Cell Discovery, Theory, & Organelles Direct Instruction Synthesize Notes on 26R

Cell Diversity and Size

First Sightings of Cells Around 1590, the invention of the microscope made it possible for people to discover and learn about objects on the micro (µ) scale. Micro = 10-6

One of the first people to observe cells was Robert Hooke One of the first people to observe cells was Robert Hooke. He looked at cork samples and named what he saw “cells”.

Robert Hook’s composite microscope

Anton von Leeuwenhoek was the first person to observe what are now called bacteria.  Matthias Schleiden found that all plants are made of cells.

Theodor Schwann, found that all animals are made up of cells. Rudolf Virchow proposed that new cells are formed only from existing cells

The Cell Theory One of the fundamental ideas of modern biology Includes 3 principles: 1. All living organisms are composed of one or more cells 2. Cells are the basic unit of structure and organization of all living organisms 3. Cells arise only from previously existing cells

Remember 2 major cell types Prokaryotes Eukaryotes

Prokaryotic cells Cells that do not contain a nucleus & membrane bound organelles Prokaryotes contain DNA, but only a single, circular molecule Which kingdoms contain living organisms with only prokaryotic cells?

PROKARYOTES UNICELLULAR ORGANISMS EXAMPLE= cyanobacteria Fossil 2 billion years old (left) and living (right). Note the similarities in appearance. Interspersed among the cyanobacteria colonies are chains of rod-shaped bacteria.

Eukaryotic cells Contain a nucleus and membrane-bound organelles More advanced – organelles allow specialized cell functions to take place in different parts of the cell at the same time Which kingdoms contain eukaryotic cells?

INTERNAL ORGANIZATION ORGANELLES: CELL COMPONENT THAT PERFORMS SPECIFIC FUNCTIONS FOR THE CELL

Parts of the cell that both eukaryotes and prokaryotes have

Most cells have a: Cell Wall Thick, rigid, mesh of fibers that surrounds the outside of the plasma membrane, protecting the cell and giving it support Which Kingdom does NOT have a cell wall?? Make sure you know what each kingdom’s cell wall is composed of!!

All cells have a: Plasma membrane Plasma membrane – flexible boundary that controls the movement of substances into and out of the cell

Plasma Membrane The plasma membrane has selective permeability: Allows some substances to pass through while keeping others out

Structure of the plasma membrane The plasma membrane can have this selective permeability because it is composed of a phospholipid bilayer Phospholipid bilayer = two layers of phospholipid molecules arranged with polar heads facing outside and nonpolar tails facing inside

Plasma membrane – phospholipid bilayer

Plasma membrane continued… Proteins are embedded in the phospholipid bilayer Held in place by polar (charged)/non-polar attractions Help cells recognize each other Recognize & bind specific substances Move substances in and out of cell

The phospholipids create a “sea” in which other molecules can float, like apples floating in a barrel of water.

All Cells Have CYTOPLASM: CELL GOO INSIDE CELL WHERE THE ORGANELLES ARE LOCATED ALSO CALLED CYTOSOL

Cytoplasm Cytoplasm= semifluid material inside the cell’s plasma membrane In prokaryotes, all of the cell’s functions take place directly in the cytoplasm In eukaryotes, all of the cell’s functions take place within organelles in their cytoplasm Cytoplasm

Cytoskeleton Supporting network of long, thin protein fibers that form a framework for the cell and provide an anchor for the organelles inside the cells

CYTOSKELETON NETWORK OF LONG PROTEIN STRANDS IN THE CYTOSOL NO MEMBRANE AIDS IN MOVEMENT OF ORGANELLES MICROFILAMENTS: THREADS OF A PROTEIN CALLED ACTIN. SMALLEST STRAND MAKES UP CYTOSKELETON

ASSIST IN MOVEMENT OF CHROMOSOME DURING CELL DIVISION MICROTUBLES: LARGEST STRANDS HOLLOW TUBES WHEN CELL IS ABOUT TO DIVIDE BUNDLES COME TOGETHER AND EXTEND ACROSS THE CELL SPINDLE FIBERS: THICK BUNDLES ASSIST IN MOVEMENT OF CHROMOSOME DURING CELL DIVISION

All cells have: RIBOSOMES MAKES PROTEINS MOST NUMEROUS ORGANELLE IN THE CELL NO MEMBRANE 60% RNA AND 40% PROTEINS MAKE UP RIBOSOME'S

PRODUCED & ASSEMBLED IN THE NUCLEOLUS Many Proteins are produced by a specialized cell, e.g. antibodies transported and used elsewhere in the organism WHEN RIBOSOMES ARE ATTACHED TO ER: PROTEINS INSERTED TO MEMBRANES PROTEINS EXPORTED FROM CELL                                                       Electron Micrograph of ribosomes. The ribosomes operate in chains when translating a mRNA.

