Answer:
B. Glucagon
Explanation:
Glucagon is a pancreatic hormone, secreted by the alpha cells of islets of Langerhans. Whenever the blood glucose level falls, glucagon is released to increase the blood glucose levels. This function of glucagon is quite opposite to the function of insulin and hence both are antagonistic hormones. Insulin reduces the blood glucose where as glucagon increases the blood glucose.
Glucoagon is large polypeptide of 29 amino acids. Since it helps in increasing the blood glucose homeostatic levels it is called as hyperglycemic hormone. It does so by stimulating certain processes such as:
- Stimulating Glycogenolysis i.e breakdown of glycogen to release more glucose from liver.
- Stimulating Gluconeogenesis i.e. synthesis of glucose from non-carbohydrate sources like proteins.
- Glucagon inhibits the process of glycogenesis i.e. synthesis of glycogen, the storage form of glucose.
Answer:
An insertion mutation occurs when an extra nucleotide is added to the DNA strand during replication. This can happen when the replicating strand "slips," or wrinkles, which allows the extra nucleotide to be incorporated.
Answer:
D) In case 1, both PS I and PS II completely lose function; in case 2, a proton gradient is still produced.
Explanation:
The light dependent reaction of photosynthesis, which produces the ATP and NADPH needed in the light independent stage of the process, includes complexes of proteins and pigments called PHOTOSYSTEMS. These photosystems (I and II) are key to the functionality of the light dependent reactions in the thylakoid.
The major pigment present in both photosystems is CHLOROPHYLL A, which absorbs light energy and transfers electrons to the reaction center. Chlorophyll B is only an accessory pigment meaning it can be done without. Hence, if all of the chlorophyll A is inactivated in the algae but leaves chlorophyll B intact as in case 1, both PS I and PS II will lose their function because Chlorophyll A is the major pigment that absorbs light energy in both photosystems.
In case 2, if PS I is inhibited and PS II is unaffected, a PROTON GRADIENT WILL STILL BE PRODUCED because the splitting of water into protons (H+) and electrons (e-) occurs in PSII. Hence, H+ ions can still be pumped into the inner membrane of the thylakoid in order to build a proton gradient even without the occurrence of PS I.
The atmosphere is the part of the carbon and water cycles but absent from the phosphorous cycle. Carbon cycle depends on photosynthesis and respiration. Water cycle connects aquatic and terrestrial biomes.
