mtracy's blog

The primary energy source for the body is glucose. However, fatty acid metabolism yeilds more energy per carbon. This is largely because a fatty acid is more reduced than a glucose molecule. That is, it can be oxidized more, having its electrons stripped and therefore yielding more energy. Fatty acid synthesis typically yeilds a chain of 16 carbons (via fatty acid synthase). Overall the oxidation of a fatty acid yeilds 6 ATP, 31 NADH and 15 FADH2. Glucose on the other hand yeilds 4 ATP, 10 NADH and 2 FADH2. The additional FADH2 and NADH can be used in the ETC to generate ATP. This energy excess from glucose produces a total of 28 ATP from the ETC, while fatty acid oxidation (from a 16 carbon chain) will yield 100 ATP from the ETC. This averages out to about 5.3 ATP per carbon in a glucose molecule and 6.6 ATP per carbon in a fatty acid molecule.

The order of Pleuronectoidei contains the flatfish and flounders. These fish live in temperate waters and live on the benthic region. As juviniles they are symmetrical, however as they develop one eye migrates to the other side of the head until both eyes are on the same side. As the name suggests, flat fish are laterally compressed. Most of these fish are dextral, with both eyes on their right, however there are some species which are sinistral, with both eyes on the left. Still, some species vary in right/left sidedness and get a mix of both types of fish. Some species have paired fins and some have fused dorsal, anal and caudal fins. As you can see, there is great diversity among the flat fishes.

The electron transport chain is the first stage of oxidation phosphorylation. During this phase, Complex 1 strips the electrons off of NADH and Complex 2 strips the electrons of FADH2. These electrons are then donated to coenzyme Q, which in turn donates the electrons to complex 3. Complex 3 then proceeds to donate its electrons to complex 4 which donates to the final electron receptor, oxygen, producing H2O. During this process, complex 1, 3, and 4 pump protons into the intermembrane space and create a concentration gradient. This concentration gradient is used to power ATP synthase, as the protons will naturally flow to an area of lower concentration on the interior of the mitochondrial matrix. To do this, the protons pass through ATP synthase, which rotates its mechanism and powers the synthesis of ATP. For every 3 protons which passes through ATP synthase 1 ATP is generated.

The Xiphiformes are an order of fish containing the bill fish and sail fish. These fish present a thuniform swimming in which only the back tail of the fish moves. This semilunate tail is very large and able to move large amounts of water and push the fish forward quickly. In addition to this, their vertebral column is unable to bend. The large bill on the front of their snout serves a dual purpose of aiding in forging as well as navigating through the water effectively. This bill is a modified upper jaw and is covered in tiny teeth like structures. Many Xiphiformes have a large sail which is able to be raised and lowered quickly. This sail may be used to heard prey, making them easier to hunt, as well as aiding in navigation in water and allowing the fish to turn easier. During hunts, sailfish may even change color. This is thought to be a method if signalling other fish.

The first stage to oxidative phosophorlation is called the Electron transport chain (ETC). During this stage, reduced electron carriers in the form of NADH and FADH2 enter the complexes of ETC. Complex 1 strips NADH of its electrons and pumps them to coenzyme Q. In addition to this complex 1 will pump protons to the intermembrane area. Complex 2 strips FADH2 of its electrons and donates them to coenzyme Q as well. However, Complex 2 does NOT pump protons. Coenzyme Q will then donate the electrons it recieves to complex 3, which pumps more protons to the intermembrane space. In turn, complex 3 donates electrons to Cytochrome C, a water soluable protein which can move around the intermembrane space. Cytochrome C transports electrons to Complex 4. Complex 4 pumps protons to the intermembrane space as well, and donates its electrons to the final electron reciever, oxygen. This process produces H2O. It is importan for these complex to pump protons to the intermembrane space to set up a proton gradient. The proton gradient is used to power the last part of oxidative phosophorylation, ATP synathse. Protons from the intermembrane space essentially store energy and release it by moving through the gradiant and back into the mitochondrial matrix through ATP synthase. For every 3 protons which pass through the protein, 1 ATP is created.

