dna rna protein synthesis

Question 1

features of dna

Answer 1

degenerate- some triplets code for the same amino acid
non overlapping-each base read once
universal- same triplets coding for same amino acids in all organisms

Question 2

gene

Answer 2

section of dna bases codes for a polypeptide or rna

Question 3

intron

Answer 3

non coding sections

Question 4

prokaryotic dna

Answer 4

dna helix , circular chromosome, coiled, supercoiled

Question 5

eukaryotic dna

Answer 5

dna heliix, wound up to fit in nucleus around histones, dna condensed to chromosome

Question 6

allele

Answer 6

1 of number of an alternative forms of a gene

Question 7

mutation

Answer 7

change in quanity or structure of dna. a change in base sequence of chromosme

Question 8

dna vs mrna vs trna

structure, size, shape, sugar, bases, location, stability

Answer 8

dna mrna trna
double polyneuctride chain single single
largest middle smallest
double helix single helix clover shape
deoxyribose ribose ribose
at gc au gc au gc
in nucleus everywhere everywhere
most stable least stable

Question 9

role of mrna and trna

Answer 9

mrna carriers genetic code to dna from ribosomes and has codon
trna carriers amino acids to ribosomes to make proteins and has anticodon, amino acid binding site

Question 10

transcription

Answer 10

making pre mrna from dna template

• dna unwinds by dna helicase - breaking the h bonds holding base pairs
• rna polymerase lines up free mrna nucletotides w dna
• rna polymerase attaches mrna nucletoides by phosphodiester bonds
• when reaches a stop triplet, detatches from dna
• rna polymerase and dna helicase work in sections at time
• now a pre mrna is made

Question 11

splicing

Answer 11

making mrna
removes introns
mrna leaves through nuclear pores

Question 12

translation

Answer 12

making polypeptides

• start codon on mrna attaches to ribosome in cytoplasm
• trna carrying amino acid and complementary anticodon attaches to mrna codon via specific base pairing
• a 2nd trna attatches to next codon same way
• the 2 amino acids on trna are rejoined by enzyme and atp forms peptide bond
• trna goes away
• this continues until stop codon
• now polypeptide chain!!!