Transcript Cells Part 1 - Lemon Bay High School

PowerPoint® Lecture Slide Presentation
by Patty Bostwick-Taylor,
Florence-Darlington Technical College
Cells and
Tissues
3
PART A
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Cells and Tissues
 Carry out all chemical activities needed to sustain
life
 Cells are the building blocks of all living things
 Tissues are groups of cells that are similar in
structure and function
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Overview
 Made of 5 Main Elements
 Carbon
 Hydrogen
 Oxygen
 Nitrogen
 And Phosphorus
 Living cells are about 60% Water
 Cells are constantly bathed in a saltwater-like
solution called INTERSTITIAL FLUID.
 All exchanges between CELLS and BLOOD are
made through this fluid
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Cells Vary in Anatomy
 STRUCTURE defines FUNCTION
 What organelles are present?
 How big/small is the cell?
 What is the SHAPE of the cell?
 Where in the body is the cell located?
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Cells Vary in Physiology
 Ability to move throughout the blood/body?
 What products are made by the cell?
 Do these products impact other cells?
 Is it able to communicate with other cells?
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Anatomy of the Cell
 Cells are not all the same
 All cells share general structures
 All cells have three main regions
 Nucleus
 Cytoplasm
 Plasma membrane
Figure 3.1a
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The Nucleus
 Control center of the cell
 Contains genetic material (DNA)
 Three regions
 Nuclear envelope (membrane)
 Nucleolus
 Chromatin
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The Nucleus
Figure 3.1b
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The Nucleus
 Nuclear envelope (membrane)
 FUNCTION: Control what enters/exits the
nucleus.
 CHARACTERISTICS:
 Consists of a double phospholipid
membrane
 Contains nuclear pores that allow for
exchange of material with the rest of the
cell
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The Nucleus
 Nucleoli
 FUNCTION: Sites of ribosome assembly
 CHARACTERISTICS: Nucleus contains one or
more nucleoli
 Dark-staining round body(s)
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The Nucleus
 Chromatin
 FUNCTION: DNA carries instructions for cell
structure and function through the production
of proteins.
 CHARACTERISTICS:
 When cell is not dividing DNA is present
as chromatin (spaghetti on a plate)
 When the cell is dividing (mitosis) DNA
condenses to form chromosomes (“X”)
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Plasma Membrane
 Barrier for cell contents
 Double phospholipid layer
 Contains
 Hydrophilic heads
 Hydrophobic tails
 Also contains
 Proteins that act as channels
 Cholesterol that makes cell membrane more rigid
 Glycoproteins provides cell surface identity
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Plasma Membrane
PLAY Membrane Structure
Figure 3.2
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Plasma Membrane Specializations
 Microvilli
 Finger-like projections that increase surface area for
absorption
 Membrane junctions
 Tight junctions
 Impermeable junctions
 Bind cells together into leak-proof sheets
 Desmosomes
 Anchoring junctions that prevent cells from being
pulled apart
 Gap junctions
 Allow communication between cells
Plasma Membrane
Specializations
PLAY Tight Junctions
PLAY Desmosomes (Anchoring Junctions)
Cytoplasm
 Cytoplasm is the material outside the nucleus and inside
the plasma membrane
 Contains three major elements
 Cytosol
 Jelly-like fluid that suspends other elements
 Organelles
 Metabolic machinery of the cell
 “Little organs” that perform functions for the cell
 Inclusions
 Chemical substances such as stored nutrients or
cell products
Cytoplasmic Organelles
Figure 3.4
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ORGANELLE
Mitochondria
Contains own circular piece of DNA
GENERAL FUNCTION
Produce ATP (energy) from glucose
Ribosomes
Free in cytoplasm and attached on ER
Assemble proteins
Endoplasmic reticulum
2 forms, smooth and rough
Smooth - transport
Rough – transports proteins
Golgi Apparatus
Packages mainly lipids for transport
Lysosomes
Double membrane structure for protection
Contains digestive enzymes
Peroxisomes
Specialized lysosomes
Contains catalase to breakdown hydrogen
peroxide
Cytoskeleton
Cell support, structure, and framework
Centrioles
Creates spindle fibers during mitosis for
separation of chromosomes.
