chat transcript - Biochemistry (genetics and mol biology)

[Anonymous]

20:14:48 [calender] Properties of genetic code?

20:14:49 [ash] ok

20:14:54 crusher enters this room

20:15:06 [crusher] hi everybody

20:15:16 [Step_1] how many barr bodies are seen in turners syndrome?

20:15:20 [Step_1] hi crusher

20:15:25 [drsr] 3 bases

20:15:26 [hutals] hey crush

20:15:34 [crusher] none bar body

20:15:39 [drsr] triplets

20:15:40 [crusher] hi hutal

20:15:54 [crusher] XO,,turner

20:16:24 [ash] a rare but vital muscle protein that connects actin with membrane spanning sacroglycan and dystroglycan complex is?

20:16:25 [Step_1] thats right, no barr bodies in turners because xo and barr body is the extra x....so no extra x

20:16:36 [ash] none in turners

20:16:41 [calender] yes...drsr......universal,contiguous,unambiguous and degenerate

20:17:32 [ash] hi crusher

20:17:39 [drsr] ?i have not gotten to genetic code,mutations etc yet

20:17:48 [crusher] hello ash

20:18:04 [hutals] how many barr bodies in klinefelters, normal female, normal male (3 separate questions)?

20:18:11 [ash] a rare but vital muscle protein that connects actin with membrane spanning sacroglycan and dystroglycan complex is?

20:18:29 [crusher] klinfelter 2..normal female 1 n male none

20:18:34 [ash] hutals 1,1,none

20:19:06 [crusher] reason for bar body is to inavctivate the extra X,chromosome

20:19:19 Roxanita enters this room

20:19:33 [ash] hi roxanita

20:19:33 [crusher] hello roxi

20:19:39 [kmonica26] You have just examined a male newborn who presented with hypotonia and dysmorphic features that included small ears, epicanthal folds, upward slanting of the palpebral fissures, broad nasal root, flat facies, and a small mouth.

20:19:41 [Roxanita] Hi

20:19:53 [calender] one barr body..in kliefelters( bec. they r pheno. male)..

20:19:54 [hutals] normal femal has 1, normal male none and klinefelters has 1

20:19:58 [kmonica26] he medical complication that is MOST likely to present in the newborn period in this infant is

20:20:10 [hutals] hey rox

20:20:16 [Step_1] hi rox

20:20:23 [ash] kmonica downs

20:20:33 [Roxanita] Hello step1, Hutals

20:20:42 [crusher] yes feature of downs

20:20:49 [kmonica26] correct

20:20:50 [ash] duodenal atresia

20:20:54 [calender] Hi Rox.

20:21:00 [kmonica26] But read the second part of question

20:21:19 [kmonica26] yes ash

20:21:22 [kmonica26] correct

20:21:24 [Roxanita] calender> hi

20:21:39 [crusher] there could be ALL,,alzhemiers later and duodenal atresia

20:21:40 [Roxanita] sorry I am late what have you done so far?

20:22:03 [calender] just started Genetics

20:22:13 [ash] what kind of mutation is duschennes and what kind is beckers?

20:22:43 [Roxanita] did you guys checked the questions on the forum?

20:22:57 [calender] mutation in a gene that encode dystrophin

20:23:09 [ash] i saw some anat

20:23:17 [drsr] is it trinucleotide repeat expansion

20:23:35 [ash] yes calender but what kind like nonsence ,missence etc.

20:24:01 [calender] insertion or deletion

20:24:14 [crusher] i think dmd is deletion

20:24:15 [drsr] trinucleotide repeat expansion

20:24:19 [ash] ok.frame shift mutation is duchennes and in frame mutation is becker

20:24:29 [crusher] and becker is point mutiuon not sure

20:25:04 [calender] yes..rt frameshift.but in two thirds are bec of insertion or deletions

20:25:05 [hutals] Glucocerebroside accumulation in the brain, liver, spleen, and bone marrow are characteristic of?

20:25:08 [ash] who is an obligate carrier in genetics?

20:25:22 [Step_1] Gaucher

20:25:31 [crusher] gaucher dis

20:25:41 [drsr] deficiency of a particu;ar enzyme

20:25:45 [ash] hutals lysosomal storage disorders

20:25:51 [ash] gouchers

20:25:57 [crusher] def of glucocerbrosidase..huge spleenomegaly

20:26:13 [drsr] right

20:26:17 [ash] who is an obligate carrier in genetics

20:27:06 [hutals] yep, Gaucher's disease

20:27:10 [crusher] what does obligate carrier means

20:27:17 [drsr] 5s rna transcibed by?

