-AAUAAA

- Pops up as a signal to clip mRNA

-then special polymerase adds "A" sequence

- Ribosomes read the mRNA

- Adds one amino acid at a time (from tRNA)

- Makes polypeptide chain

- A, G, C, U

- Also has slew of modified bases

- Makes unique structure (100 ps)

- 4 Special RNAs (ribosomal RNAs)

- 50 Ribosomal proteins

- 3 sits E, P, A

- (In Eukaryotes) Ribosomes scan from 5' end to 3' end looking for first AUG (start codon)

- Once its found --> large and small subunits will come along with the correct mRNA carrying methianine

UAC

(site P)

GUA

(Site A)

- Made of proteins

- recognizes stop codon in A site

- Binding of release factor causes hydrolisis of last amino acid in polypeptide chain

- Has a lifespan in the cell

- can be repeatedly translated

- will stick around until it "dies"

- may make 100s of copies of the same protein

- 26, 000

- Approx. same # as eukaryotes

- Plants also have roughly same number

- Whole genome duplication

- More genes

- DNA form in chromosomes

- DNA and several kinds of proteins

- DNA complexed with histone

- beads are in a form called a nucleosome (composed of histone)

- 1 bead=1 nucleosome

- 1 nucleosome- octamer of histone

- Beads= 10nM

- Basic unit of DNA packaging in Eukaryotes

- Consists of a segment of DNA wound around a histone protein core

- 4 pairs of:

H2A

H2B

H3

H4

- Associates where linker leaves nucleosome core (positively charged.  Counteracts negative charge of DNA)

- Highly conserved protein

- DNA negatively charged (from phosphates)

- Histomes; Small, positive

- Nucleosomes bunch together now are 30 nM wide called "solenoid" (tube)

- Protein scaffold with looped domains (300 nm fiber)

- 5% genes

- 5% Heterochromatin: remains condensed throughout cell cycle

- 45% Transposons

- 45% "other"

- Mobile DNA elements

- ALU= 300 bp/ approx. a million copies in your genome --> specific to primates

- Movement of transposons can cause mutations

- Protective end of the tip of the chromosome

- Made of repetitive DNA sequences

- Found around telomeres and centromere

- No genes here, very simple sequence

- AAAATATATATA ( very "A" and "T" rich)

- Foun transposable elements

- When they move they can jump in and out of a gene

- We decended from prokaryotes (bacteria)

- 2,000-5,000 genes

- Forms part of hemoglobin (protein carrier/oxygen)

- Heteromultimetric protein

- Tetramer (4 units)

- Look like functional genes

- Nonfunctional copies of real genes

- Alphaglobins

- a1a2 (fetus and adult)

- 7 different genes

- Betaglobins

- S B (adult)

- e (embryo)

- 6 different genes

- One way to regulate gene expression

- Can be performed on histone tails

- opens chromatin

- Exposes DNA

- Allows genes to be transcribed

- Needed to drive expression at a particular time in a particular cell

- Control whether gene is on

- 10-20 bp long

- Can be far away from promoter or gene that they control

- RNA polymerase

- Transcription factors (need to bind around site of the promoter)

- Regulatory proteins (cluster around promoter but bind at enhancer)

- Have to "bend" DNA to bring protein around to promoter

• ex. TATA box binding protein

- Cell division cycle

- Icludes:

• Interphase
• Prophase
• Metaphase
• Anaphase
• Telophase (Mitosis is complete)
• Cytokinesis (Cell division is complete)

- Where cells spend approx. 90% of their time

- Don't see chromosomes

- Preparation for cell divison

- Made up of 3 phases

• G1 (first gap) (growth)
• S (synthesis) (chromosomes replicated)
• G2 (second gap) (prepares for mitosis)

[image]

- chromatin has condensed

- Nuclear envelope still formed

- Spindle begun to form (made of microtubules)

-Chromosomes have aligned at the metaphase plate

- Fully formed spindle

[image]

[image]- Sister chromatids break apart and move to opposite poles

-Two new cells begin to form

- Two nuclei

- Two membranes

[image]

- Two cells enclosed off with a contractile ring

- Nuclear envelopes reinstated 2 brand new cells

- Pinched off by a cleavage furrow

1) Reproduction

2) Growth

3) Renewal

- Designed for specialized cell division

- Critical for sexual reproduction

- Allows for diverse range of offspring

- Homologous pairs arrange themselves in metaphase I indpendently of other pairs

- Generates diversity

- You can produce approx. 8 mill. assortments of maternal/paternal chromosomes

- 8 mill. (f) x 8 mill. (m)

- 64 trill. ways to combine those chromosomes and changes in genetic material in a new way

- Complete loss of function in gene

- Within a population there can be 100s (even 1000s) of alleles for the same gene

- But each person only has two (some wild types, some mutants)

- A single mutation, multiple effects

- ex. Sickle cell anemia

- affects hemoglobin

- cant form nice tetrameric figures--instead form long chains

- mutates red blood cells

- Environment

- Ex. Hydrangea-- colors of petals change depending on acidity or alkaline levels in the soil

- Quantitative trait

- Traits often determined by multiple genes (and the environment)

- Multiple different genes

-Bell shaped curve/normal distribution of phenotypes

- Multiple different genes affecting one phenotype

- Pairs of alles

- Alleles of same gene agregate in meiosis

- Alleles back together as pairs after fertilization

- Homologous pairs

- Homologous chromosomes go to opposite poles in meiosis

- Fertilization brings homologous chromosomes back together

- realized behavior of genes matched behavior of chromosomes

- came up with Chromosome Theory of Inheritance

- Proved Chromosome theory correct

- Made break through by discovering mutant white-eyed male fly

- Carry a specific amino acid

- forms link between mRNA and growing protein

- Number of chromosomes in cell

- Humans have 46