Midterm Ch. 1-5 Flashcards
(207 cards)
1
Q
what is biochemistry?
A
the study of life at a molecular level; the application of the principles of chemistry to explain biology
2
Q
what building blocks do all organisms use to create common categories of biomolecules?
A
nucleic acids, proteins, polysaccharides, and lipids
3
Q
what 4 elements are most organisms made up of?
A
carbon, oxygen, hydrogen, and nitrogen
4
Q
where do we get carbon?
A
from air through plants
5
Q
where do we get oxygen?
A
from air
6
Q
where do we get hydrogen?
A
from water
7
Q
where do we get nitrogen?
A
from either the air (N2), or soil and and plant roots
8
Q
what does the availability of nitrogen in soil cause?
A
causes limiting of plant growth, limiting the amount of food we can produce
9
Q
why is silicon the next best candidate as a chemical foundation for life?
A
it can also form 4 covalent bonds, and is highly abundant in the earths crust
10
Q
why are we based in carbon rather than silicon?
A
- C to C bonds are stronger and more stable
- there is more energy from carbon based nutrients
- combustion products of carbon (CO2) are soluble (recyclable) and silicone dioxide is insoluble
11
Q
what is conformation?
A
flexible spatial arrangement of atoms within a molecule (can be changed without breaking covalent bonds)
12
Q
what is configuration?
A
fixed spatial arrangement of atoms within a molecule (cannot be changed without breaking covalent bonds)
13
Q
how is configuration conferred?
A
either double bonds or chiral centres
14
Q
how do you link 2 amino acids?
A
through a peptide bond (cis-trans) double bond
(single double double single double double)
15
Q
what are stereoisomers?
A
mirror images
16
Q
what are traits of chiral carbons?
A
asymmetric, no double bonds, must have 4 different groups attached
17
Q
what is stereospecificity?
A
the synthesis of chemical compounds (drugs) which have asymmetric carbons resulting in a mix of all the chiral forms, each form has different biological activities
18
Q
how many different proteins do we have in our bodies?
A
~20,000
19
Q
what are the advantages of constructing biologicals as polymers?
A
- simplicity (for synthesis and degradation)
- recycling (biomolecules can be digested back to component building blocks which are reusable, can recycle amino acids
- diversity (incredibly complex molecules can be generated)
20
Q
what does every amino acid have?
A
a carboxyl group and an amino group
21
Q
what are polysaccharides and what is their purpose?
A
- they are monosaccharides linked together to form linear or branched polymers
- their roles include greater structural complexity, energy storage, and cell recognition
22
Q
what are nucleic acids and what is their purpose?
A
- they are linear polymer of nucleotide building blocks (DNA and RNA)
- they are involved in all aspects of storage and utilization of genetic info
- 2 strands that are complimentary to each other help with disease fighting etc.
23
Q
what are lipids and what are they used for?
A
- they are aggregates (rather than defined polymers) of building blocks
- they are aggregated together through non-covalent linkage
- they serve in energy storage, formation of membranes, and signaling
24
Q
what are prokaryotes?
A
small, simple, single cell organisms with a single compartment (the nucleoid) that contains nucleic acid and other biomolecules in a complex organized mix
one cell must do every function to keep alive
25
what are eukaryotes?
large complex cells, make up multicellular organisms (plants, fungi, vertebrates), contain organelles to support specialized functions, more organized but ability to respond is much slower than prokaryotes
26
how do prokaryotes (bacteria) help our gut?
they help digest food and maintain a functional immune system
27
why is our gut (microbiota) called our second brain?
it may impact mental health (depression, anxiety etc.), obesity, and intelligence
28
what are possible ways to influence the microbiota?
diet, pro and prebiotics, and fecal transplants
29
what is in vitro?
(in glass) studies the behaviour of molecules outside the context of the cell and organism ex. growing cancer cells in a dish
30
what is in vivo?