20:27:36 [ash] rna polymerase 2

20:28:06 [drsr] 3

20:28:08 [calender] Cause of Cystic Fibrosis?

20:28:40 [ash] loss of phenyl alanine at position 508

20:29:05 [ash] giving rise to abn. chloride channels

20:29:06 [crusher] deletion of phenylalanine CF...at 508 position

20:29:21 [calender] right

20:29:23 [ash] that are destroyed by proteases

20:29:30 [crusher] leading to thick secretion

20:29:37 [ash] therefore thick secretions

20:29:39 [calender] yes

20:29:42 swatu enters this room

20:30:13 [ash] who is an obligate carrier in genetics

20:30:21 [Step_1] AR, caused by multiple loss of function mutations in a cholride channel for CF

20:30:26 [calender] name of the screening test for PKU in new born?

20:30:28 [ash] hi swatu

20:30:39 [swatu] hi

20:31:30 [drsr] what are the 3 steps in the processing of a eukayotic hnRNA to finally become mRNA

20:31:40 DRRS enters this room

20:31:57 [ash] hi drrs

20:32:01 [kmonica26] A male infant develops profound hypotonia 24 hours after birth. Results of laboratory studies include: normal complete blood cell count; negative urinary ketones; glucose, 15 mg/dL; and ammonia, 1,500 mcg/dL.What is the etiology?

20:32:09 [crusher] capping..polytail and removal of introns

20:32:16 [DRRS] Hi everyone

20:32:40 [hutals] hey drrs

20:32:50 [Step_1] hi DRRS

20:33:12 [drsr] DEFICIENCY OF WHICH ENZYME-MELANOMAS

20:33:34 [crusher] tyrosinase...melanoma

20:33:48 [calender] tyrosinase

20:34:12 [drsr] HOW ABOUT THE EXCISION ENDO NUCLEASE

20:34:34 [drsr] THYMINE DIMER

20:34:43 [ash] pku-guthrie inhibition test

20:34:55 [calender] right ash

20:35:01 [hutals] A patient presents with corneal clouding and mental retardation that is, based on family history, inherited in an Autsomal recessive pattern, you impress your intern with a Dx of?

20:35:09 [drsr] MONICA WHAT IS THE ANSWER FOR UR QUEST?

20:35:18 [crusher] oh yes....thymine dimer ...disease is xwerodema pigmentosa leading to melanoma

20:35:24 [kmonica26] Urea Cycle defect

20:35:24 [swatu] hurlers?

20:35:32 [calender] ty

20:35:41 [swatu] sorry hunters

20:35:42 [crusher] sorry tyrosinase def is for ALBIM+NISM

20:35:43 [ash] hunters or hurlers hutals

20:35:50 [calender] yes.Ammonia accumulation

20:35:56 [Step_1] sounds like Hurlers (aka the hunchback of nortre dame)

20:36:05 [crusher] HURLER

20:36:05 [kmonica26] urea cycle defect will reveal a blood ammonia level that rises rapidly and can exceed 2,000 mcg/dL. The hyperammonemia may be accompanied by respiratory alkalosis and hyperlactacidemia, but ketonuria does not occur.

20:36:15 [hutals] yep, Hurler's

20:36:50 [calender] thanks kmonica

20:37:15 [Step_1] swatu, can you pick a brighter color from the rainbow on right....hard to read the dark text?

20:37:16 [ash] lower prevalence of fragile x syndrome in females as compared to males is due to?

20:37:31 [swatu] ok

20:37:33 Newone enters this room

20:37:38 [swatu] is this better?

