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Flashcards in Make Biochem MY BITCH Deck (101):
1

What are the classical and vascular types of Ehlers Danlos syndrome

Classical is joint hypermobility adn seen with mutaiton in type V collagen

Vascular is vascular and organ rupture and see deficient Type III collagen

1

What is going in on uniparental disomy?

Whats dif between Heterodisomy and Isodisomy

offspring gets 2 copies of chrom from 1 parent,none from other:

Herodisomy = meiosis I error 

Isodisomy = meisosis II error

2

What do we treat a pt with HGPRT deficiency with?

 

allopurinol (or febuxostat would be second line)

2

Explain structure of cilia and the disease caused by Dyenin arm defect

9+2 arrangement of microtubles; axonemal Dynein-ATpase likns peripheral 9 doublets--> see bending of cilium by sliding

Kartageners: immotile cilia d/t dyenin arm defect: intertility (dsfnx sperm and dsfnx fallopian tube), bronchiectasis, recurrent sinusitus, situs inversus

2

RLS in Urea cycle

Carbomyl Phostphate Synthetaes I

+ N-acetylglutamate

3

What are the 3 steps for Elongation in protein synthesis

1. Aminoacyl tRNA binds to Asite (excpet for initator methionine)

2. rRNA catalyxes peptide bond formation, transfers growing polypeptide to AA in the A site

3. Ribosome advances 3 NTs toward the 3' end of mRNA, moves the tRNA to the p site

3

RLS in Glycogenesis

Glycogen Synthase

+ Glucose-6-P, +insulin, +cortisol

-glucagon, -Epi

5

Key steps in Protein synthesis during Initiation

Initiated by GTP hydrolysis and initiation factors put together the 40S ribosomal unit with the initiator tRNA--> then released when mRNA and ribosomal 60S assemble with them

= 80S

6

RLS in Cholesterol Synthesis

HMG-CoA reductase

+insulin, +thyroxine

-Glucagon -Cholesterol

8

Enz Deficiency responsible for SCID causing excess ATP and dATP imbalance in the nucleotide pool

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Adenosine Deaminase: causes feedback inhibition on ribonucleotide reductase thus decrease DNA synthesis

9

RLS in ketogenesis

 

HMG-CoA synthase

10

Stain for the following

CT

Muscle

Epithelial cells

NeuroGlia

Neurons

Vimetin = CT

DesMin = Muscle

Cytokeratin= epithelial cell

GFAP = Neuroglia

Neurfilaments = Neurons

10

What happens when we increase ethanol metabolism in regards to NADH/NAD+

 

Will increase NADH/NAD+ ratio in liver; leads to

Pyruvate --> malate (lactic acidosis)

OXA--> malate (prevents gluconeogenesis = fasting hypoglycemia)

Glyaldehyde-3-P --> Glylcerol-3-P (causes hepatosteatosis)

11

Site of synthesis of secreatory proteins and N-linked oligosacharides addition to proteins

vs

unattached and synthesis of cytosolic and organellar proteins

vs

synthesize and secreate peptide NTs for secreation

 

Rough Endoplasmic reticulum

Free ribosomes

Nissl bodies

12

Amino Acids necessary for PURINE synthesis

Purines make me GAG: glysine, Aspartate, Glutamine

12

RLS in FA synthesis

 

Acetyl-CoA Carboxylase (ACC)

+insulin, +citrate

-Glucagon -Palmitoyl CoA

13

EnZ takes Ethanol--> Acetaldehyde

EnZ takes Acetaldehyde--> Acetate

What drugs inhibit these enZ

Ethanol --> Acetaldehyde via Alcohol Dehydrogenase and inhibited by Fomepizole

Acetaldehyde--> Acetate via Acetaldehyde Dehydrogenase and inhibited by Disulfiram

 

 

14

EnZ deficiency responsible for SCID

Adenosine Deaminase deficiency

15

What makes rRNA, mRNA and tRNA and what does alpha-amanitin do?

