Nucleotides

Question 1

Nucleotides

• what are they
• Purines
• Pyrimidines
• binding

Answer 1

• building block of nucleic acids
• adenine and guanine
• cytocine, thymine, uracil
• adenine to thymine with double bond, cytosine to guanine with triple bond

Question 2

Chromatin

• Hetero
• Eu

Answer 2

• tight, resting phase

- loose, cell division

Question 3

Tests for detection

• Southern Blot
• Northern Blot
• Western Blot
• Elisa
• PCR

Answer 3

• DNA
• RNA
• Protein
• antibodies
  amplifies small amount of DNA or RNA

Question 4

• Lesch nyhan
• adenosine deaminase def
• xanthing oxidase def
• hereditary orotic aciduros

Answer 4

NEED TO KNOW

Question 5

Purine Synthesis DeNovo

• pathway
• IMP goes into
• finished products

Answer 5

• R5P + PRPP synthetase -> PRPP + pyrophosphate aminotransferase -> 5 phosphoribosykamine -»» IMP
• IMP + adenylosuccinate synthase-> adenylosuccinate + adenylosuccinate lyase-> AMP and IMP+ IMP dehydrolase -> XMP + XMP glutamine amidotransferase -> GMP
• ATP and GTP

Question 6

Lesch Nyhan Syndrome

• genetics
• what is it, why
• normal pathway
• sxs

Answer 6

• x linked
• accumulation of Uric Acid bc of HGPRT doesn’t work
• Cannot recycle Hypoxanthine and guanine into IMP and GMP
• crystals in diaper, poor muscle tone, irritability and self mutilating behavior

Question 7

Gout

• what is it
• mutation
• findings
• acute management
• chronic management

Answer 7

• hyperurecemia causing crystal formation in joints
• activating mutation of PRPP causing increase de novo production which will increase the amount that will be broken down
• needle shaped negatively birefringent crystals
• NSAID and colcichine os indomethacin w/ pts who have renal problem
• allopurinol

Question 8

SCID

• what is it
• caused by
• prognosis
• tx

Answer 8

• severe combined immune deficiency
• adenosine deaminase is missing -> dATP levels rise -> shuts down RNR -> shut down DNA synthesis -> shuts down rapidly dividing cells in body
• 2 yrs old, death from infection
• bone marrow transplant

Question 9

Xanthine Oxidsae Def

• what happens, how
• sxs
• tx

Answer 9

• xanthine accumulation, because guanosine and xanthosine can still be broken down into xanthine but unable to break down into uric acid w/o XO
• stone formation and kidney failure
• lots of fluids to prevent stone formation and avoid foods high in

Question 10

Xeroderma Pimentosum

• what is it
• genetics
• epi
• sxs
• sequlae
• prognosis

Answer 10

• inability to repair damage caused by UV light
• AR
• children
• photo sensitivity, hyper pigmentation, pokyloderma (hyper or hypo pigmentation, thin skin, telangectasia)
• prone to develop skin CA
• will die from squamous cell CA or melanoma by 20 yrs old)

Question 11

Orotic Aciduria

• what is it
• mutation
• sxs
• tx

Answer 11

• excessive excretion of orotic acid bc of UMP synthetase
• AR
• white crystals in diaper, megaloblastic anemia, and inhibits RNA/DNA synthesis
• supplement CMP and UMP to provide neg feedback and decrease orotic acid present

Question 12

Pyrimidine 5 nucleotide deficiency

• mutation
• what is it
• causes

Answer 12

• AR disorder
• needed for pyrimidine metabolism to turn nucleotide into nucleoside but not working so have build up of pyrimidines
• hemolytic anemia

Question 13

Damage to DNA Excision enzymes

• Thymine dimers
• Cytosine Dimers
• Apurination or aprimidation
• mimastched

Answer 13

• excision
• AP endonuc
• AP endonuc
• mismatch repair

Question 14

Histones
- purpose
-

Answer 14

• package DNA

Question 15

DNA helices

• A
• B
• Z

Answer 15

• right handed w/ 10 bp to turn
• right handed w/ 11 bp to turn
• left handed w/ 12 bp to turn

Question 16

Cell cycle

• G1
• S
• G2
• M

Answer 16

• Makes proteins need for replication
• DNA synthesis
• make protein for mitosis
• mitosis

