Chapter 4: Energy and Cellular Metabolism Flashcards
(87 cards)
1
Q
characteristics of complex things that are unexpected based on the basic components
A
emergent properties
2
Q
what are the properties of living organisms?
A
- complex structure whose basic unit is a cell
- aquire, transform, store, and use energy
- sense and respond to internal & external environements
- maintain homeostasis
- store, use and transmit info
- reproduce, develop, grow, and die
- have emergent properties
- individuals adapt and species evolve
3
Q
where can organisms get energy?
A
- sunlight for plants (photosynthesis)
- chemical bonds for animals (respiration)
- open system
4
Q
what does photosynthesis yield?
A
energy store in biomolecules
5
Q
what does respiration yield?
A
- energy for work
- energy stored in biomolecules
- H2O and CO2
6
Q
broadly defined as the capacity to perform work
A
energy
7
Q
what are the various forms of energy or “work”
A
chemical work
transport work
mechanical work
8
Q
Making and breaking of chemical bonds
A
chemical work
9
Q
- Moving ions, molecules, and larger particles
* Creating concentration gradients
A
transport work
10
Q
- Moving organelles, changing cell shape, beating flagella and cilia
- Contracting muscles
A
mechanical work
11
Q
what are the two forms of energy?
A
- kinetic energy
* potential energy
12
Q
- energy of motion
- work involves movement
- thermal energy, electromagnetic energy, electrical energy
A
kinetic energy
13
Q
- stored energy
- concentration gradients & chemical bonds
A
potential energy
14
Q
- Total amount of energy in the universe is constant (closed system)
- Energy can be neither created nor destroyed
A
first law of thermodynamics
15
Q
Processes move from a state of order to randomness or disorder (entropy)
A
second law of thermodynamics
16
Q
always accompanied by either the release of energy or the input of energy
A
chemical reactions
17
Q
the study of energy flow through biological systems
A
bioenergetics
18
Q
the potential energy stored in the chemical bonds that is available to do work
A
free energy
19
Q
the initial energy required to bring the reactants into a position to react with each other
A
activation energy
20
Q
the difference in free energy between reactants and products.
A
Net free energy change of a reaction
21
Q
- releases energy because the products have less energy than the reactants
- spontaneous
A
exergonic
22
Q
*requires an input of energy
*trap some activation energy in the
products, which then have more free energy than the reactants
*nonspontaneous
A
endergonic
23
Q
where does the activation energy come from?
A
Coupling an exergonic reaction to an endergonic reaction
24
Q
biomolecules (mostly proteins) specialized to act as catalysts
A
enzymes
25
substances that increase the rates of chemical reactions
catalysts
26
how do enzymes speed up reactions?
by lowering the activation energy?
27
called substrates
reactants
28
* vitamin-derived cofactors that do not have catalytic activity but participate directly in the reactions catalyzed by enzymes
* carry chemical groups from one reaction to another
coenzymes
29
what are examples of coenzymes?
FAD
NAD
coenzyme A
30
how can enzyme activity be modulated?
* chemical factors (allosteric regulation)
| * changes in temperature and pH
31
what are the categories of enzymatic reactions?
* oxidation-reduction
* hydrolysis-dehydration
* addition-subtraction-exchange
* ligation
32
transfer electrons from one molecule to another
oxidation-reduction
33
combined or separate two molecules losing or gaining water in the process.
hydrolysis-dehydration
34
either adds, subtracts, or exchanges functional groups
Addition-subtraction-exchange reactions
35
join two molecules using enzymes called synthetases and ATP
ligation reactions
36
A combination of four nitrogenous bases in triples (codons) code for 20 amino acids
genetic code
37
a portion of DNA that codes for a piece of functional RNA
gene
38
are continuously being read and converted to mRNA
Constitutive genes
39
are turned on and off as needed
regulated genes
40
* Synthesis of mRNA by copying information from DNA
| * happens in nucleus
transcription
41
* Synthesis of protein from the information in mRNA
| * happens in cytosol
translation
42
what is involved in transcription?
* RNA polymerase
* promoter
* transcription factors
* alternative splicing
43
the enzyme that reads the DNA and makes mRNA (adds nucleotides to the 3’ end of the growing strand)
RNA polymerase
44
the region that precedes the gene that must be activated
promoter
45
bind to DNA and activate the promoter and tell the RNA polymerase where to bind the DNA
transcription factors
46
results in several possible proteins from a single gene
alternative splicing
47
What are the steps in transcription?
1. RNA polymerase binds to DNA.
2. The section of DNA that contains
the gene unwinds
3. RNA bases bind to DNA,
creating a single strand of mRNA
4. mRNA and the RNA polymerase
detach from DNA, and the
mRNA goes to the cytosol after
processing.
