Lecture Chp. 4: Cellular Metabolism Flashcards
All chemical reactions that occur in the body
Metabolic Processes
Two types of metabolic reactions
- Anabolism
2. Catabolism
Large molecules are made from small molecules (requires energy)
Anabolism
Larger molecules are broken down into smaller ones (releases energy)
Catabolism
Anabolism provides the materials needed for _____.
cellular growth and repair
Type of anabolic process
Dehydration Synthesis
Used to make polysaccharides, triglycerides, and proteins (produces water)
Dehydration Synthesis (Anabolism)
A catabolic process
Hydrolysis
Used to decompose carbohydrates, lipids, and proteins. Water is used to split the substances.
Hydrolysis
*Reverse of dehydration synthesis
Force water into the molecule to break it down
Hydrolysis
Type of reaction that releases energy
Exergonic
type of reaction that requires an input of energy
Endergonic
When you break a phosphate bond, you ____ energy
gain
the ability to do work
energy
energy stored
potential energy
energy of motion and heat
kinetic energy
Fast moving particles exhibit the energy heat
kinetic energy
- Help link endergonic and exergonic reactions
- are usually proteins
- speed up chemical reactions
enzyme
*act as a catalyst. ATP will eventually fall apart, but we can’t wait forever. So, we have enzymes b/c we need energy now!
The energy required to start a process
activation energy
Only _____ reactions are spontaneous
exergonic
Catalysts do _____
catalysis
How to catalysts increase the chances that a exergonic reaction will take place?
They manipulate chemical bonds so less activation energy is needed to start the process
Enzymes are biological _____ that bind to _____
biological catalysts; bind to substrates
Enzymes have a highly specific ______
active site
Enzymes bind to substrates through:
weak, non-covalent bons
When enzymes bind to substrates, what may happen?
Binding might change the shape of the enzyme temporarily
*induced fit
Depending on the temperature, an enzyme may bind to, alter, and release _____ molecules per second.
100,000
Composed of several non-covalently bonded enzymes
Multienzyme Complexes
Multicomplex enzymes:
rapidly accomplish a series of reactions
Most metabolic pathways:
- multiple steps
2. must be catalyzed by multiple enzymes
Aid enzymes in catalysis
cofactors
organic, non-protein molecules that aid enzymes in catalysis
Coenzymes (cofactor)
Reactions that move pairs of electrons
oxidation-reduction reactions
_____ will aid in oxidation-reduction reactions
cofactors
What is the most important coenzyme
Nicotinamide adenine dinucleotide (NAD+)
*know dinucleotide
What makes up NAD+
- AMP
- nicotinamide monophosphate
When NAD+ becomes reduced:
- it picks up 2 electrons in association with it
- creases NADH
NADH will donate the electrons it gained when NAD+ was reduced to another molecule, including:
those that make ATP
NAD+ =
oxidized
NADH =
reduced
Molecules are ____ when they lose electrons
Oxidized
*oxidation reactions
Molecules are ____ when they gain electrons (become more negative)
Reduced
*Reduction reactions
When enzymes fall apart
denatured
Increasing ambient temperatures:
-increases the rate of enzymatic work up to a point (extreme temperatures may denature the protein)
All enzymes have an ______ temperature
optimum
pH can determine:
the efficiency of enzymes
Optimum pH for most proteins is between a pH of:
6 and 8
What is the exception for an enzyme that has a very acidic pH
pepsin (stomach acid)= ph of 2
Any molecule that changes the activity of an enzyme is an _____
effector
*could increase or decrease
effectors that inhibit enzyme activity are:
inhibitors
Molecules that resemble a substrate and can occupy an active site are:
steric inhibitors
competitive inhibitors
steric inhibitors
Get food from something else (another organism)
heterotrophs
synthesize own organic molecules to obtain energy
autotrophs
All chemical reactions that occur in the body
metabolism
what is an example of a steric inhibitor?
carbon monoxide
*Binds to hemoglobin and prevents hemoglobin from picking up oxygen
Noncompetitive inhibitors bind somewhere on the enzyme other than the _____
active site
non-competitive inhibitor is also known as an
allosteric effector
A noncompetitive inhibitor changes the ____
shape of the active site
When can ATP function as an allosteric effector?
