Cell cleaves, and two daughter haploid cells (n) with half the copy of homologous chromosomes are produced
Homologous chromosomes split, and sister chromatids stay fused at the kinetochore and centromere, moving to opposite poles of the cell
Tetrads line up at the cell plate/equator and random alignment occurs. This leads tp more genetic variety. Attached to microtubules at the kinetochores
Crossing Over, synapsis, and genetic variety results, and chiasmata form
Germ-line cells (2n) prepare for meiosis
DNA Polymerase III + RNA Primase
Nucelar membranes reappear, chromosomes decondense, and uncoil, microtubules break down
Sister chromatids separate and move to opposite poles of the cell, and microtubules shorten and contract
Homologous Chromosomes line up at the equator of the cell, and centrosomes move to opposite poles of the cell
Nuclear membrane breaks down completely, microtubules from centrosomes grow and attach to the kinetochores
- Chromosomes condense and become coiled to be visible, nucleolus disappears, microtubules appear from centrosomes
Cell Prepares for Mitotic Cycle
DNA Ligase
DNA Polymerase I
RNA Primase + DNA Polymerase III
DNA Helicase unwinds dsDNA into ssDNA
Protein Kinases add phosphates from ATP for activating relay proteins, while phosphatases remove phosphorus group
Signal Transduction Pathways
Dimerization of receptor monomers
Travel to other organelles within the cell
Exocytosis (bulk transport) by transport vesicles
Transport Vesicles + microtubules
Signal Peptide Sequence binds to Signal recognition Particle (SRP)
Protein Transport System
pre-mRNA processing (eukaryotes only) + polypeptide chain synthesis in ribosomes
DNA transcribed by RNA polymerase II into pre-mRNA (in eukaryotes) and by RNA polymerase into mRNA in prokaryotes

Ribosomal Explosion

Life in Biological Organisms

Structure relates to function

Genetic information is expressed and transmitted

Gene Expression

Transcription

Translation

Protein Trafficking

Endomembrane System Proteins

Post-Translational modification + glycosylation and lipidification of proteins in rough ER

Golgi apparatus

Lysosomes

Plasma Membrane Proteins

Free Ribosomes synthesize polypeptides (with no Signal Peptide Sequence)

Mitochondria

Chloroplast

Nucleus and Peroxisomes

Gene Regulation

Prokaryotes

Operons

Lac Operon

If lactose present, it is an inducer, and inhibits lac repressor protein from binding to operator.

If glucose is present, cAMP levels are low, CAP is inactive

Lac operon is off

If glucose is absent, cAMP levels are high, CAP is active

Lac operon is on

If lactose is absent, repressor is active.

Lac operon is off

Trp Operon

If tyrtophan is present, acts as a corepressor, and can inhibit trp operon

Trp operon is off

If tyrtophan is absent, repressor is inactive

Trp operon is on

Eukaryotes

Combinatorial Gene regulation by specific transcription factors. At the transcription initiation stage.

Distal control elements and enhancers

Specific transcription factors

Cell Signaling

Hydrophilic Signaling

Tyrosine Kinase Receptor Pathway

Signal molecule binds to receptor

Auto-phosphorylation of tyrosine tails activates tyrosine kinase receptor

Activates protein kinases

Phosphorylation Cascade

Specific Transcription Factors formed (activators for binding to enhancers in nucleus).

Cell response

G-protein Receptor Pathway

G-protein binds to signal molecule. GTP binds to G-protein, and GDP knocked off. G-protein is active.

Binds to adenylyl cyclase

cAMP produced from ATP as a secondary messenger

Phosphodiesterase turns of cAMP signaling by converting cAMP to AMP.

Phosphorylation Cascade, and signal transduction pathway begins with activation of Protein Kinase A.

Specific and activator transcription factors produced.

Cell response

Hydrophobic Signaling

Signal molecule enters cytoplasm, and binds to receptor in cytoplasm

Receptor-Signal complex enters nucleus as a specific transcription factor and binds to DNA, and bind to promoter.

Cell response

Bind to enhancers, and increase expression higher than basal level

DNA bending protein, brings closer to RNA polymerase, and mediator proteins, along with general transcription factors form active transcription complex

Chromatin Modification and DNA packaging

Acetylation of protruding histone tails.

Promotes loose chromatin structure, and therefore available for transcription and gene expression. Genes turned on.

Chromatin is coiled by histones to form nucleosomes, and supercoiled into tight helical fibers, and then wrapped into looped domains on protein scaffold.

Metaphase Chromosomes form (1400 nm in length)

DNA Replication

SSB Proteins and topoisomerase stabilizes the single strands and relieves tension in ssDNA

Lagging Strand Synthesis

Synthesized in Okazaki Fragments in 3' to 5' direction by addition of several RNA primers

RNA primers replaced and removed with DNA nucleotides

Fragments of DNA annealed and stick together by phosphodiester bonds

Mitosis and Cell Division (The Cell Cycle)

Interphase (G1 + S + G2) (DNA replication occurs at the synthesis/S Phase)

Prophase

Prometaphase

Metaphase

Anaphase

Telophase

Cytokinesis, cell divides into two by cleavage of cytoplasm. DNA replication ensures identical DNA distribution into two daughter cells.

Leading Strand Synthesis

Synthesized in complementary strands continuously in a 5' to 3' direction. Only one RNA primer is needed

Meiosis and Sexual Reproduction

Interphase (G1 + S + G2)

Meiosis I

Prophase I

Metaphase I

Anaphase I

Telophase I + cytokinesis

Meiosis II

Very similar to Mitosis

Prophase II + Metaphase II + Anaphase II + Telophase II + cytokinesis

Sex gametes are produced. 4 haploid cells (n) with each one copy of chromosomes produced. Go on to form the diploid embryo (2n).

Energy is transformed to sustain living systems

Cellular Respiration

Photosynthesis