Cells!

Cells!

http://koning.ecsu.ctstateu.edu/cell/cell.html

Lesson Overview Life Is Cellular

Early Microscopes/Cell Discoveries

• Mid 1600’s: scientists use microscopes to observe living things.

• 1665, Englishman Robert Hooke• Used an early compound microscope• Nonliving thin slice of cork, a plant material. • Made of thousands of tiny, empty chambers • Called them “cells”.

• Holland: Anton van Leeuwenhoek • examined pond water, saw living things! • his own mouth• Discovered what we know today as “bacteria”


Early Microscopes/Cell Discoveries

• In 1838, German botanist Matthias Schleiden

• All plants are made of cells.

• The next year, 1839 German biologist Theodor Schwann

• All animals were made of cells.

• In 1855, German physician Rudolf Virchow

• New cells could be produced only from the division of existing cells,

Cell Theory

• 1)

• 2)

• 3)

Why a theory??

Definition of Cell

A cell is the smallest unit that is capable of performing life

functions.

Examples of Cells

Amoeba Proteus

Plant Stem

Red Blood Cell

Nerve Cell

Bacteria

Two Types of Cells

•Prokaryotic

•Eukaryotic

Prokaryotic

• Do not have structures surrounded by membranes

• Few internal structures

• One-celled organisms– Ex: Bacteria

http://library.thinkquest.org/C004535/prokaryotic_cells.html

ALL LIVING THINGS ARE MADE OF CELLSCells __________ a _____________ ORORGANELLES surroundedby _______________

= ________________

Cells __________ a NUCLEUS ANDORGANELLES surroundedby MEMBRANES

= _________________

http://www.earthlife.net/prokaryotes/welcome.html

http://summit.k12.co.us/schools/shs/computer/tkelley/types.html

Bacterial Cell

Eukaryotic• Contain organelles surrounded by membranes• Have DNA in nucleus• Most living organisms

Plant Animal

http://library.thinkquest.org/C004535/eukaryotic_cells.html

“Typical” Animal Cell

http://web.jjay.cuny.edu/~acarpi/NSC/images/cell.gif

http://waynesword.palomar.edu/images/plant3.gif

“Typical” Plant Cell

Cell PartsOrganelles-A minute structure within a plant or animal cell that has a particular job or function.

-Cells are like factories

STRUCTURE= How it is built/constructed

FUNCTION= What it DOES and How it WORKS.

How does its Structure dictate it’s Function?

Structure and Function

Cytoplasm

• Portion of cell outside of nucleus• Holds the organelles• Gel-like mixture• Surrounded by cell membrane• “cyto”= • “plasm” =

NUCLEUS

Largest organelle

in animal cells

Image from: http://www.mccc.edu/~chorba/celldiagram.htm

NUCLEUS

• Surrounded by NUCLEAR ENVELOPE

(also called NUCLEAR MEMBRANE)

DOUBLE MEMBRANE

Image from: http://www.agen.ufl.edu/~chyn/age2062/lect/lect_06/5_11.GIF

NUCLEUS

NUCLEAR PORES

Openings to allow molecules to move in and out of nucleus

Image from: http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookCELL2.html

WHAT DOES IT DO?

Contains genetic material (DNA)

DNA is spread out as CHROMATINin non-dividing cells

DNA is scrunched up as CHROMOSOMES in dividing cells

WHAT DOES IT DO?

Control center of cell

Image from:

Genetic code tells the cell’s parts what to do, gives instructions.

Image from: http://web.jjay.cuny.edu/~acarpi/NSC/12-dna.htm

NUCLEOLUS

Dark spot in nucleus = __________

Makes _______________

Image from: http://lifesci.rutgers.edu/~babiarz/histo/cell/nuc3L.jpg

NUCLEUS NUCLEOLUSSurrounded by ______________ MEMBRANE called the NUCLEAR __________________ ___________ CENTER OF CELL Nuclear ___________ allow molecules in & out CONTAINS CELL’S GENETIC MATERIAL (_______) Dark spot = NUCLEOLUS

makes ___________________ (RNA)

DNA is scrunched up as ______________ in dividing cells.

