
Which of the following statements regarding loose areolar connective tissue is CORRECT?
- A.
Avascularity is a typical feature of the tissue
- B.
Has lots of ground substance
- C.
Has few cells within the tissue
- D.
Ground substance is scant
- E.
Is found in areas that can withstand considerable stress
Correct Answer
B. Has lots of ground substanceExplanation
The correct answer is "Has lots of ground substance." Loose areolar connective tissue is characterized by having a significant amount of ground substance, which is a gel-like substance that fills the space between cells and provides support and cushioning. This tissue also contains a variety of cells, such as fibroblasts, macrophages, and mast cells. It is highly vascular, meaning it has a rich blood supply. Loose areolar connective tissue is found in various parts of the body, including the skin, mucous membranes, and around organs, where it provides flexibility and support while allowing for movement.Rate this question:
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- 38.
Which of the following statements regarding proteoglycans in connective tissue is CORRECT?
- A.
Contain glycosaminoglycans that possess a high negative charge due to the sulfate and carboxyl groups
- B.
Are not capable of attracting large amounts of water molecules
- C.
The proteins of proteoglycans are the predominant fraction of the proteoglycan molecules
- D.
Are composed of a core protein and a branched carbohydrate residue
- E.
Lack binding sites for collagen type II
Correct Answer
A. Contain glycosaminoglycans that possess a high negative charge due to the sulfate and carboxyl groupsExplanation
Proteoglycans in connective tissue contain glycosaminoglycans that possess a high negative charge due to the sulfate and carboxyl groups. This negative charge allows them to attract and bind large amounts of water molecules, contributing to the hydration and lubrication of the tissue. The proteins of proteoglycans are present in smaller amounts compared to the glycosaminoglycans. Proteoglycans are composed of a core protein and a branched carbohydrate residue. They also have binding sites for collagen type II, which allows them to interact and contribute to the structural integrity of the connective tissue.Rate this question:
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- 39.
Which of the following cell types is generally regarded as the principal cell type of connective tissue?
- A.
Plasma cell
- B.
Mast cell
- C.
Adipocytes
- D.
Fibroblast
- E.
Osteoclast cell
Correct Answer
D. FibroblastExplanation
Fibroblasts are generally regarded as the principal cell type of connective tissue. They are responsible for producing and maintaining the extracellular matrix, which provides structural support to the tissue. Fibroblasts also play a crucial role in wound healing and tissue repair by synthesizing collagen and other components of the extracellular matrix. Other cell types mentioned, such as plasma cells, mast cells, adipocytes, and osteoclast cells, have different functions and are not considered the principal cell type of connective tissue.Rate this question:
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- 40.
Which of the following statements regarding collagen biosynthesis is CORRECT?
- A.
Hydroxylation of proline residues occurs in the Golgi Apparatus
- B.
The procollagen molecule becomes insoluble within the cytoplasm
- C.
Glycosylation of specific hydroxy lysines occur in the clathrin vesicles that are migrating to the plasma membrane
- D.
Specific (procollagen) proteases remove registration peptides outside the cell membrane
- E.
Only actin microfilaments are involved in the movement of secretory vesicles
Correct Answer
D. Specific (procollagen) proteases remove registration peptides outside the cell membraneExplanation
During collagen biosynthesis, specific proteases remove registration peptides, which are sequences of amino acids that serve as signals for the correct folding and assembly of the procollagen molecule. This removal of registration peptides occurs outside the cell membrane, specifically in the extracellular space. This step is crucial for the formation of mature collagen fibrils. The other statements in the options are not correct. Hydroxylation of proline residues occurs in the endoplasmic reticulum, not the Golgi Apparatus. The procollagen molecule remains soluble within the cytoplasm until it is secreted. Glycosylation of hydroxylysines occurs in the endoplasmic reticulum, not in clathrin vesicles migrating to the plasma membrane. The movement of secretory vesicles involves both actin microfilaments and microtubules.Rate this question:
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- 41.
Which of the following statements regarding hyaline cartilage is CORRECT?
- A.
Nerves penetrate the cartilage matrix
- B.
Chondrocytes are mature cells that are unable to undergo mitosis
- C.
