MORE biochemistry and cell stuff Flashcards
(46 cards)
which one is ferric and which one is ferrous iron ion?
Which one can be absorbed, which cannot?
where is iron absorbed from the diet?
Duodenum
ferric 3+
ferrous 2+ (absorbable into the enterocytes, but due to fenton’s reaction it can’t be stored as Fe2+, so has to be converted back into Fe3+ in the blood! (or stored as something else))
which vitamin do you need to convert iron ions in the gut?
vitamin C?
describe the relationship between the electron transport chain and oxidative phosphorylation
- NADH oxidized from respiration and releases electrons
- electrons pass through ETC, releasing energy
- energy used to pump H+ across the membrane, creating a gradient
- H+ gradient provides energy to ATP synthase to generate ATP
- step 4 is called oxidative phosphorylation.
the ETC pumps protons from where to where, across what
from the mitochondrial matrix
to the intermembrane space
across the INNER mitochondrial membrane
can think of it as starting in the MATRIX, and then learning the INNER workings of it all.
where does ADP–>ATP occur
what is this process called
in the mitochondrial matrix
oxidative phosphorylation
what are eicosanoids
Give examples of subfamilies of eicosanoids
what are they made from
signalling molecules, often produced by a cell in response to damage
prostaglandins
prostacyclins
thromboxanes
leukotrienes
What are eicosanoids made from
What enzyme tends to be involved in their production
made from ARACHIDONIC ACID
(or other 20-carbon polyunsaturated fatty acids (fyi ‘eicosa’ means ‘twenty’ in Greek))
COX usually involved
how many carbon atoms in oestrogen?
18
which organism typically causes IUCD-associated genital tract infections?
Tell me the gram status, shape and (an)aerobic nature of this bug
actinomyces
gram POSITIVE ROD (on its own, but grows in a fungus-like hyphal pattern, hence the name)
Facultative anaerobe
how does botox work
inhibits ACh release from neuron
main intracellular anion
phosphate
name 3 things made from cholesterol
vitamin D
bile
steroid hormones
where are primary bile acids (cholic and chenodeoxycholic acid) made?
liver
where are secondary bile acids (deoxycholic acid and lithocholic acid) synthesised
intestine!
through deconjugation of dehydroxylation of the primary bile acids (cholic–> deoxycholic, and chenodeoxycholic –> lithocholic)
primary and secondary bile acids (99%) are absorbed where? and return where?
ileum
return to the liver by the portal circulation
what is the function of bile salts
keep cholesterol in solution
help digestion of fats
form molecular aggregates called micelle which bring about the absorption of lipids and fat-soluble vitamins
the principal rate-limiting step in the biosynthesis of cholesterol is…
the 7a hydroxylase (CYP7A1) reaction
(the activity of this enzyme is regulated by farnesoid X receptor which is activated (in part) by chenodeoxycholic acid).
cause of hyperprolactinaemia in PCOS
unopposed oestrogen
which hormones stimulate prolactin production?
which hormones inhibit prolactin production?
stimulated by TRH, and oestrogen especially in pregnancy
inhibited by dopamine (which, in a non-pregnant, non-lactating woman overrides TRH’s stimulatory effect)
how does progesterone act as anti-estrogen at cellular level?
progesterone reduces synthesis of estrogen’s receptor
TRH is what kind of peptide?
where is it released from
a tri-peptide
from the paraventricular nucleus
TRH influences the release of which hormones?
prolactin, GH, vasopressin, insulin, NA, Adr
(and directly on TSH)
How does TRH work at the TRH receptor?
receptor coupled to G proteins
stimulates phospholipase C to make IP3 and DAG
these second messengers stimulate increases in intracellular calcium and activation of protein kinase C
