Biochemistry Flashcards by Brigit high

Heterochromatin vs. Euchromatin, which is expressed?

HeteroChromatin is Highly Condensed

Euchromatin is Expressed

pg. 32

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Histone/DNA modifications that change gene expression

(there are 3)

CpG Methylation Makes DNA Mute

Histone Methylation Mostly Makes DNA Mute

Histone Acetylation makes DNA Active

pg 32

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Lesch Nyhan Syndrome

Hint: enzyme absent is mnemonic for clinical presentation

Enzyme absent: HGPRT (funtions in purine salvage pathway)

Hyperuricemia

Gout

Pissed off (aggression, self-mutilation)

Retardation (intellectual disability)

DysTonia

pg 34

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Drugs that act on microtubules

Hint: mnemoic is Microtubules Get Constructed Very Poorly

Mebendazole (antihelminthic)

Griseofulvin (antifungal)

Colchicine (antigout)

Vincristine/Vinblastine (anticancer)

Paclitaxel (anticancer)

pg 44

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Types of Collagen

Hint: mnemonic is Be (So Totally) Cool, Read Books

Type I: Bone (also, B”one” has the word one in it)

Skin

Tendon

Type II: Cartilage (also, think carTWOlage)

Type III: Reticulin (skin, blood vessels, uterus). Affected in Ehler Danlos, so think ThreE D

Type IV: Basement Membrane (think type four under the floor)

pg. 46

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Osteogenesis Imperfecta clinical presentation

Hint: mnemonic is Patients can’t BITE

Genetic bone disorder, decreased production of type I collagen

Presentation:

Bones = multiple fractures

I (eye) = blue sclerae

Teeth = dental imperfections

Ear = hearing loss

****May be confused with child abuse*****

pg 47

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X-linked recessive disorders

Warning: this is a gnarly ass mnemonic

Hint: mnemonic is Oblivious Female Will Often Give Her Boys Her x-Linked Disorders

Ornithine Transcarbamylase Deficiency

Fabry Disease

Wiskott-Aldrich syndrome

Ocular albinism

G6PD deficiency

Hunter syndrome

Bruton agammaglobulinemia

Hemophilia A and B

Lesch-Nyhan syndrome

Duchenne (and Becker) muscular dystrophy

pg 56

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Duchenne Muscular Dystrophy is due to what type of mutation?

Duchenne = deleted Dystrophin

pg 57

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Myotonic type I Muscular Dystrophy presents with what clinical presentation?

Hint: The trinucelotid repeat responsible is CTG, and that is the mnemonic

Cataracts

Toupee (Early balding in men)

Gonadal Atrophy

pg 57

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Fragile X syndrome clinical presentation

Hint: trinucleotide repeat is CGG, is also the mnemonic

Chin (protruding)

Giant Gonads

pg 58

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Trinucleotide repeat expansion diseases

Hint: mnemonic is Try hunting for my fragile cage free eggs

Try (trinucleodide)

hunting (Huntington)

for my (myotonic dystrophy)

fragile (fragile X)

cage free eggs (Friedrich ataxia)

pg 58

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Trinucleotide repeat for Huntington disease

CAG

Caudate has

less ACh and

GABA

pg 58

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Trinucleotide repeat for Friedreich ataxia

GAA

Ataxic GAAit

pg 58

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Down Syndrome is a trisomy of what chromosome?

21 (Drinking age is 21)

Associated with: duodenal atresia, Hirschsprung disease, congenital heart disease (eg AV septal defect), Brushfield spots, early-onset Alzheimer disease, increased risk for ALL and AML

pg 59

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Edwards Syndrome is a trisomy of what chromosome?

Also Clinical Findings

Hint: mnemonic for clinical findings is PRINCE Edward

18 (Election aege=18)

Clinical Findings:

Prominent Occiput

Rocker Bottom Feet

Intellectual disability

Nondisjunction

low-set Ears

pg 59

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Patau syndrome is a trisomy of what chromosome? Also what are the clinical findings?