Articular cartilage is covered by a perichondrium
- D.
Collagen type II is the predominant fiber of perichondrium
- E.
The chondrocyte is surrounded by a territorial matrix that is rich in glycosaminogycans
Correct Answer
E. The chondrocyte is surrounded by a territorial matrix that is rich in glycosaminogycansExplanation
The chondrocyte is surrounded by a territorial matrix that is rich in glycosaminoglycans. Hyaline cartilage is composed of chondrocytes, which are cells responsible for producing and maintaining the cartilage matrix. The territorial matrix is a region surrounding the chondrocyte that contains a high concentration of glycosaminoglycans, which are large molecules that help to provide structure and support to the cartilage. This matrix helps to protect and nourish the chondrocyte, allowing it to function properly in maintaining the integrity of the cartilage tissue.Rate this question:
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- 42.
Which of the following cell types is involved primarily in the synthesis of collagen type 1?
- A.
Chondrocytes
- B.
Osteoclast cells
- C.
Macrophages
- D.
Osteoblasts
- E.
Chondroblasts
Correct Answer
D. OsteoblastsExplanation
Osteoblasts are primarily involved in the synthesis of collagen type 1. Collagen type 1 is the main component of bone tissue, and osteoblasts are responsible for the formation and mineralization of bone. They produce and secrete collagen type 1, which provides the structural framework for bone and contributes to its strength and flexibility. Chondrocytes are involved in the synthesis of collagen type 2, which is found in cartilage. Osteoclast cells are responsible for bone resorption, while macrophages are involved in immune responses. Chondroblasts are immature cartilage cells and are not directly involved in the synthesis of collagen type 1.Rate this question:
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- 43.
The mast cell possesses receptor molecules on the surface of the cell for:
- A.
IgE
- B.
IgA molecules
- C.
Lactoferrin
- D.
IgM
- E.
IgD
Correct Answer
A. IgEExplanation
Mast cells possess receptor molecules on their surface for IgE. IgE is an antibody that plays a key role in allergic reactions. When IgE binds to its specific receptors on mast cells, it triggers the release of inflammatory mediators such as histamine, which leads to the characteristic symptoms of allergies such as itching, redness, and swelling. This interaction between IgE and mast cells is an important part of the immune response against parasitic infections but can also result in hypersensitivity reactions in individuals with allergies.Rate this question:
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- 44.
Which of the following statements concerning meiosis is CORRECT?
- A.
Duplication of DNA occurs in prophase 1 of meiosis 1
- B.
The genetic material produced in each of the cells during meiosis are identical
- C.
Pairing of homologous chromosomes occurs in prophase 1 of meiosis 1
- D.
Non disjunction does not occur in meiosis II
- E.
Separation of chromatids occurs during anaphase 1 of meiosis 1
Correct Answer
C. Pairing of homologous chromosomes occurs in prophase 1 of meiosis 1Explanation
Pairing of homologous chromosomes occurs in prophase 1 of meiosis 1. During this phase, homologous chromosomes come together and form pairs, a process called synapsis. This pairing is essential for the exchange of genetic material between homologous chromosomes, known as crossing over, which increases genetic diversity. The other statements are incorrect: DNA duplication occurs in S phase before meiosis, the genetic material produced in each cell during meiosis is not identical due to crossing over, non-disjunction can occur in meiosis II, and separation of chromatids occurs during anaphase 2 of meiosis 2.Rate this question:
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- 45.
Which of the following statements concerning gametogenesis is CORRECT?
- A.
Primary oocytes are all arrested in the diplotene stage of prophase 1 before birth
- B.
All primary oocytes are formed after puberty
- C.
All primary spermatocytes are formed at the time of puberty
- D.
All primary spermatocytes are formed before birth
- E.
The transformation from spermatogonia to spermatozoa takes about 16 days
Correct Answer
A. Primary oocytes are all arrested in the diplotene stage of prophase 1 before birthExplanation
Primary oocytes are indeed arrested in the diplotene stage of prophase 1 before birth. During fetal development, oogonia undergo mitotic divisions to form primary oocytes, which then enter meiosis. However, they are arrested in the diplotene stage until puberty, when they resume meiosis and complete the first meiotic division. Only a small number of primary oocytes are activated each menstrual cycle, and the rest degenerate over time. Therefore, all primary oocytes are arrested in the diplotene stage before birth.Rate this question:
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- 46.