(in the living) studies occur within the complexity of the cell or organism
31
what is the first law of thermodynamics?
- energy cannot be created or destroyed but transformed
- the total amount of energy in the universe remains constant, but forms of energy may change
- cells are highly effective transducers of energy, converting the energy of metabolized nutrients into work, heat, or generation of complex biomolecules
32
what is the second law of thermodynamics?
- natural tendency towards increasing entropy (disorder)
- the tendency in nature is towards even greater disorder
- living systems and their biomolecules require a high degree of organization
33
what does Gibbs free energy state?
that free energy (G) of any closed system can be defined by:
- enthalpy (H) reflects the number and kinds of bonds
- entropy (S) the degree of randomness (temp (Kelvin) dependent)
34
what is the Gibbs free energy equation and the free energy change equation?
G = H - TS
deltaG = deltaH - TdeltaS
35
what does it mean if deltaG > 0?
non spontaneous process, needs input of free energy to proceed
ENDERGONIC
36
what does it mean if deltaG < 0?
spontaneous process, releases free energy which can be used to do work, proceeds until equilibrium is reached
EXERGONIC
37
what does it mean if deltaG = 0?
system is at equilibrium, there is no change in free energy in the system
38
what are energy coupling link reactions?
cells can drive thermodynamically unfavourable reactions by coupling endergonic and exergonic reactions
39
what is catabolic in metabolism?
breaking stuff down, proteins and fats in the diet are broken down (energy producing) to generate ATP
40
what is anabolic in metabolism?
building things up, creating proteins within the body (energy requiring)
41
what is ATP?
- common energy currency
- serves as the link between catabolic and anabolic reactions
42
genetic info must be …?
- stored in a stable form over time
- expressed accurately in the form of gene products
- reproduced with minimal errors
43
what does DNA provide?
- the instructions for forming all other cellular components
- a template for production to identical DNA molecules to be distributed when a cell divides
44
how is DNA replicated?
DNA > transcription > RNA > translation > proteins
45
what is the structure of DNA?
- 2 complimentary strands (double helix)
- each strand is a linear polymer of 4 different building blocks (A and T, C and G)
- the linear sequence in strands encodes info
46
what is the hexokinase gene and what does it do?
an enzyme involved in glycolysis (takes glucose and produces energy) than produces messenger RNA, than goes through translation and forms a polypeptide chain , which allows the enzyme to take glucose and phosphorylate it and generate energy from sugar
47
what does the nucleotide sequence of genes dictate?
the sequence of amino acids incorporated into the corresponding protein
48
what does the amino acid sequence dictate?
it’s structure
49
what does the structure of the protein dictate?
it’s biological activity
50
gene sequences are … ?
phenotypes
51
why are random changes in genotype a good thing?
can result in a changed phenotype which offers a survival advantage that will be selected over time
52
what is water’s passive role?
the structure/function of biomolecules forms in response to interaction with water ex. protein folding is driven in an effort to bury hydrophobic residues away from water
53
what is water’s active role?
water participates in many biochemical reactions ex. peptide bond formation releases a water molecule
54
what is H2Os structure?
- O is more electronegative than H
- permanent dipole
- O has a partial negative charge
- each H has a partial positive charge
55
what is the dipole of water?
- forms electrostatic interactions
- forms H bonds
56
Hydrogen bond rule?
if it can form a H bond it must
57
what are electrostatic interactions?
electronegative atom with a H linked (donor) to another electronegative atom with a free electron pair (acceptor)
58
why are O and N common hydrogen binders?
they can both serve as H bond donors and acceptors
59
how strong/big are H bonds and what does it depend on?
H bonds are double the length of a covalent bond
pretty weak (5% the strength of a covalent bond)
strength of an H bond depends on its geometry
60
which is more stable anti-parallel or parallel beta sheets and why?
anti-parallel beta sheets are more stable due to better geometry
61
how many H bonds can water form?