Hint: clinical findings are all associated with the letter P

Trisomy 13 (Puberty=13)

Clinical Findings: cleft liP/Palate, holoProsencephaly, Polydactyly, cutis aPlasia, congenital heart disease

pg 59

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What does a microdeletion at 22q11 present with?

Hint: mnemonic is CATCH-22

Variable presentations including

Cleft palate,

Abnormal facies,

Thymic aplasia

Cardiac defects, and

Hypocalcemia secondary to parathyroid aplasia.

Associated with both DiGeorge Syndrome and Velocardiofacial syndrome.

pg. 61

What is another, more clinical name for Vitamin A?

What are its pharmacologic uses?

Retinol is vitamin A, so think retin-A (used for wrinkles and Acne)

Pharmacologically, Isotretinoin is used as a Vitamin A derivative. However, this is teratogenic.

pg 62

What is Vitamin B1’s physiologic use?

What is the name of a Vitamin B1 deficiency?

Physiologic use: cofactor for several dehydrogenase enzymes. Think ATP:

Alpha-ketoglutarate dehydrogenase

Transketolase

Pyruvate dehydrogenase

Vitamin B1 deficiency= beriberi

Think of spelling it Ber1Ber1

pg 62

What is Vitamin B2’s physiologic role?

How does a deficiency present clinically?

B2 is a component of FAD and FMN. FAD and FMN are derived from riboFlavin (B2 = 2 ATP)

Deficiency: Cheilosis (inflammation of the lips, scaling and fissures at the corners of the mouth), and Corneal vascularization

(the 2 Cs of Vitamin B2)

pg 63

What is Vitamin B3 (niacin)’s role physiologically?

How does a deficiency present clinically?

B3 is a constituent of NAD+, NADP +

(NAD is derived from Niacin), (B3 = 3ATP)

Deficiency: Pellagra.

Diarrhea, Dementia (and hallucinations), and Dermatitis (C3/C4 dermatome circumferential “broad collar” rash [Casal necklace], hyperpigmentation of exposed limbs)

The 3Ds of Vitamin B3

pg 63

Scurvy is due to what type of nutritional deficiency?

Vitamin C deficiency causes sCurvy due to a Collagen synthesis defect

pg 65

What is Vitamin K’s physiologic role?

Vitamin K is for Koagulation

Necessary for the maturation of factors II, VII, IX, X, and proteins C and S.

pg 66

Kwashiokor’s clinical presentation

Hint: mnemonic is Kwashiokor results from protein-deficient MEALS

Malnutrition

*E**dema
*A**nemia

Liver (fatty)

Skin lesions (hyperkeratosis/hyperpigmentation)

pg 67

Marasmus clinical presentation

**M**arasmus results in **M**uscle wasting (not specifically due to protein deficiency, just caloric insufficiency) pg 67

Pharmacologic role of **FOME**pizole

**F**or **O**verdoses of **M**ethanol or **E**thylene glycol Inhibits alcohol dehydrogenase pg 68

Pharmacologic role of **Di**sulfiram

**dis**courages drinking inhibits acetaldehyde dehydrogenase, causing acetaldehyde to accumulate, contributing to hangover symptoms pg 68

TCA (Krebs) Cycle intermediates Hint: mnemonic is **C**itrate **I**s **K**rebs' **S**tarting **S**ubstrate **F**or **M**aking **O**xaloacetate

**C**itrate --\> **I**socitrate --\> alpha **K**eto-glutarate --\> **S**uccinyl CoA --\> **S**uccinate --\> **F**umarate --\> **M**alate --\> **O**xaloacetate pg 73

Glucose-6-phosphate dehydrogenase deficiency blood smear findings

**He**inz bodies = denatured **He**moglobin precipitates within RBCs due to oxidative stress **Bite cells** - result from the phagocytic removal of **Heinz** bodies by splenic macrophages (think, "**Bite** into some **Heinz** ketchup") pg 75

Disorders of carbohydrate breakdown: What are the enzymes deficient in **fructose intolerance** and **classic galactosemia**?

