Bio Test 3b

Question 1

DNA ligase

Answer 1

joins DNA fragments in presence of ATP

Question 2

What are the three vectors?

Answer 2

plasmid
viruses
aritificial chromosomes

Question 3

plasmid

Answer 3

• extra chromosomal DNA molecule
• used for cloning small pieces of DNA
• has ori (replication orgin)
• selectable marker
• multiple replication sites usually with LacZ

Question 4

ori

Answer 4

allows independent replication

Question 5

selectable marker

Answer 5

allows presence of plasmid to be easily identified

Question 6

sticky, overhang or preotruding ends

Answer 6

zig-zag cut by restriction enzymes where there is a protruding amnio acid on one side

Question 7

palindromic sequence

Answer 7

sequence that is the same front and back

• ECOR1: GAATTC
• HindIII: AAGCTT

Question 8

restriction enzyme or restriction endonuclease

Answer 8

• found in bacteria and archea providing a defense mechanism against invading viruses
• cut double-stranded DNA at specific spots
• 6 bp cutter (Sequence of 6 bp is isolated)

Question 9

restriciton enzyme sites

Answer 9

site where restriction enzymes cut double-stranded DNA

Question 10

artificial chromosomes

Answer 10

for larger insert and large-scale analysis of genomes

yeast and bacterial

Question 11

when a gene is expressed what should it have?

Answer 11

ori
selection marker
multiples restriction sites
reporter gene

Question 12

process of molecular cloning

Answer 12

• DNA cleavage
• ligation of gene into vector by DNA ligase in presence of ATP. recombinant plasmid made
• transformation
• screening

Question 13

transformation

Answer 13

introducing recombinant DNA into bacteria

Question 14

screening

Answer 14

uses selective medium containing antibiotics or X-Gal;

Question 15

antibiotic

Answer 15

amplicillin; clones that contain the plasmid will grgow in medium with ampicillin

Question 16

X-Gal

Answer 16

substrate for LacZ enzyme; clones that have the gene fragment inserted in LacZgene will turn white

Question 17

transformation

Answer 17

DNA uptake by bacteria

Question 18

transfection

Answer 18

DNA uptake by animal (eukaryotes) cell

Question 19

transduction

Answer 19

injection of DNA into host cell by virus

Question 20

conjugation

Answer 20

DNA transfer between two cells via direct contact

Question 21

applications of molecular cloning

Answer 21

• expressing using proteins (insulin)
• expressing reporter protein (transgenic animals)
• pGLO plasmid

Question 22

pGLO plasmid

Answer 22

contains GFP gene under the control of ara operator araC protein binds arabinose to form complex that turns on ara operon

Question 23

process of DNA replication

Answer 23

• opening DNA double helix (helicase)
• building a primer (DNA primase)
• assembling complementary strans (DNA polymerase III)
• removing the primer (DNA polymerase I)
• joining okazaki fragments (DNA ligase)

Question 24

characteristics of replication orgin

Answer 24

• spans 100-bp
• attracts intiator proteins
• has fewer hydrogen bonds and easy to open
• odten A-T rich stretches of DNA
• numerous in humans, one in bacteria

Question 25

unique features of transcription in eukaryotes

Answer 25

- three RNA polymerase enzymes - initiation complex forms at promoter with many transcription factors - RNAs are modified after transcription - One RNA makes one type of protein (monocistronic)

Question 26

how do miRNAs regulate gene expression

Answer 26

- encoded by normal gene - first cleaved into short dsRNA by DICER - ss-miRNA forms complex with RISC - siRNA pairs with target mRNAs - causes mRNA degradation or blocks translation

Question 27

what is the start codon?

Answer 27

AUG; Met

Question 28

What is the only other codon that has only one representation?

Answer 28

Trp; UGG

Question 29

What are the stop codons?

Answer 29

UAA UAG UGA

Question 30

codon

Answer 30

every three nucleotides makes a code for amino acid

Question 31

redundancy

Answer 31

some amino acids are encoded by multiple codons

Question 32

ribosomes

Answer 32

- made of proteins and rRNAs - consist of two subunits - has 82 proteins and 4 rRNAs

Question 33

tRNAs

Answer 33

- anticodon - carries amino acid (attached to OH- group of three prime end of tRNAs) - aminoacyl-tRNA synthetase

Question 34

anticodon

Answer 34

3-nucleotide sequence on tRNA complementary to codon in mRNA

Question 35

aminoacyl-tRNA synthetase

Answer 35

enzyme that attaches specific amino acid to corresponding tRNA

Question 36

translation process

Answer 36

- initiation - elongation - termination

Question 37

initiation

Answer 37

- small subunit of ribosome loaded with met-tRNA and initiation factors- complex - initiation complex binds 5' cap of mRNA - initiation complex searching for first AUG codon - large subunit binds

Question 38

elongation

Answer 38

- new aminoacyl-tRNA binds to A site - peptide bond forms by peptidyl transferase enzyme - large subunit translocates - small subunit translocates - empty tRNA leaves ribosome

Question 39

termination

Answer 39

- A site meet a stop codon - release factor binds to A site - dissociation of the translation machinery

Question 40

antibiotics that kill bacteria by inhibiting protein synthesis

Answer 40

tetracycline | cycloheximide

Question 41

tetracycline

Answer 41

blocks binding of aminoacyl-tRNA to A site

Question 42

cycloheximide

Answer 42

blocks translocation of ribosome

Question 43

translocation

Answer 43

location of ribosome

Question 44

Where does protein synthesis begin?

Answer 44

on ribosomes in cytosol

Question 45

signal sequences

Answer 45

- direct proteins to organelles - 15-60 amino acids long - usually removed after transport - can be done through pore, across membrane and vesicles

Question 46

transport by vesicles

Answer 46

from ER golgi endosomes or lysosomes cell surface

Question 47

import protein into ER the signal sequence will.....

Answer 47

have many hydrophobic amino acids

Question 48

import proteins into the nucleus and signal sequence will....

Answer 48

have positively charge amino acids