Cell Structure and Function

Cell Structure and Function

1. The Cell Theory A. All organisms composed of one or

more cellsB. Cell is smallest living organizational

unitC. Cells arise only from division of other

cells

1. The Cell Theory A. All organisms composed of one or

more cellsB. Cell is smallest living organizational

unitC. Cells arise only from division of other

cells

Attributes of cells Attributes of cells

A. Plasma membrane

B. DNA

C. Cytoplasm

D. Obtain energy and nutrients from their environment

A. Plasma membrane

B. DNA

C. Cytoplasm

D. Obtain energy and nutrients from their environment

Cell Size 1–100µ Cell Size A. Limitations of molecular diffusion

1. Faster passage through small cell 2. More efficient communication B. Limitations of surface-to-volume ratio

1. With increase in size, greater increase in volume than surface area

a. Interaction with outside occurs only at surface b. Insufficient exchange of materials at plasma

membrane for survival

1–100µ Cell Size A. Limitations of molecular diffusion

1. Faster passage through small cell 2. More efficient communication B. Limitations of surface-to-volume ratio

1. With increase in size, greater increase in volume than surface area

a. Interaction with outside occurs only at surface b. Insufficient exchange of materials at plasma

membrane for survival

adult human

tallest trees

chicken egg

frog embryo

most eukaryotic cells

mitochondrionmost bacteria

virus

proteins

atoms

diameter of DNAdouble helix

Prokaryotic—no nucleus, circular DNA, ribosomes, peptiglycon-prokayotic cell wall

a. Carbohydrate matrix cross linked with peptide units

Eukaryotic—larger, nucleus, linear chromosomes, membraned organelles,

Compartmentalization Include true bacteria

On earth 3.8 million years Found nearly everywhere

Spores in each breath; intestines

Naturally in soil, air, hot springs

Prokaryotic—no nucleus, circular DNA, ribosomes, peptiglycon-prokayotic cell wall

a. Carbohydrate matrix cross linked with peptide units

Eukaryotic—larger, nucleus, linear chromosomes, membraned organelles,

Compartmentalization Include true bacteria

On earth 3.8 million years Found nearly everywhere

Spores in each breath; intestines

Naturally in soil, air, hot springs

Cell typesCell

types

ribosomes

cell wall

plasma membrane

food granule

prokaryoticflagellum

cytoplasm

nucleoid (DNA)

Eukaryotic CellsEukaryotic Cells Have numerous internal structures

Various types & forms Plants, animals, fungi, protists

Multicellular organisms Nucleus is control center of the cell

1. Membrane bound (nuclear envelope)

2. Contains nucleoli; synthesizes ribosomal RNA

3. DNA in chromosomes (DNA and proteins)

Have numerous internal structures

Various types & forms Plants, animals, fungi, protists

Multicellular organisms Nucleus is control center of the cell

1. Membrane bound (nuclear envelope)

2. Contains nucleoli; synthesizes ribosomal RNA

3. DNA in chromosomes (DNA and proteins)

1. Plant cells a. Square-

geometric shaped

b. Cell wall-

cellulose c. Chloroplast d. No centrioles e. Large

vacuoles

1. Plant cells a. Square-

geometric shaped

b. Cell wall-

cellulose c. Chloroplast d. No centrioles e. Large

vacuoles

chloroplast

central vacuole

rough endoplasmicreticulum

ribosomes

microtubules(part of cytoskeleton)

cell wall

mitochondrion

Golgi complex

plasmamembrane

intermediatefilaments

smooth endoplasmicreticulum

free ribosome

vesicle

nuclear porechromatin

nucleolus

nuclear envelope

nucleus

Animal Cellsa. Irregular

shapedb. Just Cell

membranec. Small vacuolesd. Centrioles

Animal Cellsa. Irregular

shapedb. Just Cell

membranec. Small vacuolesd. Centrioles

flagellum

cytoplasmrough endoplasmicreticulum

ribosome

microtubules

lysosome

mitochondrion

Golgi complex

plasmamembrane

intermediatefilaments

vesicle

smooth endoplasmicreticulum

free ribosomevesicle

nuclear porechromatin (DNA)

nucleolusnuclear envelope

nucleus

nuclear pores

chromatin

nucleolus

nuclear envelope

nuclear pores

nucleus

chromosome

chromatin

0.05 micrometers

Eukaryotic cell structure

Eukaryotic cell structure

• Organelles • Endoplasmic

reticulum consists of folded membranes attached to the nucleus

• Rough ER is site of protein synthesis and protein secretion. Proteins made here are processed and shipped out of the cell

• Organelles • Endoplasmic

reticulum consists of folded membranes attached to the nucleus

• Rough ER is site of protein synthesis and protein secretion. Proteins made here are processed and shipped out of the cell

