From 768acff07934bbc25e61c878eef6a268f84a53f1 Mon Sep 17 00:00:00 2001 From: johnruina Date: Mon, 17 Aug 2026 11:43:31 -0400 Subject: [PATCH] 2026-08-17 11:43:30: Plasma Membrane --- .obsidian/workspace.json | 27 ++++++++++---- .../Pasted image 20260817102835.png | Bin .../Pasted image 20260817103921.png | Bin .../Plasma Membrane.md | 34 ++++++++++++++++++ 4 files changed, 54 insertions(+), 7 deletions(-) rename Pasted image 20260817102835.png => Assets/Pasted image 20260817102835.png (100%) rename Pasted image 20260817103921.png => Assets/Pasted image 20260817103921.png (100%) create mode 100644 biology/Cell Structure and Function/Plasma Membrane.md diff --git a/.obsidian/workspace.json b/.obsidian/workspace.json index 78866cd..b8536c5 100644 --- a/.obsidian/workspace.json +++ b/.obsidian/workspace.json @@ -146,9 +146,23 @@ "icon": "lucide-file", "title": "Cell Size" } + }, + { + "id": "06a39bf497ec6f5c", + "type": "leaf", + "state": { + "type": "markdown", + "state": { + "file": "biology/Cell Structure and Function/Plasma Membrane.md", + "mode": "source", + "source": false + }, + "icon": "lucide-file", + "title": "Plasma Membrane" + } } ], - "currentTab": 9 + "currentTab": 10 }, { "id": "25da4f0a48a8e7cd", @@ -332,12 +346,13 @@ "obsidian-excalidraw-plugin:New drawing": false } }, - "active": "713a2ea9096a5d46", + "active": "06a39bf497ec6f5c", "lastOpenFiles": [ - "biology/Cell Structure and Function/Cell Structure and Function.md", + "Assets/Pasted image 20260817102835.png", + "biology/Cell Structure and Function/Plasma Membrane.md", "biology/Cell Structure and Function/Cell Size.md", - "Pasted image 20260817103921.png", - "Pasted image 20260817102835.png", + "biology/Cell Structure and Function/Cell Structure and Function.md", + "Assets/Pasted image 20260817103921.png", "biology/Chemistry of Life/Macromolecules.md", "biology/Chemistry of Life/Structure of Water and Hydrogen Bonding.md", "biology/Chemistry of Life/chemistry of life.md", @@ -360,8 +375,6 @@ "physics/Force and Translational Dynamics/Newton's Third Law.md", "physics/Force and Translational Dynamics/Spring Force.md", "physics/Force and Translational Dynamics/Forces and Freebody Diagrams.md", - "physics/dynamics.md", - "physics/Kinetic and Static Friction.md", "Assets/Pasted image 20260816081041.png", "physics/Work Energy and Power", "Assets/Pasted image 20260816073410.png", diff --git a/Pasted image 20260817102835.png b/Assets/Pasted image 20260817102835.png similarity index 100% rename from Pasted image 20260817102835.png rename to Assets/Pasted image 20260817102835.png diff --git a/Pasted image 20260817103921.png b/Assets/Pasted image 20260817103921.png similarity index 100% rename from Pasted image 20260817103921.png rename to Assets/Pasted image 20260817103921.png diff --git a/biology/Cell Structure and Function/Plasma Membrane.md b/biology/Cell Structure and Function/Plasma Membrane.md new file mode 100644 index 0000000..3cda242 --- /dev/null +++ b/biology/Cell Structure and Function/Plasma Membrane.md @@ -0,0 +1,34 @@ +[[Cell Structure and Function]] + +# Summary +* Phospholipids are amphipathic (both hydrophobic and hydrophilic): hydrophilic phosphate heads point towards water hydrophobic fatty acid tails point away. +* Embedded proteins have hydrophilic regions facing the cytosol or extracellular fluid. Also have hydrophobic regions that contact the fatty acid tails in membrane interior. +* Cholesterol (in vertebrate animals) acts as a fluidity buffer, preventing the membrane from getting too loose or stiff in head or cold. +* Fluid mosaic model describes a membrane with phospholipids, proteins, cholesterol, glyco(proteins/lipids) can move around the surface. +* Fatty acid affects fluidity, unsaturated with kinks increases it, while saturated makes the phospholipids pack tightly together. +* Glycoprotein and glycolipid sit on the outside and help with cell recognition. + +Plasma membrane defines the edge of every cell, it's not a wall and is flexible. +# Components of the Plasma Membrane + +Phospholipids are main structural framework as a bilayer. Hydrophobic fatty acid tails point away from aqueous environment, hydrophilic phosphate heads point towards. + +Steroids (cholesterol in vertebrates) restrain phospholipid movement at high temps and prevents them from packing tightly at low temps. + +Gylco(proteins/lipids) are carbohydrates, attached to proteins and lipids, helps cells recognize each other. + +# Fluid Mosaic Model +Describes the plasma membrane as structural framework of phospholipids embedded with proteins, steroids(cholesterol) and glyco(steroids/lipids). Describes them as being able to move freely. + +Fluid nature, phospholipids can move laterally like they're in a sea of lipids. Allows components to shift and form regions for different jobs. + +Variety of molecules creates a mosaic appearance, thus the name. + +# Factors Affecting Membrane Fluidity +* Temp +* Fatty acid composition (look below) +* Cholesterol content (look above) +# How Structure Connects to Function +Hydrophobic interior blocks polar molecules while allowing small non-polar molecules pass more freely. Basis for selective permeability. + +Embedded proteins allow for specific interactions. Receptor proteins bind to signaling molecules, transport proteins move them. \ No newline at end of file