During the propagation of a nerve impulse, the action potential results from the movement of
K+ ions form extracellular fluid of intracellular fluid
Na+ ions from intracellular fluid to extracellular fluid
K+ ions from intracellular fluid to extracellular fluid
K+ ions from intracellular fluid to extracellular fluid
D.
K+ ions from intracellular fluid to extracellular fluid
During the propagation of nerve impulse when a stimulus of adequate strength is applied to a polarised membrane, the permeability of the membrane to Na+ is greatly increased at the point of stimulation. As a result, the sodium ion channels permit the influx of Na+ ions entering than leaving, the electrical potential of the membrane changes from -70 mV towards zero. At 0 mV the membrane is said to be depolarised. While the resting potential is determined largely by K+ ions, the action potential is determined largely by Na+ ions.
An action potential is another name of the nerve impulse. The stimulated negatively charged point on the outside of the membrane sends out an electrical current to the positive point adjacent inner part of the membrane to reverse its potential from - 70 mV to +30mV.
Cellulose is the major component of cell walls of
Pythium
Xanthomonas
Pseudomonas
Pseudomonas
Carbohydrates are commonly found as starch in plant storage organs. which of the following five properties of starch (A-E) make it useful as a storage material?
A) Easily translocated
B) Chemically non-reactive
C) Easily digested by animals
D) Osmotically inactive
E) Synthesized during photosynthesis
The useful properties are
(B) and (C)
(B) and (D)
(A), (C) adn (E)
(A), (C) adn (E)
In leaves of C4 -plants malic acid synthesis during CO2 -fixation occurs in
epidermal cells
mesophyll cells
bundle sheath
bundle sheath
The haemoglobin of human foetus
has a lower affinity for oxygen than that of the adult
its affinity for oxygen is the same as that of an adult
has only 2 protein subunits instead of 4
has only 2 protein subunits instead of 4
The most active phagocytic white blood cells.
neutrophils ane eosinophils
lymphocytes and macrophages
eosinophils and lymphocytes
eosinophils and lymphocytes
The two subunits of ribosome remain united at a critical ion level of
Copper
Manganese
Manganese
Manganese
Which one of the following scientist's name is correctly matched with the theory put forth by him?
Weissmann-Theory of continuity of germplasm
Pasteur - Inheritance of acquired characters
de Vries - Natural selection
de Vries - Natural selection
The slow rate of decomposition of fallen logs in nature is due to their
low moisture content
poor nitrogen content
anaerobic environment around them
anaerobic environment around them