DNA is spread out as ________________ in non-dividing cells.

Review: Nucleus • Directs cell activities• Separated from cytoplasm by nuclear membrane• Contains genetic material – DNA• Double membrane

• Nickname: “The Control Center”• Function: holds the DNA• Parts: • Nucleolus (noo KLEE uh lus)

– Dark spot in middle of nucleus that helps make ribosomes

Organelles That Store, Clean Up, and Support

• Vacuoles• Lysosomes• Cystoskeleton

Vacuoles:Vacuoles:• The cells

‘storage units’, • Store:

VACUOLES

Large in plant cells

Image from: http://www.biologycorner.com/resources/plant_cell.gif

http://library.thinkquest.org/3564/Cells/cell93.gif

VACUOLES• Storage space for

WATER, salts, proteins (enzymes), carbohydrates, and waste

• Small in ANIMAL CELLS

• NO VACUOLES in bacteria

Vacuoles in plants• In many plant cells,

there is a single, large central vacuole filled with liquid. – Increases their ability

to support heavy structures such as leaves and flowers.

-It’s what makes lettuce crisp– When no water, it wilts


Vacuoles and Vesicles

Nearly all eukaryotic cells contain smaller membrane-enclosed structures called _____________.

Vesicles are used to store and move materials between cell organelles, as well as to and from the cell surface.

VACUOLES VESICLESStorage space for: _______________

Huge in __________cells , small in _____________ cells,Not in _________________

_____________________ are used to store and move materials between organelles

Lysosomes:• the ‘cleanup crews’ of the cell

• Small organelles filled with _________________.

• Breaks down “food:” lipids, proteins, and carbohydrates, into small molecules to be used by rest of cell.

• Also breaks down “old” organelles.

LYSOSOMES

Image modified from: http://www.people.virginia.edu/~rjh9u/lysosome.html

• Can remove junk too

LYSOSOMES

Found in Animal cells and sometimes in Plant cells, although rare

Sac containing _________________________

FUNCTION: Breaks down __________, _________________, ____________

The Cytoskeleton:• Complex network of protein filaments

• Support, maintains cell shape

• Transports materials within the cell, like a conveyor belt

• Helps cells move• Made of proteins• Microfilaments and microtubules are two of the principal protein

filaments that make up the cytoskeleton.

• Microtubules are polymers, circular chains

of a protein known as tubulin.

The Cytoskeleton:

Microfilaments

– Threadlike structures made up of a protein called actin. – Extensive networks – Produce a tough, flexible framework that supports the cell. – Help cells move.

• Microfilament assembly and disassembly is responsible for the cytoplasmic movements that allow cells, such as amoebas, to crawl along surfaces

Microtubules

– Hollow structures made up of proteins known as tubulins.

– Play critical roles in maintaining cell shape.

Microtubules

• Important in cell division

• In animal cells, structures known as centrioles are also formed from tubulins.

• Centrioles are located near the nucleus and help to organize cell division.

• Centrioles are not found in plant cells.

• Microtubules also help to build projections from the cell surface– cilia and flagella– enable cells to swim

rapidly through liquids.

Green---Nuclei

Purple----Microfilaments

Yellow----Microtubules

CENTRIOLES-organize cell division in animals cells

Help separate/sort chromosomes


Organelles That Store, Clean Up, and Support

What are the functions of vacuoles, lysosomes, and the cytoskeleton?

Vacuoles store materials like water, salts, proteins, and carbohydrates.

Lysosomes break down lipids, carbohydrates, and proteins into small

molecules that can be used by the rest of the cell. They are also involved

in breaking down organelles that have outlived their usefulness.

The cytoskeleton helps the cell maintain its shape and is also involved in

movement.

Organelles That Build Proteins

• Ribosomes• Endoplasmic Reticulum (ER)• Golgi Apparatus


Organelles That Build Proteins

• Protein Purpose/Function:• Control rate of reactions• Regulate cell processes (Enzymes in lysosomes)• Form cellular structures (Cytoskeleton)• Transport materials in and out of cell (Cell Membrane proteins)• Help fight disease

• Made of H O N C

• Cells need to build new molecules all the time, especially proteins

• Big part of the cell is devoted to their ______________________ and ____________________________.

