General physiology Mrs kalpana B Assistant professor Physiology

General physiology Mrs kalpana. B Assistant professor Physiology

LEVELS OF ORGANIZATION Living Levels: 1. CELL (makes up ALL organisms) 2. TISSUE (cells working together 3. ORGAN (heart, brain, stomach …) 4. ORGAN SYSTEMS (respiratory, circulatory …) 5. ORGANISM copyright cmassengale 2

First to View Cells • Robert Hooke • Smallest living unit • Most are microscopic copyright cmassengale 3

CELL THEORY • All living things are made of cells • Basic unit of life • Undergoes cell division copyright cmassengale 4

Plant Cell Organelles copyright cmassengale 5

Representative Animal Cell

Cell Structure • Cell Membrane • Cytoplasm • Nucleus

Cell or Plasma Membrane • Composed of double layer of phospholipids and proteins • Controls what enters or leaves the cell Outside of cell Proteins Carbohydrate chains Cell membrane Inside of cell (cytoplasm) Protein channel copyright cmassengale Lipid bilayer 8

• • Diameter 7. 5 nm Made up of phospholipids and proteins Lipids- 20 -40% Proteins-60 -70% • Lipoproteins • Glycoproteins

Phospholipids • Heads contain glycerol & phosphate and are hydrophilic (attract water) • Tails are made of fatty acids and are hydrophobic (repel water) • Make up a bilayer where tails point inward toward each other copyright cmassengale 10

Cell Membrane Proteins • Aid in cell recognition • Peripheral proteins • Integral proteins copyright cmassengale 11

ü INTRINSIC PROTEINS – ENZYMES ü PERIPHERAL PROTEINS- CYTOSKELETON ü TRANSMEMBRANE PROTEINS CHANNELS CARRIERS PUMPS RECEPTORS

• • Functions of proteins Structural support Act as antigen As channels and pores. Carrier proteins Act as enzymes Receptors

Many Functions of Membrane Proteins Outside Plasma membrane Inside Transporter Enzyme activity Cell surface receptor Cell surface identity marker Cell adhesion Attachment to the cytoskeleton

Outside of cell Proteins Lipid Bilayer Transport Protein Carbohydrate chains Phospholipids Inside of cell

The Cell Membrane is Fluid mosaic model Molecules in cell membranes are constantly moving and changing copyright cmassengale 16

Functions of the cell membrane • • • 1. PROTECTIVE FUNCTION 2. AS A SEMIPERMEABLE MEMBRANE 3. ABSORPTIVE FUNCTION 4. EXCRETORY FUNCTION 5. EXCHANGE OF GASES 6. MAINTAINENCE OF SIZE AND SHAPE OF THE CELL

ORGANELLS IN CYTOPLASM • Membrane-bound intracellular compartments. • Contain specific chemicals to perform specific cellular function.

ENDOPLASMIC RETICULUM • Interconnected network of tubular and vesicular structure • Forms the link between nucleus and cell membrane Two types • Rough endoplasmic reticulum • Smooth endoplasmic reticulum

Functions of RER Anchorage of newly synthesize proteins. Functions of the SER synthesis of lipids, processing of sugars, and detoxification of drugs and poisons -sarcoplasmic reticulum

GOLGI APPARATUS • • Cluster of flattened membranous sacs Stores, modifies and packages proteins Forms glycoprotein Molecules transported to and from the Golgi by means of vesicles

LYSOSOMES • Digest foreign molecules & damaged organelles • Contain digestive enzymes that break down wastes

MITOCHONDRIA • Surrounded by a DOUBLE membrane • Has its own DNA • Folded inner membrane called CRISTAE • Respriatory enzymes are present in cristae. Cristae contains matrix • Matrix contains DNA and RNA copyright cmassengale

What do mitochondria do? “Power plant” of the cell Burns glucose to release energy (ATP) Stores energy as ATP copyright cmassengale 26

The Control Organelle - Nucleus • Controls the normal activities of the cell • Contains the DNA in chromosomes • Bounded by a nuclear envelope (membrane) with pores • Usually the largest organelle copyright cmassengale 27

Nuclear Envelope • Double membrane surrounding nucleus • Also called nuclear membrane • Contains nuclear pores for materials to enter & leave nucleus • Connected to the rough ER Nuclear pores copyright cmassengale 28

Nucleus • Each cell has fixed number of chromosomes that carry genes • Genes control cell characteristics copyright cmassengale 29

Inside the Nucleus The genetic material (DNA) is found DNA is spread out And appears as CHROMATIN in non-dividing cells DNA is condensed & wrapped around proteins forming as CHROMOSOMES in dividing cells copyright cmassengale 30

PEROXISOMES Function to rid the cell of toxic substances, in particular, hydrogen peroxide

CENTROSOMES • Centrosome is the cellular organelles situated near the center of the cell close to the cell • Movement of the chromosome during cell division

RIBOSOMES • Protein synthesis machinery. • Free floating in cytoplasm. • Bound to rough-Endoplasmic Reticulum (RER) in Eukaryotes. • Consists of multiple subunits composed of RNA-protein complexes.

CYTOSKELETON • Provides shape and structure • Helps move organelles around the cell • Made of three types of filaments