Organelles & Their Functions

Organelles are tiny organs inside the cell that do specific jobs The advantage to have organelles is that the cell can do multiple chemical reactions at the same time

Cell Wall 1) Supports & Protects 1) Maintains cell shape 2) Plasmodesmata- channels 3) Found in Prokaryotes & Plants 4) In plants, contains cellulose (rigid shape) Rigid barrier surrounding outside of plasma membrane

Cell Membrane Sometimes called plasma membrane 1) Regulates what enters & exits the cell Only small particles can pass through 2) Defines cell boundary 2) Gives the cell shape(shape determines function)

3) Prokaryote, Plant, Animal 4) Constructed of phospholipid bilayer w/ embedded proteins

Plasma Membrane Phospholipid Bilayer - made of phosphate groups and fatty acid tails Phosphate groups are Polar (like H2O) - hydrophilic Fatty Acid tails are Nonpolar (hate H2O) - hydrophobic Cholesterol – keeps the fatty acid tails from sticking together

Plasma Membrane Boundary between the inside and outside of the cell Allows things to move in and out of the cell Selectively Permeable which means it selects what can come in and out JOB = MAINTAIN HOMEOSTASIS

Plasma Membrane

Glycoproteins Proteins on outside of plasma membrane are receptors or activation sites for enzymes and hormones Sugar proteins on plasma membrane Make cells “sticky” Determine blood type Receptors Viruses, bacteria, toxins, enzymes, hormones Cell to cell communication Alterations in these cause cancer

Cytoplasm 1) Suspends all other organelles within it 2) Colloid- both a solid & a liquid 3) Prokaryote, Plant,Animal 4) Jelly-like consistency Inside cell’s plasma membrane

Nucleus 1) Control Center of the Cell 1) Storage of genetic/hereditary material (DNA/RNA) 2) Synthesis of DNA & RNA 3) Plant, Animal

4) Big, round sphere 4) Nuclear envelope with pores surrounds nucleolus & chromatin

Nucleolus 1) Makes ribosomes (which make proteins) 3) Plant, Animal 4) Sphere inside the nucleus

Nuclear Membrane Sometimes called nuclear envelope Surrounds nucleus 1) Controls what enters & exits the nucleus 3) Plant, Animal 4) Double membrane 4) Studded w/ pores

Nuclear Pores 1) Openings in the nuclear envelope which regulate what enters/exits the nucleus 3) Plant, Animal 4) RNA travels through pores to carry genetic info to ribosomes (where proteins are made)

Chromatin 1) Hereditary material of a non-dividing cell (DNA) 2) Thin, thread-like structures 3) Prokaryote, Plant, Animal 4) Plants & Animals have histones, Prokaryotes do not

Chromosomes 1) Hereditary material of a dividing cell (mitosis or meiosis) (DNA) 2) Thick, rod-shaped structures You have 46 chromosomes 3) Prokaryote, Plant, Animal 4) Prokaryotes only have one chromosome, no histones

Ribosomes 1) Sites of protein synthesis

2) Free ribosomes- make proteins for the cell 2) Bound ribosomes- make proteins to be exported 3) Prokaryotes only have free ribosomes 3) Plant, Animal 4) Prokaryotes- have small ribosomes 4) Eukaryotes- have large ribosomes

Endoplasmic reticulum (ER) Complex, extensive network that transports materials throughout cell

Rough ER 1) Has bound ribosomes 1) Protein synthesis 1) Chemical activity & transport 2) Bound ribosomes make proteins for export from cell Transport by vesicles 3) Plant, Animal 4) Found near nucleus 4) May also be found throughout the cell Site for protein & lipid synthesis

Smooth ER 1) Site for chemical activity 1) Detoxifies poisons 1) Makes phospholipids & cholesterol 2) No ribosomes 3) Plant, Animal 4) Usually found near cell membrane 4) More alcohol/drugs, more smooth ER

Golgi apparatus 1)Manufacture(synthesis) 1)Warehousing (storage) 1)Finishing (packaging) 1)And shipping of proteins & lipids 2) Ships products in vesicles Modifies, sorts, & packages proteins into vesicles & transports them to other organelles or out of the cell