• Because proteins carry out so many of the essential functions of living things


Ribosomes • Made of small particles of ________________ and ______________• found throughout the cytoplasm in all cells and on Rough ER • Produce/Assemble proteins by following coded instructions from DNA.

• Proteins targeted for export to the cell membrane or to specilazed locations within the cell, complete their assembly on ribosomes BOUND to the RoughEndoplasmic Reticulum

RIBOSOMES

• Protein factory for cell• Join amino acids to make polypeptide

chains which make up proteins.

Image from: http://www.ust.hk/roundtable/hi-tech.series/1_b1.jpg

Image by: RIedell

RIBOSOMESCan be __________________ or __________ to Rough ER

MADE OF ______________ & ________

FUNCTION: _____________________

Found in _____________ types of cells


Endoplasmic Reticulum • Internal membrane system

• In Eukaryotic cells

• Assemble:

• Assemble some ___________________and other materials that are exported from the cell.


Rough Endoplasmic Reticulum , ER

• Involved in the synthesis of proteins • Given this name because of the ribosomes found on its surface

• Newly made proteins leave these ribosomes and are inserted into the rough ER, where they may be chemically modified.


Smooth Endoplasmic Reticulum, ER

• The other portion of the ER • Ribosomes are not found on its surface…so Smooth

• Contains collections of enzymes that perform specialized tasks• S• D


Golgi Apparatus

• Proteins produced in the rough ER move next into the Golgi apparatus, which appears as a stack of flattened membranes

-like a “flattened stack of pancakes”

• Proteins are bundled into tiny vesicles that bud from the ER and carry them to the Golgi apparatus.


• _______________, _____________, and _________________ proteins and other materials from the ER for storage in the cell or release outside the cell.

• Like a customization shop, where the finishing touches are put on proteins before they are ready to leave the “factory.”

Golgi Apparatus


Then…..Proteins are “shipped” to their final destination inside or outside the cell, via vesicles.

Golgi Apparatus


Review: Organelles That Build Proteins

What organelles help make and transport proteins?

Proteins are assembled on ribosomes.

Proteins made on the rough endoplasmic reticulum include those that will be released, or secreted, from the cell as well as many membrane proteins and proteins destined for lysosomes and other specialized locations within the cell.

The Golgi apparatus modifies, sorts, and packages proteins and other materials from the endoplasmic reticulum for storage in the cell or release outside the cell.


Organelles That Capture and Release Energy

• Mitochondria (myt oh KAHN dree uh) (plural)

• Mitochondrion (singular)

• Chloroplasts (KLAWR uh plasts)



• All living things require a source of energy. • powered by food molecules that are built using energy from the sun.

Organelles involved ------Chloroplasts and mitochondria


Chloroplasts • In plants and some other organisms

(protists, algae)

• The biological equivalents of solar power plants.

• Capture the energy from sunlight and convert it into food that contains chemical energy

=

(More on this in Chapter 8)

Contain _________________

= Green Pigment

CHLOROPLASTS

Surrounded by double membrane

Has its own DNA molecules

http://media.pearsoncmg.com/bc/bc_campbell_essentials_2/cipl/04/HTML/source/04-17-chloroplast-nl.htm

You will learn all these minute structures in Chapter 8

CHLOROPLASTSurrounded by ____________ membrane Contain_____________________,a green pigment

FOUND ONLY IN _____________ CELLS and some other photosynthetic organisms.

___________________________ is the name of the process that plants do, converting sun energy to food!

MITOCHONDRION (plural=MITOCHONDRIA

)

Look like “little sausages”

Image from: http://instructional1.calstatela.edu/dfrankl/CURR/kin150/Images/mitochondria.jpg


Mitochondria • Found in nearly all eukaryotic cells, including plants

• Mitochondria are the power plants of the cell.

Convert the chemical energy stored in food into compounds that are more convenient for the cell to use.

