cellular structure and function chapter 7 section 1: cell discovery and theory section 2: the plasma...
TRANSCRIPT
Cellular Structure and Function
Chapter 7Section 1: Cell Discovery and Theory
Section 2: The Plasma Membrane
Section 3: Structures and Organelles
Section 4: Cellular Transport
Section 1
Section 1: Cell Discovery and Theory
The invention of the microscope led to the discovery of cells.
Section 1: Cell Discovery and Theory
KWhat I Know
WWhat I Want to Find Out
LWhat I Learned
The history of Cell Theory
http://ed.ted.com/lessons/the-wacky-history-of-cell-theory#watch
Cell Discovery and Theory
History of the Cell Theory
• A cell is the basic structural and functional unit of all living organisms.
• Cells are so small that their existence was unknown before the invention of microscopes.
Cell Discovery and Theory
History of the Cell Theory
The cell theory• The cell theory is one of the fundamental ideas of modern biology,
and includes the following three principles:
• All living organisms are composed of one of more cells.
• Cells are the basic unit of structure and organization of all living organisms.
• Cells arise only from previously existing cells, with cells passing copies of their genetic material on to their daughter cells.
Discovery of Cells• Cells are about 1/500th the size of a .• In 1665 Robert Hooke used a 3-lens compound
microscope to examine thin slices of cork.• He observed that cork is made of tiny, hollow
compartments.• He gave them the name “cells”• Hooke was only looking at cell walls & empty space.
Cell Discovery and Theory
Microscope Technology
Compound light microscopes
• Use a series of glass lenses and visible light to magnify images
• Magnify images up to ~1000× actual size
Electron microscopes
• Create an image by illuminating a sample with a beam of electrons and collecting the electrons that are reflected back from the sample
• Magnify images up to 500,000× actual size
Basic Cell Types• All cells have at least one physical trait in common: a plasma
membrane.
• A plasma membrane is a special boundary that helps control what enters and leaves the cell.
• Most cells contain genetic material in some form.
• Most cells break down molecules to generate energy.
• There are two basic kinds of cells: eukaryotic and prokaryotic.
Cell Discovery and Theory
1. ___________________________________________________________
2. ___________________________________________________________
3. ___________________________________________________________
ALL ORGANISMS ARE MADE OF CELLS
THE CELL IS THE MOST BASIC UNIT OF LIFE.
ALL EXISTING CELLS ARE PRODUCED BY OTHER LIVING CELLS
_____________HOOKE
The first to ____________ cells.
Responsible for ____________ them
_____________ _____________ _____________ _____________LEEUWENHOEK SCHLEIDEN SCHWANN VIRCHOW
Made better ______________
and observed cells in greater
______________. First to observe
______________
The first to note that
_____________ were made up of
___________
Concluded that all ___________
___________ were made up of
___________
Proposed that all cells come from ____________
__________
IDENTIFY
NAMING
LENSES
DETAIL
NUCLEUS
PLANTS
CELLS
LIVING THINGS
CELLS
OTHER CELLS
CORK ANIMALCULES RESPONSIBLE FOR CELL THEORY
Basic Cell Types• Eukaryotic cells contain a nucleus and other organelles.
• Organelles are specialized structures that perform specific cell functions.
• The nucleus is the distinct central organelle that contains the cell’s genetic material.
• Eukaryotic cells are generally much larger than prokaryotic cells.
Cell Discovery and Theory
Basic Cell Types• Prokaryotic cells are cells without a nucleus or other membrane-bound
organelles.
• Smaller and simpler than eukaryotes
• Probably similar to first organisms that lived on earth
Cell Discovery and Theory
Basic Cell Types
Origin of cell diversity• Eukaryotic cells may have evolved from prokaryotic cells.
• The endosymbiont theory proposes that a symbiotic relationship formed between two prokaryotic cells, one of which lived inside the other.
• Eventually the symbiotic relationship led to the two cells becoming one.
• Because eukaryotic cells are larger and more complex, they developed specific functions.
• These specific functions led to cell diversity, and thus organismal diversity.
Cell Discovery and Theory
Eukaryotes VS. Prokaryotes
Essential Questions• How are the advances in microscope technology related to
discoveries about cells?
• What are the similarities and differences between compound light microscopes and electron microscopes?
• What are the principles of the cell theory?
