Structures of Eukaryotic Cells
-Nucleus
-Nucleolus
-Mitochondria
-Chloroplast
-Ribosomes
-Endoplasmic Reticulum
-Golgi bodies
-Lysosomes
-Vacuoles
-Plastids
-Cytoskeleton
-Villi
Nucleus:
1.-Brain of cell
2.-Cells control center
3.-Contains DNA
4.-Made up of another lipid bilayer
5.-contains pores for items to move in and out.
Nuclear Envelope:
-outside of nucleus, studded with pores
Nucleolus:
-circular structure within nucleus
-makes ribosomes
Nucleoplasm:
-cytoplasm inside
the nucleus
Chromatin:
1.-loosely coiled DNA found within the nucleus
2.-can tightly coil into a bow tie shaped “chromosome”
Chromosomes are
made up of genes.
Genes:
-segments of DNA
which code for
specific proteins
Mitochondria:
1. -cell’s powerhouse
2. -the place were the cell converts food into energy.
3. -found in all eukaryotic cells~plant-like and animal like.
4. -site of cellular respiration
sugar + oxygen  ATP energy + carbon dioxide + water
Form of energy
used by a cell
to do “work”.
-12 to 1000 mitochondria per cell
-plant cells have less than animal cells.
Why?
-less active
-require less energy
-Which cells in our body would have the most
mitochondria?
-muscle cells ~ very active
Mitochondria are made up of 2 membranes:
-outer membrane
-inner membranes known as cristae.
Cristae increase the surface area so more
energy can be produced without taking up
too much room.
Analogy:
verses
Chloroplast:
-Found only in plant-like cells
-site of photosynthesis
Sun + CO2 + H2OC6H12O6 + O2
CHLOROPLAST:
-Trap energy of the sun and convert
it into sugars which can be stored by the
plant or broken down in the mitochondria
into ATP energy.
Plant store
sugar in their
fruits, stems,
and roots.
Thylakoids: platelike structures which collect the sun’s
energy.
Grana or Granum: Stacks of thylakoids (10 to 100/chloroplast)
Stroma: Liquid part of the chloroplast
Lumen: Inside thylakoids ~ contains chlorophyll
ROY G BIV
Absorbs:
-all spectrums
of light but green
is reflected.
Ribosomes:
The cells “workbench”
Job: Makes proteins,
in their linear form, by
assembling amino acids
in the correct order
based on DNA’s code.
Ribosomes are made up of RNA and proteins.
Found attached to the endoplasmic reticulum
or
Free floating in the cytoplasm
Endoplasmic Reticulum (ER):
-Known as the “cells subway system
-Transports proteins around the cell
The E.R is a made up of a series of
interconnected, hollow channels.
Two types of E.R:
1. Smooth E.R.
-has no ribosomes
attached.
-responsible for making
phospholipids for new
membranes
2. Rough E.R.
-has ribosomes attached
-aids in protein synthesis
1.Proteins, made by the ribosomes, travel
through the hollow channels of the rough ER
into the smooth ER.
2.The end of the smooth ER pinches off
around the protein forming a “transporting
vesicle”
3. Transporting vesicle transports the newly
formed protein to the golgi body.
Golgi Complex, Apparatus or Bodies
-a stack of flattened
membranes clustered in
one area.
-Made up of a collection
of transporting vesicles.
Known as the Fed-Ex man
Job: Collects, stores, modifies
and packages materials
it receives from the
transporting vesicles/ER
and then deliver them to where
they need to go.
-Where a protein gets it 3D shape
Example: Insulin production in a pancreas cell
Lysosomes:
Nickname: Clean Up Crew or Suicide Sack
Job: Organelles which contain digestive enzymes
made by the ribosomes and processed in the
golgi.
Three Jobs:
1. Fuse to an old or damaged cell
organelle, injects its enzymes into it and digest
the old organelle .
2. Lysosomes fuse to food and digest the food for the
cell.
3. Lysosomes in an older or damaged
Cell breaks open and releases enzymes into the
Cytoplasm ~ digesting the cell from the inside out.
Example:
RBC’s
WBC’s
Sperm
lifespan
120 days
8 days
5 days
Lysosomes are rarely found in plant cells.
-when plant cells die, parts of the cell
remains.
Formation of a lysosome:
1. Ribosomes made dig. enzyme
2. Travel through ER
3. Smooth ER pinches off and dig. enzyme is
contained in a transporting vesicle.
4. Transporting vesicle fuses with golgi
5. Golgi modifies enzyme giving it a 3D shape
6. Section of golgi moves away with enzyme
inside it ~ now a lysosome.
Lysosomes
Vacuoles:
Stores excess
water, food or
waste.
Storage area for cell
Plant-like cells have 1 or 2 large central
vacuole which stores excess water or
sugars
Animals-like cells have many small
vacuoles which store excess water and
waste.
Plastids: specialized vacuoles in plants
Chloroplast:
Stores chlorophyll
Leucoplast:
Stores starch
Chromoplast:
Stores color pigments
Cytoskeleton: cell’s framework
Cyto
= cell
skeleton
= support
A woven web-like system embedded into an animal
cell’s cell membrane and cytoplasm, provides some
support to the cell.
Different animal cells have specific cells:
Cytoskeleton is made up of both:
1. Microfilaments:
-long, solid tubes of proteins
-allow for movement within cell
tissue like muscles.
2. Microtubules:
-long, hollow tubes of protein
Flagella: Long whip like tail Cilia: short hairlike
Centrioles: used by animal cells for cell division
Villi: fingerlike projections or extensions of the cell
membrane. Increases the surface area of the cell’s
membrane.
Plant and Animal Cell
Comparison
Plant cells have:
Animal cells have:
cell wall and membrane
cell membrane
chloroplast
no chloroplast
1 or 2 large vacuole
many small vacuoles
No centrioles
1 pair of centrioles
Has plastids
No plastids
Rectangular in shape
Roundish in shape
Small # of mitochondria
Large # of mitochondria