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Chapter 4, Chapter 6, Chapter 5, Exergonic reactions: release energy,…
Chapter 4
Energy converting organells
Enosymbiont theory
Mitochondria and chloroplasts were formerly small
prokaryotes that began living within larger cells.
Mitochondria
Cellular respiration: Use O_2 to make ATP and CO_2 is a side product
Chloroplasts
Photosynthesis
The Nucleus and Ribosomes
Nucleus: Eukaryote; membrane bound W/DNA
DNA
mRNA
Protein Synthesis
Nucleolus: Eukaryote; inside nucleus where we make ribosomes
Nucleoide: Prokaryote; region W/DNA
Introduction to the cell
Microscopes reveal the world of the cell
Cell thoery
All cells come from prexisting cells
Cell is the smallest unit of life
Antoni Van Leeuwenhoek
Invented lenses
Microscopes
Light microscopes
Magnification:1,000X
Resolution: 0.2 uM
Contrast: Staining
Can Display living Cells
Electron micrcopes
Magnification: 10,000,000X
Resolution
Scanning Electron Microscope(SEM)
Contrast: Coat in a Layer of Gold
Transmission Electron Microscope(TEM)
Contrast: Coat in Heavy Metals
Can't Display Living Cells
Structure and Function of cells
Prokaryotic cells
Nucleotide
Cell Wall
Flagella
Eukaryotic cells
They are divided into functional compartments
genetic control
Energy processing
Support, movement,communication
Manufacturing, distribution, and
breakdown of materials
Organells
All Cells
DNA in chromosomes
Plasma membrane
Ribosomes
Cytoplasm & Cytosol
The endomembrane system
Functions
Synthesis
Distribution
Storage
Export of Molecules
Organells
Endoplasmic Reticulum (ER)
Smooth ER
Synthesizes lipids and processes toxins
Rough ER
Produces membranes,
Surface ribosomes make membrane and secretory proteins
Nuclear Envelope
Golgi apparatus
Processes and sends out ER products to other organelles or cell surface
Lysosomes
House enzymes that breakdown ingested substances and damaged organells
Vesicles
Vacuoles
Large Vesicles W/Variety of functions
Food vacuoles
Contractile vacuoles
Plasma membrane
The cytoskeleton and cell surfaces
Function
Maintenance of cell shape
Anchorage and movement of organelles
Amoeboid movement
Muscle contraction
Composition:
Microtubles
Cilia and flagella
Microfilaments
intermediate filaments
Chapter 6
Aerobic harvesting of energy
Photosynthesis
Almost all ecosystems get energy from the sun
Sunlight energy captured by choloroplasts
Creates sugar and oxygen
absorbs CO2 and H2O
Life requires energy
Cells extract energy from fuel molecules through the transfer of electrons in chemical reactions
Reduction
Gain of electrons
Electron transferred to NAD+ making it NADH
oxidation
Loss of electrons
Electron removed from fuel molecule
NADH passes electrons to an electron transport chain. Energy is released as electrons "fall" from carrier to carrier and finally to O2
Cellular respiration
Sugar is broken down to make CO2 and H2O
exergonic process
Transfers glucose to from ATP at 32% efficiency.
1 glucose= 32 ATP
Stages of cellular respiration
Stage 1: Glycolisis
Location: Cytosol
Breaks down glucose(6C) into two molecules of Pyruvate(3C)
Input: 1 Glucose(6C), 2 ATP, 2 NAD+
Output: 2 Pyruvate(3C), 4 ATP, 2 NADH, 2 H2O
Stage 2: Pyruvate Oxidation and Citric acid cycle
Stage 2 (A)
Location: Mitochondria
Breaks oxidizes and breaks down Pyruvate(3C) into acetyl CoA (2C), CO2,and NADH
Input: 2 pyruvate (3C)
Output: 2 acytel CoA(2C), 2 CO2, 2 NADH
Stage 2 (B)
2 carbons from acetyl CoA are added
Output: 2 CO2, 3 NADH, 1 FADH2
Stage 3: Oxidative Phosphorylation; involves electron transport and chemiosmosis
Transfering Electrons from donors ( NADH/ FADH2) to acceptors (O2)
Location: inner mitochondrial chamber
Electrons + O2 + H+ = H2O
Creates electro chemical gradient which allows for the movement of ions downhill
Each glucose molecule yields:
Pyruvate Oxidation: 2 NADH
Glycolysis: 2 ATP 2 NADH
Citric acid: 2 ATP, 6 NADH, 2 FADH2
ETC: 26-28 ATP
Total: ~32 ATP
Connections between metabolic pathwys
Most calories are obtained as
Carbohydrates ( like sucrose)
Are used to make ATP by the cell
Fats
Proteins
Metabolic pathways are often regulated by
feedback inhibition
Cells use intermediates for Cellular Respiration and ATP for biosynthesis of organic molecules
Fermentation: anerobic harvesting of energy
Fermentation is a way of harvesting chemical
energy that does not require oxygen
NAD+ is recycled from NADH as pyruvate is
reduced to either:
Lactate
Alcohol and CO2
Glycolysis is used to produce ATP in anerobic conditions
Glycolysis occurs in the cytosol of the cell in nearly all organisms
Chapter 5
Energy and the Cell
Kinectic energy: energy of motion
Thermal energy: associated with the movement of atoms
Potential energy
Chemical energy: potential energy available for release in a chemical reaction
Laws of thermodynamics
Law of energy conservation
Energy transfer or transformation increase entropy
ATP: powers all forms of cellular work
Phosphorylation: drives work/ the removal of phosphate from ATP
Membrane Structure and Function
Fluid mozaic model
Fluid phospholipid bilayer
Has selective permeability
Spontaneously self assemble into simple membranes
Mosaic of diverse proteins
Perform various functions
Transport of molecules across a membrane
Passive Transport(Doesn't use energy)
Osmosis
Facilitated diffusion: Diffusion through a transport protein
Active transport(uses ATP/energy; against concentration gradient)
Bulk Transport
Endocytosis: entering the cell
Phagocytosis: one big thing
Receptor-Mediated endocytosis: lots of small things
Exocytosis: exiting the cell
Active Transport: through a transport protein against the concentration gradient
Tonicity
Hypertonic: cells shrink
Isotonic: Depends on the cell
Hypotonic: cells swell
Osmoregulation: regulation of the tonicity in our cells
How Enzymes Function
Protein catalysts: lower the activation energy
Optimal conditions
Temperature: 37*C
Ph
Cofactor: non-organic enzyme helper
Coenzyme: organic enzyme helper
A specific enzyme catalyzes each
cellular reaction
Substrate: ingredient being used in the reaction
Active site: where the substrate fits on the enzyme
Induced fit: the enzyme conforms to the shape of the substrate
Inhibitors
Competitive
competes with the subtrate for the active sight
Non competitive
Alter the binding sight without competing for it
Feedback inhabitation: helps regulate metabolism
Common uses
Pesticides
Poisins
Medical drugs
Exergonic reactions: release energy
Endergonic reaction: requieres energy and yields a product rich in energy
Brown Fat
Mitochondria in brown fat can burn fuel and
produce heat without making ATP.
Ion channels spanning the inner mitochondrial
membrane
allow H+ to flow freely across the membrane
decouples H+ flow from ATP synthase