Anton Van Leeuwenhoek – Anton Van Leeuwenhoek –

1600’s1600’s

Dutch merchant Dutch merchant used magnifying used magnifying glass to view clothglass to view cloth

Developed first Developed first usable microscope.usable microscope.

First person to view First person to view small organisms in small organisms in pond water.pond water.

Leeuwenhoek first to view Leeuwenhoek first to view bacteriabacteria

Leeuwenhoek took Leeuwenhoek took samples of pond samples of pond water and view water and view them through his them through his microscope.microscope.

SpirochetesSpirochetes AlgaeAlgae ProtistsProtists

Robert Hooke develops simple Robert Hooke develops simple microscope- 1665microscope- 1665

English physicist, English physicist, developed first simple developed first simple compound microscopecompound microscope

View cork under View cork under microscope, saw tiny microscope, saw tiny box like structuresbox like structures

Called these structures Called these structures cellulae(monks cellulae(monks chamber)chamber)

Hooke first to use the term cellHooke first to use the term cell

Hooke had discovered Hooke had discovered plant cells -- more plant cells -- more precisely, what Hooke precisely, what Hooke saw were the cell walls saw were the cell walls in cork tissue. In fact, it in cork tissue. In fact, it was Hooke who coined was Hooke who coined the term "cells": the the term "cells": the boxlike cells of cork boxlike cells of cork reminded him of the reminded him of the cells of a monastery.cells of a monastery.

Schleiden and SchwannSchleiden and Schwann develop develop Cell Theory- 1838Cell Theory- 1838

The Cell TheoryThe Cell Theory When Schleiden and When Schleiden and Schwann proposed Schwann proposed the cell theory in the cell theory in 1838, cell biology 1838, cell biology research was forever research was forever changed. changed. The cell The cell theory states that: theory states that:

All life forms are All life forms are made from one or made from one or more cells.more cells.

The cell is the The cell is the smallest form of life.smallest form of life.

Virchow modifies Cell TheoryVirchow modifies Cell Theory

Twenty years later in Twenty years later in 18551855 Rudolf VirchowRudolf Virchow proposed an important proposed an important extension of cell theory extension of cell theory that that "All living cells "All living cells arise from pre-arise from pre-existing cells"existing cells". . (("Omnis cellula e "Omnis cellula e celula"celula") This statement ) This statement has become what is has become what is known as the "known as the "Biogenic Biogenic lawlaw".".

Basic Cell StructureBasic Cell Structure Cells range in size Cells range in size

from 0.2um to 7 ft.from 0.2um to 7 ft. All cells have certain All cells have certain

basic structures.basic structures. Cell Membrane – thin Cell Membrane – thin

flexible layer,usually flexible layer,usually a bi-layer of a bi-layer of phospholipidsphospholipids

Cytoplasm – colloidal Cytoplasm – colloidal material, acts as material, acts as cushioncushion

Two basic types of cellsTwo basic types of cells

Prokaryotic cells – “pre-kernel” most Prokaryotic cells – “pre-kernel” most likely first type of cell. Capable of likely first type of cell. Capable of carrying out all requirements of life. carrying out all requirements of life. Unicellular organisms onlyUnicellular organisms only

Eukaryotic cells- “true-kernel” most Eukaryotic cells- “true-kernel” most abundant type of cells. Both abundant type of cells. Both unicellular and multicellular unicellular and multicellular organisms. organisms.

Prokaryotic Cells – Bacteria cells Prokaryotic Cells – Bacteria cells onlyonly

No membrane No membrane bound organelles.bound organelles.

No nucleusNo nucleus Simpler of the two Simpler of the two

types.types. Bacteria cells onlyBacteria cells only

EubacteriaEubacteria ArcheabacteriaArcheabacteria

Eukaryotic Cells- Protista, Fungi, Eukaryotic Cells- Protista, Fungi, Plants, and AnimalsPlants, and Animals

Membrane bound Membrane bound organelles organelles presentpresent

Nucleus presentNucleus present Most complex of Most complex of

the two types of the two types of cellscells

Cell StructuresCell Structures Cell Membrane – all Cell Membrane – all

cells have a cell cells have a cell membrane membrane

composed of a bi-composed of a bi-layer of phospholipids.layer of phospholipids.