with PFK
*ATP can bind to PFK so that cells can’t break down Glucose
The process in which organic molecules are broken down to obtain energy
cellular respiration
most eukaryotes are aerobic and complete ___ stages of cellular respiration
4
most prokaryotes are anaerobic and complete ____ stages of cellular respiration
1
cellular respiration uses:
oxygen
What are the four stages of cellular respiration
- Glycolysis
- Transition Reaction
- Citric Acid Cycle (Krebs Cycle)
- Oxidative Phosphorylation
The first two stages of cellular respiration (glycolysis and transition reaction) occur in the ____
cytosol
The second two stages of cellular respiration (citric acid cycle and oxidative phosphorylation) occur in the ____
mitochondrion
oxidative phosphorylation is where the cell:
makes a lot of ATP
During cellular respiration, Glucose is broken down into:
- ~36 to 28 ATP
- water
- carbon dioxide
A three-phase pathway in which:
- Made up of 10 steps
- Glucose is oxidized (loses electron) into pyretic acid
- NAD+ is reduced to NADH
- ATP is synthesized
Glycolysis
Phase 1 of Glycolysis:
- split glucose into 2 3-C molecules
- Requires 2 ATP
- Includes the regulatory step of ATP synthesis (Enzyme PFK)
Phase 2 of Glycolysis:
- oxidation of the 2 3-C molecules
- reduces 2 NAD+ to 2 NADH
- Phosphorylation of the 2 3-C molecules
Phase 3 of Glycolysis:
- Further oxidation of the 2 3-C molecules
- Generates 4 ATP
- Oxidation of 2 3-C molecules (removes water)
- 2 pyruvate (same as 2 pyruvic acid molecules) are formed
To maintain glycolysis, a cell needs a constant supply of ____
NAD+
Aerobic organisms use ____ to convert NADH to NAD+
oxygen
In anaerobes, what happens to NADH?
There is a build-up of NADH and pyretic acid is used to form ethanol (and carbon dioxide)
*ethanol helps oxidize NADH into NAD+
Pyruvic acid is converted to acetyl CoA in three main steps:
- Decarboxylation
- Oxidation
- Formation of acetyl CoA
carbon is removed from pyretic acid and carbon dioxide is released
decarboxylation
pyruvic acid–> acetyl CoA
Hydrogen atoms are removed from pyruvic acid and NAD+ is reduced to NADH
Oxidation
pyruvic acid–> acetyl CoA
the resulting acetic acid (from the first two steps of converting pyruvate to acetyl CoA) is combined with:
coenzyme A to form acetyl CoA
Acetyl CoA has two possible fates:
- it can enter the citric acid/krebs cycle
2. it can be used to make fats
A hydrogen atom is transferred to NAD+, forming NADH
oxidation-reduction
An eight-step cycle in which each Acetly CoA is decarboxylated and gives up electrons, generating:
- 3 NADH
- 1 FADH2
- 2 CO2
- 1 GTP
Krebs/Citric Acid Cycle
Acetyl CoA, when introduced into the citric acid cycle, will interact with _____ to form ____?
oxaloacetate (C4); citrate (citric acid)
What goes into the citric acid cycle?
Acetyl CoA
What are the products of the Citric Acid Cycle?
- 3 NADH
- 1 FADH2
- 2 CO2
- 1 GTP (ATP Analogue)
The energy from oxidizing NADH and FADH2 is used to make the ______ of ATP
*electron transport chain
phosphate bonds
The e- are send down an electron transport chain and given to:
oxygen
Oxidation phosphorylation is coupled with this:
ATP is synthesized
Add phosphate group to ADP to synthesize ATP
In the electron transport chain, a ______ is established with
chemical gradient
During the electron transport chain, Protons (H+) are pumped
1, 3, and 4 (cytochrome 2 does not add H+ ions)
During the electron transport chain, a high concentration of H+ is established in:
the intermembrane space
When a high concentration of H+ is established in the intermembrane space, a _____ is also established
electrochemical gradient
What simply passes electrons down the election chain?