• What are the differences between a prokaryotic cell and a eukaryotic cell?
Cell Discovery and Theory
Section 2
Section 2: The Plasma Membrane
The plasma membrane helps to maintain a cell’s homeostasis.
Section 2: The Plasma Membrane
KWhat I Know
WWhat I Want to Find Out
LWhat I Learned
The Cell Membrane
http://ed.ted.com/lessons/insights-into-cell-membranes-via-dish-detergent-ethan-perlstein#watc
The Plasma Membrane
Function of the Plasma Membrane• The process of maintaining balance in an organism’s internal environment is
called homeostasis.
• One of the structures responsible for homeostasis is the plasma membrane.
• The plasma membrane forms a thin, flexible boundary between a cell and its environment.
Function of the Plasma Membrane• Plasma membranes have selective permeability, meaning they
allow some substances to pass through while keeping others out.
• Control of how, when, and how much of various substances enter and leave a cell depends on the structure of the plasma membrane.
The Plasma Membrane
Video
• Selective Permeability
• Selective Permeability 2
Structure of the Plasma Membrane
The phospholipid bilayer
• The plasma membrane is composed of phospholipid bilayer – two layers of phospholipids are arranged to allow the membrane to exist in a watery environment.
• The phospholipid bilayer has polar heads facing outside and nonpolar tails facing inside the cell, allowing the membrane to keep the internal and external environments separate.
The Plasma Membrane
Phospholipids
Structure of the Plasma Membrane
Other components of the plasma membrane• The plasma membrane also contains cholesterol, proteins, and
carbohydrates.
• Some proteins called receptors transmit signals to the inside of the cell.
• Some proteins serve as support structures for the membrane.
• Transport proteins move needed substances and wastes through the membrane.
The Plasma Membrane
Structure of the Plasma Membrane
Other components of the plasma membrane• Cholesterol prevents the fatty acid tails of the phospholipid bilayer
from sticking together.
• Cholesterol contributes to the fluidity of the membrane.
The Plasma Membrane
Structure of the Plasma Membrane
Other components of the plasma membrane• Carbohydrates define the cell’s characteristics
• Help cells identify chemical signals
The Plasma Membrane
Structure of the Plasma Membrane
Other components of the plasma membrane• The fluid mosaic model describes the phospholipids in the bilayer
as a “sea” in which other components can float and move around.
• The different substances in the plasma membrane create a pattern or mosaic on the surface of the cell.
The Plasma Membrane
Fluid Mosaic Model
Essential Questions• How does a cell’s plasma membrane function?
• What are the roles of proteins, carbohydrates, and cholesterol in the plasma membrane?
The Plasma Membrane
Section 3
Section 3: Structures and Organelles
A Tour of the Cell
• https://www.youtube.com/watch?v=1Z9pqST72is
• Crash courses (animal cell then plant)• https://
www.youtube.com/watch?v=cj8dDTHGJBY• https://
www.youtube.com/watch?v=9UvlqAVCoqY
Eukaryotic cells contain organelles that allow the specializations and the separation of functions within the cell.
Section 3: Structures and Organelles
KWhat I Know
WWhat I Want to Find Out
LWhat I Learned
Cytoplasm and Cytoskeleton• The environment enclosed by the plasma membrane is a semifluid
material called cytoplasm.
• In prokaryotes, all the chemical processes of the cell take place directly in the cytoplasm.
• In eukaryotes, these processes take place within organelles in the cytoplasm.
Structures and Organelles
________________________________________________________________________________________
____________________________________________
The clear, jellylike material between the cell membrane and the nucleus that makes up most of the cell
(Most of all cell activity occurs here.)
CYTOPLASM_______________
Cytoplasm and Cytoskeleton• The cytoskeleton is a supporting network of long, thin protein fibers
that form a framework for the cell and proved an anchor for the organelles.
• Microtubules are long, hollow protein cylinders that form a rigid skeleton for the cell and assist in moving substances within the cell.
• Microfilaments are thin protein threads that help give the cell shape and enable the part or the entire cell move.
Structures and Organelles
Cell StructuresThe nucleus• Contains most of the cell’s DNA, which stores information used to
make proteins that determine a cell’s growth, function, and reproduction
• Is surrounded by a double membrane called a nuclear envelope
Structures and Organelles
____________________________________________________________________________________________________
__________________________________
__________________________________
__________________________________
__________________________________
_______________
The control center of the cell.Parts of the Nucleus:
Nuclear Membrane: The membrane that surrounds the nucleus.
