AP Biology
-
Upload
michael-conner -
Category
Documents
-
view
28 -
download
1
description
Transcript of AP Biology
AP Biology Tests back today Curve was 12 points Grades on test haven’t had 12 points
added (they are correct in ps) Study guide changes rip out page 7
(that is a different chapter) Test is December 20
History of DNA
Thomas Morgan 1900
Frederick Griffith 1928
Oswald Avery 1940
Hershey and Chase
1952
Erwin Chargaff
1950
Rosalind Franklin
1950
Watson and Crick
1953
DNA Replication
Watson/Crick
Semiconservative: when a double helix replicates, each of the daughter molecules has one old strand and one new
Vocab on Replication Origin of replication- special sites where
replication begins Replication fork- a “bubble” where parental
strands are unwound Helicase- unzips parent strand Single-stranded binding protein- binds to
unpaired DNA to stabilize them Topoisomerase- relieves strain from twisting
Replication
Vocab contd. Primer- initial nucleotide is a short
stretch of RNA Primase- an enzyme that synthesizes
the primer DNA polymerase- catalyzes the
synthesis of new DNA by adding nucleotides to a preexisting chain
Replication
DNA
3’ vs 5’
The 5’ 3’ runs in the opposite direction as the: 3’ 5’
Antiparallel- the two strands of DNA are oriented in opposite directions to each other.
DNA
DNA can ONLY add nucleotides from the 3’ side on parent Strand
DNA daughters are “built” from 5’ 3’
DNA Leading strand- the continuous strand Lagging strand- the strand that is copied
away from the fork Lagging strands called- Okazaki fragments.
Proteins
Proteins are link between genotype and phenotype
Gene expression- process by which DNA directs protein synthesis, includes two stages called transcription and translation
DNA RNA Protein
DNA
Protein Review
Amino acids - building blocks of protein
Polymer - many building blocks covalently bonded
Peptide bonds- covalent bond between amino acids
20 total amino acids
DNA/RNA
DNA RNA
Double helix Single strand
A,T,C,G A,U,C,G
Deoxyribose sugar Ribose sugar
mRNA rRNA tRNA
Codons
How many nucleotides could there be if:
1. Each kind of nucleotide base were translated into an amino acid?
2. If a two-letter sequence was in place?
3. If there were triplet bases?
Codons – the mRNA nucleotide triplets, written normally in the 5’ 3’ direction
CCU AUG AGC AGG
Codons
Vocabulary: RNA polymerase- separates DNA and
joins RNA nucleotides together, nucleotide bases assemble in a 5’ 3’ direction (no primer required)
Promoter- When RNA polymerase initiates transcription sequence
Terminator- when RNA polymerase signals the end of transcription
Transcription
Steps of Transcription1. Initiation- RNA synthesis begins2. Elongation- the RNA strand gets bigger3. Termination- the RNA transcript is
released
Transcription
RNA Processing
Pre-mRNA must be altered before it travels outside of the nucleus Alternation of mRNA ends1. 5’ cap – a modified guanine added to
the 5’ end2. Poly-A tail- 50-250 adenine nucleotides
are added to the 3’ side
Pre-mRNA must be altered before it travels outside of the nucleus RNA splicing- removal of large portions of
the RNA molecule (cut-and-paste) This means that there are long noncoding
portions of DNA are not coding for anything. Introns - noncoding regions Exons – coding regions
RNA Processing
Vocabulary: Anticodon- attached to tRNA molecules,
a nucleotide triplet. Complementary to the mRNA codon
Wobble – the flexible base pairing at the third nucleotide position.
Translation
Steps of Translation1. Initiation- brings together mRNA and
tRNA to begin synthesizing proteins2. Elongation – Amino acids are added3. Termination – A stop codon reaches A
site, and the amino acids (polypeptide) is released
Translation