Eukaryotic Cell Structure

Eukaryotic Cell Structure

• Ribosomes assemble amino acid into polypeptide chains

• a. Associated with the ER

• b. Composed of RNA and proteins

• Proteins for inside the cell

• Ribosomes assemble amino acid into polypeptide chains

• a. Associated with the ER

• b. Composed of RNA and proteins

• Proteins for inside the cell

0.5 micrometers

ribosomes

rough endoplasmic reticulum

0.5 micrometerssmooth endoplasmic reticulum

vesicles

Eukaryotic Cell StructureEukaryotic Cell Structure• Golgi apparatus

are membranous sacs associated with ER

• Processing and transport of proteins, lipids exported from the cell

• Synthesis and transport of polysaccharides

• Lysosomes are Golgi-derived vesicles containing digestive enzymes

• Golgi apparatus are membranous sacs associated with ER

• Processing and transport of proteins, lipids exported from the cell

• Synthesis and transport of polysaccharides

• Lysosomes are Golgi-derived vesicles containing digestive enzymes

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Golgi complex

vesiclesfrom ER

vesiclesleavingGolgi complex

Mitochondria provide energy for cellular functions (respiration)

a. Matrix/cristae b. Have their own DNA and ribosomes; self-

replicate C. Bounded by double membrane-numerous

a. Outer membrane is smoothb. Inner membrane is folded into contiguous

layers called cristae1. Cristae are stuffed with 100,000

enzymes2. Site of cellular respiration-Oxidation3. Divides into inner matrix and outer

compartment4. Associated with proteins of oxidative

metabolism

Mitochondria provide energy for cellular functions (respiration)

a. Matrix/cristae b. Have their own DNA and ribosomes; self-

replicate C. Bounded by double membrane-numerous

a. Outer membrane is smoothb. Inner membrane is folded into contiguous

layers called cristae1. Cristae are stuffed with 100,000

enzymes2. Site of cellular respiration-Oxidation3. Divides into inner matrix and outer

compartment4. Associated with proteins of oxidative

metabolism

Energy sources for cell activities

5 micrometers

Chloroplasts—function in photosynthesis 1) Green—contain

chlorophyll pigment 2) Stroma/grana

(thylakoid stacks) 3) Have their own DNA

and ribosomes; self-replicate

4) Up to 100 per cell 5) Become leucoplasts

when deprived of lighta. Specialized

amyloplasts store starch

b. Plastids are derived from proplastids

Chloroplasts—function in photosynthesis 1) Green—contain

chlorophyll pigment 2) Stroma/grana

(thylakoid stacks) 3) Have their own DNA

and ribosomes; self-replicate

4) Up to 100 per cell 5) Become leucoplasts

when deprived of lighta. Specialized

amyloplasts store starch

b. Plastids are derived from proplastids

Energy sources for cell activities

CytoskeletonCytoskeleton Cytoskeleton

Internal infrastructure a. Actin filaments-microfiliments

a. Muscle movement b. Pinches cell when it divides during cytokinesis

b. Microtubules 1. Hollow tubes of 13 protein protofilaments-made of tubulin 2. Function

a. Help move materials within the cell itself b. Skeletal System c. Aides in cell Division-spindle d. Cilia, Flagella, sperm tails

c. Intermediate filaments

Surface structures extensions of the plasma membrane aid in movement of simple organisms

Cytoskeleton Internal infrastructure a. Actin filaments-microfiliments

a. Muscle movement b. Pinches cell when it divides during cytokinesis

b. Microtubules 1. Hollow tubes of 13 protein protofilaments-made of tubulin 2. Function

a. Help move materials within the cell itself b. Skeletal System c. Aides in cell Division-spindle d. Cilia, Flagella, sperm tails

c. Intermediate filaments

Surface structures extensions of the plasma membrane aid in movement of simple organisms

tubulinsubunit

actinsubunits

subunit

Prokaryotes & Eukaryotes

Prokaryotes & Eukaryotes

Similarities & differences

Both surrounded by plasma membrane, but very different

Prokaryotes – Archaebacteria and Eubacteria

Eukaryotes – everything else

Similarities & differences

Both surrounded by plasma membrane, but very different

Prokaryotes – Archaebacteria and Eubacteria

Eukaryotes – everything else

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Evolution of Eukaryotic cell

Evolution of Eukaryotic cellEndosymbiotic Hypothesis

Similarities between bacteria, mitochondria and chloroplasts

Self-reproducing by binary fission

Size of organism and genome

Single circular naked DNA

Proportion of (G & C) to (A & T)

Same sized ribosome

Protein synthesis inhibited by antibiotics

Enzymes for synthesis of DNA, RNA and protein

Electron transport system

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Plant & Animal CellsPlant & Animal Cells

Similarities

Both constructed from eukaryotic cells____________________________________________________________

____________________Both contain similar organelles____________________________________________________________

______________________Both surrounded by cell membrane____________________________________________________________

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Similarities

Both constructed from eukaryotic cells____________________________________________________________

____________________Both contain similar organelles____________________________________________________________

______________________Both surrounded by cell membrane____________________________________________________________

_____________________

Plant & Animal CellsPlant & Animal CellsDifferences

Plants haveCell wall – provides strength & rigidity

Have chloroplasts, photosynthetic

Animals haveOther organelle not found in plants (lysosomes formed from Golgi)

Centrioles, important in cell division

Differences

Plants haveCell wall – provides strength & rigidity

Have chloroplasts, photosynthetic

Animals haveOther organelle not found in plants (lysosomes formed from Golgi)

Centrioles, important in cell division

Brief Look at VirusesBrief Look at Viruses

Viruses are acellular

Not considered to be living

Cause serious diseases in most organisms

Viruses are acellular

Not considered to be living

Cause serious diseases in most organisms