Review


The Cell

Plasma Membrane— semi-permeable membrane

  • Seperates cell from enviro

  • Controls passage of substances

  • Carbs— recognition of neighbots

  • Phspholipid bi-layer


  • Simple diffusion—no atp

  • facilitated diffusion—no atp

  • exocytosis and endocytosis—atp

  • active transport—atp


Nucleus— genetic material

ER + Golgi Apparatus

Mitochondria

  • Smooth out membrane

  • highly folded inner membrane


What is needed to keep a cell (or organism) alive?

  • oxygen

  • nutrients (ex. glucose)

  • ATP

  • Water

  • Homeostasis



Equilibrium of Physiological Systems

  • Homeostasis— maintenance of a stable internal environment

    • Monitor internal conditions, make adjustments

    • Ex: body temp, blood pressure

  • Set point— physiological value around which normal range fluctuates

  • Occurs at many organizational levels


Maintenance of Equilibrium

  • Negative feedback— primarily responsible for maintaining homeostasis

  • Disruptions to homeostasis→ disease


ATP Production

  • Glycolysis, Krebs cycle, electron transport chain


Glycolysis— know basics of what happens

  • What goes in→ glucose

  • What comes out→ 2 pyruvate

  • Side products

    • 2 NADH

  • Where→

  • Basis→ glucose gets split into two pyruvates and produces 2 ATP and 1 NADH (which goes to etc)

  • Not a short process

  • Each reaction is catalyzed by a protein

  • First half— energy requiring phase

  • Main takeaway— need to make a lot of stuff to do this. Its happening in cells all the time


Pyruvic Acid→ acetyl CoA

Prior to entering the Krebs Cycle inside the Mitochondria

  • NAD+ → NADH + H+


Krebs Cycle

End up regenerating first molecule at the end

Completely oxidize glucose

  • in the mitochondria matrix

  • have to have proteins present to help catalyze reaction


Electron Transport Chain→ watch video


Cellular Respiration→ watch video


ATP, or adenosine triphosphate, is made up of an adenine base, a ribose sugar, and three phosphate groups.


Transcription

  • DNA→ mRNA

  • Transcription factors— proteins that regulate transcriptions of genes

    • Enhancer— bind simulatory factors

    • Repressor— bind inhibitory factors

  • Activators can simulate transcription in three ways:

    • Recruit transcriptional machinery

    • Chromatin remodeling

    • Stimulate RNA polymerase

  • Repressors act by competition, quenching, or active repression


Translation

mRNA→ protein

Translation: DNA to mRNA to Protein | Learn Science at Scitable

Post Translational Modifiations

  • Occur on proteins after translation

  • Regulates protein compartmentalization/trafficking and activity

    • Ex: phosphorylation of a transcription factor such as NF-kB

  • Several different ways to modify after translation




Secretory Pathway

Start:

  • proteins that will be secreted outside the ER throufh a translocon via the below process:

    • SRP receptor AKA “docking protein”

    • translation arrest—until SRP-nascent-peptide-ribosome complex binds SRP receptor

    • For secretion, entire peptide/protein travel through translocon.

Pathway:

Watch video to further review

Peptide hormone example:

• Nucleus – mRNA (transcription)

• Secretory pathway

• Cytosol – mRNA/ribosome and start of translation

• ER – translation continues with translocon entry and packaging of protein into

vesicle

• Golgi - Movement to and through Golgi network and protein is processed into

peptide hormone

• Vesicle then trafficked to membrane for release from cell into blood