Intermediary Metabolism (Topic 3) Flashcards
Intermediate steps between the entrance of nutrients in the cell are used for what? (2)
- The metabolism of short-chain (2-4C) molecules
- They allow for the conversion of one biomolecule to another
There are no dedicated pathways to break down what to form ATP? (2)
There are no pathways to breakdown fat or protein to make ATP
What happens to fats or proteins? (2)
- Either converted to glucose OR
- Enter into cellular respiration pathways at various points
What are 2 issues with energy storage? (3)
- fuel availability
- best storage container
In what forms is energy stored? (3)
glycogen and fats = triglycerides
Rank these from the best storage to most available for cell usage: ATP, Glycogen, Glucose, Fat (3)
- fat (roughly 2 1/2 x as much energy stored)
- glycogen (stored? just less than fats)
- glucose (readily used, but not stored)
- ATP (bad at storage, good for quick transfers)
Where is glycogen stored? (3)
- liver (and kidney)
- muscles
In order to store something. What do you need to be able to do? (4)
Your body has to be able to make it and break it down
What are enzymes in the cytoplasm responsible for? (4)
production and breakdown
If blood sugar is high -> ___ of glycogen (4)
synthesis
If blood sugar is low -> ___ of glycogen (4)
hydrolysis
Glycogenesis = (4)
synthesis
Glycogenolysis = (4)
hydrolysis
What is the intermediate of glucose -> glycogen? (glycogenesis) (5)
glucose 6-phosphate
Where does glycogenesis and glycogenolysis occur? (5)
liver, kidney, and muscle
What is gluconeogenesis? (6)
The making of glucose from precursors that are NOT carbohydrates
Where does gluconeogenesis occur? (6)
liver and kidney
What is the starting point of gluconeogenesis? (6)
- mostly lactate
- glycerol
- some amino acids
Gluconeogenesis has the same enzymes as glycolysis except which ones? (7)
pyruvate carboxylase, PEP carboxylase, fructose 1,6-biphosphatase, and glucose 6-phosphatase
Is PEP -> pyruvate reversible? (6)
No
What enzyme converts PEP to Pyruvate? (6)
pyruvate kinase
What are the steps of gluconeogenesis starting from lactate? How many lactate do you start with? (6)
lactate -> pyruvate -> acetyl CoA -> PEP -> glucose
- you need 2 lactase
What does glucose 6-phosphatase do? (7)
it removes the phosphate group from glucose 6-phosphate
is gluconeogenesis anabolic or catabolic? (7)
anabolic (requires ATP)
- 2 pyruvate to 1 glucose takes 6 ATP
Why would your body use ATP to make glucose? (7)
To raise your blood sugar when it is low
Is glycolysis anabolic or catabolic? (7)
Catabolic
How are fatty acids catabolized since they cannot enter glycolysis? (8)
Fatty acids cannot enter glycolysis so it is broke down in the mitochondria during beta oxidation
What is beta oxidation? (8)
breakdown of fatty acids in mitochondria
What is the end product of beta oxidation? (8)
- Acetyl CoA
- reduced coenzymes (NADH and FADH2)
How many ATP can come from one 18-C fatty acid? (8)
146 ATP
How is glycerol catabolized? (8)
It enters glycolysis as an intermediate
The synthesis of fatty acids is the reverse of what? (9)
catabolism or beta oxidation
Where does the synthesis of fatty acids occur? (9)
the cytoplasm
Where do the Acetyl CoAs for fatty acid synthesis come from? (9)
from other biomolecules (such as glucose)
What does the binding of Acetyl-CoAs do in the synthesis of fatty acids? (9)
- lengthens carbon chain
- adds 2 carbons each time
Where does the glycerol come from for the synthesis of triglycerides? (9)
from intermediates if glycolysis
What happens in the synthesis of triglycerides? (9)
links 3 fatty acids to alpha-glycerol phosphate
Where does the synthesis of triglycerides occur? (9)
the smooth endoplasmic reticulum
Can glucose be readily converted to fatty acids? If so, How? If not, why not? (10)
Yes
- glucose -> pyruvate -> Acetyl CoA -> Krebs cycle -> oxaloacetate -> glycerol -> triglyceride metabolism
Can fatty acids be converted to glucose? If so, How? If not, why not? (10)
No
- fatty acids CAN be made into Acetyl-CoA and enter the Krebs cycle BUT those carbons will leave the cycle as CO2
OR
- having 1 Oxaloacetate and Acetyl-CoA for krebs cycle leaves you with 0 oxaloacetate in the end and cannot be used to be converted to glucose
What do proteases do? (11)
separate amino acids
What does proteolysis do? (11)
- removes end amino acids
- breaks specific bonds
What happens in protein metabolism? (11)
20 amino acids enter cellular respiration through various steps of glycolysis and krebs cycle
What do proteins contain that other organic molecules do not? (12)
nitrogen (in addition to C, H, and O)
What needs to be removed before proteins can enter glycolysis or krebs cycle? (12)
nitrogen
What is an amino acid called after it loses its amine group? (12)
a keto acid
What happens in oxidative deamination? (12)
An amino acid is turned into a keto acid by removing its amine group and making it into ammonia
What happens in transamination? (12)
The amine group is moving from amino acid 1 to amino acid 2
- AA1 + keto acid 2 -> keto acid 1 + AA2
Where is ammonia converted to urea? (12)
in the liver
Where is urea removed? (12)
Bladder?
Amino acids can be synthesized with opposite reactions. T/F (13)
True
How many amino acids can the body produce? (13)
11
What are the amino acids that have to be consumed (not produced) called?
essential amino acids (9 of them)
Could valine get converted to glucose? Explain. (14)
valine introduces a new intermediate which can be converted to oxaloacetate which can be used to make glucose
(need 2 valines. 2C from 2 Val + 4C from oxa = the 3 C needed for PEP)
Could leucine get converted to glucose? Explain. (14)
No, it gets broken down to acetyl CoA, and CoA cannot be used to build glucose.
What is an essential nutrient? (16)
body cannot produce them, needs to be consumed
How many essential nutrients do we have? (16)
about 50
What are the categories of essential nutrients? (16)
Water, essential amino acid, essential fatty acids, vitamins, and minerals
What is the difference between vitamins and minerals? (16)
vitamins are organic
minerals are on the periodic table
Characteristics of vitamins? (16)
- 14 essential organic nutrients
- needed in very small amounts
- various structures and functions (water vs fat soluble)
- large intake does not enhance action
What vitamins are fat soluble? (16)
A, E, D, and K
