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65 terms

a & p 2.... chapter 25

STUDY
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cells are chemical factories
that break down organic substrates to obtain energy
cells need
oxygen and nutrients
energy released
inside the cell supports growth, cell division, contraction, secretion, and various other special functions
a lot of energy is released as
...
cells synthesize new compounds to
perform maintenance or repairs, support growth, produce secretions
energy yields of glycolisis, TCA and ETS
Glycolysis..... 2 ATP
TCA cycle......2 ATP
ETS.............28 ATP
NADH from glycolysis...4 ATP
-----------------------------------------------
total 36 ATP
many cells will shift from glucose based to
lipid based ATP production. Cells will shift to proteins for energy only when lipids and carbs are unavailable.
lipids are broken down into
pieces that can be converted into puruvic acid, or channeled into the TCA cycle
which yields more energy...glucose, lipids or protein catabolism?
lipid
one drawback to lipid catabolism
lipids cannot provide large amounts of ATP in a short amount of time.
which lipoprotein is "good" chol
HDL
which lipoprotein is "bad" chol
LDL
amino acids are derived from
proteins taken in a food, tissue proteins that are broken down during normal growth, repair and tissue restructuring
fates of ingested protein
small amounts may be excreted
used to build new proteins
may be oxidized in the Kreb's cycle to produce ATP
*****LISTING QUESTION ****
protein catabolism is an impractical source for quick energy because...
********LISTING QUESTION********
1. proteins are more difficult to break down than complex carbs or lipids
2. one of the byproducts, ammonia, is a toxin that can damage cells
3. proteins form the most important structural and functional components of cells
minerals and vitamins are essential
components of your diet. your body cannot synthesize minerals, and you can generate small quantities of very few vitamins.
mineral functions
act as cofactors in a cariety of enzymatic actions
contribute to osmolarity of body fluids and play a role in transmembrane potentials, action potentials, neurotransmitter release, muscle contraction, construction and maintenance of the skeleton, transport of gases, buffer sustems, fluid absorptions, and waste removal
biochemical reactions produce heat
...
mechanisms to increase heat loss
1. peripheral vasodilation - allows more blood to flow to the skin and the heat will be lost tot he environment through radiation and conduction
2. increased perspiration - cools the body through evaporation of sweat
3. increased respiration - increases evaporative losses through the lungs
mechanisms to promote heat gain
1. decreased blood flow to the dermis - less heat is lost by radiation and conduction to the environment
(a) countercurrent exchange - diffusion
between fluids that are moving in opposite directions Heat diffuses from the warm blood flowing outward to the limbs into the cooler blood returning from the periphery
2. shivering thermogenesis - a form of muscular exercise in which heat is produced as a byproduct of oxidative metabolism
3. nonshivering thermogenesis - hormones speed up oxidative metabolism and hence more heat is produced
thermoregulatory responses differ
between individuals: acclimatization, body weight, age, tissue distribution, surface-to-volume ratios, and hypothalamic thermostats
catabolism
breakdown organic substances to release energy that can be used to make ATP or other high energy compounds (DESTROY-faster)
anabolisn
syntheses of new organic molecules (BUILD)
respiration
the process by which cells produce energy (ATP)
anaerobic respiration
GLYCOLYSIS-porceeds in the abscence of O2. occurs in the cytoplasm
aerobic respiration
TCA OR KREBS CYCLE-occurs only in the presence of O2. occurs in the motochondria
glycolysis
the anaerobic breakdown of glucose to pyruvic acid.
requires glucose molecules, cytoplasmic enzymes, atp and adp, organic phosphates and nad
TCA cycle
function-remove hydrogen atoms, form organic molecules, and transfer them to coenzymes.
