CHAPTER 2 cells

CHAPTER 2CHAPTER 2cellscells P. 38 - 44

EARLY DISCOVERIESEARLY DISCOVERIES

Anton Anton Van Leeuwenhoek Van Leeuwenhoek

- made - made microscopes.microscopes.

- saw “critters” in - saw “critters” in a drop of water.a drop of water.

- never seen - never seen before.before.

Robert HookeRobert Hooke- first to see cells in - first to see cells in slices of corkslices of cork

- ‘named’ cells.- ‘named’ cells.

Led to others studying Led to others studying cells.cells.

Matthias Schleiden- studied every part of plants.- concluded all parts were made of cells.

Theodor Schwann

- studied animals.

- concluded that all animals were made of cells.

Rudolph Rudolph VirchowVirchow

- new cells - new cells come from come from other living other living cells.cells.

These scientists’ work led to the Cell Theory.

Cell theoryCell theory

1.1. All organisms are made of cells.All organisms are made of cells.2.2. Cells are the basic unit of structure Cells are the basic unit of structure

and function in all organisms.and function in all organisms.3.3. All cells come from other cells. All cells come from other cells.

Read p. 38 - middle p. 42.

STRUCTURE OF CELLSSTRUCTURE OF CELLS (p. 38)(p. 38)

Scientists discovered there were Scientists discovered there were parts inside the cell.parts inside the cell.

A) A) Cell MembraneCell Membrane Like the protective skin of the cellLike the protective skin of the cell

- the outer covering.- the outer covering.- controls what goes in and - controls what goes in and

out.out. Food , water, oxygen enter - Wastes Food , water, oxygen enter - Wastes

leave.leave. Selectively permeableSelectively permeable: controls what : controls what

enters and leavesenters and leaves

CELL MEMBRANE

B) B) NucleusNucleus- the ‘control the ‘control

center.center.

B1) nuclear B1) nuclear membranemembrane

-controls what -controls what goes in and out of goes in and out of the nucleus.the nucleus.

Contains Contains chromosomeschromosomes::

- structures that hold - structures that hold hereditary material to hereditary material to determines what you determines what you look like.look like.

- made of - made of DNADNA..

C) C) CytoplasmCytoplasm Found inside the cell membrane outside Found inside the cell membrane outside

the nucleus.the nucleus. Gel - like substance: mostly water.Gel - like substance: mostly water. Contains small structures called Contains small structures called organellesorganelles

-all have a “job” inside the cell.-all have a “job” inside the cell.

CYTOPLASM

Cell OrganellesCell Organelles Cells work 24 hours a day, 7 days a weekCells work 24 hours a day, 7 days a week Cell Organelle: working parts of the cell.Cell Organelle: working parts of the cell.

Cell Organelles Cell Organelles

1. 1. MitochondriaMitochondria Powerhouse of cellPowerhouse of cell Food broken down and Food broken down and

energy is released.energy is released. Which cells might have Which cells might have

lots of mitochondria?lots of mitochondria?

2. 2. Endoplasmic ReticulumEndoplasmic Reticulum (E.R.) (E.R.) Folded membraneFolded membrane Like conveyer belts in the factory.Like conveyer belts in the factory.

(or a highway)(or a highway)

Transports materials throughout Transports materials throughout the cell.the cell.

3. 3. RibosomesRibosomes Most numerous organelle in the cellMost numerous organelle in the cell Some attached to E.R.Some attached to E.R. Produces protein (food) for the cellProduces protein (food) for the cell

- releases energy from food.- releases energy from food. Which cells might have the most Which cells might have the most

ribosomes?ribosomes?

4. 4. LysosomesLysosomes

- contains chemicals (enzymes) to digest - contains chemicals (enzymes) to digest wastes and ‘worn out’ parts of the cell.wastes and ‘worn out’ parts of the cell.

- called ‘suicide sacs’ - called ‘suicide sacs’

- break open and digest the cell - break open and digest the cell when it dies.when it dies.

5. 5. VacuoleVacuole Storage sacsStorage sacs

Hold food, water, and wastesHold food, water, and wastes Larger in plant cellsLarger in plant cells

ASSIGNMENT:

WORKSHEET“CELL STRUCTURE”.

ASSIGNMENT:

WORKSHEET“CELL STRUCTURE”.

COLORED PENCILS NEEDED TOMORROW!

PLANT CELLSPLANT CELLS--have two different parts than have two different parts than

animal cells.animal cells.1.1. Cell WallCell Wall

- found outside - found outside the cell the cell membrane.membrane.

- for support and - for support and protection.protection.

- non-living- non-living

2. 2. ChloroplastsChloroplasts

- where - where photosynthesisphotosynthesis takes takes place (turns sunlight place (turns sunlight into food).into food).