4 H bonds (2 donors, 2 acceptors)
62
why are most living organisms isothermic?
they need to regulate and maintain their temps
63
what helps our bodies to stay cool?
the high composition of water within our bodies, coupled with the high specific heat capacity of water
64
why does ice float on water?
ice takes up more volume, it has a lower density than water therefore ice floats on water
65
what is heat of vaporization?
the amount of heat required to vaporize a liquid at its boiling temp
66
what is specific heat capacity?
amount of heat required to raise the temp of a substance one degree (energy absorbed by a solution)
67
what is polywater?
a form of water with a higher boiling point, lower freezing point, and much higher viscosity than ordinary water
68
what type of group can interact favourably with water?
any type of group that has a charge (hydrophilic)
69
in water molecules as H bonding partners which group is the acceptor/donor?
carbon group is the acceptor
amide group is the donor
70
what is hydrophilic?
water loving - molecules are polar (have a + or -), can accept or donate, dissolvable
71
what is hydrophobic?
water fearing - molecules are non polar
72
what are amphipathic molecules?
both polar and non polar, have both hydrophobic and hydrophilic portions
ex. fatty acids
73
CO 2 and O2 are non polar and have limited solubility in water and blood why does this present a challenge?
presents a challenge for their transport, specialized transposed proteins are required for transport of CO2 and O2 (hemoglobin, myoglobin, etc.)
74
hydrophobic drive is a primary driving force for what?
for formation and stabilization of biomolecules structure
75
what are hydrophobic interactions?
the forces that hold the non polar regions of the molecule together
76
what are micelles?
mixed fatty acids as a result of interaction of water molecules (hydrocarbon tails join together, polar heads are on the surface interacting with water)
77
what are examples of non-covalent interactions?
- hydrogen bonds
- electrostatic interactions
- hydrophobic interactions
- van der waals interactions
78
what do non-covalent interactions enable?
transient, dynamic interactions and flexibility of structure and function
79
what do non-covalent forces influence?
formation and stability of biomolecules structures, recognition/interactions between biomolecules, binding of reactants to enzymes
80
what are hydrogen bonds?
functional groups have H born capacity and can form H bonds with:
- water molecules, groups in the same molecule, groups in other molecules
they are critical for biomolecular interactions but not for the formation of structures
81
what are the roles of adenine, thymine, guanine, and cytosine in H bonding?
A and T: one is a donor, one is an acceptor
G and C: on is a donor, one is an acceptor
- A and G aren’t complimentary with H bonds
82
what are electrostatic reactions?
- between charged groups can either be attractive (opp. charge) or repulsive (same charge)
- unpackages DNA by modifying amino acids that carry a positive charge
83
how does water affect the strength of electrostatic interactions?
the hydration dampens the strength, the water shields the charged groups which diminishes the strength
84
what does the strength of electrostatic interactions depend on?
the distance separating the charged groups and the nature of the intervening medium
85
what is the Van der Waals force?
interaction between permanent and induced dipoles, short range, low magnitude interactions, abundant in the core of folded proteins
86
when is the Van der Waals attraction maximal?
when 2 atoms are separated by the sum of the van der waals radii
87
how does the folding of protein contradict the 2nd law of thermodynamics?
the folding of protein involves creation of a more ordered state
88
what does the introduction of non polar molecules to water molecules cause?
a decrease in entropy
89
how does water increase entropy?
when non polar molecules release some of the ordered water
90
how does the folding of a polypeptide effect the entropy?
decrease the entropy of the polypeptide; increase the entropy of the associated water
91
what is homeopathy?
dilution of something 30 times; claims the water “remembers” the medicine in the solution
expensive water pre much
92
what is the ionization of water?
when a water molecule deprotonates to become a hydroxide ion (OH-)
93
how do strong acid and bases react in water?
they dissociate completely
94
how do weak acids and bases react in water?
do not dissociate completely and the extent of the dissociation can be quantified
95
what is the goal of a weak acid?
to donate its protons (depends how many protons are already present
96
what is the buffering region of a titration curve?
when the weak acid is strong enough to donate its proton, the flat portion of the titration curve
97
what is the pKa point of the titration curve?
the midpoint in buffering region, hasn’t been able to donate it’s proton, equal amount of base and acid forms
98
if pKa = 4.7, what is the buffering region?