20:37:48 [swatu] blah too pink i think

20:37:49 [Step_1] hunters and hurlers is similar, but hunters is a milder disease

20:37:59 [ash] yes swatu

20:38:00 [Step_1] yes, much better....thanks

20:38:01 [Newone] hello all I am new here

20:38:03 [drsr] HOW DOES CIPROFLOXACIN ACT AGAINST GM -VE BACTERIA

20:38:07 [Step_1] hi new one

20:38:18 [ash] calender, so what happens

20:38:19 [swatu] there was a mneumonic from <a href=http://www.amazon.com/exec/obidos/ASIN/0071429484/qid%3D1085033910/sr%3D2-1/valuetheplace-20>First Aid</a> that i had forgotten

20:38:26 [calender] Hi newone

20:38:30 [drsr] HI

20:38:36 [ash] drsr inhibits topoisomerase 2

20:38:44 [swatu] hunters=x linked

20:38:45 [hutals] hey newone

20:38:49 [crusher] ciprofloxacin inhib dna topisomersase hence in hibit unwinding

20:38:52 [swatu] and hurlers=AR

20:38:55 [kmonica26] A 2-day-old female infant is refusing to feed and has become increasingly lethargic and hypotonic over the past 2 hours. Results of laboratory studies include an arterial blood gas analysis that reveals a pH of 7.13, PCO2 of 27 mm Hg, and HCO3 of 14 mEq; positive urine ketones; and an ammonia conce

20:39:02 [calender] so,females are at higher risk( twice) as compare to males?

20:39:08 [drsr] YAEH

20:39:13 [kmonica26] an ammonia concentration of 600 mcg/dL. An inborn error of metabolism is suspected.

20:39:33 [ash] calender the incidence is lower in females why?not higher

20:40:06 [drsr] CAN SOMEBODY EXPLAIN TELOMERASE

20:40:40 [calender] oh.sorry.i got the Q wrong..bec. to present with dis. both chr. should be affected.thats why inci. is lower in female

20:40:54 [Newone] so how does this work?

20:42:25 [Step_1] telomerase demo here http://faculty.plattsburgh.edu/donal...ures/Telo2.gif

20:42:29 [crusher] kmonica again looks like problem in urae cycle

20:42:49 [calender] Telomers protect the end of DNA mole. from being degraded by exonucleases and are needed to complete replication

20:42:49 [kmonica26] no.....look at the Ph this time

20:43:05 [kmonica26] and ketones

20:43:31 [ash] telomeres are only present in prokaryotes.they are repetative sequences at the end of linear dna molecule.they are shortened at 5' end after each round of replication.this contributes to aging of cells and eventually death.telomerase is the enzyme used to maintain telomeres.it is present in embryoi

20:44:01 [hutals] A patient presents with 1. Hyperextensible skin 2. Tendency to bleed 3. Hypermobile joints you astutely Dx them with?

20:44:02 [kmonica26] these are ..... organic acidemias

20:44:21 [kmonica26] ehlers danlos

20:44:40 [swatu] vitamin c deficiency?

20:44:44 [Step_1] ehlers danlos (sp?)

20:44:48 [swatu] ehlers danlos

20:45:00 [ash] calender the incidence is lower in females as one of the x chromosomes is a barr body which reduces their chances of being affected.

20:45:11 [hutals] yep, Ehlers-Danlos syndrome

20:45:19 [ash] hutals ed type 4

20:45:39 [Roxanita] [ash] telomeres are only present in prokaryotes?

20:45:54 [hutals] i just know ED, not sure about the type?

20:46:12 [drsr] STEP 1- IS THERE MORE EXPAINATORY LINKS LIKE THIS FOR GENTICS

20:46:17 [ash] roxanita can you please pick another color.i cant read

20:46:28 [ash]

20:46:33 [Roxanita] [ash] telomeres are only present in prokaryotes

20:46:39 [drsr] I THOUGHT TELOMERASE IS ONLY IN EUKARYOT

20:46:40 [swatu] arent the types associated with osteogenesis imperfecta and not the ehlers danlos?

20:46:46 [Roxanita] you said that

20:46:49 [ash] yes roxanita

20:47:01 [ash] they are absent in eukaryotes

20:47:37 [drsr] TELOMERES ARE FOUND AT THE ENDS OF LINEAR DNA

20:47:39 [Step_1] i believe there are a bunch on the step 1 forum, i would need to look them up because they are from months ago....but references are usually placed in the posts

20:47:47 [drsr] WHICH IS EUKARY

20:47:47 [ash] swatu .i dont remember the page numbers but i am sure you will find the types in harrisons

20:48:05 [Roxanita] but prokariots have circular DNA

20:48:31 [hutals] Absence of Galactosylceramide Beta-galactosidase leads to thebuild up of what compound in what disease?

