40. Animal Metabolism, Nutrition, and Digestion Flashcards
metabolic rate varies with an animal’s:
activity, internal body temperature, and size
adenosine triphosphate (ATP)
the molecule that provides energy in a form that all cells can readily use to perform the work of the cell. ATP is the universal energy currency for all cells
catabolism
the set of chemical reactions that break down molecules into smaller units and, in the process, produces ATP to meet the energy needs of the cell
anabolic
the set of chemical reactions that build molecules from smaller units utilizing an input of energy, usually in the form of ATP. anabolic reactions result in net energy storage within cells and the organism
anaerobic metabolism
energy metabolism in the absence of oxygen-provides rapid but short-term energy to the cell and organism
aerobic metabolism
energy metabolism that uses oxygen gas to oxidize organic compounds, generating ATP; found in Bacteria, Archaea, and the mitochondria of eukaryotic organisms
citric acid cycle
the third stage of cellular respiration, in which acetyl-CoA is broken down and more carbon dioxide is released
electron transport chain
the system that transfers electrons along a series of membrane-associated proteins to a final electron acceptor, using the energy released as electrons move down the chain to produce ATP
metabolic efficiency
the amount of energy captured in a usable form per amount of energy in the starting molecule
what is the metabolic efficiency of aerobic respiration?
at least 34%-other 66% converted to heat and lost to the environment or used to warm the animal
glucose that is not metabolized is stored as:
glycogen, primarily in the liver and muscles
lipids such as triacylglycerol are broken down to:
glycerol and free fatty acids which enter glycolysis or the citric acid cycle to yield ATP by oxidative phosphorylation or stored as fat (adipose tissue)
what do animals preferentially rely on for long-term energy supply?
fats
carbohydrates are always spared for the:
brain and nervous system
protein can also be an energy source but only broken down when…
fat and carbohydrate reserves are depleted
metabolic rate
an animal’s overall rate of energy use
how do you measure metabolic rate?
by measuring the animal’s rate of oxygen consumption, which reflects the rate of aerobic production of ATP
the onset of activity requires immediate energy, which in animals, is provided by:
specialized energy stores in their tissues
in vertebrate muscle cells, for example, what is a ready source of high-energy phosphates that is hydrolyzed to synthesize ATP directly from ADP at the onset of activity?
phosphocreatine
although glycolysis produces relatively few ATP, it is relatively fast providing:
rapid short-term supply of energy for animals-good for short bursts of intensive activity
what supplies energy for longer activity?
aerobic respiration in the mitochondria-intially the rate of oxygen consumption increases, then levels off
once mitochondrial ATP production increases, the steady state production of ATP depends on:
adequate transport of oxygen to the tissue by the cardiovascular system as well as by diffusion of oxygen into mitochondria
recovery metabolism
an animal’s elevated consumption of oxygen following activity-represents the continued metabolic energy required to re-establish the resting metabolic state of the cells
what occurs during recovery metabolism?
the cells re-synthesize depleted ATP stores and metabolize the end products of fermentation, particularly lactic acid
“oxygen debt”
the difference between an animal’s immediate energy need at the onset of activity and energy supplied by aerobic metabolism, it is “paid back” following exercise by the animal’s recovery metabolism
heat storage seems to enable:
quick bursts of speed, has evolved as an adaptation among both predators and prey to achieve short, rapid sprints
at rest, larger animals consume:
more energy and have higher metabolic rates than smaller ones
resting metabolic rate increases with:
animal mass raised to the 3/4 power
the average rate at which each gram of body tissue consumes energy is….
LESS in larger animals compared to smaller ones
the larger the organism, the…
LOWER the metabolic rate PER GRAM of body tissue
metabolic rate increases linearly with…
speed-larger animals expend less per unit mass than smaller ones
an animal’s internal body temperature can affect the rate of chemical reactions which in turn determines how fast:
fuel molecules can be mobilized and broken down to supply energy for a cell
endotherm
an animal that produces most of its own heat as by-products of metabolic reactions-generally maintain a constant body temperature that is higher than that of their environment
ectotherm
an animal that obtains most of its heat from the environment-body temperatures regulated by changing their behaviour
endotherms have a higher…
metabolic rate than ectotherms, endotherms are able to be active over a broader range of external temperatures than ectotherms
the activity level and metabolic rate of ectotherms increase with…
increasing body temperatures
ectotherms that are of similar body mass at temperature to an endotherm have metabolic rates that are:
25% of the endotherm
even when the body temperatures are similar, ectotherms cannot sustain:
prolonged activity
endotherms benefit from having an active lifestyle but requires:
lots of food to keep warm and be active
although ectotherms cannot sustain activity for long periods, they can survive longer periods without….
food
the control of core body temperature or thermoregulation is a form of:
homeostasis and requires the coordinated activities of the nervous, muscular, endocrine, circulatory, and digestive systems.
