Unit 4: Cell Structure & Function 1.

Unit 4: Cell Structure & Function

http://koning.ecsu.ctstateu.edu/cell/cell.html 1

Discovery of Cells

• Robert Hooke (1600’s) discovered “little chambers” (cells) in cork plant

• Anton van Leeuwenhoek (1600’s)used microscope to view living things in pond water. Saw things swimming around!

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Discovery of Cells, cont.

• Matthias Schleiden (1838) concluded plants made of cells

• Thoedor Schwann (1839) concluded all animals made of cells

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Cell Theory

1. All living things are made up of cells.

2. Cells are the smallest working units of all living things.

3. All cells come from p_____________ cells through cell division.

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Definition of Cell

A cell is the smallest unit that is capable of

performing life functions.

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Examples of Cells

Amoeba Proteus

Plant Stem

Red Blood Cell

Nerve Cell

Bacteria

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Two Types of Cells•Prokaryotic

“pro-” means “before” (like “pre”)“karyon” means “nut” or kernel”No n______________Older life forms are prokaryotes

•Eukaryotic“eu-” means “true” + “karyon”= kernelHas nucleus“newer” life forms are prokaryotic 7

Prokaryotic Cells

• Do not have o___________ surrounded by membranes

• V. few internal structures

• All prokaryotes are– one-celled

organisms– B___________

http://library.thinkquest.org/C004535/prokaryotic_cells.html8

Eukaryotic Cells• Contain organelles surrounded by membranes• Most living organisms are eukaryotic

– Plants, animals, f_____, algae

Plant Animal

http://library.thinkquest.org/C004535/eukaryotic_cells.html 9

“Typical” Animal Cell

http://web.jjay.cuny.edu/~acarpi/NSC/images/cell.gif 10

http://waynesword.palomar.edu/images/plant3.gif

“Typical” Plant Cell

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Eukaryotic Cell Parts“Organelles”

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Surrounding the Cell

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Cell Membrane

• Outer membrane of cell that controls m______

in and out of the cell

• Double layers of fat “phospholipid bilayer”

http://library.thinkquest.org/12413/structures.html

What part of this word tells you that the cell membrane is made of fats?

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Cell Wall

• Most commonly found in– plant cells – bacteria – fungi

• S_____ & p_____ cells

• Made of carbohydrate

http://library.thinkquest.org/12413/structures.html 15

Inside the Cell

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Nucleus

• Directs cell activities

• Separated from c_______ by nuclear membrane

• Contains genetic material - DNA

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Nuclear Membrane

• Surrounds nucleus

• Made of t____ layers

• Openings allow material to enter and leave nucleus

http://library.thinkquest.org/12413/structures.html18

Chromatin

• Form DNA takes most of the time.

• Like spaghetti

• Made of DNA wrapped up w/p_______.

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Chromosomes

• In nucleus

• DNA wrapped up tight by proteins called “histones”

• Contain instructions for traits & characteristics


Nucleolus

• Inside nucleus

• Contains RNA to build proteins


Cytoplasm

• Gel-like mixture

• Surrounded by cell membrane

• Contains hereditary material in prokaryotes

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Ribosomes

• Each cell contains thousands

• Make proteins

• Found on e___________ r________ & floating in the cytoplasm


Endoplasmic Reticulum• Moves materials around in cell

• Smooth type: – lacks ribosomes– Located in organisms that

produce _____ like _____

• Rough type (pictured):– R_____ are embedded in

surface – Located in organs responsible

for producing proteins, like the ________


Mitochondria• Produces energy through

chemical reactions by breaking down f___ & c_________.– Also known as the

“powerhouse of the cell”

• Controls level of water and other materials in cell

• Recycles and decomposes proteins, fats, and carbohydrates


Golgi Bodies• Protein

'packaging plant'

• Move materials within the cell

• Move materials out of the cell


Lysosome• Digestive ‘factory' for

proteins, fats, and carbohydrates

• Transports undigested material to c___ m_______ for removal

• The cell will break down if lysosome breaks!


Vacuoles

• Membrane-bound sacs for storage, digestion, and waste removal

• Contains water solution

• Help plants maintain s______


Chloroplast

• Usually found in plant cells (not in animal)

• Contains green chlorophyll

• Where p__________ takes place


Centrioles

• Used during animal cell division (not present in plant & most other cells)

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Flagellum

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• Is a whiplike structure that extends outside the cell.

• Is used for movement.

Cilia

• Small, hairlike projections that extend outside the cell

• For m_______ & capturing food

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Prokaryotic Cells

• Ribosomes

• DNA or RNA

• cytoplasm

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Cell Boundaries

• Cell Membrane1. Controls what

goes in & out

2. Support & protection

• Cell Wall1. Support &

protection

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Diffusion through Cell Boundaries

• Every cell lives in a liquid environment

• Membrane controls movement of dissolved molecules back & forth (in & out of cell)

• (Remember a solution contains a– Solvent: the

substance that dissolves the other stuff (often water)

– Solute: the substance that gets dissolved (salt, sugar, ions, etc.)

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Concentration of Solutions

• The greater the ratio of solute to solvent, the higher the concentration.

• Ex:

• Solution #1: dissolve 5 g of salt in 1L of water. Concentration= 5g/L

• Solution #2: dissolve 10 g of salt in 1L of water. Concentration=10g/L

This solution has a higher salt concentration

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Diffusion• In solution, particles move constantly,

colliding & spreading out.• Diffusion is the movement of particles

from area of greater to lesser concentration (b/c of random motion.)

• Requires no energy to move substances across a membrane (b/c moved by random motion)

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Isotonic

• When solute concentration is equal throughout the solution

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OsmosisVideo

• The diffusion of water through a membrane

• Some molecules are too large to move through a membrane

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http://highered.mheducation.com/sites/0072495855/student_view0/chapter2/animation__how_osmosis_works.html

How Osmosis Workssee Fig 7-15 on p 185

• If there is a selectively permeable membrane separating 2 solutions w/differing concentrations of solute,

• Water will move from the side where it is in greater concentration to where it is in lesser concentration. (R to L in picture)

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Concentration of Solutions

• Isotonic: when the concentration of particles is the same on both sides of membrane

• Hypertonic: “above strength”- the stronger of the 2 solutions (L side)

• Hypotonic: “below strength”- the less concentrated of the 2 solutions (R side)

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How Osmosis Works in Cellssee p 186 of text, Fig 7-16

• Isotonic: Cell maintains its shape

• Hypertonic

• Hypotonic

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Unit 4: Cell Structure & Function 1.

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Transcript of Unit 4: Cell Structure & Function 1.