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29 Cards in this Set
- Front
- Back
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RNA Function |
carries out instruction stored in DNA for protein synthesis |
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Gene |
sequence of nucleotides that store information for the synthesis of protein |
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Genotype |
genetic information contained in DNA of an organism |
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Phenotype |
specific physical characteristics displayed by organism |
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Genome |
the genetic information in an organism or cell |
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Sugar-phosphate backbone |
Covalent bond link the phosphate group of one nucleotide to the sugar group of the adjacent nucleotide |
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Base Pairing |
A----------------T G---------------C |
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DNA Replication |
Function: To duplicate cells genome 2 steps 1. Two DNA strands unwind and separate 2. Each strand is used as a template for new DNA strand |
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Transcription |
Making a mRNA copy of DNA as a first step in protein synthesis |
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Translation |
using the information in mRNA to synthesize a protein RNA helps to link amino acids together from proteins |
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3 types of RNA |
- mRNA -rRNA -tRNA |
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Transcription Steps (3) |
1. Unwind the two DNA strands where gene is located 2. Only one strand is copied, called coding scan 3. RNA separates from DNA and DNA rewinds * all steps catalyzed by RNA polymerase** |
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Codons |
3 groups of nucleotides = 1 codon |
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Ribosomes |
Function: site for protein synthesis Contains: binding site for mRNA tRNA |
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tRNA |
Function: brings the correct amino acid to a ribosome during protein synthesis -cloverleaf shaped --at least one tRNA for every amino acid |
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3 stages of translation.... |
Initiation Elongation Termination |
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Initiation |
-mRNA binds to ribosome at mRNA's start codon (AUG) -tRNA binds to mRNA |
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Elongation |
-tRNA binds to mRNA and delivers second amino acid -covalent bond is synthesized between the two amino acids (peptide bond) |
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Termination |
-ribosomes reach the stop codon -newly synthesized polypeptide released from ribosome -mRNA resleased from ribosome |
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Introns |
noncoding stretch of DNA contained in a gene |
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Exons |
stretches of DNA in a gene which contain information about amino acid sequences |
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Eukaryotic Translation |
Occurs on ribosomes that are either free in the cytoplasm or attached to the membrane of the rough ER |
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Causes of mutations....(2) |
1. induced - produced by mutagens 2. Spontaneous - occur in absence of any known mutation causing agent |
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UV radiation |
non ionizing radiation that has less energy than ionizing radiation -can cause DNA damage -doesn't penetrate most substances |
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Ionizing radiation |
-contains much more energy than UV and is much more destructive -ex. - X-ays and gamma radiation |
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Nucleotide Analogs |
Some chemical mutagens function by molecular mimicry |
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Nucleotide-altering chemicals |
some function by adding or removing chemical groups important for the function of DNA |
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Ames Test |
rapid screenings for carcinogens using bacteria |
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Genes of a operon include..... |
1. Structural gene- gene which codes for protein 2. Promoter- DNA sequence that begins transcription 3. Operator- can bind to prevent transcription |