Proteins (AA chains) being made by ribosomes from mRNA                                                                                                                                      Proteins (AA chains) being made by ribosomes from mRNA Once amino acids bond together to form a chain, it is now a protein, and can be used by the body. Simplified translation on the ribosome

Translation = the language of nucleic acids translated to the language of proteins PROTEIN CHAIN JHK JHK JHK JHK JHK JHK JHK JHK JHK JHK JHK JHK JHK RIBOSOMES Allow PROTEIN CHAINS to be made correctly

Eukaryotes have organelles that prokaryotes do not have.

NUCLEUS: LARGE NEAR CENTER OF CELL CONTAINS MOST OF CELLS GENETIC INFO DIRECTS MOST ACTIVITIES OF CELL

Nucleus In eukaryotic cells, the central membrane-bound organelle that manages cellular functions and contains DNA Surrounded by a nuclear envelope – a double membrane that has nuclear pores to allow substances in and out of the nucleus

NUCLEAR MATRIX= PROTEIN SKELETON NUCLEAR ENVELOPE= DOUBLE MEMBRANE AROUND NUCLEUS CHROMOSOME= DENSELY PACKED (“X”) CHROMATIN CHROMATIN= COMBO OF DNA & PROTEIN (stretched out chromosome) NUCLEAR PORE= SMALL HOLES (Doors) NUCLEOLUS= RIBOSOME SYNTHESIS, PRODUCTION

nucleus nuclear pores

ENDOPLASMIC RETICULUM (ER) A SYSTEM OF MEMBRANE BOUND SACS AND TUBULES INTRACELLULAR “HIGHWAY” MOLECULES MOVE FROM ONE PART OF CELL TO ANOTHER 2 TYPES OF ER: SMOOTH ER= (no ribosomes) ROUGH ER= (COVERED W/RIBOSOMES)

Endoplasmic reticulum Highly folded membrane system in eukaryotic cells that is the site for protein and lipid synthesis

ROUGH ER: MAKE PROTEINS USED FOR EXPORT OUT OF THE CELL ALSO TO BE INSERTED INTO THE CELL MEMBRANE SMOOTH ER: INVOLVED IN PRODUCTION (SYNTHESIS) OF STEROID GLAND CELLS REGULATION OF CALCIUM LEVELS BREAKDOWN OF TOXIC SUBSTANCES BY LIVER CELLS

ROUGH ER SMOOTH ER

Golgi apparatus “UPS crew” Flattened stacks or sacs of membranes that modifies, sorts, and packages proteins into sacs called vesicles Vesicles can fuse with the cell’s plasma membrane to release proteins to the environment outside of the cell

GOLGI APPARATUS PROCESSING PACKAGING SECRETING ORGANELLE SYSTEM OF MEMBRANES “PANCAKES” MODIFIES PROTEINS FOR EXPORT BY CELL

Vacuoles “storage crew” Membrane-bound vesicle for temporary storage of materials such as food, enzymes, and wastes

LYSOSOME “clean up crew” SMALL SPHERICAL ORGANELLE ENCLOSE ENZYMES in a SINGLE MEMBRANES DIGEST PROTEIN, CARBS., LIPIDS, DNA, RNA When needed: OLD ORGANELLES, VIRUSES, BACTERIA THAT WERE INGESTED RARE IN PLANT CELLS

MITOCHONDRIA CONTAIN THEIR OWN DNA (circular) SURROUNDED BY A DOUBLE MEMBRANE

Mitochondria “Power-house” “Mighty Mouse” Converts fuel (sugars) into the energy molecule ATP for the rest of the cell

MITOCHONDRIA IN HUMAN LIVER CELL TRANSFER ENERGY FROM ORGANIC COMPOUNDS (pyruvate) TO ATP VIA CHEMICAL RXN’S ATP = (AdenosineTriPhosphate) MOLECULE THAT MOST CELLS USE AS ENERGY CURRENCY CAR (MITOCHONDRIA) GASOLINE (CHEMICAL RXN) GAS + ENGINE = CAR STARTS (ATP MADE) CAR RUNS (ENERGY) MITOCHONDRIA IN HUMAN LIVER CELL

SURROUNDED BY: 2 MEMBRANES CRISTAE: OUTER & INNER THE LONG FOLDS OF THE INNER MEMBRANE ENLARGE SURFACE AREA WHERE CHEMICAL RXNS TAKE PLACE

HOW CELLS MOVE CELLS USE HAIRLIKE STRUCTURES THAT EXTEND FROM THE SURFACE OF THE CELL SHORT & IN LARGE QUANTITIES = CILIA LONG & LESS NUMEROUS = FLAGELLA

Cilia and Flagella Flagella Cilia Long, tail-like projection with a whiplike motion that helps a cell move through a watery environment Cilia Short, numerous projections that look like hair and function in cell movement

Plant cells have 3 structures that animal cell lack 1. Cell wall 2. Chloroplasts 3. Central vacuole

Chloroplast Double membrane organelle that captures light energy and converts it to chemical energy through photosynthesis

Central vacuole Membrane bound space that stores water; Aids in the rigidity of the cell

Draw/Color Animal Cell Draw/Color Plant Cell Draw/Color Animal Cell