False, Eukaryotic cells always contain a nucleus, prokaryotic cells do not have a nucleus.
Answer:
A: Event in the normal life cycle of a cell
The law of conservation of matter states that matter cannot be created or destroyed. The law of conservation of energy states that energy cannot be created or destroyed. Both of the laws state that both cannot be created or destroyed, but both take on different forms, or become different kinds of matter or energy.
A substance that provides humans with their main source of energy would be; food.
Answer:
The false statement is The iron in both the hemoglobin and myoglobin has two coordination sites that bind to oxygen.
Explanation:
Hemoglobin is an oligomeric,allosteric,conjugated protein with 4 polypeptide chains joined by non covalent bonds that contain heme prosthetic group.It is an iron containing porphyrin derivative present in all vertebrate.
The tetramers of hemoglobin consists of numerous combinations of seven polypeptide chains and each of which is encoded by separate genes.
Myoglobin is a globular protein that consists of single polypeptide chain of 153 amino acid residue and a single heme group.
Globin of Mb binds with single heme group by forming co ordinate bond.The heterocyclic ring system of heme is a porphyrin derivative.It is made up of 4 pyrrole ring and 4 pyrroles are linked by methine bridges to form a tetrapyrolle ring.
The Fe atom is present either in Fe²⁺ state or Fe³⁺ oxidation state in the center of protoporphyrin IX ring.The iron atom has 6 co ordination bond,4 in the plane of flat porphyrin ring and two perpendicular to it.
