Definition of Mitochondria – Introduction to fundamental concepts of Biological Science including the organization and common characteristics of living matters, cell structures and functions, food production by photosynthesis, harvesting energy, mechanism of cells reproduction, genetics, evolutions, and Human Biology. Introduction to general chemistry including basic concepts about matter, atomic structure, chemical bonds, gases, liquid, and solids, solutions, chemical reactions, acid, bases, and salt;
organic and biochemistry including hydrocarbons and their derivatives, carbohydrates, lipids, proteins, enzymes, vitamins, and minerals, nucleic acids; principles of physics and applications to nursing including gravity and mechanics, pressure, heat and electricity; nuclear chemistry and nuclear physics, effects of radiation on human beings, and protection and disposal. The aim of the course is to acquire knowledge and skills in general biological science, general chemistry and physics.
Definition of Mitochondria
Mitochondria are spherical organelles, present in almost all cells. It has two membranes – an outer and an inner. The large space enclosed by inner membrane is called matrix containing DNA, proteins and enzymes for oxidation.
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Mitochondria are spherical organelles, present in almost all cells. It has two membranes – an outer and an inner. The large space enclosed by inner membrane is called matrix containing DNA, proteins and enzymes for oxidation.
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Mitochondria are the ‘powerhouse’ or the power-generating units of the cell, self-replicating in nature and best developed in parts of the cells where energy-requiring processes take place.
Figure: Structure of Mitochondria
➤ Shape: Globular shaped
➤ Location: Cytoplasm of cell but numerous in those cell where metabolic activity is more e.g.- Hepatocyte, cardiac cell, sperm etc,
➤ Size and shape: They are variable in size and shape. Some are only a few hundred nanometers in diameter and globular in shape, whereas others are elongated – as large as 10 1 micrometer in diameter and 7 micrometers long; still others are branching and filamentous.
➤ Structure:
- Is composed mainly of two lipid bilayer – protein membranes: an outer membrane and an inner membrane.
- Many infoldings of the inner membrane form shelves onto which oxidative enzymes are attached.
- The inner cavity of the mitochondrion is filled with a matrix that contains large quantities of dissolved enzymes that are necessary for extracting energy from nutrients
➤ Features:
- The mitochondrial membrane is a lipid bilayer protein membrane, an outer and an inner membrane.
✓ Inner mitochondrial membrane form cristae/shelves & contains enzymes, which necessary for converting the products of carbohydrate, protein and fat metabolism to CO₂ & water. [Four complex enzymes are involved i.e- NADH dehydrogenase, Succinic dehydrogenase, Cytocrome bc, and Cytochrome oxidase.]
✓ Outer mitochondrial membrane contains enzymes concerned with biologic oxidation providing raw materials for the reactions occurring inside the mitochondrion.
- Mitochondria are “self replicative”
Functions:
- Production of energy i.e. adenosine triphosphate (ATP) from nutrients.
- Oxidation of nutrients.
- Helps in oxidative phosphorilation
- Mitochondrial DNA synthesizes protein.
Replication:
Mitochondria are self-replicative, which means that one mitochondrion can form a second one, a third one, and so on, whenever there is a need in the cell for increased amounts of ATP. Indeed, the mitochondria contain DNA similar to that found in the cell nucleus. The DNA of the mitochondrion plays role in controlling replication of the mitochondrion itself.
Inheritance:
Mitochondrial inheritance is almost exclusively maternal. Sperm contributes few, if any, mitochondria to the zygote. So, the mitochondria in the zygote come almost entirely from the ovum.
N.B: Sperm contributes no mitochondria to the zygote; therefore, mitochondria come from the ovum and inheritance is strictly maternal. Oxidative phosphorilation only occur in mitochondria.
ATP generation take place in-
- At the substrate level &
- At the respiratory chain.
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