Nuclear Pores: allow some particles to move in and out of the nucleusNucleolus
Chromosomes
NUCLEUS
Cell StructuresRibosomes• Ribosomes are organelles that manufacture proteins.
– Not membrane-bound like other organelles– Produced inside the nucleus in the nucleolus
Structures and Organelles
_______________
MAKES PROTEINS FOR THE BODY.
FOUND ON ENDOPLASMICE RETICULUM AND THROUGHOUT CYTOPLASM
RIBOSOMES
_____________________________________
_____________________________________________________________________________________________
Cell StructuresEndoplasmic reticulum• The endoplasmic reticulum (ER) is a membrane system of folded
sacs and interconnected channels that serves as the site for protein and lipid synthesis.
– Two types: rough and smooth
Structures and Organelles
_______________
_______________
________________________________________________________________________________________
____________________________________________
Moves cell materials from cell membrane to nuclear membrane and visa versa.
(Can usually find ribosomes on this network.)
ENDOPLASMIC
RETICULUM
Cell StructuresGolgi apparatus • The Golgi apparatus is a flattened stack of membranes that
modifies, sorts, and packages proteins.• Proteins are packaged into sacs called vesicles, which can fuse to
the plasma membrane and release the proteins to the environment.
Structures and Organelles
______________
______________
_______________________________________
GOLGI
APPARATUS
Packages materials for the cell.
Cell StructuresVacuoles• A vacuole is a membrane bound sac used for temporary storage. • Vacuoles store food, enzymes, or waste.• Vacuoles are only found in plant cells.
Structures and Organelles
____________________________ ________________________________________________________________
_______________________
_______________________________________Stores food and water for cell
________VACUOLE
ANIMAL CELL PLANT CELL
Contains many small vacuoles Contains one large “central vacuole that takes up most of the space
inside of a plant cell
Cell StructuresLysosomes• Lysosomes are vesicles that contain substances that digest excess
or worn-out organelles and food particles.• They also digest bacteria or viruses that invade the cell.
Structures and Organelles
________________________________________________________________________________________
Helps digest, (break down), waste materials of cell.
____________LYSOSOMES
Cell StructuresCentrioles• Centrioles are organelles made of microtubules that function during
cell division.• They are located in the cytoplasm.
Structures and Organelles
____________________________________________Parts of an ANIMAL cell that help with cell REPRODUCTION
Cell StructuresMitochondria• Mitochondria convert fuel particles into usable energy.• They have an outer membrane and a highly folded inner
membrane that provides surface area for breaking the bonds in sugar molecules.
Structures and Organelles
__________________________________________________________________________Responsible for supplying ENERGY to the cell.
____________MITOCHONDRIA
Cell StructuresChloroplasts• Plant cells and some other eukaryotes contain chloroplasts, which
capture light and convert it into chemical energy in process called photosynthesis.
• They are composed of multiple small disks called thylakoids, which contain the light capturing pigment chlorophyll.
Structures and Organelles
__________________________________________________________________________________________________
__________________________________
The plant cell parts that contain the green pigment, chlorophyll, which are responsible for producing food.
CHLOROPLASTS______________________
Cell StructuresCell wall• Plant cells have a cell wall – a thick, rigid, mesh of fibers that
surround the outside of the plasma membrane.– Protect the cell and give it structure– Are made from a carbohydrate called cellulose
Structures and Organelles
____________
_________________________________________________________
__________________________________________________________
__________________________________________________________
The outer most side of an plant cell, (surrounds the cell membrane), that gives the cell structure, and a specific shape.
(More rigid than cell membrane.)
CELL WALL
Cell StructuresCilia and flagella• Cilia are short, numerous projections that look like hair.
• Move in tandem like oars in a rowboat• Flagella are longer and less numerous than cilia.
• Move with a whip-like motion• Both are made of microtubules.
Structures and Organelles
Comparing Cells• Features plant cells have that animal cells generally do not:
• Chloroplasts/chlorophyll
• Vacuoles
• Cell walls
Structures and Organelles
Centrioles
Large central vacuole
Organelles at Work• An understanding of different organelles allows for an
understanding of cellular processes.