Cytochrome 2
Take electrons and use them to reduce other molecules
Electron Carriers
The pathway of electrons
the pathway of the electrons
proteins that change color when they are reduced and oxidized
Cytochromes
Every time an electron is being passed through a cytochrom, ____ is being pumped out
H+
In Oxidating Phosphorylation, electrons are delivered to oxygen, forming ____
oxygen ions
In Oxidative Phosphorylation, oxygen atoms attract ____ to form ____.
H+; water
When H+ is pumped to the intermembrane space, if diffuses back into the matrix by way of ______
ATP Synthase
*Releases energy to make ATP
Each NADH can yield ___ ATP through ____.
2.5 ATP; the electron transport chain
each FADH2 can yield ____ ATP
- 5
* FADH2 gives electrons to the second cytochrome
The citric acid cycle generates ____ ATP from NADH
20 ATP
The citric acid cycle generates ____ ATP from FADH2
3 ATP
The two molecules of NADH made in glycolysis make:
2-3 ATP
How many ATP molecules are made directly in Glycolysis?
2 ATP
_____ are made directly in the citric acid cycle
2 GTP
Cellular respiration produces:
36-38 GTP
Why is there only one ATP Synthase pump in the electron transport chain?
only one, to keep high H+ concentration on the outside of the membrane
The cytochrome has how many proteins?
5
*(1,2,3,4, and ATP Synthase)
When there is too much ATP, ATP acts as an ____, changing the shape of enzyme PFK, shutting down Glycolysis
allosteric inhibitor
*Illustrates Negative Feedback
What happens to excess Glucose?
Carbohydrate Storage
- Glycogen (Parimarily by liver and muscle cells)
- Fat
- Converted to: amino acid
Regulation of Metabolic Pathways
- limited number of regulatory enzymes
- negative feedback
_____ is in the middle of all metabolic pathways
The Kreb Cycle
_____ contain more energy than any other macromolecule
Fat Molecules
What it the energy content of fat?
9.4 kcal/gram of fat
What is the energy content of carbohydrates?
4.1 kcal/gram of carb
What is the energy content of Protein?
4.1 kcal/gram of protein
What is the first macromolecule to be broken down by the body?
carbohydrates
What is the second macromolecule to be broken down by the body?
Proteins
What is the last macromolecule to be broken down by the body?
Fat
instructs cells how to construct proteins; stored in DNA
Genetic Information
segment of DNA that codes for one protein
Gene
complete set of genes
Genome
Method used to translate a sequence of nucleotides into a sequence of amino acids
Genetic Code
Delivers information from the nucleus to the cytoplasm
Messenger RNA
Messenger RNA is:
a single polypeptide chain
Where is a RNA molecule formed?
formed beside a strand of DNA
making of mRNA (copying of DNA) is:
transcription
RNA nucleotides are complementary to DNA nucleotides (except no _____ in RNA; replaced with _____)
Thymine; Uracil
Structure of DNA
- 2 polynucleotide chains
- Forms a helix
A pairs with ____
T
G pairs with ____
C
How do A and T and G and C pair with each other?
Through Hydrogen Bonds
What is DNA wrapped around?
histone proteins
*(forms chromosomes)
What does transfer RNA carry to mRNA?
- amino acids
- anticodon
what does tRNA do?
translates a codon of mRNA into amino acid
provides structure and enzyme activity for ribosomes
Ribosomal RNA (rRNA)
3 nitrogen containing bases on a base of tRNA that compliments codon. If match, the n we know we brought in the right amino acid
Anticodon
Codes for a single amino acid
Codon
DNA Replication is controlled by:
DNA polymerase
In DNA Replication, new nucleotides pair with ______
exposed bases
DNA molecule synthesized is ____ of original DNA and ____ new DNA
1/2; 1/2
*Semi-conservative
Describe where protein is synthesized
In Ribosomes, E site, P site, and A site
Where is the first codon?
Underneath the P site
During protein synthesis, what kind of bonds are formed?
Peptide Bond
Permanent change in genetic info
Mutation
Result when extra bases are added or deleted and bases are changed
Mutation
_____ correct mutations
repair enzymes
____ may or may not change the protein
mutations
Mutation where one amino acid is wrong
Sickle-Cell anemia