Hydrophilic – water Hydrophilic – water lovingloving

Hydrophobic – water Hydrophobic – water fearingfearing

selectively permeable.selectively permeable. flexible, but strongflexible, but strong

Inside of cell Outside of Cell

HydrophilicHydrophobic

Plant cells and certain Plant cells and certain prokaryotic cells have cell wallsprokaryotic cells have cell walls

FunctionFunction Provides support Provides support

and protection for and protection for cell.cell.

Composed of Composed of cellulose and cellulose and pectin.pectin.

NOT FOUND IN NOT FOUND IN ANIMALSANIMALS

NUCLEUSNUCLEUS First identified by First identified by

Robert Brown,1831Robert Brown,1831 Nucleus functions as Nucleus functions as

the control center for the control center for cell.cell.

Contains:Contains: Chromatin –appears Chromatin –appears

as a granular as a granular material, consists of material, consists of DNA and proteinsDNA and proteins

Nucleolus – Nucleolus – assembles assembles ribosomesribosomes

Nuclear envelope – Nuclear envelope – surrounds nucleussurrounds nucleus

CYTOSKELETONCYTOSKELETON Gives cell shape, Gives cell shape,

support, movement support, movement and is used during and is used during mitosis to aids in mitosis to aids in cell division.cell division.

Composed of two Composed of two primary filamentsprimary filaments..

Microtubules – Microtubules – hollow tubes of hollow tubes of protein, used to protein, used to maintain shape, maintain shape, aid in movement aid in movement and especially and especially important in cell important in cell division.division.

CYTOSKELETONCYTOSKELETON

Microfilaments – also known as Microfilaments – also known as actin filaments, small actin protein actin filaments, small actin protein filaments.filaments.

Provides support for cell, and aids Provides support for cell, and aids in the movement of organelles in the movement of organelles with in the cellswith in the cells

Certain cytoskeleton proteins will Certain cytoskeleton proteins will become cilia or flagellum.become cilia or flagellum.

Organelles in the Organelles in the cytoplasmcytoplasm

Ribosomes can be Ribosomes can be considered the considered the matchmakers of the matchmakers of the protein making protein making process. process.

Ribosomes are either Ribosomes are either free floating in the free floating in the cytoplasm of a cell or cytoplasm of a cell or attached to attached to endoplasmic endoplasmic reticulum in a cell.reticulum in a cell.

OrganellesOrganelles

Endoplasmic reticulum Endoplasmic reticulum (ER)(ER)

Two types, smooth no Two types, smooth no ribosomes attached, ribosomes attached, rough ribosomes are rough ribosomes are attached.attached.

ER assembles ER assembles components for cell components for cell membrane.Helps to membrane.Helps to modify certain modify certain proteinsproteins

OrganellesOrganelles Golgi Apparatus – Golgi Apparatus –

consists of many consists of many folded and stacked folded and stacked membranesmembranes

Packages and Packages and moves proteins to moves proteins to their final their final destination.destination.

Attaches Attaches carbohydrates and carbohydrates and lipids to proteins.lipids to proteins.

OrganellesOrganelles Lysosomes – enzyme Lysosomes – enzyme

containing sacks.containing sacks. Releases Releases

enzymes to break enzymes to break down lipids, down lipids, carbohydrates carbohydrates and proteins. and proteins.

Breaks down old Breaks down old organelles, organelles, removes debris removes debris and recycles it.and recycles it.

OrganellesOrganelles Vacuole- stores Vacuole- stores

materials such as materials such as water, salt and water, salt and carbohydrates.carbohydrates.