• Protein synthesis:• Begins in the nucleus with information contained in DNA
• RNA and ribosomes leave the nucleus and produce a protein on the endoplasmic reticulum.
• Proteins produced in the ER are sent to Golgi apparatus for packaging.
• Packaged proteins are delivered to other organelles where they serve a variety of functions.
Structures and Organelles
Plant vs animal cell rap• https://
www.youtube.com/watch?v=Yu21ShnKhHk
Label the organelles of this animal cell. 1. _________________
2. _________________
3. _________________
4. _________________
5. _________________
6. _________________
7. _________________
8. _________________
9. _________________
10. _________________
11. _________________
12. _________________
13. _________________
1. NUCLEOLUS
2. NUCLEUS
3. RIBOSOMES
4. VESICLE
5. ROUGH ER
6. GOLGI BODIES
7. CELL MEMBRANE
8. SMOOTH ER
9. MITOCHONDRIA
10. VACUOLE
11. CYTOPLASM
12. LYSOSOME
13. CENTRIOLES
1. ____________
2. ____________
3. ____________
4. ____________
5. ____________
6. ____________
7. ____________
8. ____________
ANIMAL CELL
1.__________________
2.__________________
3.__________________
4.__________________
5.__________________
6.__________________
7.__________________
8.__________________
9.__________________
10.__________________
11.__________________
12.__________________
PLANT CELL
Essential Questions• What are the structures of a typical eukaryotic cell, and what are
their functions?
• What are the similarities and differences between plant and animal cells?
Structures and Organelles
Section 4
Section 4: Cellular Transport
Cellular transport moves substances within the cell and moves substances into and out of the cell.
Section 4: Cellular Transport
Diffusion• Particles in solids, liquids, and gasses are in constant random
motion.
• Diffusion is the net movement of particles from an area of high concentration to an area of lower concentration.
• Additional energy is not required for diffusion because the particles are already in motion.
Cellular Transport
Cellular Transport
Diffusion
• When diffusion occurs over a long enough time, concentrations will become uniform, and the solution will reach dynamic equilibrium.
• Molecules continue to move, but the overall concentration remains the same.
Diffusion
Diffusion across the plasma membrane• Water can diffuse across the plasma membrane, but most other
substances cannot.• Facilitated diffusion uses transport proteins to move ions and small
molecules across the plasma membrane.• Diffusion and facilitated diffusion are types of passive transport –
they require no additional energy.
Cellular Transport
Osmosis: Diffusion of Water
How osmosis works• Osmosis is the diffusion of water across a selectively permeable
membrane.• Water is the solvent in a cell and its environment• It will move across a membrane until the concentration of solute is
the same on both sides.
Cellular Transport
• There are three types of solutions. • isotonic – concentrations are equal
Diffusion and Osmosis
• Hypotonic – solution has fewer solutes than a cell, cell expands and may burst
• hypertonic – solution has more solutes than a cell, cell shrivels and dies
hypertonichypotonic
Cellular Transport
Active Transport• Sometimes substances must move from an area of lower
concentration to an area of higher concentration.• Movement of particles across the cell membrane, against the
concentration gradient, requires energy and is called active transport.
• Occurs with the aid of carrier proteins, often called pumps
Cellular Transport
Active Transport
Na+/K+ ATPase pumps• Are found in the plasma membrane of animal cells• Maintain levels of sodium (Na+) and potassium (K+) inside/outside
the cell
Cellular Transport
Active Transport
Na+/K+ ATPase pumps• Large molecules like sugar need to move against a concentration
gradient into the cell.• In a process called coupled transport, sugars can pair with Na+ ions
and enter the cell through a membrane protein called a coupled channel.
• Allow sugars to enter through facilitated diffusion – saving energy
Cellular Transport
Transport of Large Particles• Endocytosis is the process by which a cell surrounds an object
in the outside environment in a portion of the plasma membrane.
• Exocytosis is the excretion of materials at the plasma membrane.
Exocytosis
Video
• Endocytosis & Exocytosis
• Crash on transport– https://www.youtube.com/watch?v=dPKvHrD1eS4
Essential Questions• What are the processes of diffusion, facilitated diffusion, and active
transport?
• What is the effect of a hypotonic, hypertonic, or isotonic solution on a cell?
• How do large particles enter and exit cells?
Cellular Transport