Specialized Structures
Cilia – moves substances over surface of
cell (respiratory cells)
Flagella – moves the cell itself (sperm)
Cell Diversity
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Cell Diversity
PLAY Tour of the Cell
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Membrane Transport
 movement of substances into and out of the cell. The Plasma
membrane is SELECTIVELY PERMEABLE; it allows some
substances to pass through while excluding others.
 Intracellular fluid: WITHIN THE CELL; nucleoplasm and
cytosol. Small amounts of gases (O2 and CO2), nutrients
and salts dissolved in water.
 Interstitial fluid: OUTSIDE OF CELL; rich and nutritious.
Contains nutrients, hormones, neurotransmitters, salts,
and waste products. Cells must EXTRACT needed
substances from this fluid in order to maintain
HOMEOSTASIS.
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What happens to membrane permeability in UNHEALTHY cells?
Explain below.
SELECTIVE PERMEABILITY is a property of healthy,
functioning cells. When cells are damaged or dying, they
lose the ability to control the movement of substances
across the cell membrane therefore losing HOMEOSTASIS.
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Passive Transport Processes
 Diffusion: Particles tend to distribute themselves EVENLY
within a solution.
 Movement is from HIGH concentration to LOW
concentration.
 Molecules will diffuse through the plasma membrane
if:
1. They are small enough to pass through pores
(membrane proteins).
2. They can dissolve in the fatty portion of the membrane.
3. They are assisted by a membrane carrier.
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Types of diffusion
Simple diffusion: unassisted movement through the
membrane. Solutes are lipid-soluble materials or small
enough to pass through membrane pores
What materials will pass through the membrane by
SIMPLE DIFFUSION?
 Lipid-soluble (fats, gases, some vitamins) or small
enough to pass (ions) through pores.
 Osmosis: simple diffusion of WATER.
 Facilitated diffusion
 Transports lipid-INSOLUBLE and large substances.
 Substances require a MEMBRANE carrier for passive
transport.
Types of Diffusion: Filtration
Filtration: Water and solutes are forced through a membrane
by fluid, or HYDROSTATIC pressure.
 Hydrostatic pressure is usually exerted by the BLOOD.
 Filtration is necessary for the KIDNEYS to do their job
properly.
 Solute-containing fluid is pushed from a HIGHER- pressure
area to a LOWER- pressure area.
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Active Transport Processes
ATP is used for transport
 Needed when:
 Substances are transported that are unable to pass by
diffusion.
 Substances may be too LARGE.
 Substances may not be able to dissolve in the FAT
CORE (lipid) of the membrane.
 Substances may have to move AGAINST a
concentration gradient
Solute Pumping
 Amino acids, some sugars, and most ions are
transported by Solute Pumps.
 Sodium-Potassium Pump: what purpose does this Solute
Pump serve?
Carries sodium ions out of an potassium ions into
the cell. This is needed for normal transmission of
impulses by nerve cells. These ions move against their
concentration gradients, from LOW to HIGH so they
must be PUMPED (forced) into the desired locations
across the cell membrane; this requires ENERGY in the
form of ATP.
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Vesicular transport
 Exocytosis: Moves materials OUT OF the cell
 Material is carried in a membranous VESICLE or
SAC.
 Vesicle migrates to plasma membrane
 Vesicle combines with plasma membrane
 Material is emptied to the outside
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Endocytosis
Extracellular substances are engulfed by being enclosed in
a membranous vesicle.
 Phagocytosis: “cell eating”
 Needed by white blood cells to consume and digest
foreign particles. The vesicle fuses with a lysosome to
digest contents and detoxify.
 What types of cells perform phagocytosis?
 SOME white blood cells
 Pinocytosis: “cell drinking”
 Receptor-mediated endocytosis: SELECTIVE
uptake of products needed by the cell.
 What products are taken into cells by this
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Receptor-mediated endocytosis
SELECTIVE uptake of products needed by the
cell.
 What products are taken into cells by this
process?
 Enzymes, hormones, cholesterol, and
iron. SOME viruses.
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings