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Chapter 5. Cell and organelles: structure and function - Coggle Diagram
Chapter 5. Cell and organelles:
structure and function
METHOD FOR CELL FRACTIONATION OBSERVATION
Cell fractionation
Isolate organelles to study their functions
Observation under Microscope
Light microscopy
Brightfield / Darkfield
Phase-contrast
Fluorescence
Confocal
Deconvolution
Super-resolution
Electron Microscopy (EM)
TEM (Transmission Electron Microscope)
SEM (Scanning Electron Microscopy)
Cryo-EM (Cryo-electron microscopy)
THE SIZE RANGE OF
CELL
Human body: ~1–10 m
Animal/plant cells: 10–100 µm
Nucleus: ~5 µm
Bacteria: ~1 µm
Mitochondria: ~1 µm
Ribosome: ~20 nm
Virus: ~100 nm
Protein: ~5 nm
Atom: ~0.1 nm
Relationships between
surface area and volume
Volume increases faster than surface area
Large cells → inefficient exchange
Small cells → efficient exchange
Biological adaptations
Folding
Increased surface area
Plants: Root hairs: extensions of root epidermal cells;increase surface area for absorbing water and minerals
Animals:
Villi: finger-like projections on SI wall
Microvilli: projections on each cell
Cell types
Prokaryotic Cells
No true nucleus
No membrane-bound organelles
DNA in nucleoid region
Examples: bacteria, archaea
Eukaryotic Cells
True nucleus
Membrane-bound organelles
Examples: plants, animals, fungi, protists
CELL AND ORGANELLES STRUCTURE AND FUNCTION
Extracellular components
Animal cell
Extracellular Matrix
glycoproteins (ex. collagen)
Glycocalyx
Intercellular Junctions
Tight junctions:
Desmosomes:
Gap junctions:
Plant cell
Cell wall
pectic,
cellulose
protein
Plasmodesmata
Plasma membrane
General structure: double layer of
phospholipids
allows sufficient passage of oxygen, nutrients,
and waste to service the volume of every cell
Cytoplasm
Cytosol
water (| 70% v/v)
protein
ions
macromolecules
Non membrane structures
Cytoskeleton
Microtubules
Microfilaments
Intermediate
Filaments
Centrosomes (MTOC)
region from which microtubules grow
Animal cells contain centrioles
Ribosome
Function: protein synthesis
Composed of rRNA + protein
types
Free ribosomes
Bound ribosomes
Proteasome
essential protein complexes responsible for the degradation of proteins by proteolysis
Single membrane organelles
Endomembrane system
Endoplasmic reticulum
Rough ER
ribosomes on surface
package proteins for secretion, send transport vesicles to Golgi, make replacement membrane
Smooth ER
synthesize lipids, metabolize
carbohydrates, detox drugs & poisons, store Ca2+
no ribosomes on surface
Golgi apparatus
synthesis and packaging of materials (small molecules) for transport (in vesicles)
produce lysosomes
Series of flattened membrane sacs
(cisternae)
Lysosome
intracellular digestion, recycle cell’s
materials, programmed cell death
Contains hydrolytic enzymes
Vacuole
storage of materials
food,
water,
minerals,
pigments,
poisons
Plants: large central vacuole -- stores water, ions
Peroxisome (glyoxysome)
break down fatty acids; detox alcohol.
Involves production of hydrogen peroxide (H2O2)
Double membrane organelles
Mitochondria
Function: site of cellular respiration
Double membrane: outer and inner membrane
Cristae: folds of inner membrane; contains enzymes for ATP production; increased surface area to n ATP made
Chloroplasts
Function: site of photosynthesis
Thylakoid disks in stacks (grana); stroma (fluid)
Contains chlorophylls (pigments) for capturing
sunlight energy
Nucleus
Function: control center of cell
Contains nucleolus and chromatin with DNA (& mRNA)
Surrounded by double membrane (nuclear envelope)
Function
• Provide structure and support
• Control metabolism
• Produce energy
• Movement
• Reproduction