20:48:34 [ash] oh sorry i meant they are only in eukaryotes and absent in prokaryotes i am sooooooo soooorrrrrrryyyyyyyy

20:48:48 [ash] thanx for pointing it out.

20:49:05 [Step_1] galactocerebroside in krab's disease

20:49:14 [swatu] galactose in galactocemia?

20:49:55 [Roxanita] for now just reading no problem ash

20:50:09 [ash]

20:50:14 [kmonica26] The mother of a 5-year-old previously healthy boy reports that he has been having frequent nose bleeds and bruises easily. On physical examination, marked splenomegaly and multiple lower extremity bruises are present.Dx

20:50:16 [ash] i am drunk

20:50:26 [hutals] the correct answer is accumulation of galactocerebroside in the brain; Krabbe's disease

20:50:55 [swatu] k

20:51:09 [ash] kmonica ,hemophilia?

20:51:11 [drsr] COLLAGEN DISORDER

20:51:27 [kmonica26] no

20:51:35 [ash] scurvy?

20:51:36 [kmonica26] Gauchers ds

20:51:37 [swatu] factor 8 def--von willebrands?

20:51:41 [kmonica26] Gaucher disease is an inherited disorder of lipid metabolism that results from the deficiency of a specific lysosomal hydrolase, acid beta-glucosidase. The disorder should be considered in the differential diagnosis of patients such as the boy described in the vignette who present with unexplained

20:52:24 [ash] wow thanx

20:52:56 [drsr] RETARDATION,SELF-MUTILATION,HYPERURICEMIA,GOUT,CHOREOATHETOSIS-dx

20:53:07 [swatu] lesch nehan

20:53:13 [swatu] cant spell it?

20:53:23 [drsr] Y

20:53:48 [ash] agree with swatu

20:53:50 [Step_1] lesch nyhan

20:54:01 [hutals] agree

20:54:17 [calender] On Southern Blot test.DNA pieces are getting bigger in next generations..Dx?

20:54:41 [calender] What is this pattern called?

20:55:04 [ash] calender anticipation

20:55:29 [calender] right...trinucleotide repeat expansion

20:55:39 [calender] Anticipation

20:55:43 [kmonica26] A 7-month-old boy has been healthy and developing normally since birth. His mother reports that for the past 2 to 3 weeks he has had decreased eye contact with her, even during breastfeedings. The infant also now startles easily at any loud noise.Dx

20:56:01 [ash] what is the difference between dna ligase in prokaryotes and eukaryotes?

20:56:05 [calender] Dis example for Anticipation?

20:56:21 [hutals] sounds normal??

20:56:27 [ash] hungtingtons

20:56:41 [crusher] leads to fragile x..myotonic dystrophy hungtinton

20:56:46 [ash] fragile x syndrome,myotonic dystrophy

20:56:56 [calender] Fragile X Syndrome,Myotonic Dystrophy

20:56:58 [ash] spinobulbar dystrophy

20:57:02 [calender] right

20:57:07 [kmonica26] Tay-Sachs disease

20:57:33 [kmonica26] Following a 6 to 9 month period of normal development, affected patients develop hypotonia, apathy, and delayed psychomotor development. They also display an exaggerated startle response, which frequently prompts parents to seek medical attention, as occurred in the vignette.

20:58:14 [swatu] huntingtons disease

20:58:24 [swatu] as an example of anticipation i meant

20:58:49 [ash] what is the difference between dna ligase in prokaryotes and eukaryotes?

20:59:09 [Step_1] patient has mental retardation, hepatospenomegaly, cherry red spot....most likely dx?

20:59:24 [ash] tay sachs

20:59:30 [swatu] tay sachs

20:59:33 [crusher] tah sacs

20:59:52 [calender] Hardy-Weinberg principle specify what ?

21:01:03 [drsr] P2+PQ=Q2=1

21:01:12 [calender] Why we use it mainly for AR ...and not for AD disorders?

21:01:55 [swatu] to determine the frequency or likelihood of occurance?

21:02:11 [drsr] ATTENUATION INVOLVES REGULATION OF WHICH PROCESS

21:02:35 [Step_1] this was a trick question that the boards will ask because they know you will get stuck on the buzz word "cherry red spots". if you have this without hepatosplenomegaly, its tay sachs....but with hepatospenomegaly its niemann pick

21:03:12 [calender] It specify a predictable relationship between gene and genotype frequencies in populations.