3) Plant, Animal 4) Stack of pancake looking membranes 4) Cis face- receives 4) Trans face- ships

Vacuoles/Vesicles 1) Storage of fluids (food & water) 1) Protection (poisonous fluids) 1) Growth in plants 2) Pumping excess water out of the cell 2) Food transport for digestion by lysosomes 3) Plant, Animal 4) Large, central vacuole in plants (largest organelle in plant cell) Membrane sac for temporary storage of food, enzymes, & wastes

Contractile vacuoles expel excess water.

Lysosomes 1) Digestion 1) Found in cytoplasm 2) Hydrolyzes macromolecules 3) Animals ONLY (“suicide sacs”) 4) Membrane sac of hydrolytic enzymes pH 5 Vesicle that uses enzymes to digest excess or worn-out cellular substances

Lysosome Formation Golgi Complex

Peroxisomes 1) Detoxifies oxygen 1) Contains enzymes that transfer H to O to make H2O 3) Plant, Animal 4) Found in cytoplasm

Mitochondria 1) Sites of cellular respiration 1) Makes ATP 2) Cristae (folds)- make ATP 2) Matrix (fluid)- storage 3) Plant, Animal 4) “Powerhouse” of the cell 4) The more energy needed, the more mitochondria Converts fuel into energy for the rest of the cell

Chloroplast (Plastid) 3) Found ONLY in plant cells 1) Photosyntheis- converts sunlight into chemical energy 2) Thylakoids (pancakes) stack to form granum (grana=plural) 2) Stroma- fluid containing enzymes 4) Chlorophyll traps light 4) Double Membrane

Chromoplast (Plastid) 1) Holds accessory pigments/ color pigments 3) Plants ONLY 4) Where you see yellow, orange, red in fall leaves

Leucoplast (Plastid) 1) Stores starches in plant cells 3) Plants ONLY 4) Starches store energy for plants 4) Lollypop shape

Centrioles 1) Used to move chromosomes during cell division 2) Cells contain 2 of these 2) Found near nucleus 3) Animal ONLY 4) “Twizzler” shape

Cilia & Flagellum 1) Aid in movement/ “locomotion” and food gathering 2) Fluid movement 3) Prokaryote, Animal

Sperm only human cell with flagella Movement Cilia Little hairs Found in respiratory, digestive and reproductive systems Flagella Tails Sperm only human cell with flagella

Cilia with a: TEM SEM

Cytoskeleton 1) Gives shape to cell 1) Movement of cell parts 1) Aids in reproduction 2) Protection 3) Plant, Animal 4) Microtubules- thin, hollow cylinders 4) Intermediate filaments 4) Actin filaments- thread-like fibers Network of protein fibers that support the cell

Plant Cell Animal Cell

Types of Cells Fibroblast Erythrocyte Connect body parts Lots of Rough ER Lots of Golgi Erythrocyte Red blood cells Carries Oxygen Concave disk No cell organelles or nucleus Fibroblasts

Red blood cells in a vein

Types of Cells Epithelial Cells Skeletal Muscle Cells Hexagonal shape Pack together in sheets Exposed surfaces Skeletal Muscle Cells Elongated Shorten to contract Smooth Muscle Cells Human Cheek epithelial

Skeletal Muscle

Smooth Muscle

Types of Cells Fat Cells Macrophage Store nutrients Huge Spherical shape Large lipid droplet in cytoplasm White adipose (adult fat) Brown adipose (baby fat) Macrophage Phagocytic cells Fight disease Pseudopods to crawl to infection sites Lots of lysosomes

Fat Cells

Cross-section of the Pancreas from a person with Diabetes Mellitus showing fibrosis with fat and amyloid replacement in islet cells

Macrophage - SEM

Types of Cells Nerve Cells Reproductive Cells Neurons Gather info Control body functions Reproductive Cells Oocyte (egg) Largest cells in human body Carries all organelles to pass to offspring Sperm Long and streamlined Only contain DNA