final

Watson and Crick's Discovery 1. Double helix

2. Sugar-Phosphate Backbone

3. Strict base-pairing of nucleotides

4. Anti-parallel strands (emergent property of the orientation of complementary nucleotides when hydrogen bonding)

Nucleic acids 1. polymers called polynucleotides made of monomers called nucleotides

2. Composed of

Nucleotide Composed of three parts:

1. nitrogen-containing (nitrogenous) base

2. five-carbon backbone (pentose)

3. one or more phosphate groups

Pyrimidines C

T

smaller nucleotides

Purines A

G

larger nucleotides

Semi-conservative DNA replication Each parental strand from a double helix is used as a template strand to make a daughter strand along its entire length

7 proteins involved in DNA replication 1. Helicase

2. Single-strand bonding proteins

3. Topoisomerase

4. DNA polymerase I

5. DNA polymerase III

6. DNA primase

7. DNA ligase

Helicase unwinds the parental double helix

single-strand binding protein stabilize unwound template strands/prevent the strands from coming back together

topoisomerase prevents the DNA strands from getting tangled together as helicase breaks them apart by break

swiveling

DNA polymerase I replaces RNA primer at the end of an Okazaki fragment/beginning of next Okazaki fragment with DNA

DNA polymerase III synthesizes DNA in 5' to 3' direction/moves along template strand

linking new complementary nucleotides on

DNA primase primes template strand by adding RNA nucleotides to strand as primer

DNA ligase joins the Okazaki fragments together by joining 3' end of old Okazaki fragment to the 5' end of adjacent Okazaki fragment

Primer short chain of RNA nucleotides synthesized by primase required to begin DNA replication

Origin of replication short stretches of DNA having a specific sequence of nucleotides; located in the middle of replication bubble; where replication from 3' to 5' begins

replication bubble forms around the origin of replication; contains two replication forks

replication forks ends of replication bubble that move away from each other in opposite directions and bubble expands

leading strand strand continuously replicated toward the replication fork

lagging strand strand replicated in Okazaki fragments away from the replication fork

Okazaki fragments segments of the lagging strand

unidirectional replication one strand replicated in the direction of the replication forks; other strand replicated in the opposite direction of replication fork

Central Dogma of Molecular Biology DNA makes RNA makes Protein

downstream template for RNA transcription; direction of transcription

upstream regulatory elements such as the promoter; opposite direction of transcription

Transcription synthesis of RNA using information from DNA

mRNA RNA transcript of a protein-coding genes; carries genetic message from DNA to protein-synthesizing machinery of the cell

Translation synthesis of a polypeptide using information in RNA

RNA polymerase pries two strands of DNA apart and joins together RNA nucleotides complementary to the DNA strand

thus elongating the RNA polynucleotide; assembles only in 5' to 3' direction

promoter DNA sequence where RNA polymerase attaches and initiates transcription

terminator sequence in bacterial DNA that signals the end of transcription

transcription unit stretch of DNA that is transcribed into an RNA molecule

Stages of transcription 1. Initiation

2. Elongation

3. Termination

transcription factors collection of proteins in eukaryotes that mediates the binding of RNA polymerase

transcription initiation complex complex of transcription factors and RNA polymerase

TATA box nucleotide sequence containing TATA about 25 nucleotides upstream from the start point

RNA processing converting pre-mRNA to mRNA; 5' end receives a 5' cap and 3' end receives a poly-A tail; 3 steps

1. Addition of 5' cap

2. Addition f poly-A tail

3. RNA splicing

5' cap modified form of G nucleotide (G-P-P-P ) added to 5' end of pre-mRNA

Poly-A tail 50-250 A nucleotides added to the 3' end of pre-mRNA

RNA splicing removing non-coding regions of the RNA transcript (introns) from in between the coding regions (exons)

introns intervening sequences; non-coding segment sof nucleic acid that lie between coding segments (exons)

exons coding regions of nucleic acid that will eventually be expressed

transcription initiation site +1 part of gene; starting point; nucleotide where RNA synthesis (transcription) begins

translation formation of proteins using a series of codons along an mRNA molecule

codons sequences of three nucleotides that

together

tRNA transfers amino acids from the cytoplasm to a growing peptide in a ribosome; specific amino acid at one end and anticodon at other end

ribosome adds each amino acid brought in by tRNAs to the growing end of a poly peptide chain; consists of small subunit and large subunit

anticodon nucleotide triplet at one end of tRNA that is complimentary to a codon on mRNA

degenerate code more than one codon representing the same amino acid

small subunit of ribosome binds to mRNA and recruits large subunit at the first 5' AUG (start codon) with its associated MET tRNA

P site holds the tRNA carrying the growing polypeptide chain

A site holds the tRNA carrying the next amino acid to be added to the chain

E site where discharged tRNAs leave the ribosome

transcriptional regulation mode of gene regulation by transcription factors binding to regulatory DNA

5' end phosphate group

3' end hydroxyl (OH)

similarities between replication and transcription 1. result in synthesis of nucleic acids

2. read 3' to 5'

3. made 5' to 3'

4. synthesize anti-parallel

5. use nucleotides as substrates

differences between replication and transcription 1. final product of replication is two double-stranded molecules; final product of transcription is one single-stranded molecule

2. replication requires primer; transcription does not

3. replication results in DNA as product; transcription results in RNA as product

4. replication uses T; transcription uses U

7 Properties of Life 1. Response to stimuli/environment

2. Reproduction

3. Made of cells

4. Reproduce

5. Evolve

6. Consume energy

7. Self-regulation/homeostasis

emergent properties new properties that arise with each step up the hierarchy of life

due to the arrangement and interactions of parts as complexity increases

6 Bid Ideas 1. Structure-function relationships

2. Emergent properties

3. Cell theory

4. Theory of evolution

5. Regulatory mechanisms

6. Energy transformations

structure-function relationships Organisms have physical features (structures) that have evolved to efficiently serve a particular function; if one sees similar structures in an unfamiliar context it is assumed it serves a similar function; similar structure = similar function