RNA pol I = rRNA

RNA pol II = mRNA (inhibited by alpha amanitin from mushrooms=hepatotoxic)

RNA pol III= tRNA

*prokaryones only have 1 RNA polymerase that makes all these

16

Prokaryotic only, degrades RNA primers and replaces them with DNA; can excise in 5'--3' direction

DNA polymerase I

16

Differences in following mutations;

Silent

Missense

Nonsense

Frameshift

silent: NT substitute for codes for same AA; often in 3rd position (tRNA wobble)

MIssense: NT substitution in changed AA (like in SS disease)

Nonsense: NT substitution that codes for early stop (UAG, UGA, UAA)

Frameshift: Deletion or insertion resulting in misreading of downstream NTs; get truncated shitty protein

17

normally inhibit G1 to S progression, mutation here results in unrestrained cell division

p53 and Rb

18

What is the start codon and what does it code for?

What are the stop codons?

 

Start = AUG; codes for methionine

Stops: UAA, UGA, UAG

19

RSL in De novo pyrimidine synthesis

Carbamoyl Phosphate Synthetase II

20

Difference between Indirect and Direct ELISA

Indirect: uses test antigen to see if a specific antibody is present in the pts blood; a secondar antiB coupled to color generating enZ is added to detect first antibody

Direct: uses a test antibody to see if specific antiG present in pts blood; secondary antoB coupled to color generating enZ to detect it

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21

RLS in Glycogenolysis

Glycogen Phosphorylase

+Epi, +Glucagon +AMP

-G-6-P, - insulin, -ATP

22

3 yo child comes in that shows signs of MR. Parents note that he has violent behaviors and often slaps his face. His labs show Hyperuricemia.

Dx?

Cause?

Tx?

Lesch-Nyan syndrome

deficiency in purine salvage from absent HGPRT

also (hyperuricemia, Gout, Pissed off, Retardation and dysTonia)

tx: Allopurinol or Febuxostat

24

Golgi is key distribution for proteins and lipids from ER--> vesicles and plasma membrane

Modifies ____to serine and threonine and _____ to aspergine

Most importantly puts this on proteins that are destined for the lysosome

O-oligos to serine and threonine

N-oligoon aspartine

***Mannose-6-Phosphate for lysosomal trafficking

25

Where RNA polymerase and other TFs bind to DNA upstream from gene locus; AT RICH sequence with TATA box and CAAT boxes

mutation here results in decreased level in gene transcription

Promoter region

26

Congentital microdeletion of short arum of Chrom 5 (46XX or XY) what is this and what do we see associated

Cri-du-chat

microcephaly, ID, high pitched mewing (cat like) cry, epicanthal folds and VSD

27

Mother comes in with her 3 yo daughter. She is worried she is falling behind her developmental milestones, both physically and mentally. The daughter has hypotonia and brittle, kinky hair. Dx and cause

Dx is Menkes diesase: CT disorder d/t impaired Cu absorption and transport: see decreased activity of lysyl oxidase (Cu is a cofactor) = brittle hair, MR, hypotonia

29

Membrane enclosed organelle key in catbolism of VLCFA, branched chain FA and AA, has oxidase + catalse to metabolize alcohol to make plasmogen

and

Barrel shapped protein that degrades damaged or ubiquitin tagged proteins and depends on Ca++

Peroxisome

Proteosome

30

Difference btwn these single strand DNA repair mech:

 Nucelotide Excision repair

Base excision repair

Mismatch repair

Nucleotide excision repair: Endonucleases release oligoNT with the damaged base; DNA polymerase fills gap then ligase fills and reseals

Base excision repair: Base-specific glycolysase sees altered base and creates AP site; then one or more NT removed by AP-endonuclease that cleave the 5' end, lyase cleaves the 3' end and DNA pol fills the gap

Mismatch repair: newly made strand is recongnized as mismatched then get remoeved and gap is filled

31

What are the key nuclear localizing signals necessary to get in and out of nucleus?

