CELL AND CELL MEMBRANE

Patricia Caldani MS

Define the cell theory Describe the difference between Prokaryotic

and Eukaryotic Be familiar with the basic organelles and the

roles of the different organelles Describe the function of the plasma membrane Explain how active transport differs from

passive transport Define osmosis and be able to predict the

direction of water movement based upon differences in solute concentration

All organisms are made of cells

Cell is the basic unit of structure and function.

Spontaneous Generation: The idea that things or organisms just __________________.

To study cells, biologists use microscopes and the tools of biochemistry

Light microscope (LM): visible light passes through the specimen and then through glass lenses.Electron microscope (EM): focuses a beam of electrons through the specimen or onto its surface.Magnification is the ratio of an object’s image to its real size.Resolving power is a measure of image clarity.

Cell-The smallest unit of life that can perform all life processes.

Composed of smaller parts packaged together to form a fully functioning whole

Organelles have their own unique functions, and are ____________________ together

Cell Theory

Cell theory lays out the basic rules that apply to the smallest unit of life.

This cell doctrine states that: All organisms are composed of one or more

cells. Cells are the basic unit of structure and

function in organisms. All cells _________________ only from other

cells.

Two Basic Types of Cells

Prokaryotic Cells Eukaryotic Cells

Features of Prokaryotes

Pro = “before”, karyon = “nucleus” Lack a __________________-bound nucleus. The only membrane in prokaryotic cells is

the plasma membrane--the outer boundary of the cell itself.

Ribosomes are their organelle. Always single-celled Reproduce by ______________ fission

Prokaryotes-Bacteria

Prokaryotes are molecules surrounded by a membrane and cell wall.

Prokaryotic cells lack characteristic Eukaryotic sub cellular membrane enclosed “organelles”

Prokaryotes- Archaebacteria

SAME As bacteria since they ____________ a nucleus and don’t have membrane bound organelles.

DIFFERENT in that they have _______________ that are more like a Eukaryotic cell.

Features of Eukaryotes

Eu = “true”, karyon = “nucleus” Possess:

Nucleus Plasma membrane Organelles

Eukaryotic cells can reproduce via meiosis and mitosis

Prokaryotic and eukaryotic cells

differ in size and complexity

All cells are surrounded by__________________ membrane.

All cells have ribosomes

All cells contain chromosomes that have genes in the form of DNA.

Eukaryotes

There are many organelles inside of the cell - small structures that help carry out the day-to-day operations of the cell. 

ER Golgi Apparatus Ribosomes Nucleus Mitochondria Lysosomes Chloroplast Vacuoles Vesicles

Eukaryotic Cell

Cell MembraneIs the protective layer that covers the cell’s surface. Found in all cells Description :Double layer of phospholipids with proteins Selectively permeable Support Protection Controls _________________________ of materials in/out of cell Barrier between cell and its environment Maintains homeostasis

Cell WallFound only in PLANT cells Gives ______________ to the cell Location: Plant, Fungi, & Bacteria, but not animal cellsDescription: Outer layer, Rigid & strong , made of celluloseProtects the cell, maintains its shape, prevents excessive uptake of water.

Endoplasmic ReticulumThe ER includes membranous tubules and internal, fluid-filled spaces

Two connected regions of ER:Smooth ER looks smooth because it ________________ ribosomes.

involved with the production of lipids (fats), carbohydrate metabolism, and detoxification of drugs and poisons. In muscle cells releases calcium to trigger muscle contractions

Rough ER looks rough because ribosomes are __________________ to the outside

The ribosomes assemble amino acids into units of proteins

ER (Endoplasmic Reticulum) A folded membrane that moves material in the cell

ER is part of the internal delivery systemER is responsible for moving proteins and other carbohydrates to the Golgi Body.Location: All cells except prokaryotesDescription Network of tubes or membranes Smooth without ribosomes Rough with embedded ribosomes Connects to nuclear envelope & cell membrane

Rat cellThe endoplasmic reticulum is clearly visible in the

cell.

The Golgi apparatus is the shipping and receiving center for cell products

Many _____________________vesicles from the ER travel to the Golgi apparatus for modification of their contents.

-Center of manufacturing, warehousing, sorting, and shipping.

-Sorts and packages materials into transport vesicles.

-Gathers simple molecules and combines them to make complex molecules

Ribosome synthesis proteins Ribosomes participate in protein

synthesis. are the protein ______________ or the protein

synthesizers of the cell. Site where translation occurs. Found floating in the Cytoplasm or in the

Endoplasmic Reticulum. A ribosome is made up of two subunits

Ribosome: makes protein for the cell

Location: All cells Small bodies free or attached to ER Made of rRNA & protein

Ribosomes in a human liver cell

Nucleus site of DNA and RNA

The cell nucleus acts like the brain of the cell. The cell nucleus contains most of the genes in a eukaryotic cell.The cell nucleus is separated from the cytoplasm by a double membrane called the nuclear envelope.Pores: regulate the passage of certain large macromolecules and particles.-The nucleus directs protein synthesis by synthesizing messenger RNA (mRNA).

Nucleus

Nucleolous

Location: All cells except prokaryotesFound inside the cell's nucleusFunction Make ribosomes

Nuclear Membrane

Location: All cells except prokaryotesSurrounds nucleus Double membrane Selectively permeable Function Controls movement of materials in/out of nucleus

ChromosomesCarry all of the information used to help a cell grow, thrive, and reproduce. Chromosomes are made up of DNA. Find chromosomes and genetic material in the Nucleus

Loose and TightChromosomes are not always visible. Usually uncoiled and loose strands called chromatin. During reproduction they wrap up very tightly.

