Nucleic acids

Question 1

Genetic Code

Answer 1

-linear
-triplet
-non overlapping
degenerate
-unambiguous
-universal
code for production of polypeptides

Question 2

triplet code

Answer 2

• polynucleotide strand has 3 times the number of bases than amino acid chain
• 3 bases removed polypeptide would have fewer amino acids
• if polypeptide has 3 more bases polypeptide has more amino acid

Question 3

Characteristics

Answer 3

• triplet code= 3 bases code for each amino acid
• 64 codes (only 20 amino acids founds in proteins)
• punctuated= 3 non coding codes (stop codon)
• universal= all organisms have same triplet code for amino acid
• non overlapping= each base occurs only occurs in 1 triplet
• degenerate= more than one codon for each amino acid

Question 4

Protein synthesis

Answer 4

sequence of bases represents information carried in DNA and determines sequence of amino acids in proteins

Question 5

Transcription

-definition

Answer 5

• one strand of DNA acts as template for production of mRNA (complementary)
• occurs in nucleus

Question 6

Translation

-definition

Answer 6

• mRNA acts as template to where complementary tRNA molecules
• amino acids link to form polypeptide
• occurs on ribosomes in cytoplasm

Question 7

Transcription

-process

Answer 7

• DNA helices breaks H bond
• two strands separate and unwind (bases exposed)
• RNA polymerase binds to template strand of DNA
• RNA nucleotides align
• RNA polymerase moves along DNA to form bonds adding RNA nucleotides
• synthesis of molecule of mRNA
• RNA polymerase separates from template strand when reach stop codon
• new RNA detaches from DNA

Question 8

Translation

-process

Answer 8

• mRNA small so leaves through nuclear pore
• goes to ribosomes containing rRNA
• reads code and polypeptide assembled
• tRNA collects amino acid and takes to ribosomes
• built to make polypeptide

Question 9

Ribosomal RNA

Answer 9

site of translation of genetic code into protein

Question 10

Transfer RNA

Answer 10

• single stranded
• folds to clover leaf shape
• one end is amino acid attachment site
• one end sequence of 3 bases (anti codon)

Question 11

remaining combinations

Answer 11

• some start stop

- several triplets code for amino acids

Question 12

DNA function in cells

Answer 12

-forms code for protein synthesis

Question 13

Mutation

Answer 13

• base sequence codes for different MRNA sequence
• wrong amino acid
• wrong protein
• wrong function

Question 14

ensure correct amino acid added

Answer 14

• each tRNA has specific linkage with one amino acid type
• tRNA joins to mRNA
• codon joins base pairs with anti codon of tRNA

Question 15

after translation

Answer 15

• B moves to space and adds amino acid to chain
• A released to combine with other identical amino acid
• B moves to A’s position