Proline, Arginine, Lysine; need to be PALs to get in the nucleus club! and it requires ENERGY to get in

32

What are p-bodies (this is for you Megan!)

mRNA quality control occurs at cytoplasmic p-bodies that hve exonucleases, decapping enZ and microRNAs: mRNAS that can be sotred here for future translation

33

What metabolism takes place in the Cytoplasm

Glycolysis, FA synthesis, HMP shunt, Protein synthesis (RER), steroid synth (SER) and cholesterol synthesis

34

What are the key steps in collagen synthesis and where do they occur?

1. Synthesis in RER; make collagen alpha chains = precollagen (Gly-X-Y)

2. Hydroxylation (RER) of specific proline and lysine residues (need vit C)

3. Glycosylation (RER) of pro-alpha-chains residues and mae procollagen by H+ and S-S bonds--> triple helix of 3 alpha chains (CC = Osteogensis Imperfecta)

4. Exocytosis of procollagen to ECM

5. Proteolytic processing OUTside fibroblast :Clevage of S-S bonds to get insoluble tropocollagen

6. Cross-linking (outside fibroblast) make Covalent Lysine-Hydroxylysine links to reinforce collagen fibrils

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35

What metabolism occurs in the Mitochondria

Fatty acid oxidation, acetyl-CoA production, TCA cycle, oxidative phosphorylation

36

Rare disorders, often prsent with myopathy, lactic acidosis and CNS disease. Muscle biopsy shows ragged red fibers

Mitochondrial myopathies; has transmission only through the mother

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37

RSL in 

38

RLS in HMP shunt

Glucose-6-Phosphate Dehydrogenase (G6PD)

+NADP+

-NADPH

39

3 year child comes in with multiple fractures, blue sclera, poor hearing and poor dental hygeine. 

Dx and cause of disease

Osteogenesis Imperfecta

Autosomal Dominant with decreased production of type I collagen

39

RLS in Glycolysis and it's regultors

Glycolysis limited by: PFK-1

+ by AMP and F,2,6-BP

- by ATP and citrate

40

Normal fnx of Na/K pump?

What effect does Oubain have on the Na/K pump?

What about Glycosides?

 

Pump 3 Na out, bring 2 K+ in--> the loss of Na+ creates a drive for the Na/Ca+ exchange (bring Na+ in and Ca++ out) to maintain low intracellular Ca++ in the heart for less cnx

Oubain inhibits via binding to K+ site

Glycosides (digoxin) will block Na/K pump thus get increase in intracellular Ca++ and increase force of cnx

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42

What is the process of RNA processing starting with hnRNA

nuclear RNA makes hnRNA--> mRNA then

Cappin at 5' prime end  (7-methyguanine cap)

Polyadenylation of 3' end (signal is AAUAAA)

Splicing out introns

all this shit happens in nucleus

44

You want to clone yourself because, hey, you are AWESOME! How would you do that and what personality disorder do you suffer from?

Isolate eukaryotic mRNA of interst

Expose mRNA to reverse transcriptase to make cDNA

insert cDNA into bacterial plasmids with antibiotic resistance genes

transofrm recomb plasmid into bacteria and surviving bacterio go on antibiotic medium to make DNA

you have Narcissitic personality disorder you weirdo

45

RLS in Fatty Acid Oxidation

Acetyl-CoA carboxylase

+Insulin, +Citrate

-Glucagon, - palmitoylCo-A

46

RLS in TCA cycle

Isocitrate Dehydrogenase

+ by ADP

-by ATP or NADH

48

Responsible for accuracy of AA selection when you are building a protein

Aminoacyl tRNA synthetase; its the 'matchmaker' and there is 1 per AA, if correct match will make peptide bond

 

50

Difference btwn Southern, Northern, Western, S.Western blot

Southern: electrophoresis of DNA which is then visualized

Northern: RNA sample is electrophoresed; reflects level of gene expression

Western: protein is electrophoresed (confirmatory after HIV+ELISA)

S.Western: DNA-binding proteins are labeled

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51

What drugs act on microtubules?