3.7-5.7
99
if Ph = pKa what does this mean for the solution?
the solution is best able to resist changes in pH
100
if pH is above pKa what does this mean?
there will be more unprotonated form
(below is protonated)
101
what happens to an acid after it donates its proton?
it turns into a base
102
what do disulfide bonds do and where are they found?
- stabilize proteins by maintaining overall structure inter or intramolecular covalently between 2 cysteine residues
- seen in extremophiles (higher temp, extreme pH), seen in proteins that are extracellular
103
what is keratin made of and what does it do?
- made up up disulfide bonds
- seen in proteins that make up your hair and seen in rhino horns (obvi more disulfide bonds for stronger structure)
104
what is zwitterion?
the dipolar (both positively and negatively charged) ion of an amino acid
ex. glycine
105
what are peptide bonds?
covalent linkages between the carboxyl group of one amino acid and amino group of another amino acid
106
how do peptide bonds form?
by condensation reaction involving the generation of a water molecule
(lose O from carboxyl group, lose 2 Hs from amino group = H2O)
- formation of peptide bonds are the same, independent of the residues being joined
107
what does the formation of peptide bonds eliminate and why?
the charges on the alpha-carboxyl and alpha-amino charged groups, which is important for folding
108
what is an example of post-translational modification?
Phosphorylation
109
what are polypeptide main chains?
- the constant portion of the polypeptide (side cabins are the variable portion)
- results in a repeating pattern within the main chain (NCCNCC)
110
what is the partial double bond characteristic and what is the consequence of it?
- rotation around C-N peptide bond is restricted
- as a consequence the 6 atoms of the peptide group are rigid and planar (limits structural flexibility)
111
what is the partial double bond configuration?
- creates cis-trans isomers
- can anticipate peptide bonds in the trans position because in cis configuration there is likely steric interference
- the O of the carbonyl group and the H of the amide nitrogen are usually trans to each other
112
what is the primary protein structure?
- linear arrangement of amino acids in a polypeptide
- presented from the N amino (start) terminus to the C carboxyl terminus
- has info specifying correct folding
- can’t predict 3D structure
113
what is the secondary structure?
- represents localized patterns of folding in a polypeptide
- maintained by H bond between main chain amide and carbonyl groups
- elements of 2nd structure found in different proteins
- they retain the same characteristics
114
secondary structure examples?
- alpha-helicies
- beta-sheets
115
what are the 2 key rules of secondary structure?
- optimize the H bonding potential of the main chain carbonyl and snide groups
- represent a favoured combination of the polypeptide chain
116
what is the structure of the bonds Phi Ca-N and Psi Ca-C?
each alpha carbon is held within the main chain through single bonds about which there is complete freedom of rotation (can spin all the way around)
117
what is the range for Phi and Psi?
-180 — 180
118
what are partial double bonds in secondary structure?
a consequence of resonance; present between the amino acids in proteins
119
why is there not many confirmations of secondary structure polypeptides?
steric interference
120
what are the traits of an alpha helix?
- right handed helix with 3.6 residue/turn
- stabilized by H bonds which run parallel to the axis of the helix
- carbonyl groups point towards C terminus; amide groups point towards N terminus
121
in an alpha helix each carbonyl of residue n H bonds with amide group of residue…?
residue n+4
122
why is proline not found in alpha-helicies?
because of its rigidity
123
why is glycine uncommon in alpha-helicies?
because of its flexibility
124
what groups of amino acids are not found in alpha helicies and why?
