Bioenergetics Flashcards
study of energy transfer within living things
bioenergetics
3 reasons for studying bioenergetics
- the role of energy is fundamental to biological processes like growth, development and metabolism
- the ability to harness energy from a variety of metabolic pathways is a property of all living organisms
- life is dependent on energy transformations. living organisms survive because of exchange of energy within and without
2 laws of bioenergetics
- energy cannot be created nor destroyed, but can be change from one form to another
- energy transfer will always proceed in the direction of increased entropy, and the release of free energy
light → chemical → electrical
sight
chemical → mechanical
muscle contraction
chemical → electrical
action potentials
light → chemical
vitamin D
water → water vapor
sweating (change of state)
4 examples of energy transfer within the human body or other biological systems
- eye sight
- muscle contraction
- vitamin D formation
- photosynthesis
light energy → chemical energy in plants
photosynthesis
(3 lessons from the first law of thermodynamics)
the main forms of energy within the body are:
- heat
- light chemical
- mechanical entropy
- “free energy”
(3 lessons from the first law of thermodynamics)
a form of energy that cannot be reused in chemical reactions and is synonymous to increased randomness or disorder
entropy
(3 lessons from the first law of thermodynamics)
referred to as G or Gibb’s free energy;
“free energy”
(7 lessons from the 2nd law of thermodynamics)
all reactions proceed in the direction of:
a. entropy
b. a release of free energy (Kcal/Mol)
(7 lessons from the 2nd law of thermodynamics)
the more ___ the change in Gibb’s free energy, the ____ the release of free energy during a chemical reaction
- negative
- greater
(7 lessons from the 2nd law of thermodynamics)
chemical reactions that have a negative change in Gibb’s free change are termed
exergonic reactions
(7 lessons from the 2nd law of thermodynamics)
free energy not used to do work is expressed as _____
heat
(7 lessons from the 2nd law of thermodynamics)
reactions that have no net change in substrate or product, and have no change in free energy, are termed _____
equilibrium reactions
(7 lessons from the 2nd law of thermodynamics)
all reactions are potentially ____
reversible
(7 lessons from the 2nd law of thermodynamics)
the amount of free energy release of a chemical reaction can be modified by _________
altering substrate and product concentrations
atp is also called
adenosine triphosphate
atp is composed of
anenine + ribose + phosphate group
which phosphate group contains the most energy?
last phosphate group (PO4)
process of breaking the bonds of atp;
occurs continually in cells;
ATPase can weaken and break last PO4 bond releasing energy and free PO4
phorphorylation
3 roles of ATP in metabolism
- used for active nutrient breakdown
- used for physiological processes
- used for biosynthetic reactions
roles of ATP in metabolism
- formed by substate-level phosphorylation
- oxidative phosphorylation
- photophosphorylation
roles of ATP in metabolism
- turnover
- storage
proteins that increase the rate of reaction by lowering the energy of activation;
catalyze nearly all the chemical reactions taking place in the cells of the bodyl
not altered or consumed during reaction;
reusable
enzymes
3 mechanisms by which enzymes accelerate reactions
- maintain precise substrate orientation (lower entropy of substrates)
- change substrate reactivity by altering its electrostatic structure
- exert physical stress on bonds in the substrate to be broken (induced fit)
3 types of enzyme specificity
- absolute
- group
- linkage
catalyze one type of reaction for a “single” substrate
absolute type of enzyme
catalyze one type of reaction for “similar” substrates
group type of enzyme
catalyze one type of reaction for a “specific” type of bond
linkage type of enzyme
(determine which type of enzyme)
urease catalyzes only the hydrolysis of urea
absolute type of enzyme
(determine which type of enzyme)
chymotrypsin catalyzes the hydrolysis of peptide bonds
Linkage
(determine which type of enzyme)
hexokinase adds a phosphate group to hexoses
group
2 importance of enzymes
- lower a reaction’s activation energy
- speed up reactions
- precise, very specific yet flexible
3 cellular respirations
- glycolysis
- citric acid cycle
- electron transport chain
(determine the step in glycolysis)
begins with the phosphorylation of glucose into glucose 6-phosphate, using an ATP and a kinase enzyme
step 1
(determine the step in glycolysis)
the aldehyde end of the molecule is oxidized and phosphorylated by a dehydrogenase enzyme and NAD+;
this produces 1,3-bisphospho-glycerate and NADH
step 6
(determine the step in glycolysis)
the phosphorylation of fructose 6-phosphate into fructose 1,6-biphosphate with a kinase enzyme
step 3
(determine the step in glycolysis)
the phosphate group is transferred onto an ADP with a kinase enzyme, forming 3-phosphoglycerate and ATP
step 7
(determine the step in glycolysis)
the phosphate group is “isomerized” to a new position in 2-phosphoglycerate
step 8
(determine the step in glycolysis)
“isomerizes” glucose 6-phosphate to fructose 6-phosphate with an “isomerase” enzyme
step 2
(determine the step in glycolysis)
“cleaves” the fructose ring into a dihydroxy-acetone phosphate and a glyceraldehyde 3-phosphate
step 4
(determine the step in glycolysis)
“water is lost” to form phosphoenol-pyruvate
step 9
(determine the step in glycolysis)
“isomerized the dihydroxyacetone phosphate into another glyceraldehyde 3-phosphate
step 5
(determine the step in glycolysis)
the “phosphate is transferred” to an ADP yielding “pyruvate” and “ATP” with a “kinase” enzyme
step 10
glucose is converted to two molecules of pyruvate;
an anaerobic reaction in cytoplasm
glycolysis
total number of reactions in glycolysis
10
(summary of glycolysis)
what happens in steps 1-5?
energy investment phase
(summary of glycolysis)
what happens in steps 6-10
energy-generating phase
(state what phase of glycolysis)
2 ATP molecules are hydrolyzed;
the 6-carbon glucose molecules is converted into two 3-carbon segments
energy investment phase
(state what phase of glycolysis)
producing q NADH and 2 ATPs for each pyruvate formed
energy-generating phase
how many ATPs are used in phase 1 of glycolysis?
2
total number of ATPs made in phase 2 of glycolysis
4
what is the net result of glycolysis?
synthesis of 2 ATPs from glycolysis
these are made in the cytoplasm and must be transported to the mitochondria to join the electron transport chain and make ATP
2 NADH
