Bcmbintr 310 November 5, 2008

8/14/2019 Bcmbintr 310 November 5, 2008

1/4

'1 r " ~ ' / 'BCMBINTR 310 r-tf:7 , ~ November 5, 2008 Exam 3 - Version A (75 points)Show Your Work

1. Consider the following reaction:Fructose-6-phosphate + ATP -> Fructose-l ,6-bisphosphate + ADP ~ G O I = - 14,2 kllmol

Write the two half reactions and their ~ G O I ,

(3 pts) h " " ~ " '.i

(3 pts) A'r" . -t Hl 6GOI = ,.," ,'::, kllmol(2 pts) The enzyme that catalyzes this reaction is called (no abbreviation):

:1I ;.J I ~ " ' : \ ' \ '. . . . . . . . :. ' ~ f ' \ l ~ . .. ~ : ~ - - : j"

(2 pts) Name one allosteric effector that controls the rater,of this reaction.IIl . t':"""-'" -:,;/

(2 pts) How will a high concentration of this effector affect the rate of this reaction?,.- , .) '\'-' 'v', i ' :' 1'\ ' .J!: h- t ~ . ",(.C" i '. ' r _ \ --yJ- .'

'. t '_ 1,": . ~ ; .-'.. ,

1 ' . '. ""'j-.'... ' '. ,.:'.' j;'"\,I' , 4' " { tt"i. to'" __l\> l ,:. , . j . ~ \ " v ' .. ', ~ ~ - . . 2. (4 pts) Consider the following reaction: CH3-CO-COO' + NADH + H+ -7 CH3-CHOH-COO'+ NAD+ ." .: ..

Pyruvate Lactate Lv.1,1/, " ' ~ . - - ' ~ 'l': " '. -T!.(: '."N.'" '.;,", .--.,;. r '.[, '\.... ' \.J: , ~ . L 1 ~ I t : ~ c , \ . : , ~ \\. ..\ ~ x . : .. ~ .': ..,;{'.. .,i1) Which molecule is the oxidizing agent? -- 1l!-'-,,-\I......,Y,,-',-,,-,-,'.. _ " , : : : ~ . _ ~ J . , ~ , ~ I , . ; \ u,.,:..-.. - t ' " , : : . ~ , -

(2) Which molecule becomes oxidized?---'--'----

3. (4 pts) Draw the Haworth projection ofthe following d i s a c c h ~ r i d e : g l u c o s e - ~ - l ,4-g1ucose. \ l . ~ i) ~ . ~ . " . . ' 1.\ "'-!' r

(1 pt) What is the name of this disaccharide? l . \ ~ , ,; ' ,- '" , ~ ) "/ ' ~ = : ' ~ , ( ~ ' . \ i " ', , j & -t' ) . ~ : . r 4 r ' ~ \ ~ I l ~ " ~ ' ~ ' ~ ~ " _ " ' ~ - < ' cp __ . . ' \ / '" 1-/,. " : , r ~ / ,\ . .,', ). - .... . ' ~ . ''''1 '.' .,", .:;>:.1


2/4

4. (3 pts) Define the anomeric carbon. Does sucrose have free anomeric carbon atoms?-:, , ' ~ : " . ~ ~ " ' ~ ._. ....,."

< ., cu,

./Il ... " .....,--"'_.. ,' -..I ) ~ : . ' ,,'. ':1"(" + - - - - I ~ .: ) , i ~ ; . ;.5. (2 pts) The six-membered ring 6 f ' ~ u g a r s shown with cyclic formulas is called:.;::'/ /

6. (4 pts) How many polymeric forms exist for starch? What are these called? How do these differ from, / ' ... -,---.7:5 ( ,one another? . '

, ~ \.. ''', :.:',','

7. (4 pts) Draw the Fisher projection ofL-Glucose. Does this molecule have any enantiomers? If yes,;'. . ". . ,,,.,. ; .what do we call It? l. .

..: .:.. L" .'

. -.

i j L , ,:... _., ... I)'

", f'''- ' ..":_'

8. (3 pts) Name three coenzymes used in biologically important reactions.~ , ' \ " - tI ~ " \ \..J i

9. (2 pts) In metabolic pathways, what does 'activation' mean?'.' I ,.

