HLE U7 00 skh 2015 cell theory and organelles honors

(1)

(2)

What is this

(3)

The Compound Light

Microscope

 can produce magnifications of 50X to

(4)

Electron Microscope

 Uses a beam of electrons

 Magnifying powers in excess of

100,000X

(5)

Robert Hooke (1665)

 British scientist

 used a microscope to study a thin slice of cork from the bark of an oak tree

 named the box-like structures “cells”

(6)

Anton van Leeuwenhoek

(1600s)

 Dutch businessman; his single-lens microscope magnified

(7)

Robert Brown (1831)

 Scottish botanist; used newly developed stains; first to

(8)

Matthias Schleiden

(1838)

(9)

Theodor Schwann (1839)

(10)

Rudolf Virchow (1855)

 German physician; studied cell reproduction

(11)

Cell Theory

(12)

Cell Theory

1. All living things are made up of cells

2. Cells are the basic units of

structure and function in living things

(13)

The Cell

(14)

The Cell

(15)

Two Main Types of

Cells

Eukaryotic cells

Found in plants, fungi, animals and Protists

1. Have a true nucleus containing chromosomes

2. Contain several membrane bound

organelles

(16)

Two Main Types of

Cells

Prokaryotic cells

- Ex: Bacteria

- 1/10th the size of eukaryotic cells

- No nucleus

(17)

Prokaryotic cell

(18)

Why are Cells Small

The Volume of a cell determines the amount of metabolic activity it carries out

The Surface Area of the cell determines the amount of

substances that are carried into the cell and the amount of waste

(19)

Why are Cells Small

As a cell gets bigger the volume increases

(20)

Parts of the Eukaryotic

Cell

(21)

(22)

Cell Organelles

 “little organs”

 specialized parts of the cell which carry out specific life functions

(23)

1. Plasma Membrane

( Cell Membrane )

 separates cell from surrounding environment

 controls the movement of molecules into or out of the cell

 selectively permeable (semi-permeable)

 visible with the compound

(24)

The Cell Membrane Structure

Fluid Mosaic Model

Phospholipid Bilayer

Made up of two layers of phospholipids

 Flexible structure with freely moving

pieces

(25)

phospholipid

(26)

Phospholipid bilayer

 Polar heads: hydrophilic

(water-loving); in contact with cytoplasm/extracellular fluid

 Non-polar tails: hydrophobic

(27)

Phospholipid Bilayer

(28)

Fluid Mosaic Model of Membrane

Structure

 Integral proteins: are proteins

extend through the membrane or

(29)

Fluid Mosaic Model of Membrane

Structure

Peripheral Proteins are on the outer/inner surface of membrane

They act as receptors and they attract substances to cell

membrane and aide in

(30)

(31)

Fluid Mosaic Model of Membrane

Structure

Carbohydrates are on the outer surface for cell communication

Cholesterol is imbedded in the bilayer to give the membrane additional

support

(32)

(33)

Cell Membrane

(34)

Fluid Mosaic Model of Membrane

Structure

(35)

2. Cytoplasm

 watery material within the cell membrane

 suspends organelles

 site of chemical reactions

(36)

3. Nucleus

 contains DNA on

structures called chromosomes

 surrounded by a nuclear

membrane that has pores (selectively permeable)

 visible under the

(37)

Nucleus

(38)

4. Nucleolus

 located within the nucleus

(39)

In notebook: Sketch and label the Nucleus, Cytoplasm and Cell Membrane of these three cells

________________________________________________________________________

(40)

5. Ribosomes

 site of protein synthesis

 some ribosomes are found in the cytoplasm

(41)

The Endomembrane

System

 Includes the:

1. Endoplasmic reticulum 2. Golgi apparatus

(42)

6. Endoplasmic

Reticulum

 network of channels for carrying substances from one part of the cell to another

(43)

There are two types of endoplasmic

reticulum (ER)

 Rough ER is

(44)

There are two types of

endoplasmic reticulum (ER)

 smooth ER

 lacks ribosomes

 involved in synthesis of

lipids

 metabolism of

carbohydrates

 detoxification of drugs

(45)

(46)

7. Golgi apparatus

(47)

8. Golgi apparatus

 stacks of membranes forming flattened

sacs

 process, package, store cell products to be

secreted (transported out of the cell)

Ribosomes ►RER ►SER ►Golgi ► Vacuole ► cell membrane ►release from cell

Golgi apparatus animation

(48)

Exocytosis

Exocytosis – release of a substance outside – release of a substance outside of the cell membrane by the fusion of a

of the cell membrane by the fusion of a

vacuole

(49)

9. Lysosomes

 sac of digestive

enzymes

 digest organic

molecules, worn-out cell structures,

(50)

(51)

10. Vacuoles



variety of functions:

1) food vacuoles

2) contractile vacuoles in freshwater protists pump out excess water (In action)

3) plant cells have a large central vacuole for water and nutrient storage

(52)

(53)

11. Mitochondria

 “powerhouse of the cell”

 site of cellular aerobic respiration:

glucose + oxygen is converted to energy in the form of ATP

 each cell contains between 300-800

mitochondria depending on activity level

 has a double membrane

 inner membrane has many foldings =

(54)

(55)

Mitochondria

_Mitochondria

 although most of a cell's DNA is

contained in the cell nucleus,

(56)

Endosymbiotic Theory

 mitochondria are descended from independent prokaryotes that

were engulfed by other cells but not digested

 the mitochondria gave the cell that engulfed it a selective

(57)

Endosymbiotic Theory

(58)

12.

12. Centrioles/Centrosome

Centrioles/Centrosome

 small bundle of

microtubules

 found in pairs near cell

nucleus

 A pair is called is called a

Centrosome

 involved in cell division  found in animal cells but

(59)

Plant Cells

 DO NOT have Centrioles  Have Chloroplasts

 Have Cell Wall – Cellulose

(60)

13. Plastids

 Found ONLY in plants and algae  Double Membrane

 Three types:

1. Chloroplast – Green and site of Photosynthesis (See Next two slides)

2. Leucoplast – Colorless and store starch – mainly found in roots

(61)

(62)

Chloroplasts

(63)

Chloroplasts

 contain their own DNA

 chloroplasts are also part of the

(64)

14. Cell Wall

 found in plant cells only

 made of cellulose

 provides protection & structure for the cell; prevents

(65)

15. Cytoskeleton

 a network of fibers extending throughout the cytoplasm

 is made up of microtubules and

microfilaments

 functions:

(66)

 Microfilaments are made up of a protein called actin.

(67)

 The cytoskeleton can change the shape of a cell

– _{This allows cells like}

amoebae to move

Figure 4.19B

(68)

(69)

Cilia and Flagella

 Cilia and Flagella are motile appendages that

(70)

 Flagella propel the cell

in a whip like motion

• _Cilia_{move in a}

coordinated back-and-forth motion

(71)

Spindle Fibers

 Centrioles lie near the nucleus

(72)

Microtubule Arrangement

 Centrioles and Spindle Fibers: ( 9 Triplets)

Consists in 9 Triplets of

(73)

Microtubule Arrangement

 Cilia and Flagella: ( 9 + 2 )

Consists in 9 Pairs of microtubules around

(74)