- amino acids with side chain branches (Val, Thr, Ile) because of steric interference
- amino acids with H bonding groups near the main chain (Ser, Asp, Asn)
125
if the helix is super long has does this affect the dipole?
the longer the helix = the greater the dipole
126
each helix dipole by H bonding has a net dipole what are they?
- N terminus has a partial positive dipole charge
- C terminus has partial negative charge
127
what are the negatively charged residues at the N - terminus and the positively charged residues at the C - terminus?
- negatively charged at N: Asp, Glu
- positively charged at C: Lys, Arg, His
128
what do amphipathic helicies residues look like?
- residues separated by 3 or 4 positions in the primary sequence will be on the same side of an alpha helix
- residues separated by 2 residues in the primary structure will be on opposite sides of the helix
129
what are beta-sheets?
- involve multiple (4 or 5) B strands arranged side by side
- fully extended polypeptide chains
- stabilized by H bonds between C=O and -NH
- either parallel (more flexible) or anti parallel (more stable)
130
what are amphipathic beta sheets?
- side chains tend to alternate above and below the polypeptide chain
- alternating polar and non polar residues within the primary structure of a beta-sheet = amphipathic
131
what is the tertiary structure of a protein?
- the final folding pattern of a single polypeptide chain
- the long range of aspects of sequence interactions within a polypeptide
132
how might residues in primary structure and tertiary structure relate?
residues separated by great distance in primary structure may be close in proximity in tertiary structure
(primary structure determines tertiary structure)
133
the stability of a protein in tertiary structure reflects what?
the difference in free energies if the folded and unfolded states
134
in tertiary protein structure the protein conformation with the lowest free energy is what?
- the most stable
- the one with the max. number of weak interactions
135
in tertiary protein structure how is stability defined?
stability is the tendency to maintain a native conformation
136
if proteins can’t spontaneously fold to their native conformation what do they need the help of?
chaperones or heat shock proteins (proteins with larger and more complex structures)
137
in a protein in the unfolded state there is the greatest amount of what?
entropy/disorder
138
what is denaturation?
unfold a protein
- disruption of native conformation with loss of biological activity
- cooperative and usually reversible process
139
how much energy does denaturation need?
- very small energy, only a few H bonds
140
what is quaternary structure?
- consists of multiple polypeptide chains
- may involve multiple copies of the same or different polypeptides
- reserved for proteins of more complex biological function
- subunits formed usually associate through non-covalent interactions
141
what are the biological advantages of quaternary structure?
- help stabilize subunits and prolong life of proteins
- unique active sites produced at the interfaces between sub unuts
- help facilitate unique/dynamic combinations of structure/function
- more efficient
142
what are the biological roles of protein structure/function?
enzymes, storage and transport, physical cell support/shape, mechanical movement, decoding cell info, hormones/hormone receptors etc.
143
how many proteins do bacteria have?
5000
144
how many proteins do fruit flies have?
16,000
145
how many proteins do humans have?
25,000 (minimum; could be up to 1 mil)
146
how big are typical proteins? (biggest and smallest)
100 — 1000 amino acids in length typically
- smallest is 51 (insulin)
- largest is 34,350 (titin)
147
what are examples of fibrous proteins?
keratin, collagen, silk
148
what are examples of globular proteins?
myoglobin, hemoglobin
149
what is keratin?
the main component of hair, wool, horns, and nails
150
what structure does keratin at the primary level?
pseudo-seven repeat where positions A and D are hydrophobic (non polar)
- non complex
151
what structure does keratin form at a secondary level?
an alpha helix
- residues from positions A and D end up on the same face of the helix which results in a hydrophobic strip along the length of the helix
- every 4th residue will be non polar
152
2 amphipathic helicies of keratin interact how and what is the result?
interact by burying hydrophobic face together which results in a formation of a coiled coil
153
what does a coiled coil of keratin involve?
