Monohybrid Crosses

Phenotype

Determined by genotype and is the result of proteins produced

Different alleles cause

different sequences

Amino acids are made up by?

different proteins

Codon is? Start and stop codons?

3 base pairs of mRNA that code for an amino acids (triplet codes). Start and stop codons signal the start and end of protein synthesis

A reading frame is

a sequence of codons

Genetic Code Characteristics

Redundant: all but 2 amino acids have a > 1 codon
Unambiguous: one codon = only one amino acid
Non-overlapping: codons read one at a time
Nearly universal: all codons specify the same amino acids in all organisms
Conservative: if >1 codon for an amino acid, first two bases are usually the same

Point Mutation

One or a small number of base changes, examples

Chromosome-level mutations

Larger in scale

Missense mutation

Changes an amino acid

Silent mutations

No changes (due to redundancy)

Frame shift mutations

Shifts reading frame, altering meaning of all subsequent codons

Nonsense mutations

Changes codon to stop codon

Most point mutations are neutral or-

Deleterious

Chromosome level mutation

-Can change chromosome number or structure

-Can be beneficial, neutral, or deleterious

Dr. Esther Miriam Zimmer Lederberg

American microbiologist

Dr. Christine Nüsslein Volhard

German biologist who did research on early embryonic development with fruit flies. She won the Nobel Prize

Transcription

RNA Polymerase vs. DNA Polymerase

Three main steps of transcription

Initiation, elongation, termination

Sigma

Find the DNA and promote

Initiation

RNA polymerase opens double helix, transcription bubble, template threaded through active site. Incoming bases diffuse to active site, complementary base pairing.

Why are promoters needed?

Sigma can’t bind without the special locations of the promoters (-10, -35)

Instead of Helicase, what opens up the helix?

RNA Polymerase

Bacteria ctive site has what type of chemical reaction in Initiation?

Where condensation reaction

During bacteria Elongation, RNA polymerase moves along the DNA template until when?

Until it runs into a transcription-termination

During bacteria Termination what structure to separate the transcript from the RNA polymerase?

Hair pin

Bacteria summary

Eukaryote Summary

During Splicing what’s the difference between exons and introns?

Exons are coding regions and introns are non-coding regions

Spliceosome

Splits away the introns

What is added after splicing? How do they help?

A cap and a tail.

Cap

Helps ribosomes bind and protects from degradation

PolyA Tail

Needed for translation, protects from degradation. Also dissembles RNA like hairpin, termination signal

Translation is ?

a conversion from one language to another

In translation, ribosomes what?

Synthesize proteins

In eukaryotes is transcription and translation physically separated or no?

Physically separated

What does a tRNA Adapter do?

-Holds amino acids

-Interacts with mRNA stand

-Transfer amino acid to growing polypeptide strand

-The Anticodon = matches codon of mRNA

What does an anticodon do?

Matches codon of mRNA

Dr. William Augustus Hinton

Graduated Harvard in 3years, wrote the textbook on syphilis and helped develop the Hinton Flocculation test for it.

Operon

set of coordinately regulated bacterial

genes, transcribed together into one mRNA

LacI

Continuatively active gene (always turned on). It’s a repressor gene.

lacZ

Dr. Roger Kornberg

How are genes regulated in eukaryotes?