Cell Structure and Function

Cell Structure and Function

Scientists responsible for the tools and foundations of cell biology:

Robert Hooke1665term “cell”observed cork


Anton van Leeuwenhoek

1674used high quality lenses to

improve microscopepond water - animalculesrecognized cells as basic

unit of life


Robert Brown1830’s discovered the cell’s nucleusnucleus directs cell division


Matthias Schleiden1838plants composed of cells


Theodor Schwann1839animals composed of cells


Rudolf Virchow1855new cells arise from the

division of preexisting cells

Cell TheoryThe work of these scientists provided information significant to the development of the cell theory

All living things are composed of cells Cells are alike in chemical composition and structure Cells are the smallest working unit of living things All cells arise from other cells

All living organisms are alike because they are composed of cells… by studying the composition and chemistry of the cell, we understand the chemistry and composition of all kinds of life forms

Breaking it down…… introduction to biochemistry

What is biochemistry???

Bio chemistryThe study of matter and the changes in matter

Pertaining to life

ProteinsCarbohydrates Lipids

Nucleic Acids

Macromolecules

Polymer: Very large molecule made from individual pieces

MonomerAKA: Subunit

• Hydrolysis: Breaks apart the polymer into monomers

• Water needed to break the bond

• Dehydration Synthesis: AKA: Polymerization

• Links the monomers together to form the polymer

• Produces water

What do monomers look like?• Hydrocarbon: Molecule containing Hydrogen and Carbon

Ethane

Ethene

EthyneUnsaturated

Saturated

Molecular Structure

CHAIN BRANCH RING

Substituted Hydrocarbon

• Hydroxyl -OH• Add –ol suffix to name• Creates an alcohol• Used to disinfect or as a

fuel

Methanol

Methane

• Carboxyl Group -COOH• Creates a carboxylic

acid or organic acid• Found in citrus fruits,

vinegar (ethanoic acid)

Methane

Methanoic Acid

• Amine -NH2• Includes novocaine,

painkiller

Methylamine

Methane

Carbohydrates

Proteins

Lipids

Nucleic Acids

Group Project- Make a Biological Molecule

• Build a biological molecule to hang from the ceiling.

• Include all major structures. • Sketch out model before building. • You will have 20 minutes in class today and

tomorrow to collaborate and 30 minutes to build on Friday.

• Be creative!!!

Enzyme Salad Lab• Test Tubes Containing the following

– 1. Frozen + Gelatin– 2. Fresh + Gelatin– 3. Canned + Gelatin– 4. Gelatin

• Place the test tubes in an ice bath. Once tube 4 has gelled, record observations in the table.

Observations Before Ice Bath

Observations After Ice Bath

Frozen + GelatinFresh + GelatinCanned + GelatinGelatin

Discussion Questions1. Why did test tube #4 contain only gelatin?

2. What could account for the different results in the tubes?

3. How could the canning process change bromelin?

4. What could you do to fresh pineapple that would allow the salad to gel?

Catalyst

Enzymes

Organic Molecules that compose “life’s building blocks”Organic Group Polymer Monomer Functions of polymers

in the cell

Carbohydrates Sugars EnergyStorage of energyBuilding materials

Proteins Amino Acids EnzymesBuilding blocksMessengersTransport etc…all the life’s work

Lipids Long chains of carbon and hydrogen

Cell membrane building blocksEnergy storageChemical messengers

Nucleic Acids Nucleotides Hold recipes for proteins “Code of Life”

Enzyme activity (video)

A. Enzymes put molecules together……SYNTHESIS.

B. Enzymes take molecules apart…… DIGESTION.

C. Enzymes control chemical reactions…….LIFE.D. Enzymes make chemical reactions require less energy.

Enzyme A Enzyme B

Substrate

Lock and Key Theory for Enzyme Action

http://www.youtube.com/watch?v=lrKgjbqZTwU

Cells and cell types

Prokaryotic vs. Eukaryotic Cells

• No Nucleus• Small and simple• No organelles• Sticky capsule• Contains cell wall

(peptidoglycan)• First cells• Live in a wide variety of

environments• Include bacteria

• Nucleus• Organelles• Unicellular or multicellular• Cytoskeleton• Some have cilia• Include all cells but

bacteria

Single Cell• Monera• Prokaryotic – lacking a

nucleus and any organelles • Reproduce by binary fission –

splitting into two• Ex. Bacteria • Protista

• Eukaryotic – Nucleus present• Have organelles that carry

out specific functions• Ex. Amoeba, paramecium,

euglena

Multi Cell

• Fungi• Eukaryotic – Nucleus present• Cell Wall composed of chitin• Saprophytic (food comes from dead

organic material)• Individual cells are not completely separate

from neighboring cells• Ex. Bread mold, mushrooms, Athlete’s foot

• Animal• Eukaryotic – Nucleus present• Heterotrophic – food comes

from organic material• No cell wall or chloroplast• Do have centrioles

• Plants• Eukaryotic – Nucleus present• Cell Wall composed of cellulose• Autotrophic – can produce their

own food• Chloroplasts, large vacuoles

http://youtu.be/ASYG1JQy7K4

http://youtu.be/4DWaAIVlW3k

Quick Quiz!! If you found a new organism and it was multicellular, did not contain chloroplasts, but did have cell walls, which kingdom would you expect it to belong

to? A. MoneraB. ProtistaC. FungiD. PlantaeE. Animalia

How did the first cells form?Oparin – Haldane Hypothesis (1920’s)

Prebiotic Soup:

Methane (CH4)Hydrogen gas (H2)Ammonia gas (NH3)Water vapor (H2O)Very Little Oxygen!!

