kin 217 - the genetic code chapter 39

genetic code

the ________________ links nucleic acid and amino acid information

codon

three nucleotides called a ______ encode an amino acid

true

the code is non-overlapping

t or f

false

code is read in the 3' to 5' direction

t or f

degenerate

the code is _____________ in that some amino acids are encoded by more than one codon

4

there are ___ bases

20

how many amino acids can me coded

64

how many possibilities of codes are there

3

how many stop codons are there

true

there are multiple codons for most amino acids

t or f

tRNA / transfer RNA

______________________ molecules function as an adaptor molecule b/w a codon and an amino acid

1

there is at least ______ tRNA molecule for each amino acid

73-93

a strand of RNA is between ____________ nucleotides in length

L-shapped

the 3-D shape of a tRNA molecule is _________________

inosine

tRNA molecules have unusual bases such as _________ or modified bases

CCA terminus

this end of the tRNA is where the amino acid gets attached

anticodon loop

this end of tRNA interacts w mRNA

cloverleaf pattern

tRNA appears to be in a _______________ in 2-D

H-bond

many nucleotides in tRNA will ______________ to make stems and loops

phosphorylated pG

the 5' terminal residue is usually a ____________________ on a tRNA

adenosine

amino acids get attached to a hydroxyl group of ____________ in the 3' CCA region of the acceptor stem

anti codon

the _____________ is in a loop near the center of the tRNA sequence

base pairs

the anticodon forms ________ with the codon

5' to 3'

by convention sequences are written in the ______________ direction

CAU

what is the anticodon that pairs with AUG

CCU

what is the anticodon that pairs with AGG

false

tRNA molecules cannot be recognized by more than 1 codon

t or f

third base

recognition of the _____________ in the codon by the anticodon is sometimes less discriminating

wobble

how one amino acid can be coded by several codons because of the third base

true

codons that differ in the first two nucleotides must be recogized by different tRNA

t or f

first base

the ___________ of the anti codon determine the degree of the wobble

inosine

if the first base is ______________ the anticodon can recognize 3 codons

aminoacyl-AMP

the first step to activating amino acids is to make __________________

aminoacyl-tRNA synthetase

the second step of activating amino acids is to use ________________________ to make aminoacyl-tRNA

false

each aminoacyl-tRNA synthetase can be used for any amino acid

t or f

true

specificity of aminoacyl-tRNA synthetase is attained by various means in different enzymes dictated by the features in a amino acid

t or f

synthetases

_____________ are the true translators of the genetic code that assign a particular amino acid to specific tRNA

recognition sites

characteristics of tRNA molecule is used as a ____________ by the synthetases to achieve specificity

ribosome

the site of protein synthesis

70S

the ribosome sediments is at _____ made of a 50S subunits and a smaller 30S subunit

2/3

_______ of the ribosome mass is made of RNA

1/3

___________ of the ribosome mass is made of protein

short duplex

ribosomes fold into complex structures with many _______________________

ribosomal RNA

___________________________ is the actual catalyst for protein synthesis