Completing the SetsHave 46 chromosomes (23 pairs)Chromosomes work with other nucleic acids in the cell to build proteins and help in cell division.

Mitochondria-The Power House

Referred to as the ___________ plants of the cell

MitochondriaLocation: All cells except prokaryotesDescription: Double membrane

Outer membrane smooth Inner membrane folded into cristae

Function: A. Breaks down sugar B. Site of aerobic cellular respiration

Mitochondria in a human liver cell

Lysosomes Lysosomes hold enzymes that were created by the cell. The purpose of the lysosome is to digest things. Little digestion machines which work when the cell

absorbs or eats some food.

These enzymes work best at pH______ Rupture of one or a few lysosomes has little impact on a

cell Massive rupture of many lysosomes can destroy a cell

.

The lysosomes play a critical role in the programmed destruction of cells in multicellular organisms. Important role in development. called programmed cell death, or

______________________________

LysosomesOrganelle that eats worn out cell parts. It contains digestive enzymes.Location: Animal cells, and Plant cells Description Small and round with a single membrane Function Breaks down larger food molecules into smaller molecules

Examples of Lysosomal Activity

Ducks have no lysosomal activity between digits of toes = webbed feet

Chickens have activity = no Lack of apoptosis in humans can lead to

webbed fingers called syndactyly

Chloroplast

Sites of _______________________________________They convert solar energy to chemical energy and synthesize new organic compounds such as sugars from CO2 and H2O.Found in leaves and other green organs of plants and algae.The membranes divide the chloroplast into three compartments: intermembrane space, stroma, and thylakoid space.

The stroma: contains DNA, ribosomes, and enzymes.The thylakoids: flattened sacs that play a critical role in converting light to chemical energy.

ChloroplastLocation: Plants and algaeDescription : Green, oval  containing chlorophyll (green pigment)

thylakoids : Grana: Stroma:

Function: Uses energy from sun to make food for the plant-photosynthesis

Vacuoles

large storage bubble that holds things the plant needsVacuoles are found in both animal and plant cells. The functions of the vacuole include:

Isolating materials that might be harmful or a threat to the cell

Containing waste productsContaining water in plant cellsMaintaining hydrostatic pressure/turgorMaintaining an _______________________pH Exporting unwanted substances from the cell

Vacuoles Role In Plant Structure

Plants use cell walls to provide ______________and surround cells.

Most of a plant cell's volume depends on the material in vacuoles.

A drooping plant has lost much of its water and the vacuoles are shrinking..

VesiclesSmall sack that moves material in and out of the cell.Location: Plant cells have a single, large vacuole

Animal cells have small vacuolesDescription: Fluid-filled sacs ________________________ organelle in plant cells Function Store food, water, metabolic & toxic wastes

Peroxisomes generate and degrade H2O2 in performing various metabolic functions.

Contain enzymes that transfer hydrogen from various substrates to oxygen.

Contains an enzyme that converts H2O2 to water.

Break fatty acids down to smaller molecules that for cellular respiration.

Peroxisomes in the liver detoxify alcohol

Cytoplasm

The ____________________-like material inside of the cell membrane. Keeps organelles in placeLocation: All cellsDescription: Clear, thick, jellylike material (cytosol)

Organelles found inside cell membrane Contains the cytoskeleton fibers

Function: Supports and protects cell organelles

Cytoskeleton

Location: All cells Description: Made of microtubules -

microfilaments Function: Strengthen cell & maintains the

shape Moves organelles within the cell

Cell Membrane

Plant cell has a rigid cell wallAnimal cell membrane is a flexible lipid bilayer. The lipid molecules have a polar, hydrophilic head and two hydrophobic hydrocarbon tails. Different proteins on the surface are used for various functions such as cell surface receptors, enzymes, surface antigens, and transporters

Membrane Transport of Small Molecules

Transport Processes- homeostasis maintains constant conditions in a living organism.  Membrane control is essential for this.

Passive transport This is movement across the membrane without any

energy input.  There are 3 forms:  diffusion, facilitated diffusion and

osmosis Active Transport

- transport of a substance against the concentration gradient

-requires energy -must use transport proteins and ATP

Semi-Permeable Molecules that pass through the phospholipid bilayer easily...

Hydrophobic molecules (oil soluble): O2, N2 Nonpolar: benzene Small uncharged Polar  molecules:  H2O, Urea, glycerol, CO2

Molecules that don’t pass through the phospholipid bilayer easily... Large uncharged Glucose Polar molecules  Sucrose Ions (charged) H+ , Na+ , HCO3 , K+Ca2+ , Cl- , Mg2+

Therefore the three characteristics of a molecule that determine the permeability of the membrane to that species are . . . 1) polarity - (Hydrophobic vs Hydrophylic) 2) charge - (charged vs uncharged) 3) size - (large vs small)

Household Membranes

Form groups of 3 or 4, brainstorm and list 3 things in and around the house that are semipermeable-let certain things in but not others.

Item ________________ Describe the ways in which this item is semipermeable.

Are the things passing through because of active process or passive process? Explain.

Osmosis-Diffusion of Water

Active Transport