Microtubules Get Constructed Very Poorly

Mebendazole (helminthic)

Griseofulvin (fungal)

Colchisine (gout)

Vincristine/blastine (cancer)

Paclitaxel

52

Site of steroid synthesis adn detox of drugs and proteins, lack surface ribosomes adn ar in liver hepatocytes and parts of adrenal cortex and gonads

Smooth ER

53

What are the following structures in tRNA?

T-arm

D-arm

Acceptor stem:

T-arm; has the Thymine/suedouridine/cytosine sequenced needed for t-RNA ribosome binding

D-Arm: has dihyrouracil residues for tRNA recognition by correct aminoacyl-tRNA syntehase

Acceptor Stem: the 3' end with the CCA AA aceptor site (think Can Carry Amino acids) also called the anti-codon 

54

RLS in Gluconeogenesis

Fructose 1,6-Bis phosphatase

+ by ATP and Acetely-CoA

- by AMP, F,2,6, BP

55

How do we progress from G1 to Mitosis

G1--> S: cycD binds CDK4 = cycD/CKD4 will phosphorlyate Rb thus Rb released from E2F

Unbound E2F transcribes shit needed for S phase and we get CycE binds to CDK2

CycE/CDK2 allows us to progress to S phase

G2--> M: CycA to CDK2 results in mitotic prophase

cdc25 activatesCycB to CKD1 = CycB/CDK1 

CycB/CDK1  break down env and lamins 

56

Prokaryotic only: resonsible for elongation of leading strand by addine deoxynucleotides to the 3' end and elongates lagging strand til reaches primer of preceding fragement:

thus grow 5' to 3'

has exonuclease activity to 'proof read' each added NT in a 3'--5' direction

DNA polymerase III

57

What is difference and simularities in Prader Willis and Angelman

Both are dt imprinting on Chrom 15

Prader: maternal imprinting thus Paternal is deleted = hyperphagia, obesity, ID, hypogonadism, hypotonia

AngelMan= Paternal imprinting and gene from dad is silent whle Maternal is deleted; see inapp laughter, seizures, ataxia and severe ID

MAMA and POP for

Maternal gene, Angelman, Mood, Ataxia

POP= Prader, Obese, Papa

58

Elastin is the stretchy shit in lungs, large arteries, vocal cords, ligamenta flavum. What AA is it rich in?

Why is it so elastic?

How is it broken down?

What disease is it invovled in?

Rich in Proline and lysine

Has crosslinking extracellularly that gives it elastic properties

Broken down by elastase (this is inhibited by alhpa-1-antitrypsin)

Marfan see defect in fibrillin = sheath around elastin

Emphysema: from alpha-1AT deficiency 

wrinkles from aging

59

RLS in De Novo  Purine synthesis

PRPP

- AMP, -IMP, -GMP

60

Three Postranslational modifications to proteins

Trimming

Covalent alterations

Chaperone protein

Trimming: remove C or N termial polypeptides from zymogen to make mature poroteins

Covalent alterations: Phosphorylation/Glycosylation/Hydroxylation/ Methylation/ Acetylation and ubiquitination

Chaperone protein: intracell protein that facilitates or maintains protein folding (in yeast some are heat shock proteins like Hsp60 expressed at high temps to prevent denaturation)

61

6 mo old has coarse facial features, clouded corneas and decreased joint movement. 

Labs show elevated levels of lysosomal enZ. 

Dx and pathogenesis

I cell disease: lysosomal storage disorder

defect in Phosphotransferase results in NO 6-mannose-phosphate on proteins supposed to go to lysosome

62

What is nonhomologous end joining and what disease is it messed up in?

Brings 2 ends of DNA fragments together to repair ds breaks; messed up in ataxia telangiectasia

63

Nicotinamides (NAD+ from _____ NADP+) and flavin nucleotides (FAD+ from _____).

NAD+ is generally used in______ processes to carry reducing equivalents away as NADH.