Saclike structure, most Saclike structure, most plants will have a large plants will have a large single vacuole. The single vacuole. The pressure in this large pressure in this large vacuole helps give vacuole helps give support to heavy support to heavy structure in plants. structure in plants. Animals will have Animals will have several small vacuoles several small vacuoles also called vesicles.also called vesicles.

Vacuole

OrganellesOrganelles Mitochondria – Mitochondria –

powerhouse of the cell. powerhouse of the cell. Take glucose and Take glucose and converts it to energy that converts it to energy that the cell can use (ATP).the cell can use (ATP).

Double folded membrane Double folded membrane found in over 97% of all found in over 97% of all eukaryotic cells, eukaryotic cells, including plant cells.including plant cells.

Once believed to be its Once believed to be its own organism.own organism.

Has its own DNAHas its own DNA

Organelles – special to plantsOrganelles – special to plants Chloroplasts – used Chloroplasts – used

in photosynthesis. in photosynthesis. Converts light energy Converts light energy to chemical energy. to chemical energy.

Found in plants and Found in plants and certain protists. certain protists. NEVER in ANIMAL NEVER in ANIMAL CELLS.CELLS.

Contains chlorophyll Contains chlorophyll and other pigments.and other pigments.

Has its own DNAHas its own DNA

Origin of the CellOrigin of the Cell First cells believed to be a First cells believed to be a

prokaryotic. prokaryotic. Built in mechanisms for survival.Built in mechanisms for survival. Eukaryotic cells believed to have Eukaryotic cells believed to have

formed a symbiotic relationship with formed a symbiotic relationship with prokaryotic organisms.prokaryotic organisms.

Mitochondria and Chloroplasts Mitochondria and Chloroplasts believed to have been separate believed to have been separate prokaryotic organisms at one time. prokaryotic organisms at one time. DNA in these organelles come from DNA in these organelles come from mother only.mother only.

The primordial Earth was a very different place than today, with greater amounts of energy, stronger storms, etc. The oceans were a "soup" of organic compounds that formed by inorganic processes (although this soup would not taste umm ummm good). Miller's (and subsequent) experiments have not proven life originated in this way, only that conditions thought to have existed over 3 billion years ago were such that the spontaneous (inorganic) formation of organic macromolecules could have taken place.

Getting things into the cellGetting things into the cell The cell membrane is a The cell membrane is a

selectively permeable selectively permeable membrane, but things membrane, but things must get into the cell. must get into the cell.

Water can enter the cell Water can enter the cell through a process called through a process called Osmosis.Osmosis.

Glucose will enter the Glucose will enter the cell through facilitated cell through facilitated diffusiondiffusion

Large protein move into Large protein move into the cell by endocytosisthe cell by endocytosis

DiffusionDiffusion

Diffusion is the movement of Diffusion is the movement of molecules from a region in which molecules from a region in which they are highly concentrated to a they are highly concentrated to a region in which they are less region in which they are less concentratedconcentrated..

Does not require any energy Does not require any energy (passive).(passive).

Allows particles to reach lowest Allows particles to reach lowest state of energy. state of energy.

Diffusion Across Cell Diffusion Across Cell MembraneMembrane

Molecules such as:Molecules such as: OxygenOxygen Carbon dioxideCarbon dioxide NitrogenNitrogen Important to allow cell to function Important to allow cell to function

when energy is not availablewhen energy is not available Allows for respiration to occurAllows for respiration to occur

OsmosisOsmosis

Movement of water from an area Movement of water from an area of low solute to an area of higher of low solute to an area of higher solute.solute.

No energy required (passive)No energy required (passive) Only water movesOnly water moves Major method of getting water into Major method of getting water into

the cell.the cell.

OsmosisOsmosis

OsmosisOsmosis

Solutions and Solutions and ConcentrationsConcentrations

Hypertonic solutions contain higher concentrations of solutes than those in surrounding cells resulting in the cell shrinking in size.

Hypotonic solutions contain lower concentrations of solutes than those in surrounding cells resulting in the cell swelling.

Isotonic solutions contain equal concentrations of solutes than those in surrounding cells and the cell volume remains unchanged .