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BIOCHEMISTRY Evaluations 10 Set B

SUBJECT: BIOCHEMISTRYTOPIC: EVALUATION #10 Set B

(Recombinant DNA and Nutrition 1)LECTURER: DR. UY and Prof. TorresDATE: MARCH 2011

Question #: Correct Answer: Explanation:

1A. DNA Ligase

+ ATP

DNA Ligase covalently attaches a free 5' phosphate to a 3' hydroxyl andATP for energy. DNA polymerase is for elongation. Telomerase is an

enzyme for providing telomeres for cell division (telomeres are sequence ina DNA that is removed every cycle of division - parang fuel siya ng car).Recombinase are enzyme promoting DNA recombination and is not for

joining DNA fragments.

2A. Somatic

Gene Therapy

SGT is when the therapeutic genes are transferred into the somatic cells ofa patient(for treating); Germ-line gene therapy corrects them invitro/in

embryo; cloning creates a copy; Genetic engineering is themodifying/manipulation of certain genes (remember GMO?)

3 C. mRNA

Reverse transcriptase uses mRNA (messenger RNA) to synthesize cDNA

(complemantary DNA); ssDNA is Single stranded DNA, dsDNA is doublestranded DNA both are not used by Reverse transcriptase

4 BONUS

5D. All of the

choices

cDNA library contains only complementary DNA molecules synthesizedfrom mRNA; this complementary DNA has already undergone post-

translation modification removing all unnecessary sequences like introns,promoter sequence, etc. Primarily, cDNA is composed mostly, if not all, of

exons or sequences that is functional when expressed.

6 C. Western BlotWestern blot is used to identify proteins; Northern blot is used for probing

RNA; Southern blot is for DNA

7 C. PlasmidPlasmids can be good cloning vectors because they carry an origin of

replication and are therefore able to replicate independently. Plasmid also isvery easy to isolate, abundant (easy to grow) and cheaper.

8 D. All of theabove

All can be used as a host for recombinant DNA technology. Self-explanatory

9

C. Screening ofDNA in the

library or ongel

Probes are single stranded NA used to hybridize with a target DNA. Usuallythey are marked radioactively so they can easily be identified.

10D. All of the

aboveBlood, Bone, egg cell as well as other things from the body (hair, sperm,

nails etc.) can be used as a source of DNA or mRNA

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D. Restrictionfragment

lengthpolymorphism

Mutations change the size of specific sequences in the genome. Thedifferent sizes may help in identifying one DNA from another using Southern

blotting (DNA remember?). Restriction Fragment polymorphism is alsounique to individuals just like fingerprints. PCR or plymerase chain reactionis technique for making new strands for usage in other techniques. cDNA is

only a complementary DNA. REverse transcriptase is an enzyme thatproduces a DNA using mRNA as the primer.

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B. Degradeforeign DNA

that enters thebacterium

Restriction enzymes are made by bacterial cells to protect themselvesagainst foreign DNA (such as viruses) by cutting it up into pieces. Bacterial

cells modify their own DNA so that the restriction enzymes will not cut it.

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C. Makestaggered

double strandcut..

Remember that they are usually palindromes so they leave some 5' hangingso that it is complementary to the sticky end of the same site. Restriction

enzymes do no cut at the same base pair. Restriction enzymes are also cutat specific sites and can only be annealed by that restriction enzyme only.

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Portruding.

14D.

Transformation CaCl2

Heatshock + CaCl2 would make the bacterial cell unstable enabling theentrace of the plasmid into it. Electrophoresis is not always succesful.Infection with a bacteriophage has too many risks and can impede the

procedure or experiment.

15 B. Probe Look at number 9 for definition of probe

16

A. DNA isamplified atmany points

w/in.

They are usually amplified at one point to be able to recreate copies of thespecific gene.

17 B. TCCGAIt is not a palindrome. Palindromic sequences are sequences that when

reversed is complementary to the original sequence. Example is TTCGAA

which has a complement of AAGCTT.\

18 C. VectorVector: Small DNA used for recombinant DNA technology accessory

chromosome, can replicate but not part of hosts genome

19 A. 5' GTG 3'The Normal DNA (Hb-A) uses Glu which is GAG and in the Hb-S this is Val

which is 5' GTG 3'

20 A. RNA Northern blotting is used for RNA

21 A. NormalUnlike the mother and the father who carry the gene at 376, the baby does

not carry it hence the baby will be normal.

22D. All of the

abovePrenatal diagnosis, newborn screening and carrier (heterozygote) detection

can use recombinant DNA for human genetic testing.

23 C. 4Tip: the father is usually very different from the mother (they aren't relatedkasi) and the children will probably share DNA samples from the motherand the father so look for one that is completely different from the father.

24 A. TetracyclineThe plasmid although primarily encoded to be resistant to ampicillin andtetracylcin was introduced to PstI which cut the plasmid at a single site in

the ampicillin-resistant gene so it will only be tetracycline resistant.

25B. Ampicillin

resistantBecause it was cut at a single site in the ampicillin-resistance gene.

