Structure and Function Structure and Function of the Cellof the Cell

Chapter 4Chapter 4

4.1 Discovering the cell…4.1 Discovering the cell…

1665 – Hooke looked at plants under the microscope and saw little boxes– He named them “cells”

1673 – Van Leeuwenhoek was the first to see living cells

Fast Forward…150 years!Fast Forward…150 years!

Schleiden – all plants are composed of cells

Schwann – all animals are composed of – all animals are composed of cellscells

Virchow – cells come only from other cells – cells come only from other cells

These three scientists’ work lead to the These three scientists’ work lead to the modern modern CELL THEORYCELL THEORY

The Cell TheoryThe Cell Theory

1. All living things are composed of cells

2. Cells are the basic unit of an organism

3. Cells only come from the reproduction of preexisting cells.

Cell DiversityCell Diversity

Red Blood Cells Bacterial Cells

Parasitic CellUlcer causing bacteria cells

Your body has over 200 different Your body has over 200 different types of cells!types of cells!

Cell SizeCell Size

Most cells are microscopic

Cell size is limited by the surface area tovolume ratio

Cell ShapeCell Shape

Shape is determined by the function Shape is determined by the function of the cellof the cell

Internal OrganizationInternal Organization

ProkaryoticProkaryotic Vs.Vs. Eukaryotic Cells Eukaryotic Cells

“Before Nucleus”

No Nucleus or Membrane organelles

Single cell organisms

“True Nucleus”

Yes Nucleus and Membrane organelles

Multicellular and singleCell organisms

Surface Area to Volume RatioSurface Area to Volume Ratio

Surface AreaSurface Area : L x W x # of sides : L x W x # of sides

VolumeVolume: L x W x H: L x W x H

RatioRatio : surface area/volume : surface area/volume

Now you try….Now you try….

1.1. Obtain a copy of the lab: Modeling Obtain a copy of the lab: Modeling Cells: Surface Area to Volume AND Cells: Surface Area to Volume AND box paperbox paper

2.2. Cut out boxes and tape them Cut out boxes and tape them together (3 boxes total)together (3 boxes total)

3.3. Complete lab worksheet about Complete lab worksheet about surface area to volume ratiosurface area to volume ratio

All Eukaryotic Cells Have…All Eukaryotic Cells Have…

1.1. A cell membraneA cell membrane

2.2. A nucleusA nucleus

3.3. Other organellesOther organelles

Parts of the Eukaryotic CellParts of the Eukaryotic Cell

The structures are determined by the functions of each part

1. Cell Membrane1. Cell Membrane

FunctionFunction: outer layer of a cell that : outer layer of a cell that allow substances into and out of the allow substances into and out of the cellcell

Selectively permeableSelectively permeable – allows only – allows only certain things to cross the membranecertain things to cross the membrane

Parts of the MembraneParts of the Membrane

Membrane Lipids– Phospholipids

arranged due to their hydrophobic and hydrophilic ends

– Lipid bilayer– Steroid

(cholesterol) embedded within

Parts of the Membrane (cont)Parts of the Membrane (cont)

Membrane ProteinsMembrane Proteins– Peripheral proteinsPeripheral proteins

– attached to either – attached to either side of the cell side of the cell membranemembrane

– Integral proteinsIntegral proteins – – embedded within embedded within the cell membrane the cell membrane and extends out on and extends out on both sidesboth sides

Fluid Mosaic ModelFluid Mosaic Model

Membrane behaves like a liquidMembrane behaves like a liquid– Lateral movement of lipids and proteinsLateral movement of lipids and proteins

MosaicMosaic – changing pattern of proteins – changing pattern of proteins and lipids in the membraneand lipids in the membrane

OrganellesOrganelles

““Mini organs” of the cellMini organs” of the cell

Each organelle has its own structure Each organelle has its own structure and functionand function

All cells have different types and All cells have different types and numbers of organellesnumbers of organelles

NucleusNucleus

FunctionFunction: to store the hereditary : to store the hereditary information of the cell (DNA) and to information of the cell (DNA) and to control the cellcontrol the cell

Contains: nuclear envelope, nuclear Contains: nuclear envelope, nuclear pores, nucleolus, and chromatin pores, nucleolus, and chromatin (chromosomes)(chromosomes)

MitochondriaMitochondria

Function: Function: makes makes ATPATP

““Powerhouse of the Powerhouse of the Cell”Cell”

Rough Endoplasmic ReticulumRough Endoplasmic Reticulum

Function: Function: Makes Makes proteins, proteins, glycoproteins, and glycoproteins, and membranes for membranes for export out of the export out of the cellcell

Covered in Covered in ribosomesribosomes

Smooth Endoplasmic ReticulumSmooth Endoplasmic Reticulum

Function: Function: Makes Makes lipids, metabolizes lipids, metabolizes carbohydrates, and carbohydrates, and detoxification detoxification center for the cellcenter for the cell

RibosomesRibosomes

Function:Function: Protein Protein synthesis synthesis

Attached to E.R. Attached to E.R. or free in or free in cytoplasmcytoplasm

Made in nucleus Made in nucleus and completed in and completed in cytoplasmcytoplasm

Golgi ApparatusGolgi Apparatus Function:Function:

Manufacturing, Manufacturing, warehousing, sorting, warehousing, sorting, and shipping materials and shipping materials out of the cellout of the cell

LysosomesLysosomes

Function:Function: Digests Digests (breaks down) (breaks down) macromolecules macromolecules the are in the cell, the are in the cell, such as proteins such as proteins and carbs.and carbs.

Also breaks down Also breaks down dead cellsdead cells

PeroxisomesPeroxisomes Function:Function: Breaks Breaks

down fatty acidsdown fatty acids

Detoxification Detoxification center in liver cellscenter in liver cells

CytoskeletonCytoskeleton

Function:Function: Support Support system of the cell, aid system of the cell, aid in movement within in movement within the cellthe cell

3 Structural Types:3 Structural Types:

microtubulesmicrotubules

microfilamentsmicrofilaments

intermediate filamentsintermediate filaments

CytoplasmCytoplasm

Function:Function: Holds Holds organelles in the organelles in the cellcell

Site of all chemical Site of all chemical reactions in cellreactions in cell

Cilia and FlagellaCilia and Flagella

Function: Function: Locomotion and Locomotion and movement of movement of materials around materials around the cellthe cell

Animal cells onlyAnimal cells only

Cell WallCell Wall

Function:Function: Protects Protects the cell, gives the the cell, gives the cell shape and cell shape and structural supportstructural support

Plant cellsPlant cells

ChloroplastsChloroplasts

Function: Function: PhotosynthesisPhotosynthesis

Makes energy from Makes energy from the sunthe sun

In plant cellsIn plant cells

Central VacuoleCentral Vacuole

Function:Function: Stores Stores materials materials especially water especially water and waste productsand waste products

In plant cellsIn plant cells