2


3/4

10. The following monosaccharideOH01H ---c H

~ c =====0__f__3 C I ~...:.. _. / ~ vl ...H --'..;;c ---HI r_.'J; ' OH < ~ J u - ~ ~ ) ' ~ I ' . ' .::// .....'" . " .(l) (2 pts) has 19 carbon atoms, is classified as a fanda \..... ' / ( ~ . i , \. ! 'I.- j!(2) (2 pts) is the (D or L?) \:J ",j isomer.

"I " . , ~ . > .._':" C J . J - \ \ . } ( ~ ' l - , ~ ..._ ("0- -ivl'1

,// '\ - ; ~ . ~

. /'o' .. .(3) (2 pts) Number the carbon atoms, and label the chiral c e n t e r ( s ) . . ' ~ ; : ) .,.,' " " > ii., ' , ' ," ; '1"1J4) (1 pt) A cyclic hemiacetal is formed as a result of interaction between the functional groups'\ 'l

.\ /. "onC# - + = ! a n d C # ~ . /1

Explain why:

t', ". '.. \ .\-.:,p .

/11. (2 pts) A transcription factor isa. a subunit of RNA polymerase II that does not have a prokaryotic analogue. 7-b. the part of the promoter sequence closes t to the start of transcription./ ' a protein other than RNA polymerase that is involved in transcription.d. a sequence that determines whether an upstream element will be an enhancer or silencer.

. / 12. (2 pts) The following are all structural motifs for proteins that bind to DNA except:a. Helix-turn-helix ) f p- barrel c. Zinc finger d. Leucine zipper

/13. (2 pts) How many codons are possible in a system in which a sequence of three bases specifies asingle amino acid? a. 20 b. 24 c. 27 /64

-/14. (2 pts) In protein synthesis formation of new peptide bonds is catalyzed bya. elongation factor EF-Tu b. elongation factor EF-Tsc. elongation factor EF-G ,If. peptidyl transferase

',15. (2 pts) Which of the following is necessary for chain termination in protein synthesis?a. termination codons ofmRNA b. release factors c. GTP I- all ofthe above

./16. (2 pts) Which of the following terms describes an enzyme that transfers a phosphate group from ATPto a substrate?

/k inase b. isomerase c. mutase d. dehydrogenase3


4/4

\\?17. (2 pts) In bacteria, translation of the mRNA begins

/ . during the synthesis ofthe mRNA. b. after synthesis of the mRNA has been completed.c. after 5' capping ofthe mRNA.d. after all processing steps (capping, polyadenylation, and removal of introns) have taken place.

',18. (2 pts) Protein synthesis in prokaryotes always starts witha. a methionine residue /. a formylmethionine residue c. a cysteine residue d. no specific residue

. '19. (2 pts) During elongation, the charged tRNA-aa binds to the 'i . ~ ;f.. "A". ~ i t : , , ~ n the ribosome. b. " P " ~ ~ t ~ , ? ? the ribosome. c. "E" site on the ribosome.().J,'4< . j ."< ' ~ . . . \ J"" ' I - : l

./20. (2 pts) The final form o ( ~ ~ b . i n _ e u ~ a r y o t ~ s has all these features, except:a. There will be a special nucleotide cap on the 5' end of the mRNA.b. There is usually a poly A tail on the 3' end of the mRNA. / - The mature, active mRNA contains introns.d. Only a single protein is made from any mature mRNA molecule. e. All of these are true.

../21. (2 pts) The protein which marks proteins for degradation is called:a. Chaperonin j. Ubiquitin c. Proteasomin d. Apoptosin e. None of these

,,22. (2 pts) By definition, a spontaneous reaction is one in which -- / : ~ , ~ j . energy is released. b. energy is absorbed. c. the energy change is zero.,,23. (2 pts) In general, catabolism /. iS,an oxidative process. ' . b. is a reductive process.

".,;/"\. _ ,.. ,.: . ~ _ .{! i f ~ ) ' , ... {t./24. (2 pts) How many enzymes of glycolysis are control points for the pathway?a. 1 b. 2 1-3 d. 4 e. All the enzymes serve as control points.

./25. (2 pts) A polysome is;I. a complex consisting of one mRNA to which several ribosomes are attachedb. a polypeptide chain in the process of being formedc. an intermediate stage in the self-assembly of ribosomes d. an aggregate of ribosomal proteins

4

Documents

Bcmbintr 310 November 5, 2008