Start Discovering Solved Questions and Your Course Assignments
TextBooks Included
Active Tutors
Asked Questions
Answered Questions
signal transduction occurs when an extracellular signaling molecule activates a cell surface receptor in words this receptor change intracellular
clathrin-coated pits and vesicles are included in both the endocytosis of material at the plasma membrane and the exocytosis of
phagocytosis is the ingestion of huge particles like as bacteria and cell debris by large endocytic vesicles called as phagosomes in order to
endocytosis is the uptake of extracellular macromolecules across the plasma membrane into the cell the objects to be ingested is
nuclear transport is an energy-dependent process mediated through saturable receptors export and import receptors are by to distinguish and bind to
the movement of na and glucose from the lumen of the intestine across the epithelial cell to the blood sets up a
the passive transport of molecules across a membrane does not require an input of metabolic energy rate of the diffusion or transport is proportional
a pure phospholipid bilayer with its hydrophobic interior is permeable to water and gases such as o2 co2 n2 and small
the internal composition of the cell is maintained because the plasma membrane is selectively permeable to small molecules a lot of biological
the cytosolic surface of the erythrocyte plasma membrane is covered through a network of peripheral
the peripheral membrane proteins are less strongly bound to the lipid bilayer than integral membrane proteins and can be
since erythrocytes red blood cells do not hold any sub cellular organelles they are essentially a membranous sac for carrying
membrane proteins are classify as either integral intrinsic or peripheral extrinsic depending on how tightly they are linked with membrane the
the carbohydrate sets are covalently attached to various variant proteins to form glycoproteins carbohydrates are a shorter percentage of the weight
the cell membrane is a slim semi-permeable membrane which surroundings the cytoplasm of a cell membrane function is to defend the integrity of the
while describing normalising selection it was said that in uniform environments selection limits the variability of populations and evolves a genetic
directional or progressive selection is the mode of selection associated with environmental change we said earlier that in an unchanging environment
theodosius dobzhansky and boris spassky demonstrated the working of normalising selectioion a behavioural trait in two populations of drosophida
an interesting observation made by an american biologist hc bumpus 1899 provides a good explanation for normalising selection bumpus collected some
in the absence of any large scale envirorrmental change that is in more or less uniform environments populations often maintain a stable genetic
while discussing the darwinian premise of natural selection we observed that the term selection is synonymous with non-random reproduction and that
sickle cell anaemia in man is caused by a defective chain of haemoglobin the abnormal haemoglobin known as mbs differs from natural haemoglobin hha
in the previous sub-section we discussed the possible ways by which variabiliti can be generated we shall now examine one instance that illustrates
mutations are the only kind of variability generating mechanism in prokaryotes and asexually reproducing organisms but in eukaryotes where sexual
each gene has a characteristic mutation rate mutation rates are often described as an average per gene basis for instance drosophila has one