Unit 2: Membranes, Energy, and Cell Communication

Mer som dette

Nuclear Energy

Ved Alice Henningsen

Energy Systems

Ved Kimberly Harrison

chemical reaction

Ved Kanyanat wawsawad

Biomimicry

Ved Jose SAnchez

Subtopic

Integral Proteins

Cotransport Proteins

Active Transport Pumps

Carrier Protein

Channel Protein

Hydrophobic R groups

Peripheral Proteins

Hydrophilic R groups

Transport across Membranes

ATP Required

Endocytosis & Exocytosis

Active Transport

No ATP Required

Co-transport

Osmosis

Facilitated Diffusion

Diffusion

Unit 2: Membranes, Energy, and Cell Communication

Cell Signaling

Light reactions in photosynthesis

ATP production: chemiosmosis (protons pumped across thylakoid membrane, create sproteon gradient, drives ATP synthase)

e-: from H20, gives to NADP+

location: thylakoid membrane of chloroplast

e-: from NADH and FADH2, gives to O2

ATP production: chemiosmosis through ATP synthase

location: inner membrane space

ATP production in aerobic respiration

Chemiosmosis

Lots of ATP produced

proton gradient drives ATP synthase, ADP + Pi --> ATP

ETC

O2 combines with e- and protons to form water

H+ pumped into intermembrane space, creates proton gradient

e- go through protein complexes

NADH and FADH2 made from glycolysis and citirc acid cycle, give e- to ETC

Citric acid cycle

ATP generation: 2 ATP made through substrate level phosphorylation

Glycolysis

ATP usage: 2 ATP consumed in first 5 steps of glycolysis

ATP generation: 2 ATP made thourgh substrate level phosphorylation

Tyrosine Kinase receptor pathway

activated signaling proteins --> cascades --> gene expression

Phosphorylated tyrosines --> signaling proteins

activates kinase --> autophosphorylation of tyrosine

Ligand binds to dimer

GCPR receptor

Pathway

cAMP activates first kinase

Adynylyl cyclase converts ATP --> cAMP

Activated G protein activates adenylyl cyclase

GPT --> GTP and activates G protein

Ligand binds to GCPR receptor

Cell Energy

Cellular Respiration: ATP Production

ATP: The Energy Currency

ATP used in:

Chemical Work (Biosynthesis)

Transport Work (Active Transport)

Mechanical Work (Motor Proteins)

ATP Synthesis: ADP + Pᵢ → ATP (Requires energy)

ATP Hydrolysis: ATP → ADP + Pᵢ (Releases energy)

Photosynthesis: ATP & Energy Transfer

Comparison to Cellular Respiration

ATP is generated using a proton gradient in both mitochondria and chloroplasts.

Both processes use electron transport chains.

Calvin Cycle (Stroma)

ATP & NADPH used to fix CO₂ into glucose.

Light-Dependent Reactions (Thylakoid Membrane)

Electron transport & proton pumping to create ATP and NADPH.

Electron Transport Chain (ETC) & Chemiosmosis

ATP is generated by oxidative phosphorylation.

Proton (H⁺) gradient in the intermembrane space drives ATP Synthase.

Stages of Cellular Respiration

Oxidative Phosphorylation (ETC + Chemiosmosis) (Inner Mitochondrial Membrane)

Outputs: ATP (32-34), H₂O

Inputs: NADH, FADH₂, O₂

Citric Acid Cycle (Krebs Cycle) (Mitochondrial Matrix)

Outputs: ATP, NADH, FADH₂, CO₂

Inputs: Acetyl-CoA, NAD+, FAD

Pyruvate Oxidation (Mitochondrial Matrix)

Inputs: Pyruvate, NAD+

Outputs: Acetyl-CoA, NADH, CO₂

Glycolysis (Cytoplasm)

Inputs: Glucose, ATP, NAD+

Outputs: Pyruvate, ATP (net 2), NADH

Energy Transfer in Cells

Types of Metabolic Pathways

Anabolic Pathways ( Photosynthesis: synthesis of glucose using light energy)

Catabolic Pathways (Cellular Respiration: breakdown of glucose for ATP)

Laws of Thermodynamics

2nd Law: Energy transfer increases entropy.

1st Law: Energy is transferred and transformed, not created or destroyed.

Membranes

Factors Affecting Fluidity

Fatty Acid Composition (unsaturated vs saturated)

Temperature (higher = more fluid)

Cholesterol (maintains fluidity at various temperatures)

Functions of membranes

Signal Transduction

Selective Permeability

Structure of Membranes

Glycolipids

Cell recognition, stability & protection

Glycoproteins

Cell-cell recognition & signal reception

Phosplipid Bilayer

Maintains Flexibility

Phospholipids

Hydrophilic Head (phosphate group)

Hydrophobic Tails (fatty acids)