COLLEGE OF NATURAL AND APPLIED SCIENCES
FACULTY OF BIOLOGICAL SCIENCES
DEPARTMENT OF ANIMAL AND ENVIRONMENTAL BIOLOGY
RESPIRATION IN INVERTEBRATES
COMPILED & PRESENTED
DEPARTMENT OF ANIMAL AND ENVIRONMENTAL BIOLOGY 2012/2013 SESSION
COURSE: FSB201 (CELL BIOLOGY)
COURSE LECTURER: DR. NOUTCHA
DATE : 7TH MARCH, 2013
Respiration is one of the characteristics of ALL LIVING THINGS. In the simplest terms, "respiration" simply means "breathing". But more formally, the term depends on what type of respiration been referred to. Essentially, "respiration" refers to gaseous exchange of unwanted carbon dioxide and much-needed oxygen for the body's use. In direct terms, oxygen is essential for life. There are two types of 'respiration': pulmonary (visible breathing) and cellular (which is not visible). Regular, visible (pulmonary) respiration is simply another term for breathing - or the inhalation-exhalation process. In this process, the unwanted gas expelled is mainly carbon dioxide. This is then replaced during the inhalation breathing phase by the oxygen content within the air inhaled. The other kind of respiration is called "cellular respiration". It occurs in the very local level of the cell itself, where a gaseous exchange takes place as unwanted carbon-dioxide is expelled through the cell walls and oxygen is diffused into the cell for energy purposes within the cell itself. Animals in general are divided into Vertebrates and Invertebrates. Vertebrates are animals with a vertebral column or backbone and Invertebrates are animals without a backbone. Invertebrates include organisms from the following phyla: Porifera, Cnidaria, Nematoda, Mollusca, Annelida, Arthropoda, Echinodermata, etc. Invertebrates can be further divided into two groups according to their level of complexity and specialization. These are: 1. Lower Invertebrates: This comprises of the phyla Protozoa, Porifera, Cnidaria, Platyhelminthes and Nematoda. These generally lack specialized organs or organelles to carry out various living functions such as respiration, excretion, reproduction, etc, hence their small size. 2. Higher Invertebrates: These are more complex in body structure and their organs are specialized. They include phyla such as Mollusca, Annelida, Arthropoda and Echinodermata.
CELLULAR RESPIRATION IN INVERTEBRATES
Cellular respiration is the set of the metabolic reactions and processes that take place in the cells of organisms to convert biochemical energy from nutrients into adenosine triphosphate (ATP), and then release waste products. The reactions involved in respiration are catabolic reactions, which break large molecules into smaller ones, releasing energy in the process as they break high-energy bonds. Respiration is one of the key ways a cell gains useful energy to fuel cellular activity. Cellular respiration is considered an exothermic redox reaction. The overall reaction is broken into many smaller ones when it occurs in the body, most of which are redox reactions themselves. Although technically, cellular respiration is a combustion reaction, it clearly does not resemble one when it occurs in a living cell. This difference is because it occurs in many separate steps. While the overall reaction is a combustion, no single reaction that comprises it is a combustion reaction. Nutrients that are commonly used by animal and plant cells in respiration include sugar, amino acids and fatty acids, and a common oxidizing agent (electron acceptor) is molecular oxygen (O2). The energy stored in ATP can then be used to drive processes requiring energy, including biosynthesis, locomotion or transportation of molecules across cell membranes. AEROBIC RESPIRATION IN CELLS OF INVERTEBRATES
Aerobic respiration requires oxygen in order to generate ATP. Although carbohydrates, fats, and proteins can all be processed and consumed as reactants, it is the preferred...