48
what happens during mRNA processing?
introns are removed
49
what are the translation components?
* mRNA
* rRNA
* tRNA
* ribosomes
* amino acids
50
contains the blueprint that is translated to make protein
mRNA
51
form part of the ribosome
rRNA
52
anticodons of tRNAs carry amino acids to complimentary codon of ribosomal mRNA
tRNA
53
what happens in translation?
1. each tRNA molecules attaches at one end to a specific amino acid
2. the anticodon of the tRNA molecule pairs with the appropriate codon on the mRNA
3. amino acids are linked in the order specified by the mRNA code
54
what are some post-translational modifications?
* protein folding
* cross-linkage
* cleavage
* addition of other molecules/groups (lipids/sugars)
* assembly into polymeric proteins, formation of quaternary structure
55
strong bonds between different parts of the protein (S-S)
cross linkage
56
removal of small peptide fragments
cleavage
57
what are the steps of protein synthesis?
1. gene activation
2. transcription
3. mRNA processing
4. translation
5. post-translational modification
58
what does protein synthesis demonstrate?
subcellular compartmentalization
59
has a high energy phosphate bond that stores energy
ATP (adenosine triphosphate)
60
requires oxygen and yields the most ATP
aerobic metabolism
61
does not use oxygen and yields much less ATP
anaerobic metabolism
62
breaking down fuel
catabolic
63
what do catabolic pathways produce?
ATP
64
what are the catabolic pathways?
* glycolysis
* citric acid cycle
* electron transport chain
65
* produce small amounts of ATP directly
* most important contribution to ATP synthesis are the high energy electrons carried by NADH and FADH2 to the electron transport system
glycolysis and citric acid cycle
66
where is the electron transport chain located?
mitochondria
67
what is produced in glycolysis?
```
one molecule
of glucose is converted by a
series of enzymatically
catalyzed reactions into two
pyruvate molecules, producing
a net release of energy
```
68
does glycolysis require energy?
no
69
what happens in the citric acid cycle?
```
1. , each 3-carbon
pyruvate formed during glycolysis reacts with
coenzyme A (CoA) to form one acetyl CoA
and one carbon dioxide (CO2
2. The 2-carbon acyl unit of acetyl CoA
enters the citric acid cycle pathway,
allowing coenzyme A to recycle and
react with another pyruvate
3. The citric acid cycle makes a
never-ending circle, adding
carbons from acetyl CoA with
each turn of the cycle and
producing ATP, high-energy
electrons, and carbon
dioxide
```
70
says that potential energy stored by
concentrating H+ in the intermembrane space is used to make the high-energy
bond of ATP.
chemiosmotic theory
71
what is the final step in aerobic ATP production?
energy transfer from high-energy
| electrons of NADH and FADH2 to ATP
72
how is the final step of ATP production carried out?
This energy transfer requires mitochondrial
proteins known as the electron transport system (ETS), located in the inner
mitochondrial membrane
73
what proteins does the electron transport system include?
include enzymes and iron-containing
| cytochromes
74
the synthesis of ATP using the electron transport system
oxidative phosphorylation
75
requires oxygen to act as the final acceptor of electrons and H+
oxidative phosphorylation
76
H+ flow back into the matrix
| through this protein
ATP synthase
77
how many ATP are produced in the ETS?
```
Each three H+
that shuttle
through the
ATP synthase
make a
maximum of
one ATP.
```
78
how much ATP does anaerobic metabolism produce?
one glucose metabolized anaerobically yields 2 ATP
79
how much ATP does aerobic metabolism produce?
one glucose metabolized aerobically through the citric acid cycle yields 30-32 ATP
80
What is the total result of aerobic metabolism?
* 6 H2O
* 30-32 ATP
* 6 CO2
81
how do aerobic and anaerobic metabolism during the citric acid cycle differ?
* anaerobic uses lactate
| * aerobic uses pyruvate
82
The sum of all the chemical reactions that take place in the body
metabolism
83
breakdown biomolecules releasing energy in the process
catabolism
84
energy utilizing reactions that synthesize a biomolecule
anabolism
85
what are molecules in pathways?
* intermediates
| * The product of one reaction becomes the substrate of another
86
What is involved in the cell regulation of metabolic pathways?
1. controlling enzyme concentrations
2. producing modulators that change reaction rates
- feedback inhibition
3. using different enzymes to catalyze reversible reactions
4. compartmentalizing enzymes within organelles
5. maintaining optimum ratios of ATP to ADP
87
what do reversible reactions that require two enzymes allow for?
allow for more control over the reaction