21:03:27 [ash] 28 yrs female gave birth to 1850 gm ,infant after a difficult preg.+oligohydramnios.infant is placed in neonatal icu and tissue from umbilical cord is sent to cytologic evaluation.karyotype xy.no apparent abnormalities.no biochemical abn.iugr is caused by?1)chromosomal deletion.2)placental mosaicis

21:03:29 [calender]>[Step_1] This is a good one..ty

21:03:57 [ash] mosaicism.3)triple nucleotide repeats

21:04:08 [ash] 4)fetal trisomy

21:04:21 [ash] 5)genomic imprinting

21:05:14 [crusher] 2.placental mosiasm

21:05:56 [calender] fetal trisomy

21:06:12 [hutals] in G6PD deficiency the decrease in NADPH can lead to _____ if exposed to _____?

21:06:14 [calender] sorry.

21:06:43 [ash] hutals hemolysis stress

21:06:50 BlakeH enters this room

21:06:53 [calender] it is placental mosaicis

21:06:59 [kmonica26] hemolysis exposed to ceratin drugs, stress

21:07:05 [Step_1] hemolytic anemia. sulfa drugs, fava beens

21:07:06 zoya enters this room

21:07:10 [ash] right crusher and calender

21:07:23 [BlakeH] Hello

21:07:23 [ash] hi blake and zoya

21:07:23 [calender] hemolysis and ..stress

21:07:35 [hutals] hemolytic anemia;oxidizing agents( fava beans, sulfonamides, primaquine) and antituberculosis.

21:07:43 [zoya] hi

21:07:55 [hutals] hey blake and zoya

21:08:12 [Step_1] hi zoya, hi blakeH

21:08:15 [BlakeH] any specific biochem topic???

21:08:32 [crusher] wwgenetic .....>blake

21:08:37 [kmonica26] he mother of a 3-month-old infant reports that the boy is demanding frequent feedings and has a noticeably protuberant abdomen. Physical examination reveals doll-like facies and marked hepatomegaly. Laboratory findings include a serum glucose level of 20 mg/dL and an elevated venous lactate level o

21:08:44 [Step_1] just finishing up genetics

21:09:01 [BlakeH] ok

21:09:06 [kmonica26] DX?

21:09:56 [crusher] def og g 6 phosphaste

21:10:04 [ash] in a population of jews the freq. of heterozygotes for tay sachs was 0.1.what is the probability that the first child of 2 individuals from this population with no family h/o the disease will have tay sachs?

21:10:16 [hutals] von gierkes??

21:10:18 [kmonica26] lycogen storage disease (GSD) Type I (von Gierke disease), which is characterized by hypoglycemia in early infancy, a protuberant abdomen due to hepatomegaly, and the distinctive appearance of so-called doll's facies or cherubic face. The disorder results from a deficiency of hepatic glucose-6-phos

21:10:26 [ash] galactosemia

21:10:29 [kmonica26] yes crusher

21:10:37 [kmonica26] right

21:11:03 [ash] in a population of jews the freq. of heterozygotes for tay sachs was 0.1.what is the probability that the first child of 2 individuals from this population with no family h/o the disease will have tay sachs?

21:11:18 [BlakeH] large ears, large testes, hypermobile joints????

21:11:40 [ash] blake fragile x syndrome

21:11:54 [BlakeH] sequence????

21:12:11 [ash] cgg

21:12:19 [crusher] tay sa is AR dis,,so being chaces of dises is 25% or .25

21:12:21 [hutals] fragile x

21:12:27 [BlakeH] right

21:12:45 [calender] step_1 pl. explain your Q.

21:12:51 [crusher] the frequency rate given is .01

21:12:53 [ash] crusher that is a part of the answer.you are thinking on the right lines

21:13:05 [calender] I think it should be half of .1

21:13:30 [crusher] yes i,m calculating ash

21:13:35 [Step_1] calendar, which question?

21:13:39 [ash]

21:14:09 [calender] probability of tay-sachs

21:14:15 [crusher] .1X .25=.025 ash not sure though

21:14:17 [calender] in next generation?

21:14:40 [BlakeH] Plasmodium falciparum doesnt survive well on Africans Erythrocytes of sickle cell pts,,,What factor is responsible for this explanation?????