26 * C. blueLac Z is used to determine if the plasmid contains the DNA. White =

present, blue = none. It is grown on antibiotic containing-x-gal medium andso it is blue as it is not ampicillin resistant.

27C. 3' C A G G A

G T T 5'First you write down the sequence from 5' to 3' (bottom to top) then get it's

complementary strand so that it's 3' - 5'

28 D. ddTTPs

Dna polymerase is the enzyme for the elongation of the sequence, whiledNTPs are the source of nucleotides to add in the sequence. ddNTPS (ex.are ddATPs and ddGTPs) are used to terminate elongation. In this case

since the 3' end is adenosine the ddNTP used is ddATP as oppposed toddTTP.

29 A. oneautomated sequencing method as the name implies uses only one reaction

tube for efficieny and faster way of determining the sequence.

30 B. Microarray

VNTRs are used for testing of individuals like parental testing (since VNTRsre unique to individuals). Hybridization is a process of complementation andnot an actual technique for comparison. Western blotting is a specializedtechnique for determining protein in a sequence. Microarray is the best

answer since it is a specialized technique for comparing patterns ofexpression in two different cell types like a normal and cancerous cell.

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31

C. Reducingthe intestinal

time thusreducingcontact

Fiber is not digested and it usually passes through the GIT largely intact sothere intestinal transit time is reduced since it does not spend time being

absorbed etc. while carrying it carcinogens and colonic mucosa along withit.

32

B. can besynthesized by

the body insufficient amts.

Essential nutrients are supplied b the diet but non-essential nutrients can besynthesized by the body example of which is carbohydrades (cheap and

readily available ika nga.)

33

D. they yieldmore calories

per gram when

oxidized

Remember the 4, 4, 9, 7. Fats yield 9 kcal when oxidized but it is not theprimary source of energy.

34D. it contains

all the essentialamino acids

The higher the value o the dietary protein, the higher its ability to supply theessential amino acids required for the body. The standard used is the

Protein Digestibility Corrected Amino Acid Scoring which is based on theprofile of essential amino acids and the digestibility of protein.

35B. negative

nitrogenbalance

Catabolism > anabolism = negative nitrogen balance (less nitrogen);Anabolism > catabolism = positive nitrogen balance (nitrogen produced);

catabolism = anabolism = equilibrium.

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B. It is causedby prolonged

excessivelack calories

Kwashiorkor is due to protein deficiency and not caloric deficiency. It ischaracterized by hypoalbuminemia, anemia, edema, pot belly,

depigmentation of the skin, loss of hair/chage of hair to red and bulky stool.

37 C. Milk

PDCAAS or protein digestablity-corrected amino acids is the standard by

which to evaluate protein quality. Milk has 1.00 value in PDCAAS,suggesting that milk is a very good source of protein. 1.00 means that itcontains all the essential amino acids.

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A. It is thecheapestsource ofenergy forFilipinos

Since Filipinos are rice eaters, it is the most readily available source.

39B. Linoleic

AcidPalmitic acid and Stearic acid are saturated FA while Arachidonic acid is a

Polyunsaturated-omega-6 FA.

40C High Protein

dietKidneys reabsorb protein but if its function is impaired, it will have difficulty

reabsorbing protein hence a high protein diet is not appropriate.

41C. 2000 - 2300

kcalsThe energy intake should be more or less proportional to the energyrequirement per day to be able to carry out normal body functions.

42A. Carbon

dioxide andoxygen

Indirect calorimetry calculates heat prodction based on respiratory gasesmeasured over a unit of time> Oxygen consumption and CO2 production.

43

C. Fatty acidswith doublebonds in thecis.raise

Correct: Fatty acids with double bonds in the TRANS configuration raiseplasma cholesterol levels (kaya nga transfat eh!)

44 D. 2200 (289 x 4) >carb + (70 x 9) >fat + (110 x 4) >protein = 2200 cals

45 C. About 15% The patient's caloric intake is adequate having 2200 calories a day. The

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of the caloriesare derived

from theproteins.

patient also conforms to the recommended guidelines for her diet having anincreased amount of protein since she is pregnant. The answer is C since

440 calories produced by the protein in the diet represent about 20% of thedaily caloric intake.

46 D. Lignin

Lignin is a complex polymer; the chief constituent of wood other thancarbohydrates; binds to cellulose fibers to harden and strengthen cell walls

of plants while dextrins, glycogens and starches are availablecarbohydrates and can be used by the body.

47C. Patient onimpending

thyroid storm

A growing child, a recovering person and a pregnant woman would manifestwith a POSITIVE NITROGEN BALANCE.

48

B.

Hypoalbuminemia

Low protein; Albumin = Protein; HYPOalbuminemia

49 C. KetosisInadequate carbohydrates will make the body look for other energy sourceswhich will be in the form of Fats and Proteins. If this happens, there will be

an increase in ketone bodies hence ketosis

50

C. RQ of lessthan 1

suggestsstarvation

RQ < .70 means fat is converted to carbohydrate; RQ> 1 means fatsynthesized from carbohydrate; Any RQ greater than 1 indicates net

synthesis of fatty acids and triglycerides.

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