Cell Structure and Function

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Cell Structure and Function
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Why are cells small?
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Viruses
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Virus Morphologies
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viral capsids
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Cellular OrganismsProkaryotes and Eukaryotes
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Life on Earth
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Cell
All cellular organisms have a Protoplast the
cytoplasm and its surrounding plasma membrane
Some organisms have a Cell Wall (polysaccharide)
plants fungi some protists most bacteria
Bacteria often have a Capsule Which is a gooey
outside covering for protection (polysaccharide)
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ProkaryotesBacteria and Archaea
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The cytoplasm is an active environment
tRNA
protein
ribosome
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Few bacteria have internal membrane systems.This
bacterial species does.
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Three major morphologies
rods
cocci
spirochaetes
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Prokaryotes are usually much smaller than
Eukaryotes
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Life on Earth
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Eukaryotic Cell
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Paramecium
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The Nucleus
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Eukaryotes
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Nucleus
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Activities of the Nucleus

• Replication of DNA
• Gene Expression Synthesis of RNA
• Ribosome subunit assembly (in nucleolus, where
  rRNA genes are expressed)

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Nucleus
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Activities of the Nucleus

• Replication of DNA
• Gene Expression Synthesis of RNA
• Ribosome subunit assembly (in nucleolus, where
  rRNA genes are expressed)

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Nucleolus and rRNA genes
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Invagination Hypothesis
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1. The original eukaryotic cells probably had no
cell wall
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2. RNA splicing in eukaryotic genes
Intron 1
Intron 2
Intron 3
Intron 4
Exon 1
Exon 2
Exon 3
Intron 1
Intron 2
Intron 3
Intron 4
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Bacteria transcribe and translate simultaneously
no time for RNA splicing
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DNA Packaging - Chromosomes
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HumanKaryotype
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Chromosome Structure
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Chromosomes
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Centrioles in Centrosome also build the Spindles
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Flagella and cilia
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Structure of Flagella Cilia
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How Flagella and cilia move
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Cytoskeleton
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Ribosomes Sites of protein synthesis
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Ribosomes Sites of protein synthesis
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Membrane Systemssynthesis, degradation and
transport

• Nucleus
• RER
• SER
• Golgi Apparatus
• Lysosomes

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Rough Endoplasmic Reticulum
nucleolus
nuclear envelope
ribosome
rough endoplasmic reticulum protein synthesis
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Nucleus, RER, SER membranes are continuous
ribosome
nucleus
Rough ER protein synthesis
Smooth ER lipid synthesis
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Golgi Apparatussynthesis of molecules for export
and degradation
cis face receiving
transport vesicle
new vesicle forming
transport vesicles carrying cargo molecules
trans face shipping
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DEGRADATION
EXPORT
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Digestion Eating and Recycling
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Energy Transformation
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savings bond
cash
sunlight
sugar
sugar
ATP
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Mitochondria and Chloroplast Comparison
Similar to Bacteria
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Mitochondrion
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Chloroplasts
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Endosymbiont Hypothesis
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Endosymbiont Hypothesis
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Invagination Hypothesis
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Vacuoles
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Vacuole
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Plant Vacuoles
plasmolysis
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Practice
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Practice