MITOCHONDRIA• Surrounded by aDOUBLE membrane

• Folded inner membrane increases surface areafor more chemical

reactionsImage from: http://www.biologyclass.net/mitochondria.jpe

•Has its own DNA

MITOCHONDRIA

Come from cytoplasm in EGG

You inherit your mitochondria from your mother!

http://www.wappingersschools.org/RCK/staff/teacherhp/johnson/visualvocab/p14%5b1%5d.jpg

MITOCHONDRION (pl. MITOCHONDRIA)

Surrounded by _____________ membrane

Contains its own ___________

_____________ of cell


Mitochondria and Chloroplasts

• Chloroplasts and mitochondria contain their own genetic information in the form of small DNA molecules.

• The endosymbiotic theory suggests that chloroplasts and mitochondria may have descended from independent microorganisms.



What are the functions of chloroplasts and mitochondria?

Chloroplasts capture the energy from sunlight and convert it into food that

contains chemical energy in a process called photosynthesis.

Mitochondria convert the chemical energy stored in food into compounds

that are more convenient for the cells to use.


Cellular Boundaries

• Cell Membrane• Cell wall


Cellular Boundaries

• Cells are surrounded by a barrier known as the cell membrane.

• Many cells, also produce a strong supporting layer around the membrane known as a cell wall.


function: provide support and protection for the cell.

Who has a cell wall?

Prokaryotes

plants

Algae

fungi

and many prokaryotes

Animal cells do not have cell walls.

• Lie outside the cell membrane • Most are porous enough to allow water, oxygen, carbon dioxide, and

certain other substances to pass through easily.

Cell Walls


Cell Membranes

FUNCTION:• R• S

• Found in ALL cells, prokaryotes and eukaryotes


Cell Membranes

• double-layered sheet called a __________ ___________

• gives cell membranes a flexible yet strong structure• forms a barrier between the cell and its surroundings.


Cell Membranes:The Properties of Lipids

• oily fatty acid chains interact strongly with water.

• The fatty acid portions of a lipid are _______________, or “water-hating,” • the glycerol end of the molecule is ________________, or “water-loving.”

LIPID TAILS ARE HYDROPHOBIC

HYDROPHILIC

“water loving”

HYDROPHOBIC

“water-hating”

Image by Riedell


Cell Membranes:The Properties of Lipids

When such lipids are mixed with water, their hydrophobic fatty acid “tails” cluster together while their hydrophilic “heads” are attracted to water.

A lipid bilayer is the result.


The Properties of Lipids

• Head groups of lipids in a bilayer are exposed to water• Fatty acid tails form an oily layer inside the membrane

from which water is excluded.

• Oil and water do not mix

Cell Membrane:The Fluid Mosaic Model • Protein molecules

are embedded in the lipid bilayer.

• Form channels and pump

• moves materials across cell membrane

• carbohydrate molecules attached to proteins

• act like chemical identification cards


The Fluid Mosaic Model proteins can move around and “float” different kinds of molecules make up the cell membrane,

so…..scientists describe the cell membrane as a “fluid mosaic.”

Fluid= can move “mosaic” has different parts

Cell membranes MOVE!

Molecules in cell membranes are

constantly moving and changing

= “Fluid Mosaic Model”

Animation from: http://www.sp.uconn.edu/~terry/images/anim/fluidmem.gif


The Fluid Mosaic Model

• Many substances can cross biological membranes, • Some are too large or too strongly charged to cross the lipid bilayer.

• If a substance can cross a membrane = permeable membrane

• If a substance cannot pass through = impermeable membrane

• Most biological membranes are selectively permeable, • some substances can pass across them and others cannot. • Selectively permeable membranes = semipermeable

membranes.


Cellular Boundaries

What is the function of the cell membrane?

The cell membrane regulates what enters and leaves the cell and also protects and supports the cell.

Only in Plant Cells:

Compare

Only in Plant Cells Only in Animal Cells

Compare/Contrast

Prokaryotes• DNA not in a nucleus• No membrane bound

organelles• No mitochondria

• Cell wall • Cell membrane• Ribosomes

Eukaryotes• Has a nucleus• Membrane bound

organelles• Mitochondria/Chloroplast

• Some cell walls• Cell membrane• Ribosomes

Documents

Cells!