2 right hand helicies wrapped around each other in a left hand fashion
154
what does the strength of keratin arise from?
covalent linkages of individual units (linked by disulfide bonds) into higher order structures
- the extent of the disulfide bonds determines the strength
155
what is collagen?
the major structural protein within your body holding you together, major protein of vertebrates (25% of total protein)
156
what is the structure of collagen at a primary level?
repeats of Gly-X-Y
- X is often proline
157
what is the structure of collagen at a secondary level?
forms a left handed helix of 3 residues per turn (different shape than an alpha helix) 3 left handed helicies wrap around each other in a right handed fashion to get a stronger more stable structure
158
where are proline and glycine residues in collagen secondary structure?
- the bulky side chains of proline are on the outside of the coiled-coil
- the small side chains of glycine residues are in the tightly packed core of the coiled-coil
159
where does the strength of collagen arise from?
same as keratin but instead of disulfides the linkages occur from residues that undergo post translational modification (adding hydroxyl groups to proline and lysine)
- increasing brittle character of aging connective tissue and tougher meat
160
what do enzymes in collagen need to perform post translation modifications (stable cross links)?
vitamin C
161
how does scurvy affect collagen?
vitamin C deficiency leads to weakened structure of collagen which manifests in skin lesions, fragile blood, bleeding gums etc.
162
what do collagen genetic diseases all have in common?
can be associated with brittle and abnormal bone structure, weakened cardiovascular capabilities, loose skin and joints, hyper flexibility
163
what is silk?
- produced by insects and spiders for formation of webs and cocoons (both need to be strong and flexible)
164
what is the structure of silk at a primary level?
has a 6 residue repeat (GSGAGA)
165
what is silk made for at the secondary structure level?
primarily for beta-sheets (the fully extended polypeptide of beta offer considerable strength)
- one of the strongest know materials
166
what makes silk strong?
fully extended polypeptides
167
what makes silk flexible?
- association of strands by H bonding
- association of sheets by van der waals and hydrophobic interactions
168
what are the side chains of silk and how do they come together?
one side chain alanine, one side chain glycine and they zipper together (both have non polar side chains)
169
what are prions diseases?
- infectious disease based in the misfiling of a self protein into a pathological, infectious conformation
- they are fatal, untreatable neurodegenerative diseases
170
misfolding dependent epitopes are termed what?
disease specific epitopes (ideal vaccine targets
171
what do antibodies induced against DSEs do?
only bind the unhealthy form of protein (PrPsc) and spare the function of the healthy form (PrPc)
172
what is a ligand?
a molecule that is reversibly bound by the protein
173
what is a binding site?
a specific site (or multiple) on the protein where a ligand binds
(complimentary for shape, charge, hydrophobicity, and H bonding potential)
174
what is induced fit?
the binding of a ligand causes a conformational change of a protein, which can change the properties of the protein
175
what are the challenges for oxygen deliver and storage in multicellular organisms?
for multicellular organisms the solubility of oxygen to too low to meet oxygen requirements through passive diffusion, amino side chains not well suited for reversible binding of oxygen
176
what is the solution for oxygen delivery and storage?
specialized proteins for O2 storage and delivery
177
what is myoglobins structure?
tertiary structure that binds a single oxygen molecule in the muscles, has a single heme
178
what is hemoglobin’s structure?
quaternary structure, 4 structures each with an oxygen molecule, 4 heme groups, can bind 4 oxygen molecules
179
what is myoglobin and what does it do?
monomeric protein that facilitates oxygen storage and peripheral tissue
180
what is hemoglobin and what does it do?
tetrameric protein found in red blood cells that transport oxygen from lungs to the periphery (hemoglobin has lower affinity for O2 than myoglobin)
181
what does cellular iron do?
bound in forms that make it less reactive
182
what does heme consist of?
protoporphyrin ring rusted bound to a single Fe2+ iron atom
183
can Fe2 and Fe3 bind oxygen?
