Cell Structures- 7.2Cell Structures- 7.2

Animal Cell

Plant Cell

The Outer CellThe Outer Cell

Cell membrane- a thin, flexible barrier Cell membrane- a thin, flexible barrier around the cell. Cell membranes are around the cell. Cell membranes are semi-permeable, meaning that they allow semi-permeable, meaning that they allow certain materials in and out of the cellcertain materials in and out of the cellCell Wall- Thick, outer covering of plant Cell Wall- Thick, outer covering of plant cells, bacteria cells, fungi cells and algae cells, bacteria cells, fungi cells and algae cells. Cell walls provide support and cells. Cell walls provide support and protection for the cell. Made of cellulose protection for the cell. Made of cellulose (plants) and chitin (fungi)(plants) and chitin (fungi)

Picture It!Picture It!

Cell Membrane

Cell Wall

The NucleusThe Nucleus

Scottish botanist Robert Brown first identified the Scottish botanist Robert Brown first identified the nucleus in 1831nucleus in 1831

The nucleus controls much of the cell’s activity The nucleus controls much of the cell’s activity and contains the cell’s hereditary information in and contains the cell’s hereditary information in the form of DNA (Deoxyribonucleic Acid) the form of DNA (Deoxyribonucleic Acid)

Almost all eukaryotic cells including plant and Almost all eukaryotic cells including plant and animal cells contain a nucleusanimal cells contain a nucleus

Prokaryotic cells like bacteria have no nucleusProkaryotic cells like bacteria have no nucleus

The Nucleus, Cont.The Nucleus, Cont.

Model of a Nucleus

An Actual Nucleus

“Matrix” Nucleus

Inside the NucleusInside the Nucleus

Chromatin- the granular material inside the Chromatin- the granular material inside the nucleus. It is made of DNA bound to protein, and nucleus. It is made of DNA bound to protein, and carries the hereditary information in the cellcarries the hereditary information in the cellChromosomes- chromatin condenses to form Chromosomes- chromatin condenses to form chromosomes during cell divisionchromosomes during cell divisionNucleolus- Small dense region inside the nucleus Nucleolus- Small dense region inside the nucleus that is responsible for the assembly of that is responsible for the assembly of ribosomes, which make proteinsribosomes, which make proteinsNuclear membrane- outer covering of the Nuclear membrane- outer covering of the nucleus, allows a steady stream of RNA in and nucleus, allows a steady stream of RNA in and out.out.

NucleolusChromatin

Chromosomes

CytoskeletonCytoskeletonNetwork of protein Network of protein filaments that helps the filaments that helps the cell maintain its shapecell maintain its shapeAlso involved in many Also involved in many forms of cellular forms of cellular movementmovementMicrotubules are hollow Microtubules are hollow protein tubes that protein tubes that maintain cellular shape maintain cellular shape and serve as “tracks” on and serve as “tracks” on which organelles can which organelles can traveltravelMicrofilaments- protein Microfilaments- protein filaments that provide filaments that provide structure for the cellstructure for the cell

Organelles in the CytoplasmOrganelles in the Cytoplasm

The cytoplasm is the liquid The cytoplasm is the liquid “goo” like material inside “goo” like material inside the cell. It is made of water the cell. It is made of water and salts, and contains all and salts, and contains all the cell organelles (little the cell organelles (little organs)organs)Ribosomes are made of Ribosomes are made of RNA and protein. They RNA and protein. They assemble proteins following assemble proteins following the coded information the coded information stored in the nucleus.stored in the nucleus.

Electron Microscope image of Ribosomes

Endoplasmic ReticulumEndoplasmic Reticulum

Internal membrane Internal membrane system in which cell system in which cell membrane membrane components are components are made and proteins made and proteins are modifiedare modifiedSmooth ER- does not Smooth ER- does not contain ribosomescontain ribosomesRough ER- “studded” Rough ER- “studded” with ribosomeswith ribosomes

Smooth ER

Rough ER

More Cytoplasmic OrganellesMore Cytoplasmic Organelles

Golgi Apparatus- packages and ships Golgi Apparatus- packages and ships materials, attachs necessary materials, attachs necessary carbohydrates and lipids to proteins. This carbohydrates and lipids to proteins. This organelle is a stack of sac-like membranesorganelle is a stack of sac-like membranesLysosomes- breaks down carbohydrates Lysosomes- breaks down carbohydrates and lipids, also “eats” dead organelles- and lipids, also “eats” dead organelles- cleans up the cellcleans up the cellVacuoles- store food and water for cells to Vacuoles- store food and water for cells to use, plant cells have huge organellesuse, plant cells have huge organelles

Can you find the vacuole?

Energy! Energy! Energy!Energy! Energy! Energy!

Mitochondria- Found in Mitochondria- Found in both animal and plant both animal and plant cells. Breaks down cells. Breaks down glucose (food) to release glucose (food) to release energyenergy

Chloroplasts- Found in Chloroplasts- Found in plant, algae and some plant, algae and some bacteria cells. bacteria cells. Autotrophic, the organelle Autotrophic, the organelle that converts sunlight into that converts sunlight into glucoseglucose

Putting it All TogetherPutting it All Together

An Amazing JourneyAn Amazing Journey

Tiny little cells are so very complex! Imagine taking a magic journey inside one of your cells… what would you see????