Fructose intolerance: Aldolase B Classic Galactosemia: Galactose-1-phosphate uridyltransferase **F**ructose is to **A**ldolase **B** as **G**alactose is to **U**ridyl**T**ransferase (**FAB GUT**) pg 76

Maple Syrup Urine Disease enzyme deficiency, and what substrate builds up?

Decreased levels of branched-chain alpha keto-acid dehydrogenase (B1) Blocked degradation of branched chain amino acids (**I**soleucine, **L**eucine, **V**aline) Think**: I** **L**ove **V**ermont **Maple Syrup** from maple trees (with **B1ranches)** pg 80

Clinical presentation of homocysteinuria Hint: mnemonic is **HOMOCY**stinuria

Excess homocysteine causes: **H**omocysteine in urine **O**steoporosis **M**arfanoid body habitus **O**cular changes (downward and inward lens subluxation) **C**ardiovascular effects (thrombosis and atherosclerosis) k**Y**phosis, intellectual disability pg 80

What substrate(s) build up in cystinuria? Hint: mnemonic is COLA

**C**ysteine **O**rnithine **L**ysine **A**rginine pg 81

Glycogen Storage Diseases (Name the 4 types) Hint: mnemonic is **V**ery **P**oor **C**arbohydrate **M**etabolism

type 1: **V**on Gierke Disease type 2: **P**ompe Disease type 3: **C**ori disease type 5: **M**cArdle Disease (note: first aid doesn't even say wtf type 4 is...) pg 83

Clinical presentation and deficient enzyme VonGierke Disease

Von**G**ierke Disease Clinical presentation: increased **g**lycogen in liver, increased blood lactate, increased triglycerides, increased uric acid (**g**out), and hepatomegaly Deficiant enzyme: **G**lucose 6-phosphate pg 83

Clinical Presentation and deficient enzyme Pompe disease

**P**ompe disease Clinical presentation: cardiomegaly, hypertrophic cardiomyopathy, hypotonia, exercise intolerance, and systemic findings lead to early death Deficieny enzyme: Lysosomal acid alpha **1,4** glucosidase **P**om**P**e trashes the **P**um**P** **(1,4)** pg 83

Clinical Presentation and deficient enzyme McArdle Disease

**M**cArdle disease Clinical presentation: increased glycogen in muscle that can't be broken down --\> painful **M**uscle cramps, **M**yoglobinuria (red urine) with strenuous exercise Deficient enzyme: skeletal muscle glycogen phosphorylase (**M**yophosphorylase) **M**cArdle = **M**uscle pg 83

Tay-Sachs Disease Deficient enzyme and clinical presentation

T**A**y-Sa**X** disease Clinical presentation: progressive neurodegeneration, developmental delay, "cherry-red" spot on macula, lysosomes with onion skin, no hepatosplenomegaly (vs. Neimann-Pick) Deficient Enzyme: He**X**osaminidase **A** pg 84

Niemann Pick Disease Clinical Presenation and deficient enzyme

Niemann Pick Disease (**No Man Picks** his nose with his **Sphinger**) Clinical Presenation: Progressive neurodegeneration, hepatosplenomegaly, foam cells (lipid laden macrophages), cherry-red spot on macula Deficient enzyme: **sphingomyelin**

Hunter Syndrome Clinical Presentation, Deficient enzyme, and mode of transmission

**Hunter** syndrome Clnical presentation: Developmental delay, gargoylism, airway obstruction, aggressive behavior, **NO corneal clouding** (vs Hurler syndrome) Deficient enzyme: Iduronate sulfatase Mode of Transmission: **X-linked recessive** **Hunters** see clearly (**no corneal clouding**) and aim for the **X** pg 84