NADPH is used in______ processes (steroid and fatty acid synthesis) as a supply of reducing equivalents. 

vitamin B3,

vitamin B2

catabolic

anabolic

64

Phosphorylation of glucose to yield glucose-6-phosphate serves as the 1st step of glycolysis (also serves as the 1st step of glycogen synthesis in the liver). Reaction is catalyzed by either ____ or ______, depending on the tissue.

 

At low glucose concentrations,_______ sequesters glucose in the tissue.

At high glucose concentrations, excess glucose is stored in the liver. 

hexokinase or glucokinase

hexokinase

65

Compare and contrast Hexokinase and Glucokinase

Location

Km and Vmax

INduced by insulin

Feedback inhibited by G-6-P

Hexokinase is in most tissues but NOT liver or B cells pancrease; Has a Low Km, Low Vmax. Not induced by insulin and IS inhibited by G-6-P

Glucokinase is in the Liver and B cells pancrease. Has HIGH Km and HIGH Vmax and is induced by insulin but not inhibited by G-6-P

66

What are the Irreversible steps in Glycolysis?

 

Q image thumb

glucose--> G-6-P by Hexokinase or Glucokinase

Fructose-6-P--> Fructose 1,6 Bis PHosphate by Phosphofrucktokinase-1 (RLS)

PEP--> Pyruvate via Pyruvate kinase

67

What steps in glycolysis requre ATP?

What steps Generate ATP?

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Need ATP: Glucose--> G-6-P by hexo or glucokinase and 

Fructose-6-P --> Fructose 1,6 Bisphosphate

Generate: 1,3 BPG--> 3-PG and

PEP--> pyruvate

68

Regulation by F2,6 BP

What 2 enZ are same bifuncitonal enZ and how are they regulated?

FBPase-2 (fructose bisphosphatase-2) and PFK-2 (phosphofructokinase-2) are the same bifunctional enzyme whose function is reversed by phosphorylation by protein kinase A.

 

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69

Explain the regulation of PFK-2 and FBPase-2 in the fed and fasting state

Fasting state: HIGH glucagon--> Increased cAMP--> Increased protein kinase A--> Increased FBPase-2, and DecreasedPFK-2: less glycolysis, more gluconeogenesis.

Fed state: HIGH insulin--> Decreased cAMP--> Decreased protein kinase A--> Decreased FBPase-2, Increased PFK-2, more glycolysis, less gluconeogenesis. 

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70

What is the function of the Pyruvate Dehydrogenase Complex?

What 5 cofactors does it require?

What complex is it simular to?

Mitochondrial enzyme complex linking glycolysis and TCA cycle. Differentially regulated in fed/fasting states (active in fed state). 

Reaction: pyruvate + NAD+ + CoAacetyl---->  CoA + CO2 + NADH. 

1. Pyrophosphate (B1, thiamine; TPP)

2. FAD (B2, riboflavin)
3. NAD (B3, niacin)
4. CoA (B5, pantothenic acid)

5. Lipoic acid

Simular to alpha-keotoglurate

71

Your 2 yo son was play in your magical potion set and may have ingested something... he has rice-water stools, is vomitting and his breath smells like garlic. What enZ is inhibited?

Arsenic poisoning!

inhibits lipoic acid thus Pyruvate Dehydrogenase won't work!

(TLC For Nancy)

72

This causes a build up in pyruvate resulting in shunting to lactate and alanine. What is the EnZ defiency?

What do we do to treat these pts?

How will they present?

Pyruvated DH complex deficiency: Causes a buildup of pyruvate that gets shunted to lactate (via LDH) and alanine (via ALT). X-linked. 

Findings: Neurologic defects, lactic acidosis,  serum alanine starting in infancy. 

Tx: INCREASE intake of ketogenic nutrients (e.g., high fat content or lysine and leucine). 

73

What Products do we get from the TCA cycle?

Where does the TCA cycle occur?

What is the RLS in this processes?

The TCA cycle produces:  3 NADH, 1 FADH2, 2 CO2, 1 GTP per acetyl-CoA = 10 ATP/ acetyl-CoA (2× everything per glucose).

 occur in the mitochondria. 