During the proliferation phase of the menstrual cycle, which hormone influences the endometrial lining of the uterus?
- A.
Progesterone
- B.
Luteinizing hormone (LH)
- C.
Follicle stimulating hormone (FSH)
- D.
Estrogen
- E.
Relaxin
Correct Answer
D. EstrogenExplanation
Estrogen is the hormone that influences the endometrial lining of the uterus during the proliferation phase of the menstrual cycle. This hormone is responsible for thickening the endometrium, preparing it for potential implantation of a fertilized egg. Estrogen also promotes the growth of blood vessels in the endometrium, ensuring proper nourishment for a potential pregnancy. Additionally, it stimulates the production of cervical mucus, which helps sperm reach the egg. Overall, estrogen plays a crucial role in preparing the uterus for pregnancy during the proliferation phase of the menstrual cycle.Rate this question:
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- 47.
During the menstrual cycle
- A.
The follicular cells of growing follicles secrete primarily progesterone
- B.
Follicle stimulating hormone causes the corpus luteum to secrete estrogen
- C.
Luteinizing hormone stimulates the corpus luteum to secrete primarily progesterone
- D.
Luteinizing hormone stimulates several primordial follicles to develop
- E.
The pituitary gland secretes progesterone
Correct Answer
D. Luteinizing hormone stimulates several primordial follicles to develop -
- 48.
During the process of fertilization
- A.
The theca interna cells release estrogen as a result of contact with the sperm
- B.
Enzymes released from cortical granules cause a conformational change of the zona pellucida and oocyte plasma membrane
- C.
The sperm's plasma membrane fuses with the cells of the corona radiata
- D.
The sperm first penetrates the basal lamina
- E.
After the sperm makes contact with the zona pellucida, more sperms are allowed to penetrate the developing oocyte
Correct Answer
B. Enzymes released from cortical granules cause a conformational change of the zona pellucida and oocyte plasma membraneExplanation
During the process of fertilization, enzymes released from cortical granules cause a conformational change of the zona pellucida and oocyte plasma membrane. This conformational change prevents any other sperm from penetrating the oocyte, ensuring that only one sperm is able to fertilize the egg. This mechanism is important for maintaining the genetic integrity of the resulting embryo and preventing polyspermy, which could lead to abnormal development.Rate this question:
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- 49.
During the second week of development
- A.
The inner cell mass is composed of three germ layers
- B.
Blood vessels develop in the allantoic sac
- C.
The uteroplacental circulation developes within the yolk sac
- D.
Syncytiotrophoblast erodes the lining of the maternal blood vessels to establish the primitive uteroplacental circulation
- E.
The cytotrophoblast erodes the maternal blood vessels of the endometrium
Correct Answer
D. Syncytiotrophoblast erodes the lining of the maternal blood vessels to establish the primitive uteroplacental circulationExplanation
During the second week of development, the syncytiotrophoblast erodes the lining of the maternal blood vessels to establish the primitive uteroplacental circulation. This process allows for the exchange of nutrients, gases, and waste products between the mother and the developing embryo. The syncytiotrophoblast is a multinucleated layer of cells that forms the outermost layer of the blastocyst and plays a crucial role in the implantation and development of the placenta. By eroding the maternal blood vessels, the syncytiotrophoblast creates a connection between the maternal and fetal circulatory systems, enabling the exchange of materials necessary for the embryo's growth and development.Rate this question:
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- 50.
Which of the following statements is CORRECT during the first two weeks of development?
- A.
The zygote undergoes several meiotic divisions
- B.
The morula with its corona radiata implants into the endometrium
- C.
The inner cell mass gives rise to the syncytiotrophoblast and cytotrophoblast
- D.
The trophoblast gives rise to the epiblast and hypoblast layer
- E.
The prochordal plate develops from the hypoblast layer
Correct Answer
E. The prochordal plate develops from the hypoblast layerExplanation
During the first two weeks of development, the prochordal plate develops from the hypoblast layer.Rate this question:
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