The enzyme phosphofructokinase catalyzes the conversion of fructose-6-phosphate and adenosine triphosphate (ATP) to fructose 1,6-bisphosphate and adenosine diphosphate (ADP). Adenosine monophosphate (AMP) activates the enzyme phosphofructokinase (PFK) by binding at a site distinct from the substrate-binding site. This is an example of:.

This is an example of allosteric regulation or modulation.

Explanation: Allostery is a process by which a ligand binds to a site on the enzyme that is different from the substrate binding site. This site is different from the active site and it is called allosteric site. Allostery can be positive or negative. If the binding of the ligand to the allosteric site of the enzyme activates the binding of the substrate to the active site of the enzyme, it is known as positive allostery but if the binding of a ligand to the allosteric site of the enzyme inhibits the binding of the substrate to the enzyme active site, it is known as negative allostery or allosteric inhibition. The binding of ADP to the allosteric site of phosphofructokinase (PKF) activates the enzyme, it is therefore a positive allostery.

answer: - few nutrients

high pressure

low temperatures

explanation: 1. few nutrients:   open-ocean zone is located way far from the land, which is the main source of the essential nutrients.2. high pressure: pressure increases by 1 atmosphere for every 10 meters increase in depth.3. ample sunlight: a large fraction of the sunlight is reflected back to the atmosphere from the sea surface. 4. varying salinity: below the thermocline, the water is isolated from the atmosphere so the salinity remains stable over the year.5. low temperatures:   the temperature of open-ocean zone ranges from a low of -2°c to an average of 17°c

an individual’s sex (i.e., whether they are a male or female) is determined by the sex chromosomes. most people have two sex chromosomes, one that is inherited from their mother and one that is inherited from their father. typically, females have two x chromosomes (xx) and males have one x chromosome and one y chromosome (xy). conditions caused by changes (“mutations”) in genes located on the x chromosome are considered x-linked.

x-linked recessive inheritance

most x-linked conditions are recessive. this means that in a person with two x chromosomes (most females), both copies of a gene (i.e., one on each x chromosome) must have a change or mutation whereas in a person with one x chromosome (most males), only one copy of a gene must have a mutation. a female with a mutation in one copy of a gene on the x chromosome is said to be a “carrier” for an x-linked condition. a male with a mutation in a gene on the x chromosome is typically affected with the condition. because females have two copies of the x chromosome and males have only one x chromosome, x-linked recessive diseases are more common among males than females. however, x-linked recessive diseases can occur in both males and females.

for x-linked recessive disorders, an unaffected carrier mother who has a mutation in a gene on the x chromosome can transmit either the x chromosome with this mutation or a “normal” x chromosome to her children. if the father is unaffected, none of her daughters will be affected and all of her daughters will be unaffected—since they will inherit at least one normal x chromosome from their father. however, each daughter will have a 50% chance of being an unaffected carrier like her mother and a 50% chance of both x chromosomes being normal.