21:15:29 [Step_1] i don't think i had a question about probability of tay sach calendar....are you sure it was my question?

21:16:06 [calender] oh sorry step_1 ..it was ash's Q.

21:16:15 [ash] very close crusher.remember that there are 2 parents.so the probability that each is a heterozygote is 0.1 and since tay sachs is ar 0.25.therefore the probability that the child will have it is 0.1*0.1*0.25=0.0025

21:16:32 [calender] ty ash

21:16:34 [ash] but a good try i am impressed

21:16:43 [Step_1] no prob.....i was thinking my memory had failed

21:16:52 [calender]

21:17:44 [ash] blake 1in 50 is a heterozygote and therefore the chances of rbc survival after 80 days is less which is needed for p.falciparum growth

21:17:45 [BlakeH] Its called Natural selection, responsible for some gnes variations

21:17:51 [crusher] thanks ash for explan

21:18:06 [BlakeH] my bad for not makin clear the Q

21:18:22 [ash] crusher i am impressed by your efforts

21:18:29 [crusher] thanks

21:19:32 [hutals] In PKU, what amino acid becomes essential?

21:19:41 [calender] What is isochromosome?

21:20:03 [Step_1] tyrosine because can't be made from phenylalanine

21:20:13 [crusher] tyrosine is essential cos it dec and phenyalanine inc

21:20:36 [BlakeH] division of a chromosome along the axis perpendicular to its normal axis of division

21:20:59 [calender] rt Blake

21:21:13 [ash] in a certain population the freq. of color blindness is .01 in malesassuming that the population is in hardy weinbergs equilibrium at this locus the freq. of color blindness in women is?

21:21:25 [hutals] yep, tyrosine

21:21:51 [crusher] .01 X .01=.001 as.

21:22:08 [crusher] as color blindness is X linked

21:22:11 [hutals] 0.01 also??

21:22:12 [BlakeH] Happy Puppet Syndrome????

21:22:28 [hutals] oops, xlinked

21:22:36 [crusher] so for female to be dis both X shold be effected

21:22:40 [ash] right crusher 0.01*0.01=0.0001

21:22:57 [ash] blake angelman

21:23:09 [BlakeH] cause???

21:23:42 [crusher] deletion of mother on chromosome 15

21:23:46 [ash] genomic imprinting deletion of maternal chr.15 tip

21:23:55 [BlakeH] Rt

21:24:04 [Step_1] micro deletion of maternal origin for angelman

21:24:14 [calender] Use of Northern Blotting?

21:24:21 [Step_1] "mom is an angel"

21:24:30 [ash] rna

21:24:39 [crusher] papa==prader willi=obese

21:24:41 [BlakeH] P for Paternal

21:24:51 [Step_1] P-rader willi is P-aternal

21:25:24 [Step_1] RNA

21:25:34 [BlakeH] Leber hereditary optic neuropathy????

21:25:54 [BlakeH] Type of inheritance???

21:26:07 [ash] mitochondrial

21:26:08 [crusher] no-R-thern blotting for R-NA

21:26:13 [calender] yes.to detect which cell type express mRNA from a particular gene.

21:26:33 [Step_1] btw, a real question had prader willi and describe obese hypogonadism and mental retardation

21:26:49 [crusher] mitochondrial mother gives dis to all her chidren cos mitochondria gene is tramsmitted by mom only

21:26:59 [ash] concordance rate for monozygotes is 0.5 and for dizygotes is 0.2.what is the heretibility?

21:27:15 [Step_1] agree mitochondrial

21:27:25 [BlakeH] right

21:27:36 [BlakeH] why only mothers???

21:27:55 [BlakeH] what happen to fathers mitichondria???

21:28:17 [ash] as the mitochondria of sperm are in its tail which dont take part in fertilization

21:28:30 [Step_1] sperm lose their mitochondria during fertilization so affected males do not transmit

21:28:41 [BlakeH] right

21:28:43 [ash] concordance rate for monozygotes is 0.5 and for dizygotes is 0.2.what is the heretibility?

21:28:57 [crusher] i think cannot cross zona placidum

21:29:51 [hutals] Sickle cell anemia is caused by what defect and what is it's prevalence?

21:30:12 [drsr] PT MUTATION

21:30:20 [BlakeH] missense mutation

21:30:27 [BlakeH] point

21:30:30 [crusher] point mutation 1.400?