RLS: Isocitrate Dehydrogenase

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74

75

What is the function of Citrate Synthase?

Isocitrate DH?

alpha-KG-Dehydrogenase?

All enZ in the TCA cycle

Oxa + Acetyl-CoA--> (citrate synthase)--> Citrate

Isocitrate--> (Isocitrate Dehydrogenase)--> alpha-KG

Alpha-KG--> (alpha KG Dehydrogenase)--> Succinly CoA

76

What is the location and purpose of the Electron transport chain

What role does NADH and FADH2 play?

NADH electrons from glycolysis enter mitochondria via the malate-aspartate or glycerol-3- phosphate shuttle. FADH2 (=1.5ATP) electrons are transferred to complex II (at a lower energy level than NADH = 2.5 ATP).

The passage of electrons results in the formation of a proton gradient that, coupled to oxidative phosphorylation, drives the production of ATP. 

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77

What inhibits Complex I in the ETC

What inhibits Complex III?

What inhibits Complex IV?

What inhibits complex V?

Rotenone blocks Complex I (decrease gradient)

Antimycin A blocks Complex III (decrease gradient)

Cyanide and NO block Complex IV (decrease gradient)

Oligomycine block Complex V (blocks the ATP synthase)

78

What are common uncoupling agents of the ECT pathway and what do they do?

2,4-Dinitrophenol (used illicitly for weight loss), aspirin (fevers often occur after aspirin overdose), thermogenin in brown fat. 

Increase permeability of membrane, causing a proton gradient and O2 consumption. ATP synthesis stops, but electron transport continues. Produces heat. 

79

What is the purpose of the HMP shunt (pentose phosphate pathway)

What products are generated?

Where in the cell does this occur?

Provides a source of NADPH from abundantly available glucose-6-P (NADPH is required for reductive reactions, e.g., glutathione reduction inside RBCs, fatty acid and cholesterol biosynthesis).

Additionally, this pathway yields ribose for nucleotide synthesis and glycolytic intermediates.

2 distinct phases (oxidative and nonoxidative), both of which occur in the cytoplasm. No ATP is used or produced. 

80

What is the difference between the oxidative and non-oxidative reaction in the HMP shunt?

Oxidative (irreversible) G-6-P--> --> (G6PDH)-->  CO2 + 2 NADPH + Ribulose-5-Pi

G6PDH is the RLS in the HMP shunt

Non-oxidative (reversible): Ribulose-5-P Ribuse-5-P + G3P + F6P

81

What is the Respiratory Burst? 

What role does it have in disease pathology?

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Activation of phagocyte NADPH oxidase complex (in neutrophils and monocytes) to use O2 as a substrate. Key in immune response--> get rapid release of ROS

NADPH key for generation and neutralization of ROS

Myeloperoxoidase is blue-green heme containig pigment that gives sputum its color

CC: Chronic granulomatous disease: high risk for inection by catalase + species (S.aureus, Aspergillus) that acan neutralize their own H2O2 and leave phagocytes without ROS to fight infections

82

Glucose 6 Phosphate DH defiency has implications in several disease pathologies.

What is it's role in anemias and infections?

NADPH is necessary to keep glutathione reduced, which in turn detoxifies free radicals and peroxides.

LOW NADPH in RBCs leads to hemolytic anemia due to poor RBC defense against oxidizing agents (e.g., fava beans, sulfonamides, primaquine, antituberculosis drugs). 

Infection can also precipitate hemolysis (free radicals generated via inflammatory response can diffuse into RBCs and cause oxidative damage). 

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83

You are doing rotations in the heme clinic and your attending has you looking at blood smears. He tells you one of them has a pt with G6PDH deficiency. What will you see on the slide? What is the inheritance?

Heinz bodies—denatured Hemoglobin 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.” 

X-linked recessive disorder; most common human enzyme deficiency; more prevalent among blacks.malarial resistance.