ETS
cytochrome system responsible for most of the energy production in living cells. a complex bound to the inner mitochondrial membrane
glucogenesis
the formation of glycogen from fatty acids and proteins instead of carbohydrates
glycogenesis
the conversion of glucose to glycogen when the glucose in the blood exceeds the demand
substrate level phosphorylation
when an enzyme uses the energy released by a chemical reaction to transfer a phosphate group to a suitable acceptor molecule
oxidative phosphorylation
capture of energy as ATP during a series of oxidation-reduction reactions. a sequence that occurs in mitochondria. involves coenzymes and the electron transport system
oxidation
loss of electrons--becoming "+"
*electrons carry chemical energy
reduction
acceptance of electrons--becoming "-"
*electrons carry chemical energy
glycoenolysis
when blood glucose levels dec, this takes place in the liver, and glucose is returned to the blood.
lipogenesis
creation of triglycerides (fat-- fatty acids and glycerol) - move out of bloodstream to store in adipose tissue, (converting excess glucose into lipids)
free fatty acids
water-soluble lipids that can easily diffuse across cell membranes; they are an important energy source during periods of starvation (when glucose supplies are limited)
lipoproteins
-lipid-protein complexes that contain large glycerides and cholesterol with a superficial coating of phospholipids and proteins
nutrition
the absorption of nutrients from food
malnutrition
unhealthy state resulting from inadequate or excessive intake of one or more nutrients
bioenergetics
study of how organisms acquire and use energy
thermoregulation
The homeostatic regulation of body temperature
transamination
enzymatic transfer of an amino group from an amino acid to a keto acid; cells of the liver, skeletal muscles, heart, lung, kidney and brain perform a lot of transaminations
deamination
the removal of an amino group from an amino acid, it generates an ammonia molecule or an ammonium ion (highly toxic).
essential amino acids
(amino acids your body cannot make them) that must be acquired through the diet.
nonessential amino acids
amino acids your body can make
absorptive state
period following a meal, when nutrient absorption is under way. 3 meals a day = 12 hours in absorptive state each day
postabsorptive state
extends from the end of the absorptive state to the next meal; your body relies on internal energy reserves; 12 hours each day
five metabolic components include
liver, adipose tissue, skeletal muscle, neural tissue, and other peripheral tissues
liver... metabolic component
the focal point for the metabolic regulation and control. Liver cells can breakdown or synthesize most carbohydrates, lipids, and amino acids. Contains significant energy reserves (glycogen deposits)
adipose tissue..metabolic component
stores lipids, primarily in the form of triglycerides.
skeletal muscle...metabolic component
contains substantial glycogen reserves, and the contractile proteins can be mobilized and the amino acids used as an energy source
neural tissue...metabolic component
does not contain energy reserves, depends on aerobic metabolism for energy production
peripheral tissue...metabolic component
are able to metabolize glucose, fatty acids, or other substrates under the direction of the endocrine system.
inborn errors of metabolism
inherited inability to produce specific enzymes involved with amino acid metabolism: ex.- phenylketonuria (PKU), albinism, lactose intolerance, Tay-Sach's disease, and hypercholesterolemia
obesity
20% over ideal weight, serious health risks. Obese individuals take in more food energy than they are using
hypervitaminosis
when dietary intake exceeds the ability to store, utilize, or excrete a particular vitamin
anorexia nervosa
individual who is underweight and thinks that they are still too fat, refuse to eat normal amounts of food
bulimia
individual goes on an "eating binge", the meal is then followed by induced vomiting, laxatives (promote movement of material through the digestive tract), diuretics (promote fluid loss in urine
acclimatization
adjusting physiologically to an environment over time
heat cramp
characterized by profuse sweating, cardiovascular and thermoregulator mechanisms are intact
heat exhaustion
there are unreplaced losses of salts and water, sweating, weakness, reduced blood pressure, rapid pulse, normal or slightly elevated temperature
heat stroke
results from a breakdown in thermoregulation. Sweat glands cease to function and body temperature rises. The patient lapses into a coma; the skin is flushed, hot an dry
hypothermia
below-normal body temperature