Unit 5: Protein Synthesis
Terms in this set (45)
Who is the central dogma of molecular biology?
What is replication?
Copies DNA (DNA->DNA)
What is transcription
Converts DNA message into intermediate molecule called mRNA (DNA-> RNA)
What is translation?
Interprets an RNA message into string of amino acids called polypeptides (RNA-> Proteins)
In prokaryotic cells replication transcription and translation are located where?
In prokaryotic cells translation begins when?
Begins while the mRNA is still being synthesized (transcription)
In eukaryotic cells replication and transcription occur where?
In eukaryotic cells where does translation occur?
What are the differences between DNA and RNA
RNA single stranded (DNA double)
RNA sugar ribose (DNA Sugar deoxyribose)
RNA uracil in place of thymine in DNA
What are the 3 types of RNA transcription produces?
Messenger RNA (mRNA)
Transfer RNA (tRNA)
Ribosomal RNA (rRNA)
What is messenger RNA (mRNA)
code for translation
What is transfer RNA (tRNA)?
Bring amino acids from the cytoplasm to a ribosome to help make growing
What is ribosomal RNA (rRNA)?
forms part of ribosome
Process of transcription (function of enzymes)
Catalyzed by RNA polymerase
Process of transcription (Unwinding of DNA)
Unwinds at specific site (gene)
Process of transcription (Complimentary bases in RNA)
How is transcription similar to replication?
Both occur in nucleus
Both involve unwinding DNA
Both involve complementary base pairing
What are polypeptides
RNA making proteins
What is a codon?
3- letter code on RNA for an amino acid
How many combinations of codons are possible?
64 combinations (ONLY 20 amino acids)
Many AA coded by more than one codon
What do start codon do?
Signals start of translation
What do stop codons do?
Signals end of amino acid chain
What does universal code mean?
-Same in all organisms
suggests common ancestor
Scientist can insert gene from one organism to another to make a functional protein
What are the two important "tools" needed to translate a codon into an amino acid?
Ribosome and tRNA
What is a ribosome?
Site of protein synthesis
Made of rRNA
What are the functions tRNA?
Carries free floating amino acids from cytoplasm to ribosome
Attaches to specific amino acids
Has "3 letter" anticodon
What occurs in the cytoplasm for translation?
mRNA binds to ribosome
Ribosome pulls mana strand through one codon at a time
Exposed codon bonds to complementary tRNA bearing an amino acid
Amino acids bond to each other
Your cells can control when gene is turned __________
on or off
Why are certain genes expressed in each type of cell?
Cells are specialized in multicellular organisms
Some mutations affect a ________ while others affect an ___________
single gene, entire chromosome
What is a mutation?
Any change in an organism's DNA
Mutations that affect a single gene usually happen during __________
Mutations that affect group of genes or chromosome happen during _________
What is a point mutation?
One nucleotide is substituted for another
What is a frameshift mutation?
Involves insertion or deletion of a nucleotide in DNA sequence
What is a gene duplication?
exchange of DNA segments through crossing over during meiosis
What is a gene translocation?
results from the exchange of DNA segments between mohomologus chromosomes
Mutations may not affect what?
What is the impact of a mutation on a phenotype?
Chromosomal mutations affect many genes and have big effect on organism
How do gene mutations change mutations?
A premature stop codon
Change of protein shape or the active site
Change gene regulation
How do gene mutations do not change the organism?
Mutation may be silent
Mutation may occur in a noncoding region
Mutation may not affect protein folding or the active site
What do mutations in body cells do not affect?
Mutations in sex cells are either what two things to offspring?
harmful or beneficial
What does natural selection do?
Removes mutant genes
How are mutations caused?
Mutagens (UV ray and chemicals)