Section 7.3Section 7.3

Movement Through the Movement Through the MembraneMembrane

Cell MembraneCell Membrane

The cell membrane is the flexible outer The cell membrane is the flexible outer covering found on the outside of cellscovering found on the outside of cellsIt regulates what enters and leaves the cell It regulates what enters and leaves the cell and also provides protection and supportand also provides protection and supportCell membranes allow food and water in Cell membranes allow food and water in and gases and wastes outand gases and wastes outThey are semi-permeable, which means They are semi-permeable, which means that some things are allowed through, and that some things are allowed through, and others are notothers are not

Cell Membrane, Cont.Cell Membrane, Cont.

The core of the cell The core of the cell membrane is a lipid membrane is a lipid bi-layer (a double bi-layer (a double layer of lipids)layer of lipids)Proteins act as Proteins act as channels through the channels through the membranemembraneCarbohydrate chains Carbohydrate chains are there for cell are there for cell identificationidentification

DiffusionDiffusion

Every cell is in a liquid environment– with a Every cell is in a liquid environment– with a liquid interior and surrounded by liquid. The cell liquid interior and surrounded by liquid. The cell membrane separates these two liquid membrane separates these two liquid environments.environments.Concentration of a solution is the mass of the Concentration of a solution is the mass of the solute that is dissolved in a certain volume of solute that is dissolved in a certain volume of solventsolventIn a solution, molecules move constantly. In a solution, molecules move constantly. Across a membrane, they move from a high to a Across a membrane, they move from a high to a low concentration. This is called diffusionlow concentration. This is called diffusion

Diffusion, Cont.Diffusion, Cont.

Diffusion causes many substances to Diffusion causes many substances to move across the cell membrane, but it move across the cell membrane, but it does not require energydoes not require energyDiffusion happens automatically, when Diffusion happens automatically, when there is a concentration difference or the there is a concentration difference or the solutions are in equilibrium (equal solutions are in equilibrium (equal concentrations on both sides)concentrations on both sides)In equilibrium, however, the molecules In equilibrium, however, the molecules move rapidly in both directionsmove rapidly in both directions

OsmosisOsmosis

Osmosis is diffusion, but not all diffusion is Osmosis is diffusion, but not all diffusion is osmosis.osmosis.

Osmosis is the movement of water across Osmosis is the movement of water across a semi-permeable membranea semi-permeable membrane

Water moves from an area of high water to Water moves from an area of high water to an area of low water concentrationsan area of low water concentrations

When equilibrium is reached, it moves in When equilibrium is reached, it moves in both directionsboth directions

Osmotic PressureOsmotic Pressure

Osmosis exerts pressure on a certain side Osmosis exerts pressure on a certain side of the cell membraneof the cell membraneHyPERtonic- Area of high concentrations HyPERtonic- Area of high concentrations of particles such as salt or sugar (high of particles such as salt or sugar (high PERticles)PERticles)HypOtonic- Area of high concentration of HypOtonic- Area of high concentration of water (high Hwater (high H22O-- hypOtonic)O-- hypOtonic)

Isotonic- concentrations of particles and Isotonic- concentrations of particles and water are equalwater are equal

Solution TypesSolution Types

If you place a cell (like an egg) in a high- If you place a cell (like an egg) in a high- particle solution (Hypertonic) then water particle solution (Hypertonic) then water will rush out of the egg and the egg will will rush out of the egg and the egg will shrivelshrivelIn a Hypotonic (High water) solution, water In a Hypotonic (High water) solution, water will rush into the egg and the egg will swellwill rush into the egg and the egg will swellIn a Isotonic solution, no change will be In a Isotonic solution, no change will be noticed because the water will move in noticed because the water will move in both directions, in and out of the eggboth directions, in and out of the egg

Facilitated DiffusionFacilitated Diffusion

The word facilitate means to “assist” or to The word facilitate means to “assist” or to “help”“help”

In facilitated diffusion, proteins that are In facilitated diffusion, proteins that are embedded in the membrane help bigger embedded in the membrane help bigger molecules go through by acting as a channelmolecules go through by acting as a channel

There must be a concentration difference, There must be a concentration difference, meaning this will not take place in equilibriummeaning this will not take place in equilibrium

Extra energy is not neededExtra energy is not needed

Active TransportActive Transport

““Active” implies that you need energyActive” implies that you need energy

This is transport that needs energy in This is transport that needs energy in order to take placeorder to take place

Endocytosis- food is taken into a cell– Endocytosis- food is taken into a cell– Phagocytosis is a type of this, it is literally Phagocytosis is a type of this, it is literally “cell eating”“cell eating”

Exocytosis is the exit of materials out of a Exocytosis is the exit of materials out of a cell– usually wastecell– usually waste

HomeworkHomework

Define Vocabulary 7.3 and 7.4 on page Define Vocabulary 7.3 and 7.4 on page 196196

Due TuesdayDue TuesdayAlso: Progress ReportAlso: Progress Report