Earth’s Conditions:volcanic eruptionsUV radiationlightningmeteor bombardment

Idea based on the behavior of energy and molecules found in all living things

UV radiation synthesized the first organic compounds from inorganic precursors

Testing the HypothesisStanley Miller (1953)

Set up experiments using O-H hypothesisProduced simple amino acids

1 week!!!

Amino Acids- building blocks for all life forms, protein components

Molecules + Energy = Larger molecules and chemical compounds

Results = Theory of How Earth’s Life Began

Evidence:

20 amino acidscommon sugarslipidsDNA and RNAATP

Molecules of

LIFE

These have all been recreated in the laboratory. All the steps to making simple cells have been recreated under lab conditions!!

Quick Quiz!! What organelles are made up of lipids?

1. Cell membrane2. Nuclear membrane3. Endoplasmic

reticulum4. Golgi Bodies5. All of the above

Cell m

embra

ne

Nuclear

membran

e

Endoplas

mic ret

iculum

Golgi B

odies

All of th

e above

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Conclusion = Theory of How Earth’s Life Began

1.) The Earth consisted of prebiotic soup from which small organic compounds were made

2.) Small molecules were joined to make larger molecules

3.) Molecules organized into droplets with different Characteristics than the molecules alone.

4.) Origin of heredity: formation of DNA allows primitive cells to reproduce themselves and pass on info.

Endosymbiont Hypothesis

Lynn Margulis (1970) proposed an evolutionary explanation for eukaryotic cells

…Eukaryotic cell is the result of prokaryotic cells living enclosed in one cell Symbiotic:mutually benefiting from the relationship

Prokaryotes vs. Eukaryotes

Prokaryotic CellsNo nucleusSimple cellsFunction simplyEx. – BacteriaPrecursors to eukaryotes

Eukaryotic CellsNucleus presentComplex and organizedcomplex and specialized

functionsEx. – all body cells, plant cells,

fungi, etc.Evolutionarily advanced over

prokaryotic cells

Cell MembraneFunction:

-Separates the cell from its surroundings-Protects the cell

contents- Determines what raw

materials will enter*- Releases waste

products produced inside of cell*

*Transport Mechanisms

Cell MembranePhospholipid Bilayer

…flexible barrier allowing only lipid soluble substances

into the cell…fluid mosaic model =

individual phospholipids can move around within the membraneProteins

…pump for specific substances into/out of cells

…open channels for certain materials

Carbohydrates…membrane stabilizers (cholesterol)…chemical identification of the cell

Nucleus

Functions:- control center, cell activities are primarily directed from the nucleus- Contains the DNA and proteins = CHROMATIN- Chromatin condenses during reproduction to form CHROMOSOMES

Quick Quiz!! The majority of chromosomes are made up of what kinds of molecules?

A. CarbohydratesB. LipidsC. ProteinsD. Nucleic Acids

Nucleus

Membrane boundporous membrane

Nucleolus

Dark staining structure within the nucleusContains r-RNA, makes ribosomes

Cell Fluids

Nucleoplasm:Inside of the nucleus

Plasm = fluidCyto = cell

Cytoplasm: Outside of the nucleus

Cytoplasm

Organelles in the cytoplasm of all eukaryotic cells:RibosomesEndoplasmic ReticulumGolgi ApparatusLysosomesCytoskeletonVacuolesMitochondria

Organelles in some eukaryotic cells:CholoroplastsCell WallFlagellaCiliaCentrioles

Ribosomes

Tiny structure where proteins are assembled from amino acids

Endoplasmic ReticulumNetwork of membranes dividing cytoplasm and directing the flow of material through the cell

Rough – ribosomes attached, rough appearanceSmooth – no ribosomes, smooth appearance

Quick Quiz!! Because ER is made from membranes, what type of organic macromolecule would you expect it to be constructed

from?

A. CarbohydratesB. LipidsC. ProteinsD. Nucleic Acids

Carbohy

drates

Lipids

Protei

ns

Nucleic

Acids

18% 18%18%

47%

Golgi ApparatusTightly grouped membranous structure where proteins are condensed, collected, and packaged for storage or shipment out of the cell

Produces lysosomes, vesicles, and vacuoles

Lysosome, Vacuoles, and Vesicles:

Lysosome: sac-like structure containing enzymes for cellular breakdown; recycling plant

Vacuoles and Vesicles: - store carbs, water, salts,

fats, etc.-Vacuoles may be larger-In plants, vacuole provides support- Vacuoles stay in cells- Vesicles bring things

into/out of cells

Quick Quiz!! After a protein has just been produced, where is it most likely to go?

A. A ribosomeB. The ERC. A vesicleD. The Golgi

Apparatus

A riboso

me

The ER

A vesic

le

The Golg

i Appara

tus

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Cytoskeleton

Microtubule and microfilament network that provides a frameworkMovement of proteins inside cellMovement of the cell

Mitochondrion

Contain their own DNATakes chemical fuel (glucose) and converts it into small useable packages (ATP)

Organelles in some eukaryotic cells but not all…

Chloroplasts

Contain their own DNALight absorbing structure that package ENERGY in glucose

Cell Walls

Structure that surrounds cell membraneProvides support and rigidity to cellsIn plants, composed of celluloseIn fungi, composed of chiten

Flagella

Tail-like structures used for locomotion

Cilia

Short, hair-like structures on the surface of the cellUsed for locomotion and to move materials near cell

Centrioles

Only in animal cellsUsed in cell division

Quick Quiz!! In addition to centrioles, what else is made of microtubles?

A. CytoskeletonB. MitochondriaC. Cell wallsD. RibosomesE. Endoplasmic

reticulum

Cytosk

eleton

Mito

chond

ria

Cell w

alls

Ribosomes

Endoplas

mic ret

iculum

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Documents

Cell Structure and Function