Chapter 8: Metabolism Flashcards
all chemical reactions that take place in cells to break down or build molecules
Metabolism
is a series of linked reactions, each catalyzed by a specific enzyme
Metabolic Pathway
types of metabolism
- Anabolism
- Catabolism
that break down large, complex molecules to provide energy and smaller molecules
Catabolic Reactions
use ATP energy to build larger molecules
Anabolic reactions
Stages of Metabolism
Stage 1: Digestion and Hydrolysis
Step 2: Degradation
Step 3: Oxidation
____ __ ____break down large molecules to smaller ones that enter the bloodstream
Stage 1: Digestion and Hydrolysis
______ breaks down molecules to two- and three-carbon compounds
Stage 2: Degradation
_____ oxidation of small molecules in the citric acid cycle and electron transport provide ATP energy (electrons are carried by NADH and FADH2)
Stage 3: Oxidation
Is the energy form stored in cells.
ATP (Adenosine triphosphate)
ATP requires…..
7.3 kcal/mol (or 31 kJ/mol) to convert ADP + Pi to ATP.
What does ATP consists of?
- adenine (nitrogen base),
- a ribose sugar
- Three phosphate groups
The hydrolysis of ATP to ___ releases __ ____ (31 kJ)/mole.
- ADP
- 7.3 kcal
The hydrolysis of ADP to ___ releases 7.3 kcal (___ ___)/mole.
- AMP
- 31 kJ)/mole.
- Used in anabolic reactions
- The energy-storage molecule.
- Coupled with energy-requiring reactions
ATP
Hydrolysis products
ADP + Pi
often associated with the loss of H atoms
Oxidation
is associated with the gain of H atoms
Reduction
3 coenzyme in metabolism
- NAD+
- FAD
- Coenzyme A
Abbreviation of NAD+
Nicotinamide adenine dinucleotide
Participates in reactions that produce a carbon-oxygen double bond (C=O)
NAD+
NAD+ is reduced when an oxidation provides…
2H+ and 2e-
Contents of NAD+
- ADP
- Ribose
- nicotinamide
Participates in reactions that produce a carbon carbon double bond (C=C).
FAD
Abbreviation for FAD
flavin adenine dinucleotide
FAD is reduced to…
FADH2
contents of FAD
- ADP
- Riboflavin (Vitamin B2)
WHat does Coenzyme A consists?
- pantothenic acid (vitamin B5)
- phosphorylated
ADP - aminoethanethiol
Used to transfer acetyl groups.
Coenzyme A
WHere does Stage 1, Digestion of Carbohydrates begin?
In the mouth
Stage 1, Begins in the mouth where ____ ____ breaks down polysaccharides to ____ _____ (dextrins), ____, and some ____.
- salivary amylase
- smaller polysaccharides
- maltose
- Glucose
Stage 1 Continues in the ___ ____ where ____ ____ hydrolyzes ____ to maltose and glucose.
- small intestine
- pancreatic amylase
- dextrins
Stage 1. Hydrolyzes ____, ____, and ____ to monosaccharides, mostly glucose, which enter the ______ for transport to the cells
- maltose, lactose, and sucrose
- bloodstream
Stage 2: ______
Glycolysis
Stage 2:Glycolysis Is a metabolic pathway that uses ____, a digestion product.
glucose
what does Glycolysis breaks down/degrade?
glucose (6C) molecules to pyruvate (3C) molecules
Glycolysis is an _____ process
anaerobic
Pyruvate products in Aerobic conditions in humans, animals and microorganisms
Acetyl CoA
Pyruvate products in Anaerobic conditions in humans, animals and microorganisms
Lactate
Pyruvate products in Anaerobic conditions in some microoganisms
Ethanol
Where does pyruvate anaerobic conditions occurs?
In the mitochondria
Under aerobic conditions (oxygen present),
▪ Three-carbon pyruvate is ________
decarboxylated
Under anaerobic conditions (without oxygen),
▪ Pyruvate is
reduced to lactate
Lactate in muscle
During strenuous exercise,
▪ Oxygen in the muscles is depleted.
▪ Anaerobic conditions are produced.
▪ Lactate accumulates.
▪ Muscles tire and become painful.
Occurs in anaerobic microorganisms such as yeast
Fermentation
Fermentation
▪ Regenerates ____
to continue glycolysis.
NAD+
The first step in conversion of pyruvate to ethanol is a ______ reaction to produce _____.
- decarboxylation
- acetaldehyde
Substances that remove or add H atoms in oxidation and reduction reactions
Coenzymes
Stage 3 in digestion of carbohydrates
Citric acid cyle
Operates under aerobic conditions only.
CItric acid cycle
Oxidizes the two-carbon acetyl group in acetyl
CoA to 2CO2
Citric acid cycle
Are oxidized and reduced as hydrogen and/or electrons are transferred from one carrier to the next.
Electron carriers
Examples of electron carriers
- FMN
- Fe-S clusters
- Coenzyme Q
- cytochromes.
electron carrier AH2
reduced
electron carrier A
oxidized
electron carrier B
oxidized
electron carrier BH2
reduced
Accept hydrogen and electrons from the reduced coenzymes
Electron carriers
abrreviation of FMN
Flavin mononucleotide
Accepts 2H+ + 2e- to form reduced coenzyme FMNH2.