The article "Protective systems of immunocompetant organs in fishes from different ecological and systematic groups" by Lapivora et al., discusses the different factors which influence how the immune, antioxidant and monooxygenease systems function within fish. The species examined in this study were the Nothern Pike, Zander and Bream. These fish were caught in the tributary of the Rybinsk resivour and placed in aquariums for at least 1 day after catching to reduce stress. Fish were then evicerated, and had their organs (speel, liver and kidneys) frozen. Ratios of organ weight to body weight were taken as a condition factor. Samples of these organs were taken, stains and smears done and mitochondrial fractioning processed. The bream had the most different ratio of immune system cells, while pike and zander were fairly similar. This may be due to their similar diet and overall function. Both the Zander and pike are predetory pirciverous fish. Thus they need higher amounts of immune system cells to protect against infection which may be obtained from prey they eat. Bream however are more sedentary and benthophagic, thus this increased immune system is not as necessary.

Cells gain energy through a number of pathways that generate ATP. The first pathway in this process is called glycolysis. This process has many reactions in it, though essentially a molecule of glucose is oxidized using NAD+. The end product of glycolysis is NADH, 2 ATP and 2 Pyruvate. The pyrvate then enters the next stage, where it is transformed into Acetyl-CoA. Acetyl-CoA formation also requires NAD+ and produces NADH and CO2. Once Acetyl-CoA is produced it may enter the krebs cycle. The Krebs cycle fully oxidizes Acetyl-CoA into CO2 an H20. This process produces a total of 8-NADH, 2-FADH2 and 2-ATP per glucose molecule. Taking into account glycolysis, acetyl-CoA formation and the krebs cycle producs a total of 10-NADH, 2-FADH2 and 4-ATP. The ATP produced is of course free to be used by the cell. However, the NADH and FADH2 are used to power the electron transport chain and further ATP synthesis.

When a muscle lacks oxygen or requires a lot of energy in a short amount of time, will perform anerobic respiration rather than areobic respiration to produce its energy. This process involved glycolsis, in which ADP and NAD+, an oxidized electron carrier is converted to ATP, NADH (a reduced electron carrier) and pyruvate. The next step of anerobic respiration is called fermentation. In animal cells this is through lactic acid fermentation, but yeast and plants ethanol fermentation is used. In lactic acid fermentation pyruvate is catalyzed to lactate via lactate dehydrogenase. This process also oxidizes NADH to NAD+. This NAD+ may therefore be used for another step of glycolosis in order to produce ATP for the muscle to use. Unfrotunately this prcoess much less effecient than aerobic respiration which uses oxygen, and a lot less energy is produced. Lactic acid will also begin to build up in the cells.

The order of Gobiifromes contains 210 genera and 1,700 species of fish and are some of the smallest known vertebrates. Gobies are primarily marine fish, although they occasionally wander into adjacent freshwater areas. Their pelvic fins are united and form a sucker, which is used to adhere to objects such as plants and rocks. There are some species of sandy substrate dwelling goby which form a symbiotic relationship with shrimp. These shrimp are blind and unable to defend themselves. They will however, dig burrows in the soft sandy substrate in which both organisms may live. In return, the goby alerts the shrimp of incoming danger. There are also species of reef dwelling gobies which exhibit bidirectional sex change. Generally these fishes are protogynus and transition from female to male. Scientist have induced the opposite transition to occur by removing a female in the presence of males. The largest male present will then transition to a female. Likewise when two males were placed in the same area, the largest transitions to female. This is supposedly to have a matching pair of male and female. However it is unlikely this would occur in the wild, as the gobies would be more likely to migrate to a new area as this is more energy efficient.

Percomorpha is a vast group of fishes and the groups contained within it are heavily debated and ever changing. Some simply state that it contains "perch like fish." However that is like saying a peperoni pizza looks like a pizza as the perches themselves are a group within the percomorphs. This group contains the families: Batrachoidae, Centraichidae, Percidae, and so forth. The Batrachoidae are the toadfish. These fish have broad eyes which are dorsally oriented so they may peek above the water. This fish also has the ability to make sound using its swimbladder. Centrachidae are the sunfish. These fish are laterally compressed and have a continues dorsal fin with 5-13 spines. These are fish such as the largemouth and smallmouth bass. The perceidae are the Perches. Perches live in temperate freshwater bodies and are a highly diverse group. Examples of perch include the yellow perch, white perch, and walleye.