cells and tissues - lemon bay high school part 1.pdfby patty bostwick-taylor, florence-darlington...

PowerPoint® Lecture Slide Presentation

by Patty Bostwick-Taylor,

Florence-Darlington Technical College

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings

PART A3

Cells and

Tissues


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


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


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?


Cells Vary in Physiology

Ability to move throughout the blood/body?

What FUNCTIONS do organelles perform to

maintain homeostasis?

What products are made by the cell?

Do these products impact other cells?

Is it able to communicate with other cells?


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


The Nucleus

Control center of the cell

Contains genetic material (DNA)

Three regions

Nuclear envelope (membrane)

Nucleolus

Chromatin


The Nucleus

Figure 3.1b


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


The Nucleus

Nucleoli

FUNCTION: Sites of ribosome assembly

CHARACTERISTICS: Nucleus contains one or

more nucleoli

Dark-staining round body(s)


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”)


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


Plasma Membrane

Figure 3.2

Membrane StructurePLAY

./animations/03_01_MembraneStructure.html

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

Desmosomes (Anchoring Junctions)PLAY

Tight JunctionsPLAY

./animations/03_03_Desmosomes.html

./animations/03_02_TightJunctions.html

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

ORGANELLE GENERAL FUNCTION

MitochondriaContains own circular piece of DNA

Produce ATP (energy) from glucose

RibosomesFree 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

PeroxisomesSpecialized 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


Cell Diversity

Tour of the CellPLAY

./animations/03_04_TourOfCell.mpg


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.


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.


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.

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.

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.


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


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

process?


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.

cells and tissues - lemon bay high school part 1.pdfby patty bostwick-taylor, florence-darlington...

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