Chapter 4 - Metabolic Reactions Flashcards
(47 cards)
Metabolism
Sum of all chemical reactions in the body
Cellular Metabolism:
Sum of all chemical reactions
occurring in a cell; metabolic reactions usually occur in
pathways or cycles
What are the 2 types of metabolic reactions?
Anabolism
Catabolism
Anabolism
Small molecules are built into larger ones;
requires energy
Catabolism
Larger molecules are broken down into
smaller ones; releases energy
Anabolism provides…?
Provides materials for maintenance, cellular growth and repair; requires A T P made during
catabolism; example: Dehydration synthesis:
* Smaller molecules are bound together to form larger ones
* H2O produced in the process
* Used to produce polysaccharides, proteins, triglycerides
Catabolism breaks down larger molecules into…?
smaller ones; A T P is produced; Example: Hydrolysis:
* Used to decompose carbohydrates, proteins, lipids
* Uses H2O to split the substances
* Reverse of dehydration synthesi
Enzymes (protein catalysts):
- proteins that cause specific reactions
- Increase rates of chemical reactions
- Lower the activation energy necessary to start reactions
- Each enzyme is specific to a particular substrate
Metabolic Pathways:
- Series of enzyme-controlled reactions leading to formation of a product
- Each new substrate is the product of the previous reaction
- Each step of a pathway is catalyzed by a different enzyme
example of negative feedback
What are the 3 factors that alter Enzymes?
Cofactor
Coenzyme
Denaturation
Cofactor
- Non-protein substance that combines with the enzyme to activate it
- Some help fold active site into proper conformation
- Some help bind enzyme to substrate
- Can be ion, element, or small organic molecule (coenzyme)
Coenzyme
- Organic molecule that acts as cofactor
- Most are vitamins, which are essential organic molecules that humans
must get from their diet
Denaturation
- Inactivation of an enzyme (or any other protein), due to an irreversible
change in its conformation - Results in enzyme being unable to bind to substrate
Energy
- Capacity to change something, or the ability to do work
- Common forms of energy: Heat, light, sound, electrical
energy, mechanical energy, chemical energy - Energy cannot be created or destroyed, but can be
changed from one form to another
Cellular Respiration
- Process that transfers energy from molecules, and makes
it available for cellular use - Most metabolic reactions use chemical energy
Many metabolic processes require…?
Chemical energy, which is stored in ATP
Energy is help in _____ _____ and released when bonds are ______
Chemical Bonds
&
Broken
Oxidation releases _____ from glucose and other molecules, via loss of ____ _____ and their _____
Energy
&
Hydrogen Atoms
&
Electrons
In cells, enzymes lower activation energy needed for
oxidation in reactions of cellular respiration meaning…?
Energy is transferred to ATP:
* 40% is released as chemical energy
* 60% is released as heat; maintains body temperature
ATP (Adenosine Triphosphate):
- Molecule that carries energy in a form the cell can use
- Main energy-carrying molecule in the cell; energy from
ATP breakdown is used for cellular work
ATP consists of what 3 portions?
Adenine
Ribose ( a sugar )
3 Phosphates in a chain
- Second and third phosphates are attached by high-energy
bonds; energy can be quickly transferred to other
molecules
Cellular Respiration of glucose occurs in 3 interconnected
reaction sequences:
- Glycolysis (anaerobic)
- 2ATP
- Citric acid cycle (aerobic)
- 2ATP
- Electron transport chain/oxidative phosphorylation
(aerobic) - 32 – 34 ATP
Glycolysis and the Electron Transport Chain are stepwise
reaction sequences
Citric Acid Cycle occurs in a metabolic cycle in which the
final product reacts to replenish original substrate
Cellular respiration of glucose requires a supply of glucose
and O2. Final products of cellular respiration
- Carbon dioxide
- Water
- ATP (chemical energy, 40%)
- Heat (60%)
Cellular Respiration includes 2 types of reactions
- Anaerobic reactions: do not require O2, and make little
ATP - Lactic acid production
- Aerobic reactions: require O2, and make most of ATP
