Ch 24 Oxygen Flashcards
do to oxygens low solubility it makes transport in blood difficult….. how have we overcame this
- metalloproteins (metal ions reversely bind oxygen)
= hemoglobin (Hb) increases oxygen carrying capacity by 50x
describe oxygen transport in lungs vs tissues
lungs/alveoli
= oxygen moves fluid into blood via diffusion (driven by a partial pressure gradient) and binds to hemoglobin which keeps PO2 low allowing more O2 to enter the blood
(high PP in alveoli, low in blood)
tissues/cells
= mitochondria use O2 which lowers PP, O2 then leaves hemoglobin and diffuses into cells
describe hemoglobins
main respiratory pigment that carries both respiratory gases
consist of
heme - iron containing molecule that binds oxygen & gives blood its red color
globin - protein part, 4 globin molecules & provides structure, holds heme & regulates binding
mammalian hemoglobin is a ____ consisting of ___ heme-globin subunits
tetramer, has 4 heme-globin subunits
in vertebrates hemoglobin is found in ____ cells
blood cells
describe myoglobin and vertebrate myoglobins are always a ____ unit
protein found in muscle cells that stores and binds oxygen for the muscles
always a single unit
adults mostly use ___ & ___ globin
alpha and beta
what’s special about antarctic icefish and why are they like this
- has no hemoglobin and no myoglobin in skeletal muscle
due to:
- low temps allow oxygen to be more soluble / metabolism slows
small fractions of ____ are actually dissolved in the blood….. it is mostly bound to _____ _____
oxygen
mostly bound to respiratory pigments in red blood cells
oxyhemoglobin vs deoxyhemoglobin
oxy = O2 bound to iron
deoxy = detached O2 from iron
what does 100% saturation mean
all O2 binding sites on Hb are oxygenated
what stays the same in a O2 dissociation curve & O2 equilibrium curve
the x axis stays the same!
- PP of O2 in blood
myoglobin vs hemoglobin equilibrium curve respiratory pigments
myoglobin - no cooperativity (hyperbolic)
hemoglobin - cooperativity (sigmoidal)
low vs high affinity pigments
low - requires high O2 PP
- harder to bind oxygen but easier to release, better at delivering
high - low O2 PP
- easy to bind oxygen, good for picking up oxygen
what does O2 affinity refer to
how strongly a molecule binds to oxygen
high hemoglobin = ____ pH = ____PCO2
what about low?
high hemoglobin = high blood pH= low PCO2
low hemoglobin = low blood pH= high PCO2
at higher temps = ___ affinity
lower affinity
~ unloads oxygen more easily
2,3-BPG ____ hemoglobin affinity
lowers affinity for oxygen
- encourages oxygen release