FMN Coenzyme
FMN Coenzyme Accepts 2H+ + ___ to form reduced coenzyme _____.
- 2e-
- FMNH2.
Contains flavin, ribitol,and phosphate.
FMN coenzyme
what does FMN coenzyme contains?
- Flavin
- Ribitol
- Phosphate
Are groups of proteins containing iron ions and sulfide.
Fe-S clusters
Fe-S clusters accept electrons to reduce Fe3+ to ___.
- Fe2+
Fe-S clusters lose electrons to re-oxidize Fe2+ to ___.
Fe3+
A mobile electron carrier derived from quinone
Coenzyme Q (Q or CoQ)
CoQ, is reduced when the ___ ____ accept 2H+ and 2e-.
- keto groups
- 2e
Reduced form of Coenzyme Q.
CoQH2 or QH2
▪ Proteins containing
heme groups with
iron ions
Cytochromes
Uses electron carriers.
Electron transport
Electron transport transfers ____ ions and electrons from ____
and ____ until they combine with oxygen
- hydrogen
- NADH
- FADH2
ATP energy from glucose. The complete oxidation of glucose yields…
6 CO2
2 H2O
32 ATP
ATP from two pyruvate under aerobic conditions
▪ 2 pyruvate are oxidized to 2 acetyl CoA and 2 NADH.
▪ 2 NADH enter electron transport to provide 5 ATP.
break fat globules into smaller particles called micelles in the small intestine.
Bile salts
hydrolyze ester bonds to form monoacylglycerols and fatty acids, which recombine in the intestinal lining
Pancreatic lipases
transport the triacylglycerols to the cells of the heart, muscle, and adipose tissues
Chylomicrons
Breaks down triacylglycerols in adipose tissue.
- Forms fatty acids and glycerol.
Fat Mobilization
Beta-oxidation of fatty acids reactions
Reaction 1: Dehydrogenation
Reaction 2: Hydration
Reaction 3: Oxidation
Reaction 4: Cleavage
used peripherally as an energy source when glucose is not readily available
Ketone bodies
Where are ketone bodies produced?
mostly in the liver
Where are ketone bodies transported?
Cells in the heart, brain, and skeletal muscle
a metabolic pathway that produces ketone bodies
Ketogenesis
occurs in diabetes, diets high in fat, and starvation
Ketosis
acetoacetate produces acetone
decarboxylation
acetoacetate produces β- hydroxybutyrate
Reduction
Where does digestion of proteins (stage 1) begins?
In the stomach
Begins in the stomach where HCl in stomach acid activates pepsin to hydrolyze ____ ___
- pepsin
- peptide bond
Digestion of proteins, continues in the ____ ____ where _____ and
_____hydrolyze peptides to amino acids
- small intestine
- trypsin
- chymotrypsin
Digestion of protein is _____ as amino acid enter the _____ for transport to cell
- complete
- bloodstream
In ATP Synthase
Protons _____ _____ to
the _____ through a channel in the __ ____
- flow back
- matrix
- F0complex
In ATP synthase
- Proton flow provides the energy that drives____ _____ by the ___ _____.
- ATP synthesis
- F1 complex
F1 complex of ATP synthase: Center subunit (y)
surrounded by three protein subunit:
- loose (L)
- tight (T)
- open (O)
F1 complex of ATP synthase: energy flow
Energy from the proton flow through F0 turns the center subunit (y)
During ATP synthesis: ADP
ADP and Pi enter the loose L site
During ATP synthesis: Center subunit
The center subunit turns changing L site to a tight T conformation
During ATP synthesis
ATP is formed in the T site where it remains
strongly bound.
During ATP synthesis: After ATP
The center subunit turns changing the T site to an open O site, which releases the ATP
Contains subunits for ATP synthesis.
F1 Complex
Contains the channel for proton flow.
F0 complex
he subunit in F1 that binds ADP and Pi.
L site
The subunit in F1 that releases ATP
O site
The subunit in F1 where ATP forms.
T site
ATP energy from glucose: complete oxidation of glucose
▪ 6 CO2
▪ 6 H2O
▪ 32 ATP
Aerobic conditions: Complete oxidation of glucose
32 ATP
Aerobic conditions: FADH2
1.5 ATP
Aerobic conditions: Acetyl CoA in citric acid cycle
10 ATP
Aerobic conditions: NADH
2.5 ATP
Aerobic conditions: Pyruvate decarboxylation
2.5 ATP
- Amino acids are degraded in the liver
- The reaction is catalyzed by a transaminase or
aminotransferase.
Transamination
▪ Removes the amino group as an ammonium ion from glutamate.
▪ Provides a-ketoglutarate for transamination.
Oxidative deamination
▪ Detoxifies ammonium ion from amino acid degradation
Urea Cycle
- Large amounts of acetyl CoA accumulate
- Two acetyl CoA molecules combine to form acetoacetyl CoA
ketogenesis
where does ketosis occurs?
In diabetes, diets high
in fat, and starvation