Cycles & Transport Mechanisms Flashcards
What is the primary role of the TCA cycle in the production of ATP?
Transfer electrons from substrates to coenzymes
What is the electron transport system’s role in the generation of ATP?
It creates a steep concentration gradient across the inner mitochondrial membrane
How does a decrease in the level of cytoplasmic NAD affect ATP production in mitochondria?
ATP production decreases
NADH produced by glycolysis in skeletal muscle fibers leads to production of two ATP molecules in mitochondria, but NADH produced by glycolysis in cardiac muscle cells leads to production of three ATP molecules. Why?
Different intermediaries
Why is oxidative phosphorylation the most important mechanism for generating ATP?
It produces more than 90% of ATP used by body cells
What contributes to the increased amount of urea in blood during the post absorptive state?
Protein digestion
What consequence(s) is (are) the result of a dietary deficiency of one or more essential amino acids?
Protein deficiency disease occurs. Protein synthesis comes to a half.
Why are proteins an impractical source of quick energy, a “last ditch” source of energy?
Proteins are more difficult to break apart than are carbohydrates or lipids. NH4, a by-product of protein catabolism, is toxic. Protein catabolism threatens homeostasis.
Why do athletes in intensive training try to maintain a positive nitrogen balance?
They actively synthesize N compounds, so must absorb more than they secrete
Why does a diet that is deficient in pyridoxine (vitamin B6) affect protein metabolism?
The first step in amino acid catabolism requires a coenzyme derivative of B6-
Why are high-density lipoproteins (HDLs) considered beneficial?
They reduce fat and cholesterol in the bloodstream
Why is catabolism of dietary carbohydrates and proteins considered “not as productive” as catabolism of lipids?
Lipids release almost twice the energy of proteins or carbohydrates
Why are LDL’s considered “bad cholesterol”?
They deliver cholesterol to peripheral tissues. They often end up in arterial plaques.
Why does hypervitaminosis more commonly involve fat-soluble vitamins?
Excess fat-soluble vitamins are stored in body lipids
What characteristic of lipoproteins allows them to be made water-soluble?
They have a superficial coating of phospholipids and proteins
Which of the following vitamins can be synthesized inside the body?
Vitamins D & K
How would a decrease in the amount of bile salts in the bile affect the amount of vitamin A in the body?
It would decrease Vitamin A
How would the BMR of a pregnant woman compare with her own BMR before she became pregnant?
Higher when pregnant
What effect does vasoconstriction of peripheral blood vessels have on an individual’s body temperature on a hot day?
An increase in body temperature
In cold condition, how does blood flow change to restrict heat loss?
Heat transfer from warm blood in arteries warms cooler venous blood
Which of the following is a true statement?
Glycogenesis will facilitate the storage of glucose in cells
What is NOT true with regard to glycolysis?
It is an anaerobic process that occurs in the cytoplasm. The first step of glycolysis phosphorylates glucose and traps it in the cell. The breakdown of glucose can lead to lactic acid accumulation.
What process in the liver increases after you have eaten a high-carbohydrate meal?
Glycogenesis
In infants, the highly vascularized tissue b/w the shoulder blades is referred to as ___ fat and contains adipocytes that have many___?
Brown, mitochondria
In training for competitive sports what might increase athletic performance?
Increased carbohydrates in the diet 3 days prior to an event
What happens during the process of transamination?
A keto acid is converted into amino acid that can leave the mitochondria