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84

You are using your own cells to look for enZ deficiencies for FUN bc that's fun, right?!? You find you are lacking the enZ fructokinase. What symptoms do you have? Why has this happened to you?!?

Symptoms: fructose appears in blood and urine.  Pts are asymptomatic so stop freaking out
Disorders of fructose metabolism cause milder symptoms than analogous disorders of galactose metabolism because fructose doesn't get trapped in cellls

You got this because of genetics: Autosomal recessive

85

You stopped at a friends house to see their little 6 mo old child. Rascal is trying his first sip of juice today! yay, he loves it!

A few days later your friend calls saying her son has been vomitting and looks orange. What's going on?!?

Hereditary deficiency of aldolase B. Autosomal recessive. Fructose-1-phosphate accumulates, causing a DECREASE in available phosphate, which results in inhibition of glycogenolysis and gluconeogenesis.

Symptoms present following consumption of fruit, juice, or honey.

Urine dipstick will be ⊝ (tests for glucose only); reducing sugar can be detected in the urine (nonspecific test for inborn errors of carbohydrate metabolism).

Symptoms: hypoglycemia, jaundice, cirrhosis, vomiting.

Treatment:Decrase intake of both fructose and sucrose (glucose + fructose). 

86

Your neighbor has an 8 month old daughter. She is very cute but doesn't smile much. You are on your peds rotation and noticing she is behind on some milestones, she doesn't seem able to track objects. You mention your concern to your friends and they take her to be looked at and find out she has cataracts (shots are up to date and no infections)

Whats going on?

Hereditary deficiency of galactokinase. Galactitol accumulates if galactose is present in diet. Relatively mild condition. Autosomal recessive.

Symptoms: galactose appears in blood and urine, infantile cataracts.

May present as failure to track objects or to develop a social smile. 

"galactoKINase and fructoKINase are KINDER deficiencies)

87

Your preceptor tells you to go follow Dr. Cowmilk for the remainder of the day as she is busy. You join her team as they are finishing up a case and hear them recommend to limit intake of Galactose and Lactose from the infants diet and explains to the mother that if they don't, the child may develope jaundice, hepatomegaly, infantile cataracts and may die. 

What EnZ deficeincy does this child have?

Why does it cause these terrible symptoms?

Absence of galactose-1-phosphate uridyltransferase. Autosomal recessive. Damage is caused by accumulation of toxic substances (including galactitol, which accumulates in the lens of the eye).

Symptoms: failure to thrive, jaundice, hepatomegaly, infantile cataracts, intellectual disability. Can lead to E. coli sepsis in neonates.
Treatment: exclude galactose and lactose (galactose + glucose) from diet. 

88

What enZ takes Glucose--> Sorbital to trap it in the cell (will create osmotic gradient)?

What can sorbital be further converted into to avoid this osmotic gradient?

What cells lack the above enZ thus are at risk for osmotic damage?

Glucose--> Sorbital via aldose reductase.

 sorbitol --> Rructose using sorbitol dehydrogenase;

tissues with an insufficient amount of this enzyme are at risk for intracellular sorbitol accumulation, causing osmotic damage (e.g., cataracts, retinopathy, and peripheral neuropathy seen with chronic hyperglycemia in diabetes).

*Schwann cells, retina, and kidneys have only aldose reductase. Lens has primarily aldose reductase. 

 

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89

What is the difference between Primary and Secondary Lactose intolerance 

Insufficient lactase enzyme -->dietary lactose intolerance. Lactase functions on the brush border to digest lactose (in human and cow milk) into glucose and galactose.

Primary: age-dependent decline after childhood (absence of lactase-persistent allele), common in people of Asian, African, or Native American descent.

Secondary: loss of brush border due to gastroenteritis (e.g., rotavirus), autoimmune disease, etc. Congenital lactase deficiency: rare, due to defective gene.
Stool demonstratespH and breath showshydrogen content with lactose tolerance test. Intestinal biopsy reveals normal mucosa in patients with hereditary lactose intolerance.

90

How can you dx someone with lactase deficiency?

