1.
All of the following are important as a cause of negative resting membrane potential (RMP) except:
Correct Answer
C. Cl ions
Explanation
The resting membrane potential (RMP) is the electrical potential difference across the cell membrane when the cell is at rest. This potential is negative due to the combined effects of various ions. K ions play a crucial role in establishing the negative RMP by diffusing out of the cell through leak channels. Na ions also contribute to the RMP by actively being pumped out of the cell. Proteins, which are negatively charged, are also important as they cannot freely cross the cell membrane, creating an imbalance of charges. However, Cl ions do not directly contribute to the negative RMP as they tend to move into the cell, therefore they are not important as a cause of the negative RMP.
2.
Normal RMP os a nerve is:
Correct Answer
B. - 70 mv
Explanation
The normal resting membrane potential (RMP) of a nerve is -70 mV. This means that the inside of the nerve cell is negatively charged compared to the outside. The RMP is maintained by the balance of ions across the cell membrane, with more negative ions inside the cell and more positive ions outside. This electrical potential is essential for the proper functioning of nerve cells, as it allows for the transmission of electrical signals necessary for nerve communication and coordination.
3.
It is the concentration of a solution in terms of particles:
Correct Answer
D. Osmole
Explanation
Osmole is the correct answer because it is a unit of measurement used to express the concentration of a solution in terms of particles. It represents the number of particles (such as ions or molecules) in a solution. Osmole is commonly used in the field of chemistry and biology to quantify the number of solute particles present in a given volume of solvent. Osmolality and osmolarity are related terms that also measure the concentration of a solution, but they express it in terms of osmoles per kilogram of solvent and osmoles per liter of solution, respectively. Osmotic pressure, on the other hand, is a measure of the force required to prevent the movement of solvent across a semipermeable membrane due to differences in solute concentration.
4.
All of the following are related to hypertonic solutions except:
Correct Answer
C. Glucose 5% is one of its examples
Explanation
The correct answer is "glucose 5% is one of its examples." This is because glucose 5% is an example of an isotonic solution, not a hypertonic solution. Hypertonic solutions have a higher concentration of solutes compared to cells, causing water to move out of the cells and making them shrink. Glucose 5% is an isotonic solution, meaning it has the same concentration of solutes as cells and does not cause any change in cell size.
5.
1- movement of water from high concentration gradient to low concentration gradient under the effect of hydrostatic pressure
2- movement of water from high concentration gradient to low concentration gradient sccording to concentration difference
Correct Answer
D. 1- Filtration 2- Diffusion
Explanation
The correct answer is 1- Filtration and 2- Diffusion. Filtration is the movement of water from high concentration gradient to low concentration gradient under the effect of hydrostatic pressure. Diffusion is the movement of water from high concentration gradient to low concentration gradient according to concentration difference.
6.
All of the folloing are concidered as endocytosis mechanism except:
Correct Answer
A. Stimulus dependent secretion
Explanation
Stimulus dependent secretion is not considered as an endocytosis mechanism because it involves the release of substances from the cell, rather than the uptake of substances into the cell. Endocytosis mechanisms, such as receptor-mediated endocytosis, phagocytosis, and pinocytosis, all involve the uptake of substances into the cell through various mechanisms.
7.
Which of the following is not a component of recptor mediated endocytosis:
Correct Answer
C. Pseudopedia
Explanation
Pseudopedia is not a component of receptor-mediated endocytosis. Receptor-mediated endocytosis is a process by which specific molecules are taken up by cells through the binding of ligands to receptors on the cell surface. Cargo receptors are responsible for recognizing and binding to the specific molecules to be internalized. Uncoated vesicles are formed during the process of endocytosis to transport the internalized molecules. Adaptin is a protein that helps in the formation of coated vesicles. However, pseudopedia is not involved in receptor-mediated endocytosis and is unrelated to this process.
8.
The main stimulator for exocytosis at the neuromuscular junction is:
Correct Answer
A. Ca ions
Explanation
The correct answer is Ca ions. Calcium ions play a crucial role in exocytosis at the neuromuscular junction. When an action potential reaches the presynaptic terminal, voltage-gated calcium channels open, allowing calcium ions to enter the terminal. The increase in calcium concentration triggers the fusion of synaptic vesicles with the presynaptic membrane, leading to the release of neurotransmitters into the synaptic cleft. These neurotransmitters then bind to receptors on the postsynaptic membrane, initiating a response in the muscle fiber. Therefore, calcium ions are the main stimulator for exocytosis at the neuromuscular junction.
9.
Stoppage of bleeding by formation of blood clot:
Correct Answer
C. Hemostasis
Explanation
Hemostasis refers to the process of stopping bleeding by forming a blood clot. It involves a series of complex mechanisms that work together to prevent excessive blood loss from damaged blood vessels. These mechanisms include vasoconstriction, platelet aggregation, and coagulation. Vasoconstriction reduces blood flow to the injured area, platelet aggregation forms a temporary plug, and coagulation forms a stable blood clot. Together, these processes ensure that the bleeding stops and the damaged blood vessel is repaired.
10.
The three main components of reflex arc:
Correct Answer
D. Receptor, center, effector
Explanation
A reflex arc is a neural pathway that controls reflex actions. It consists of three main components: a receptor, a center, and an effector. The receptor detects a stimulus and sends signals to the center. The center processes the information and determines the appropriate response. Finally, the effector carries out the response by producing a motor output. Therefore, the correct sequence of the three main components of a reflex arc is receptor, center, effector.
11.
Which of the following is an example of positive feedback vicious mechaism:
Correct Answer
B. Child birth
Explanation
Childbirth is an example of a positive feedback vicious mechanism because it involves a self-amplifying cycle. During labor, contractions of the uterus stimulate the release of oxytocin, which leads to stronger contractions. As contractions become stronger, more oxytocin is released, further intensifying the contractions. This cycle continues until the baby is born.
12.
Cascade mechanism end or stop or inhibited by the following mechanism:
Correct Answer
D. A negative feedback mechanism
Explanation
A negative feedback mechanism can end or inhibit the cascade mechanism. Negative feedback occurs when the output of a system inhibits or reduces the activity of the system itself. In this context, the cascade mechanism is likely a series of events or reactions that are initiated by a stimulus. When a negative feedback mechanism is activated, it counteracts the effects of the cascade mechanism, thereby stopping or inhibiting its progression. This allows the system to return to a state of equilibrium or homeostasis.
13.
All of the following can pass through lipid bilayer except:
Correct Answer
B. Na ions
Explanation
The lipid bilayer is composed of hydrophobic tails that repel ions, making it difficult for them to pass through. However, lipid soluble substances, such as O2 and CO2, can easily pass through the lipid bilayer due to their ability to dissolve in the hydrophobic interior of the membrane. Na ions, on the other hand, are charged and cannot easily pass through the hydrophobic region of the lipid bilayer. Therefore, Na ions cannot pass through the lipid bilayer.
14.
Regarding glucose transport, which is false:
it can be transported by secondary active mechanism
b- it may be by a carrier protein with concentration gradient without use of energy
c- it may be by pinocytosis
d- it is never to be through leak channel
Correct Answer
C. It may be by pinocytosis
Explanation
Glucose transport can occur through various mechanisms, including secondary active transport, facilitated diffusion by carrier proteins, and pinocytosis. Pinocytosis is a process where cells engulf extracellular fluid and its contents, including glucose molecules. Therefore, the statement that glucose transport may occur by pinocytosis is true.