USMLE Step 1 - uWorld High
Yield Notes 2026 Exam All
Answers and Illustrations
Given
What are the two major microtubular motor proteins? Which does
anterograde axonal transport, which does retrograde axonal transport? -
ANSWER ✔✔Kinesin, Dynein
Kinesin: Anterograde
Dynein: Retrograde`
,What do you think, immunologically speaking, when you see someone
with recurrent Neisseria infections? - ANSWER ✔✔Inability to form
the membrane attack (MAC) complex
this is a common complement deficiency
What is the defect in Chronic Granulomatous disease? What is the
pathophysiology? - ANSWER ✔✔NADPH Oxidase deficiency leads
to the inability to kill intracellular organisms
Characteristic triad of ataxia telangiectasia? - ANSWER
✔✔cerebellar ataxia, telangiectasias, increased risk of sinopulmonary
infections
What is the major immune deficiency of ataxia telangiectasia? -
ANSWER ✔✔IgA deficiency, which predisposes to infections of the
upper and lower airways (and other mucous membranes)
There's a useful mnemonic for Ataxia Telangiectasia and the gene that's
mutated. What is it? - ANSWER ✔✔ATM
Ataxia
Telangiectasia
,Mutated
ATM gene is responsible for DNA break repair
What is one reason that lead intoxication causes hypochromic anemia? -
ANSWER ✔✔Mitochondrial iron transport is important for Heme
synthesis! It's inhibited by lead. So you don't make heme in your
mitochondria and you get hypochromic anemia.
What is the biochemical problem in Lesch-Nyhan syndrome? (And, only
if you got that right, what are the really cool symptoms of it?) -
ANSWER ✔✔Defective purine catabolism, so buildup of purines. It's
an X-linked recessive disorder with mutated HGPRT gene
(hypoxanthine-guanine phosphoribosyltransferase, if you want to
impress people).
Now, if you got HGPRT and purine catabolism right, you can say: self-
mutilating behavior on top of mental retardation, choreoathetoid (think
Chorea) movements and spasticity.
What is the defect in Niemann-Pick disease?
What causes that?
3
COPYRIGHT©JOSHCLAY 2025/2026. YEAR PUBLISHED 2026. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
STATEMENT. ALL RIGHTS RESERVED
, What is the common macular finding? - ANSWER ✔✔Sphingolipid
degradation is defective
Caused by an autosomal recessive defect in sphingomyelinase
Cherry Spot on the macula? Niemann Pick's or Tay Sach's.
If a baby gets exposed to an unclean knife (...) and subsequently
develops rigid paralysis, what is the diagnosis, where do we think this
might happen, and how do we prevent it? - ANSWER ✔✔Neonatal
Tetanus
Developing Countries
Maternal immunization with tetanus toxoid is the best way to prevent it
an adeuately immunized mom will transfer IgG's across the placenta to
the neonate
Which microtubule associated protein aids in anterograde transport of
intracellular vesicles and organelles? Which end of the microtubule do
they go towards? - ANSWER ✔✔Kinesin.
Towards the (+) rapidly growing end.
Yield Notes 2026 Exam All
Answers and Illustrations
Given
What are the two major microtubular motor proteins? Which does
anterograde axonal transport, which does retrograde axonal transport? -
ANSWER ✔✔Kinesin, Dynein
Kinesin: Anterograde
Dynein: Retrograde`
,What do you think, immunologically speaking, when you see someone
with recurrent Neisseria infections? - ANSWER ✔✔Inability to form
the membrane attack (MAC) complex
this is a common complement deficiency
What is the defect in Chronic Granulomatous disease? What is the
pathophysiology? - ANSWER ✔✔NADPH Oxidase deficiency leads
to the inability to kill intracellular organisms
Characteristic triad of ataxia telangiectasia? - ANSWER
✔✔cerebellar ataxia, telangiectasias, increased risk of sinopulmonary
infections
What is the major immune deficiency of ataxia telangiectasia? -
ANSWER ✔✔IgA deficiency, which predisposes to infections of the
upper and lower airways (and other mucous membranes)
There's a useful mnemonic for Ataxia Telangiectasia and the gene that's
mutated. What is it? - ANSWER ✔✔ATM
Ataxia
Telangiectasia
,Mutated
ATM gene is responsible for DNA break repair
What is one reason that lead intoxication causes hypochromic anemia? -
ANSWER ✔✔Mitochondrial iron transport is important for Heme
synthesis! It's inhibited by lead. So you don't make heme in your
mitochondria and you get hypochromic anemia.
What is the biochemical problem in Lesch-Nyhan syndrome? (And, only
if you got that right, what are the really cool symptoms of it?) -
ANSWER ✔✔Defective purine catabolism, so buildup of purines. It's
an X-linked recessive disorder with mutated HGPRT gene
(hypoxanthine-guanine phosphoribosyltransferase, if you want to
impress people).
Now, if you got HGPRT and purine catabolism right, you can say: self-
mutilating behavior on top of mental retardation, choreoathetoid (think
Chorea) movements and spasticity.
What is the defect in Niemann-Pick disease?
What causes that?
3
COPYRIGHT©JOSHCLAY 2025/2026. YEAR PUBLISHED 2026. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
STATEMENT. ALL RIGHTS RESERVED
, What is the common macular finding? - ANSWER ✔✔Sphingolipid
degradation is defective
Caused by an autosomal recessive defect in sphingomyelinase
Cherry Spot on the macula? Niemann Pick's or Tay Sach's.
If a baby gets exposed to an unclean knife (...) and subsequently
develops rigid paralysis, what is the diagnosis, where do we think this
might happen, and how do we prevent it? - ANSWER ✔✔Neonatal
Tetanus
Developing Countries
Maternal immunization with tetanus toxoid is the best way to prevent it
an adeuately immunized mom will transfer IgG's across the placenta to
the neonate
Which microtubule associated protein aids in anterograde transport of
intracellular vesicles and organelles? Which end of the microtubule do
they go towards? - ANSWER ✔✔Kinesin.
Towards the (+) rapidly growing end.