Question 17

Mitosis

• Prophase
• Early Prophase
• Late Prophase
• Metaphase
• Anaphase
• Telophase

Answer 17

• prelude to mitosis
• chromosomes clump and nuc membrane dissolves
• chromosomes pair up
• chromosomes line up along middle
• chromosomes get pulled apart
• chromosomes are separated

Question 18

Therapeutic Radiation

• what does it do
• cells affected

Answer 18

• causes DNA double stand breaks so that replication cannot occur
• rapidly dividing cells, malignant

Question 19

DNA replication

• read in
• produced in
• semi conservative
• origin

Answer 19

• 3 to 5 direction
• 5 to 3 direction
• always parent and daughter strand
• multiple sites

Question 20

PCR steps

• 1
• 2
• 3

Answer 20

• denature, separate w/ heat
• primer binds w/ cooling
• elongation, will make copies

Question 21

DNA replication

• 1
• 2
• 3
• 4

Answer 21

• helicase unwinds
• single strand binding stabilizes unwound
• primase lays 8-10 on leading strand, DNA poly 3 replicates and on lagging strand will make shorter stands with more primers that DNA poly 1 will remove
• DNA ligase connects Okazaki fragements on lagging strand

Question 22

Topoisomerase 1 and 2

• function
• chemo drug
• antibiotic

Answer 22

responsible for removing supercoils and relaxing DNA

• etoposide
• fluoroquinolones

Question 23

Telomerase

- function

Answer 23

• elongates parental strand telomere so that DNA does not get cut off

Question 24

Promoter

• Core promoter
• HOX genes
• Homeotic genes

Answer 24

• in front of where gene will be transcribed
• transcription start site
• DNA sequence that codes for transcription factors that are needed for morphogenesis -> layout of body
• development of anatomical structures

Question 25

Types RNA - mRNA - rRNA - tRNA

Answer 25

- carries coded DNA message into cytoplasm to be made into protein - produce ribosome which is the structure that synthesizes protein - transfer RNA, bring in AA when building proteins

Question 26

Ribosomes - prokaryotic - eukaryotic - made in

Answer 26

- 70 -> 50 + 30 - 80 -> 60 + 40 - nucleolus

Question 27

Transcription Promoters - CAAT box - TATA box

Answer 27

- binding spot for transcription factors | - core promoter, anfor prokaryotesd is general binding site for gene transcription

Question 28

Transcription - Pre initiation - Promoter clearance - Elongation - Termination - modification

Answer 28

- TFIID binds TATA box via TBP and 5 more transcription factors and RNA poly combine around TATA box forming pre-initiation complex - RNA poly binds first base on DNA and clears promoter - RNA poly moves down DNA in and copies it - termination sequence that marks end of transcription - transcribed mRNA must be modified to move out of nucleus

Question 29

TRanscription Reg - rate controlled by - enhancer genes - repressor genes

Answer 29

- activators and repressors - increase transcription, located anywhere on same chromosome as gene they are enhancing - stop transcription and jump from chromosome to chromosome

Question 30

Modification of mRNA - splicing - cap - tail

Answer 30

- introns get removed w/ snRNPs and stay IN nucleus while exons will exit - 5 methyl gunosine cap, protecrs mRNA from ribonucleases and serves as ribosome binding site - poly a tail at 3' end to prevent genes from degrading and guide RNA to 30s ribosome

Question 31

Translation - what is it - needs - start codon - stop codon - enzyme to attach AA - initiation - elongation - termination

Answer 31

- creation of protein from mRNA - tRNA - AUG (methionine) - UGA, UAA, UAG - peptidyl transferase - small ribosomal unit attaches to cap of mRNA and moves to start codon, tRNA with meth binds, large ribosomal subunit binds, the second tRNA with next AA enters the A site, binding of meth to AA in A spot, ribosome move mover one codon - continue running down the mRNA to attach more and more AA to make protein - stop codon encountered and release factor enters A site causing ribosome to dissociate

Question 32

Mutation - frameshift - point - silent - missense - nonsense

Answer 32

- added or removing one base and causing entire reading frame to be moved - same amount of bases but changed from one base to different base - does not change AA - different AA - codes for stop codon and makes truncated protein that is not function