21:30:55 [Step_1] missense mutation, 1:400 african americans

21:30:58 [calender] high in African American

21:31:01 [ash] valine for glutamate at b6 position

21:31:28 [BlakeH] cafe au lait + acoustic neuromas???

21:31:30 [Step_1] actually, i think its point mutation

21:32:02 [swatu] neuroblastoma

21:32:06 [ash] and that point mutation is missence mutation step_1

21:32:21 [hutals] AR single missense mutation in the beta globin; 1:400 blacks

21:32:27 [ash] blake chromosome 22

21:32:43 [calender] Down Syndrome pt. presents with 46 chromosomes...How is it possible?

21:32:54 [ash] neurofibromatosis2

21:32:55 [BlakeH] name of disease??

21:32:59 [BlakeH] yep

21:33:06 [crusher] sh] concordance rate for monozygotes is 0.5 and for dizygotes is 0.2.what is the heretibility..whats ans >>>>>Ash

21:33:10 [Step_1] good point (aks missense) ash ....don't listen to my missense

21:33:12 [BlakeH] type of inheritance??

21:33:21 [ash] calender it is a robertsonian translocation

21:33:27 [crusher] neurofibrantosis 2

21:33:32 [swatu] robersonianism

21:33:33 [calender] rt. ash

21:33:45 [ash] blake ad

21:34:00 [BlakeH] rt

21:34:00 [kmonica26] thalASSEAMIA

21:34:12 [hutals] Skin sensitivity to UV light secondary to a DNA repair defect is characteristic of what?

21:34:25 [crusher] 5% of down are cos of robertsonian translocation

21:34:32 [swatu] XPigmentosum

21:34:34 [Step_1] xeroderma pigmentosum

21:34:56 [crusher] xeroderma pig..defective endonucleases

21:35:13 [calender] What is RFLP?

21:35:16 [hutals] yep, xeroderma pigmentosim

21:35:45 [Step_1] Restriction Fragment Length Polymorphism

21:35:48 [crusher] RFLp is used to dect the caiuseitive gene ,,it break the DNA at specific gene

21:36:05 [ash] crusher it is a formula concordance for monozygotic=cmz and for dizygotics is cdz.the formula is cmz-cdz/1-cdz.=0.5-0.2/1-0.2=0.375

21:36:26 [Step_1] organisms may be differentiated by analysis of patterns derived from cleavage of their DNA

21:36:50 [hutals] Sphingosine + fatty acid yields?

21:37:03 [Step_1] ceramide

21:37:26 [crusher] agree with step1

21:37:27 [ash] can we discuss molecular biology now it is already 9.30

21:37:39 [hutals] yep, ceramide

21:37:58 [Step_1] i agree, i was leaving it to Rox.....where is Rox?

21:39:03 [BlakeH] gotta go people , cya on friday

21:39:21 [ash] bye blake

21:39:24 [Step_1] maybe she got disconnected....in that case, lets move onto mol bio

21:39:34 [Step_1] bye blake, thanks for chat

21:39:36 [drsr] OK

21:39:45 [BlakeH] no pro

21:39:46 [hutals] later blake, cya fri

21:39:49 [crusher] bye blake

21:39:59 [calender] I have to go now..today feel sleepy...good night everybody

21:40:13 [drsr] BYE

21:40:31 [ash] bye calender

21:40:39 [hutals] nite calendar, bya fri

21:40:49 [Step_1] bye calendar

21:40:57 [hutals] At which end of the tRNA is the aa bound?

21:41:02 [crusher] bye calender

21:41:08 [ash] 3'

21:41:14 [crusher] 3 oh end

21:41:17 [Step_1] 3' end

21:41:19 [drsr] RT

21:41:31 [crusher] ACC=accepter arm

21:41:31 [hutals] yep, The amino acid is covalently bound to the 3' end of the tRNA.

21:41:46 [hutals] Can RNA polymerase initiate chains?

21:41:58 [Step_1] yes

21:42:06 [ash] various uses of variable number of tandem repeats

21:42:08 [swatu] yes

21:42:23 [hutals] yes they can

21:42:32 [ash] yes hutals

21:42:45 [drsr] TRNA MADE BY RNA POLYMERASE______

21:43:05 [ash] various uses of variable number of tandem repeats are?