- contains - contains chlorophyllchlorophyll. (green). (green)

Two basic types of cellsTwo basic types of cells1) 1) Prokaryotic cellsProkaryotic cells- no membranes around internal no membranes around internal

structures (structures (no nucleusno nucleus))

- simplest type of cell:- simplest type of cell:Bacteria ex. Pond ScumBacteria ex. Pond Scum

Two basic types of cellsTwo basic types of cells2) 2) Eukaryotic cellsEukaryotic cells- Nucleus surrounded a Nucleus surrounded a

membrane.membrane.- most complex type of cell:most complex type of cell:- all plants and all plants and

animals.animals.

TRANSPORT IN CELLSTRANSPORT IN CELLS (CH. 3 (CH. 3 p. 74)p. 74)

- how materials move how materials move from cell to cell.from cell to cell.

DiffusionDiffusion- the movement of the movement of

particles from high particles from high concentration areas concentration areas to low to low concentration concentration areas.areas.

Ex. dye in waterEx. dye in water

EquilibriumEquilibrium

- when the - when the particles are particles are spaced evenly.spaced evenly.

In cells, water In cells, water carries food, carries food, wastes, etc.wastes, etc.

- must enter/leave must enter/leave the cell through the cell through diffusion.diffusion.

- it must go thru it must go thru the cell the cell membrane.membrane.

(it is (it is selectively selectively permeablepermeable))

Diffusion is a type Diffusion is a type of of passive passive transporttransport..

- no energy is - no energy is used to move the used to move the particles.particles.

Active TransportActive Transport- uses energy.uses energy.- - moves particles from low - moves particles from low

concentrations to high concentrations to high concentrations.concentrations.

DRAWING ON BOARD.DRAWING ON BOARD.

ASSIGNMENT:ASSIGNMENT:SECTION REVIEW SECTION REVIEW

QUESTIONS.QUESTIONS.P. 45 1P. 45 1

P. 51 1+2P. 51 1+2P. 78 1+2P. 78 1+2

OsmosisOsmosis

- another method of cell transport of - another method of cell transport of water but it must move thru a cell water but it must move thru a cell membrane.membrane.

- high concentration to low - high concentration to low concentration.concentration.

Osmosis ExamplesOsmosis Examples

- a wilting plant “straightens up” - a wilting plant “straightens up” after being watered.after being watered.

Reverse osmosisReverse osmosis can kill plants can kill plants

- water is taken away from the - water is taken away from the roots by the drier soil.roots by the drier soil.

Example 2:Example 2:

Salt on leeches Salt on leeches draws out their draws out their moisture.moisture.

ASSIGNMENT:ASSIGNMENT:

WORKSHEETWORKSHEET“CELL TRANSPORT”“CELL TRANSPORT”

CELL RESPIRATIONCELL RESPIRATION (P. (P. 83)83)- the process that the process that

creates energy from creates energy from food and oxygen.food and oxygen.

- The cell gives off The cell gives off carbon dioxide (COcarbon dioxide (CO22) ) and water (Hand water (H22O) as O) as wastes.wastes.

- It takes place in the It takes place in the mitochondria.mitochondria.

Respiration gives you energy to run, Respiration gives you energy to run, breathe, talk, etc.breathe, talk, etc.- you take in food and oxygen.- you take in food and oxygen.

- you give off H- you give off H22O and COO and CO22

Fermentation Fermentation (P.84)(P.84)- a process which creates energy a process which creates energy withoutwithout using using

oxygen.oxygen.ex. yeastex. yeast

- uses nutrients and gives off CO- uses nutrients and gives off CO2 2 and alcohol.and alcohol.- used to make bread and wine/beer.- used to make bread and wine/beer.

You only use fermentation only during You only use fermentation only during heavy heavy exercise.exercise.During exercise, you don’t get enough oxygen.During exercise, you don’t get enough oxygen.

- your cells release energy thru fermentation.- your cells release energy thru fermentation.- wastes created H2O, CO2, and - wastes created H2O, CO2, and lactic acidlactic acid..- causes ‘burning’ feeling.- causes ‘burning’ feeling.- sore muscles.- sore muscles.

-releases 18x less energy than respiration.-releases 18x less energy than respiration.

ASSIGNMENT:ASSIGNMENT:

WORKSHEETWORKSHEET“RESPIRATION”“RESPIRATION”

PHOTOSYNTHESIS p. 82 (light) (to make)

- the process used by plants to make food.

-needs light, CO2, H2O, and chlorophyll

- it traps energy and uses it to break down water into hydrogen and oxygen.

Where does it takes place in the cell?

Oxygen is given off as a waste.Oxygen is given off as a waste.

Hydrogen combines with carbon to Hydrogen combines with carbon to make a sugar (glucose).make a sugar (glucose).

Glucose is stored/used as food or Glucose is stored/used as food or used to build new structures (ex. used to build new structures (ex. stems)stems)

- animals eat the plants and - animals eat the plants and receive energy from the stored receive energy from the stored sugars.sugars.

- the energy is passed on.- the energy is passed on.

All living things depend upon sunlight. *(except….)

Respiration and Photosynthesis Respiration and Photosynthesis are linked. are linked.