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”
Lesson Overview Life Is Cellular
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 CellsAmoeba 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 nucleusImage 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
NUCLEOLUSDark 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:• 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
Lesson Overview Life Is Cellular
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
Lesson Overview Life Is Cellular
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 smallmolecules that can be used by the rest of the cell. They are also involvedin breaking down organelles that have outlived their usefulness. The cytoskeleton helps the cell maintain its shape and is also involved inmovement.
Organelles That Build Proteins
• Ribosomes• Endoplasmic Reticulum (ER)• Golgi Apparatus
Lesson Overview Life Is Cellular
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
Lesson Overview Life Is Cellular
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
Lesson Overview Life Is Cellular
Endoplasmic Reticulum • Internal membrane system
• In Eukaryotic cells
• Assemble:
• Assemble some ___________________and other materials that are exported from the cell.
Lesson Overview Life Is Cellular
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.
Lesson Overview Life Is Cellular
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
Lesson Overview Life Is Cellular
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.
Lesson Overview Life Is Cellular
• _______________, _____________, 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
Lesson Overview Life Is Cellular
Then…..Proteins are “shipped” to their final destination inside or outside the cell, via vesicles.
Golgi Apparatus
Lesson Overview Life Is Cellular
Review: Organelles That Build ProteinsWhat 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.
Lesson Overview Life Is Cellular
Organelles That Capture and Release Energy
• Mitochondria (myt oh KAHN dree uh) (plural)
• Mitochondrion (singular)
• Chloroplasts (KLAWR uh plasts)
Lesson Overview Life Is Cellular
Organelles That Capture and Release Energy
• 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
Lesson Overview Life Is Cellular
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
Lesson Overview Life Is Cellular
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
Lesson Overview Life Is Cellular
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.
Lesson Overview Life Is Cellular
Organelles That Capture and Release Energy
What are the functions of chloroplasts and mitochondria?
Chloroplasts capture the energy from sunlight and convert it into food thatcontains chemical energy in a process called photosynthesis.
Mitochondria convert the chemical energy stored in food into compoundsthat are more convenient for the cells to use.
Lesson Overview Life Is Cellular
Cellular Boundaries• Cell Membrane• Cell wall
Lesson Overview Life Is Cellular
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.
Lesson Overview Life Is Cellular
function: provide support and protection for the cell.
Who has a cell wall? ProkaryotesplantsAlgaefungiand 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
Lesson Overview Life Is Cellular
Cell Membranes
FUNCTION:• R• S
• Found in ALL cells, prokaryotes and eukaryotes
Lesson Overview Life Is Cellular
Cell Membranes • double-layered sheet called a __________ ___________
• gives cell membranes a flexible yet strong structure• forms a barrier between the cell and its surroundings.
Lesson Overview Life Is Cellular
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
Lesson Overview Life Is Cellular
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.
Lesson Overview Life Is Cellular
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
Lesson Overview Life Is Cellular
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
Lesson Overview Life Is Cellular
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.
Lesson Overview Life Is Cellular
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
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