21:43:13 [ash] 3

21:43:27 [hutals] t by 3

21:43:28 [drsr] ANTICIPATION

21:43:49 [ash] no

21:44:07 [hutals] mneumonic is 1,2,3= RMT (rhymes)

21:44:11 [drsr] WHEWRE THE SEVERITY OF THE DISESASE INCREASES

21:44:50 [hutals] are you referring to the wobble thing?

21:45:19 [ash] variable number of tandem repeats are used in dna fingerprinting

21:45:42 [hutals] oops, i was way off

21:45:46 [ash] and forensic medicine

21:46:09 [ash] thats ok hutals happens to everyone

21:46:45 [hutals] But now that i looked it up .... Define tRNA wobble.

21:47:26 [ash] a high linkage will give what score by logarythm of odds?

21:47:41 [drsr] 3' END & 5' END OF THE CODON ON MRNA ARE LOSLY BOUND

21:47:52 [crusher] tRNA wobble need 12 postion to correctly transcribe position 3 not necessory called wobble

21:48:01 [zoya] to establish paternity,zygosity or identity from blood or other sample

21:48:31 [crusher] 3 ash

21:48:40 [Step_1] third position of codon on mRNA and first position of 5' of anticodon of tRNA are bound less tightly than the other pair and, therefore, offer unusual base combos

21:49:14 [drsr] THAT IS CORRECRT

21:49:16 [hutals] Accurate base pairing is required only in the first 2 nucleotide positions of an mRNA codon, so codons differing in the 3rd 'wobble' position may code for the same tRNA/amino acid.

21:49:17 [ash] right zoya and good crusher

21:50:14 [hutals] Euchromatin vs Heterochromatin?

21:50:22 [crusher] it is called LOD score

21:50:53 [Step_1] Euchromatin is less condensed and transcriptionally active

21:50:57 [ash] euchromatin less tightly packed and active

21:50:57 [drsr] DENSELY CONDENSED DNA -HETEROCHROM

21:51:03 [crusher] hetero ...tigthy pack with H1 while euchtrom=loose without H1

21:51:16 [ash] heterochromatin tightly packed and inactive

21:51:30 [Step_1] yep, thats right

21:51:49 [ash] the codon is redundant means?

21:52:02 [drsr] WHERE DO THE DNA BINDING PROTIENS BIND?

21:53:06 [drsr] ?HYBRIDIZATION?

21:53:16 [Step_1] the same amino acid can be specified by more than one codon.

21:54:08 [hutals] agree

21:54:12 [ash] i have to go guys.my husband is waiting for dinner.goodnite it was a good discussion.thanx for your inputs

21:54:34 [hutals] nite ash, see you fri

21:54:47 [Step_1] thanks for chat ash, good night

21:54:56 [ash] byeall

21:55:17 [crusher] thanks ash for nic e q and ur participation

21:55:21 [crusher] goodnite

21:55:53 [hutals] Describe key structural differences between nucleotides.

21:57:03 [crusher] purine =double ring pyrimidine single ring

21:57:41 [hutals] 1) Purines have 2 rings. 2) Pyrimidines have 1 ring 3) Guanine has a ketone. 4) Thymine has a methyl

21:58:01 [Step_1] name the purines and name the pyrimidines

21:58:29 [hutals] Purines (A,G) Pyrimidines (C,T,U)

21:58:43 [crusher] purine=adenine and guanine...pyrimidine=cytosine..uracil and thymidine

22:00:06 [Step_1] mneumonic is "CUT the PY (pie)" or CUT for PYrimidine. and "PURe AS gold" for A and S being PURines

22:00:14 [crusher] ok guys i gotta leave too

22:00:45 [Step_1] ok, maybe we should call it quits early tonight since many have gone?

22:01:03 [crusher] thanks for the chat..every one..

22:01:15 [hutals] sounds good to me, we had a good 2 hrs of biochem which is more than enuf for me

22:01:18 [zoya] bye

22:01:26 [Step_1] thanks crush, good night

22:01:32 crusher exits from this room

22:01:50 [hutals] ok, nite everyone, cya all fri

22:02:08 [Step_1] by, thanks for chatting

[Ito]

hey ppl
jsut wanted to join your chat sessions
I keep missing it...
I'm on Canadian time -5GMT
what time zone are u guys going on?