Stool demonstrates Decreased pH and breath shows Increased hydrogen content with lactose tolerance test. I

ntestinal biopsy reveals normal mucosa in patients with hereditary lactose intolerance. 

91

What AA are Essential and what does that mean?

Glucogenic: methionine (Met), valine (Val), histidine (His).

Glucogenic/ketogenic: isoleucine (Ile), phenylalanine (Phe), threonine (Thr), tryptophan (Trp).

Ketogenic: leucine (Leu), lysine (Lys). 

"Lucy & I Met Val For His Three Listed Trips" or PVT TIM HaLL

92

What are the Basic and Acidic Amino Acids?

Basic:  Arginine (Arg), lysine (Lys), histidine (His). Arg is most basic.
His has no charge at body pH. 

 

Acidic: Aspartic acid (Asp) and glutamic acid (Glu). Negatively charged at body pH. 

93

What is the purpose of the Urea cycle?

Amino acid catabolism results in the formation of common metabolites (e.g., pyruvate, acetyl- CoA), which serve as metabolic fuels. Excess nitrogen (NH3) generated by this process is converted to urea and excreted by the kidneys. 

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94

Patients with Hyperammonium obviously have too much NH4+, but why is this such a big deal?

What symptoms will we see?

How can we treat pts with Hyperammonium?

Can be acquired (e.g., liver disease) or hereditary (e.g., urea cycle enzyme deficiencies).

Results in excess NH4+, which depletes α-ketoglutarate, leading to inhibition of TCA cycle.

Symptoms: tremor (asterixis), slurring of speech, somnolence, vomiting, cerebral edema, blurring of vision 

Treatment: limit protein in diet. Lactulose to acidify the GI tract and trap NH4+
for excretion. Rifaximin to DECREASE colonic ammoniagenic bacteria. Benzoate or phenylbutyrate (both of which bind amino acid and lead to excretion) may be given to DECREASE ammonia levels 

95

Newborn with  poorly regulated respiration and body temperature, poor feeding, developmental delay, intellectual disability and High NH4+ levels in urine. What could be going on?

N-Acetlyglutamate defiency (or Carbomoyl phosphate synthetase I defiency) 

Required cofactor for carbamoyl phosphate synthetase I.

Absence of N-acetylglutamate -->hyperammonemia.

 

96

Newborn baby is showing signs of Hyperammonium

You draw labs and it shows the following:

High Orotic acid in blood and urine

LOW  BUN

DX?

Ornithine tranxcarbamulase deficiency

Most common urea cycle disorder. X-linked recessive

 Interferes with the body’s ability to eliminate ammonia. Often evident in the first few days of life, but may present later. Excess carbamoyl phosphate is converted to orotic acid (part of the pyrimidine synthesis pathway).

Findings: HIGH orotic acid in blood and urine, LOW BUN, symptoms of hyperammonemia. No megaloblastic anemia (vs. orotic aciduria). 

A image thumb
97

_____ may be located anywhere upstrea, downstream or within the transcribed gene. 

______ are located 25 bp upstream from associated genes

_____ are lcated 70 bp upstream from gene

Enhancers

TATA box

CAAT

98

Major AA  responsible for transfering Nitrogen to the liver for disposal

During catabolism fo proteins, AA groups are transferred to Alhpa-ketoglutarate to form glutamate; which is then processed in liver to make urea and is primary disposal form of nitrogen in humans. 

Q image thumb

Alanine

99

Has 5' to 3' exonuclease actvity in addition to 5' to 3' polymerase and 3' to 5' exonuclease activity. The 5' to 3' exonuclease activity is used to remove RNA primer (which initiates DNA polymerization) and to remove damaged DNA. 

DNA polymerase 1

100

What is the role of snRNPs

Key in splicing! They are make by RNA pol II and help remove introns from teh RNA transcript. Need them to make mRNA

101

What is the role of snRNPs

Key in splicing! They are make by RNA pol II and help remove introns from teh RNA transcript. Need them to make mRNA