Flashcards in Intro to Metabolism Deck (42):
What is the difference between catabolism and anabolism?
catabolism: utilization of compounds for the generation of energy
anabolism: utilization of energy to produce compounds
What do fats, polysaccharides, and proteins get broken down into during energy production?
fats: fatty acids and glycerol
polysaccharides: glucose and other sugars
____ is an important intermediate in several pathways
Define glycogenesis and glycogenolysis.
glycogenesis: synthesis of glycogen
glycogenolysis: breakdown of glycogen
The pentose phosphate pathway generates what?
NADPH and 5 carbon sugars (ribose) for nucleotides
What are the starting and ending products of glycolysis
glucose -> pyruvate
What are some important side products from glycolysis in some tissues?
What is gluconeogensis and where does it take place?
synthesis of glucose from pyruvate; restricted to liver and kidney
____ is also the source for carbohydrates in glycoproteins and proteoglycans
Acetyl-CoA from carbohydrate and/or protein can be utilized to make ___
Acetyl-CoA is a substrate for what? (4)
1. TCA cycle
3. cholesterol synthesis
4. ketone bodies
____ ____ are also required for complex lipids, components of membranes
Some AAs can produce acetyl-CoA, some AAs can produce carbohydrate intermediates. In both cases, what happens to the AA?
1. AA is eliminated as urea
2. AA is re-utilized to form another AA
AAs are the source of nearly all the ___ in compounds making up an organism
More than one pathway may be required for some special compounds. Describe what Phospholipids and Nucleotides require.
Phospholipids: require contribution from lipids, carbohydrates, and AAs
Nucleotides: require contribution form AAs and carbohydrates
Gluconeogeneis only occurs where?
liver and part of kidney
Red blood cells contain no ____, and cannot utilize ___ ___ metabolism
mitochondria; aerobic carbohydrate
Organs participate in specialized pathways associated with their function. ___ hormones are produced in endocrine glands
Some storage forms of molecules are restricted to certain organs. Where are glycogen and triacylglycerols stored?
glycogen: only in muscle and liver
triacylglycerols: only in adipose tissue
Pathways may be found only in certain sub cellular locations. Fatty acid oxidation and fatty acid synthesis both occur where?
Fatty acid oxidation occurs only inside _____, while fatty acid synthesis occurs only in ____
note: this arrangement prevents "futile cycling"
Control of a pathway is through control of ___ activity
A key regulated enzyme of glycolysis is affected ____ by a product of the pathway. This is an example of what?
allosterically; example of feedback inhibition
True or false? an enzyme responds the same way to the same hormone in different tissues
false; responds differently
For each of the following components, give their associated amount of calories/gram:
There are no essential carbohydrates since there are biochemical mechanisms to synthesize required carbohydrates from non-carbohydrate molecules
The "typical" western diet consists of about half the calories from _____
In regards to fiber, cellulose and himicelluloses ____ stool bulk and ____ transit time
In regards to fiber, lignins ____ stool bulk and bind what two things
increase; bind cholesterol and carcinogens
In regards to fiber, pectin and gums decrease rate what 3 things?
decrease rate of gastric emptying
decrease rate of carbohydrate absorption
decrease serum cholesterol
What does the glycemic index show?
the effect of a standard amount of carbohydrate on blood glucose concentration compared to the effect of a standard amount of glucose
A higher glycemic index would be expected to ____ blood glucose faster and lead to a greater release of ____
What is the recommended protein intake?
0.8 g/kg body wt/day
Protein intake needs to be increased during growth and illness. True or false?
What are the essential AAs?
Threonine, Tryptophan, Valine, Arginine, Histidine, Lysine, Phenylalanine, Leucine, Isoleucine, Methionine
mnemonic: These Ten Valuable Amino-acids Have Long Preserved Life In Man
____ is sometimes considered essential for growing children
Positive nitrogen balance: more nitrogen ingested than excreted occurs during what two periods?
Negative nitrogen balance: more nitrogen is excreted than ingested occurs when?
starvation; diseases; severe burns
Fats require essential fatty acids. What are these two essential fatty acids?
Linoleic acid (18:2), Linolenic acid (18:3)
What is the recommended intake of fat in a balanced diet? give in percentage of total calories
In regards to under-nutrition, describe Marasmus.
1. Occurs in both adults and children
2. extreme emanation from prolonged negative energy balance
3. loss of protein from muscle, heart, liver, and kidneys