1. List the four biomolecules we

studied.

2. State the function (job) of each bio- molecule.

3. Draw and label an enzyme, substrate, &

active site

Are All Cells Alike?

All living things are made up of cells. Some organisms are composed of only one cell. Other organisms are made up of many cells.

1. What are the advantages of a one-celled organism?

2. What are the advantages of an organism that is made up of many cells?

Cell Theory

• 1. All living things are made of cells.1. All living things are made of cells.• 2. New cells are produced from existing 2. New cells are produced from existing

cellscells• 3. Cells are the basic unit of structure and 3. Cells are the basic unit of structure and

function in living things.function in living things.

Prokaryotes vs. Eukaryotes• Prokaryotes Prokaryotes

(bacteria) (bacteria) have no nucleus have no nucleus and very few and very few organelles. DNA is organelles. DNA is not not containedcontained

• Eukaryotes Eukaryotes (protists, fungi, plants and (protists, fungi, plants and animals) larger,more animals) larger,more complex,DNA is inside the complex,DNA is inside the nucleusnucleus

Prokaryotes Eukaryotes

Cell membraneContain DNA

NucleusEndoplasmic

reticulumGolgi apparatus

LysosomesVacuoles

MitochondriaCytoskeleton

DNA is free floating

No membrane bound organelles

Compare/contrast prokaryotic cells and eukaryotic cells. Include what they have incommon as well as the big differences.

Pro no Eu do Quiz

1. What does Pro no mean?

2. What does Eu do mean?

3. What do both eukaryotes and prokaryotes have?

Pro no Eu do Quiz

Plant Cells Vs. Animal Cells• Some structures are specific to Some structures are specific to

either plant cells or animal cells only:either plant cells or animal cells only:

– Only plant cells containOnly plant cells contain::•Cell wallCell wall•ChloroplastsChloroplasts•Large central vacuolesLarge central vacuoles

– Only animal cells contain:Only animal cells contain:•CentriolesCentrioles

Plant Cells

Nuclearenvelope

Ribosome(attached)

Ribosome(free)

Smooth endoplasmicreticulum

Nucleus

Rough endoplasmic reticulum

NucleolusGolgi apparatus

Mitochondrion

Cell wall

CellMembrane

Chloroplast

Vacuole

Animal Cells

Centrioles

Nucleolus

NucleusNuclearenvelope

Rough endoplasmic reticulum

Golgi apparatus

Smooth endoplasmicreticulum

Mitochondrion

CellMembrane

Ribosome(free)

Ribosome(attached)

http://www.youtube.com/watch?v=yKW4F0Nu-UY&feature=related

A. NUCLEAR ENVELOPE-REGULATES WHAT ENTERS AND LEAVES NUCLEUS

B. NUCLEOLUS – PRODUCES RIBOSOMES

C. CHROMOSOMES - CONTAIN GENETIC MATERIAL (DNA)

Organelle Quiz I

1.Which organelle separates the inside of the cell from the surrounding environment?

2.Which organelle is the energy bank for the cell?

Mitochondria vs.

Chloroplasts

• Mitochondria make Mitochondria make energy from chemicals energy from chemicals (food molecules)(food molecules)

• Chloroplasts useChloroplasts use

energy from light energy from light

through photosynthesisthrough photosynthesis

ATP - Life’s Energy Currency

Energy is released when ATP is hydrolyzed (broken down) to ADP.

ATP is restored from ADP and an input of energy.

ATP’s energy is used to drive endergonic (energy-requiring) reactions.

…Remember “ATP”?

• ATP stores energy for cell activitiesATP stores energy for cell activities like like active transport & movement within the active transport & movement within the cellcell

Cell Membrane• Regulates what enters and leaves the Regulates what enters and leaves the

cell and provides support and cell and provides support and protectionprotection

• Structure – lipid bilayer with Structure – lipid bilayer with embedded proteinsembedded proteins

Cell Wall

• Provides support and Provides support and protection for plant protection for plant cell walls cell walls

• Made of porous cellulose Made of porous cellulose so it so it does notdoes not regulate regulate what what enters and leavesenters and leaves

Smooth ER vs. Rough ER• Rough ER - ribosomes on the ER make Rough ER - ribosomes on the ER make

proteins, the ER modifies the proteinsproteins, the ER modifies the proteins• Smooth ER - makes lipidsSmooth ER - makes lipids• Ribosomes assemble proteinsRibosomes assemble proteins

Cytoskeleton• Network of Network of

protein protein filamentsfilaments

• Maintains Maintains shapeshape

• Involved in Involved in cell cell movementmovement

Animal Cells Plant Cells

Centrioles

Cell membraneRibosomes

NucleusEndoplasmic reticulum

Golgi apparatusLysosomesVacuoles

MitochondriaCytoskeleton

Cell WallChloroplasts

Phospholipids Form Biological Membranes

Fluid-Mosaic Plasma MembraneFluid-Mosaic Plasma Membrane

•Cholesterol is wedged between phospholipid molecules in the plasma membrane of animals cells.