Fe2 binds reversibly, Fe3 does not bind O2
184
what does the electron donating characteristic of nitrogen prevent?
the conversion of Fe2 to Fe3
185
Fe2 seeks 6 coordinating interactions where do they come from?
4 come from interactions with heme, a 5th comes from interaction with an imidazole group of a proximal histidine residue, and the 6th is for O2 binding
186
how does carbon monoxide exert its deadly effects?
by competing with oxygen for bond to heme (CO binds heme 200 times greater affinity than O2)
187
what is myoglobin made of?
small globular protein consisting of a single polypeptide of 153 residues arranged in 8 alpha-helicies
188
what are allosteric protein forms?
T (inactive) and R (active)
T and R are rapid in equilibrium
189
a protein that binds O2 with high and constant affinity would do what?
would saturate effectively with O2 in the lungs but not release it to the tissues
190
a protein with lower O2 affinity does what?
would be able to release O2 to tissues but would not have sufficient affinity to saturate in the lungs
191
what do allosteric activators do?
stabilize the R state
192
what do allosteric inhibitors do?
stabilize the T state
193
how does T transition to R?
with the T state hemoglobin the iron atom is just outside the plane of the heme ring; with transition to R state the iron moves into plane of the ring
194
what is the p50 of hemoglobin?
the partial pressure of O2 found in periphery
195
what is 2,3 bisphospho-D-glycerate?
a heterotrophic allosteric inhibitor of hemoglobin; it decreased hemoglobin’s affinity for oxygen
(carries 5 units of negative charge)
196
what is fetal hemoglobin like compared to adult hemoglobin?
fetal Hb has a higher oxygen affinity
adult Hb has 6+ residues at the binding site, fetal Hb has 4
197
adaptation to high altitude can rapidly occur through what?
increased production of 2,3 BPG (this decreases Hbs O2 affinity to ensure sufficient O2 delivery to periphery)
198
what is the bohr effect?
describes the pH dependence of hemoglobin’s affinity of O2
199
why do active tissues have lower pH?
increased muscle activity increases production of CO2 which then decreases pH (in extreme exercise muscles produce lactic acid to further decrease pH)
200
what are the 2 primary challenges to cellular respiration and metabolism?
- delivering sufficient O2 to tissues
- removing CO2 (the exhaust of metabolism) from the periphery
201
what is mechanism 1 for O2 delivery and CO2 removal?
CO2 is taken up in red blood cells and converted to bicarbonate and a proton by the enzyme carbonic anhydrase, CO2 is converted into a soluble form for transport to the lungs and the decreases pH decreases Hbs O2 affinity to promote O2 release
202
what is mechanism 2 for O2 delivery and CO2 removal?
CO2 can form a covalent carbamate linkage to the N terminus of each chain of Hb to form carbaminohemoglobin
- converts CO2 to more soluble form to assist its transport to the lungs, CHG has a lower O2 affinity to promote O2 release, the released proton promoted O2 release through the bohr effect
203
what does sickle cell anemia result from?
a molecular disease of hemoglobin:
- results from a single amino acid change
- formation of fibers from the deoxy form of Hbs
- fibers tend to form capillaries (where O2 is the lowest) which blocks blood flow to the body
204
who has resistance to malaria?
individuals heterozygous for sickle cell anemia
205
what is malaria?
infects red blood cells, infection decreases pH in rbcs which causes release of oxygen from Hb
206
why can’t people with sickle cell anemia get malaria?
deoxy hemoglobin form fibres that deform the red blood cells, the deformed red blood cells containing malaria are selectively destroyed by the sperm
207
how is hemocyanin different from hemoglobin?
hemocyanin uses copper rather than iron (blue blood), 2 copper atoms bind a single oxygen molecule, no gene ring group, the copper atom is coordinated through histidine residues, hemocyanin is not localized within specialized O2 transport cells
