Cellular Organelles Cellular Respiration

The Cell

Cytoskeleton Supports the Cell Microtubules Microfilaments

Special Structural Features of Cell Membranes Microvilli Cilia Stereocilia Flagella Function?

Cell Structures for Support and Movement: Cilia, Flagella, Centrioles Cilia and flagella movement: 9 + 2 microtubule arrangement Centrioles: used in cell division

The Cell

Centrioles

Endoplasmic Reticulum (ER) and Ribosomes Ribosomes: used in protein assembly: Free and membrane bound Endoplasmic reticulum (ER): packages the proteins: Smooth ER: no ribosomes, lipid synthesis Rough ER: has ribosomes, protein manufacture

Endoplasmic Reticulum (ER) and Ribosome Protein Synthesis Stores Calcium

Ribosomes Function: Transfer of messages from DNA Fixed to ER or free in cytoplasm

RER & SER SER: Synthesis and conversion of FA, steroids, and lipids RER: Protein synthesis, storage, modification & transport vesicles SER: Synthesis and conversion of FA, steroids, and lipids In muscle: Ca2+ storage

Golgi Apparatus Receives substances from ER, refines and packages them

Golgi Apparatus Modification (labeling) of proteins TEM “Post office” of cell Modification (labeling) of proteins Packaging into secretory (to ECF) or storage vesicles

Vesicles Ship and Store Cellular Products Vesicles: storage, secretory membrane-bound spheres Examples: secretory, endocytic, peroxisomes, lysosomes

Organelles

Lysosomes Digestion (~ 50 enzymes) of bacteria and old Organelles “Garbage Can of the Cell” Tay-Sachs disease is a fatal genetic disorder in which harmful quantities of a fatty substance called ganglioside GM2 accumulate in the nerve cells in the brain. Infants with Tay-Sachs disease appear to develop normally for the first few months of life. Then, as nerve cells become distended with fatty material, a relentless deterioration of mental and physical abilities occurs. The child becomes blind, deaf, and unable to swallow. Muscles begin to atrophy and paralysis sets in. A much rarer form of the disorder which occurs in patients in their twenties and early thirties is characterized by unsteadiness of gait and progressive neurological deterioration. Patients with Tay-Sachs have a "cherry-red" spot in the back of their eyes. The condition is caused by insufficient activity of an enzyme called hexosaminidase A that catalyzes the biodegradation of acidic fatty materials known as gangliosides. Gangliosides are made and biodegraded rapidly in early life as the brain develops. Patients and carriers of Tay-Sachs disease can be identified by a simple blood test that measures hexosaminidase A activity. Both parents must be carriers in order to have an affected child. When both parents are found to carry a genetic mutation in hexosaminidase A, there is a 25 percent chance with each pregnancy that the child will be affected with Tay-Sachs disease. Prenatal monitoring of pregnancies is available if desired. 5

Peroxisomes Major function: Degradation of long chain Fatty Acids Smaller than Lysosomes - Different set of enzymes Peroxisomes seem to be to be self-replicating. They don’t come off the Golgi apparatus as secretory vesicles as originally thought. Major function: Degradation of long chain Fatty Acids Generate hydrogen peroxide  contain catalase 6

Mitochondria: Provide Energy to the Cell Double membrane: inner membrane contains enzymes that break down foods Liberated energy used to create ATP

Energy Storage Fat: triglycerides, long-term energy storage in animals Glycogen: short-term energy storage in animals, carbohydrate storage

Metabolism Definition = “All chemical reactions that take place within an organism.” Metabolic pathways = network of linked reactions

Anabolism: requires enzymes: Cells Use and Transform Matter and Energy: Two Basic Metabolic Pathways Anabolism: requires enzymes: Making/assembling large molecules May require energy (ATP) Used in building up cell components Used in storing energy

Catabolism: requires enzymes: Cells Use and Transform Matter and Energy: Two Basic Metabolic Pathways Catabolism: requires enzymes: Breakdown of molecules May release energy Used in breaking down nutrients/recycling cell components Used to access energy storage

Cellular Respiration: Cells Use Glucose and Oxygen to Supply ATP Glucose provides energy for the cell

Three Stages of Cellular Respiration Glycolysis: in cytoplasm: Split glucose Produce two ATP and two pyruvate molecules Krebs cycle: in mitochondria: Extract high-energy electrons Produce two ATP and carbon dioxide Electron transport system: in mitochondria: Energy from electrons used to produce ATP Produce water and carbon dioxide

Cellular Respiration: An Overview

Fats and Proteins: Additional Energy Sources

Pyruvate has 2 Possible Fates: Anaerobic catabolism: Pyruvate Lactate Aerobic catabolism: Pyruvate Citric Acid Cycle

Electron Transport Chain On the inner membrane of the mitochondria Protein complexes including enzymes and iron- containing proteins called cytochromes Chemiosmotic Theory Movement of electrons through the etc to produce ATP

Steps in the Electron Transport System

Fats and Proteins: Additional Energy Sources Fats: triglycerides have twice the energy of carbohydrates Proteins: same energy as carbohydrates

Anaerobic Pathways: Energy Extraction Without Oxygen

Structure and Function of the Nucleus Functions: Contains the genetic information of the cell Controls the cell Structural features: Double-layered nuclear membrane Nuclear pores Chromosomes/chromatin Nucleolus

Nucleus Control Center Nuclear envelope with nuclear pore complexes for diffusion and active transport Chromatin (DNA and proteins) DNA forms genes One or more nucleoli