•At warm temperatures, it restricts the movement of phospholipids and reduces fluidity.

•At cool temperatures, it maintains fluidity by preventing tight packing.

Diffusion through Cell Boundaries

• Particles move from an area of Particles move from an area of high concentration to an area of high concentration to an area of lower concentrationlower concentration

• No energy is requiredNo energy is required

•For example, if we start with a permeable membrane separating a solution with dye molecules from pure water, dye molecules will cross the barrier randomly.

•The dye will cross the membrane until both solutions have equal concentrations of the dye.

•At this dynamic equilibrium as many molecules pass one way as cross the other direction.

Osmosis• Diffusion of Diffusion of waterwater through a selectively through a selectively

permeable membranepermeable membrane

•Differences in the relative concentration of dissolved materials in two solutions can lead to the movement of ions from one to the other.

–The solution with the higher concentration of solutes is hypertonic.

–The solution with the lower concentration of solutes is hypotonic.

–Solutions with equal solute concentrations are isotonic

Osmosis is the passive transport of water

•In the absence of other forces, a substance will diffuse from where it is more concentrated to where it is less concentrated, down its concentration gradient.

Each substance diffuses down its own concentration gradient, independent of the concentration gradients of other substances.

The solute is more concentrated on the The solute is more concentrated on the right side. Which side is hypertonic? How right side. Which side is hypertonic? How will will dynamicdynamic equilibriumequilibrium be reached? be reached?

Isotonic"ISO" means the same

• Concentration of Concentration of solutes (salts) is solutes (salts) is the same inside and the same inside and outside of cell. outside of cell.

• Water flows in and Water flows in and out in equal out in equal amounts amounts

• No effect on cellNo effect on cell

Hypotonic "HYPO" means less

• Concentration of Concentration of solutes is less solutes is less outside the cell outside the cell than in.than in.

• Water flows in Water flows in

• The cell swell The cell swell with water and with water and becomes “turgid”becomes “turgid”

Hypertonic“Hyper” means more

• Concentration of solutes is Concentration of solutes is greater outside the cell than greater outside the cell than insideinside

• Water flows out of cellWater flows out of cell• The cell shrivels and may The cell shrivels and may

die.die.

• This is why it is dangerous to This is why it is dangerous to drink sea water drink sea water

• This is also why "salting This is also why "salting fields" was a common tactic fields" was a common tactic during war, it would kill the during war, it would kill the crops in the field, thus crops in the field, thus causing food shortages.causing food shortages.

•For example, Paramecium, a protist, is hypertonic when compared to the pond water in which it lives.

–In spite of a cell membrane that is less permeable to water than other cells, water still continually enters the Paramecium cell.

–To solve this problem, Paramecium have a specialized organelle, the contractile vacuole, that functions as a bilge pump to force water out of the cell.

As a plant cell looses water, its volume shrinks.

•Eventually, the plasma membrane pulls away from the wall.

•This plasmolysis is usually lethal.

•Many polar molecules and ions that are normally impeded by the lipid bilayer of the membrane diffuse passively with the help of transport proteins that span the membrane.

•The passive movement of molecules down its concentration gradient via a transport protein is called facilitated diffusion.

Facilitated Diffusion

Transport proteins allow facilitated diffusion

Active transport is the pumping of solutes against their gradients

•Some proteins can move solutes against their concentration gradient, from the side where they are less concentrated to the side where they are more concentrated.

•This active transport requires the cell to expend its own metabolic energy.

Endocytosis

• Cell takes material into cell by infolding of the cell Cell takes material into cell by infolding of the cell membranemembrane

• PhagocytosisPhagocytosis – eating – cell engulfs large particles – eating – cell engulfs large particles• Pinocytosis Pinocytosis – drinking – cell takes in liquid– drinking – cell takes in liquid• www.endocyte.com/ animation/animation.htm

Cell Differentiation – THE PROCESS BY WHICH CELLS CHANGE

Cell Specialization – TO BECOME WELL SUITED TO PERFORM DIFFERENT FUNCTIONS.

Levels of Biological

Organization

• OrganismOrganism• Organ systemOrgan system• OrganOrgan• TissueTissue• CellCell• OrganelleOrganelle• DNADNA• AtomsAtoms