Bio Unit 3: Cell Structure and Function

light microscope

• uses light passing through lenses to enlarge image of a specimen

• up to 1500x actual size

• light has to be able to pass through

limitations of light microscope

• can’t see past 1500x

  • light = wave, visible light = 300-740 nm)

  • if something is too small, light is bigger than it and it can’t reflect

cell stains

• colors cells to see structure (most cells are translucent)

• each type of stain applies to certain organelles

electron microscope

• uses beam of electrons, not light to form image on computer

• powerful and expensive

• used in a vacuum (so air doesn’t interfere w/electrons)

  • nothing living

• 2 types: scanning and transmission

scanning electron microscope

• electrons bounce of specimen

• shows outside surface

• up to 1 million x actual size

transmission electron microscope

• pass through specimen 

• shows internal structure

• up to 50 mil x actual size

• artificial color (visible light too big)

Nucleus

• “control center”

• contains DNA and instructions for making molecules

nuclear envelope

• surrounds nucleus

• things can move through it (RNA)

chromosomes

genetic info - spread in form of chromatin

nucelolus

inside nucleus, makes ribosomes

vacuoles

storage - sac w/membrane that holds water, salts, proteins, and carbohydrates

• plants have a large vacuole (makes cell more rigid)

vesicles

transport - smaller, move things around cell

lysosomes

cleaning - enzymes inside them break down macromolecules and “junk”

• animal cells only!

cytoskeleton

gives cell shape, helps cell move, acts like a conveyor belt

• includes cilia(hair) and flagella(tail) in some prokaryotes and single celled eukaryotes

centriole

near nucleus, help divide cells

ribosomes

make proteins (follow instructions from DNA)

Endoplasmic Reticulum (ER)

• rough ER assembles lipids for cell membrane, proteins, other materials 

• smooth ER contains specialized enzymes

Golgi Apparatus/Bodies

sorts, modifies, packages stuff from ER for storage, release out of cell

Protein process

ribosomes make proteins → ER (maybe) modifies proteins → Golgi apparatus packages and ships proteins

Chloroplasts

• turns sunlight into food (photosynthesis)

• contains chlorophyll (green!)

• plant cells only!

mitochondria

• chemical energy → convenient and usable energy

cell wall

• porous

• support, shape, protection for cell

• prokaryotes, some eukaryotes like plants have this

cell membrane

• lipid bilayer

• selectively permeable

nucleus found in

eurkaryotes (prokaryotes just have DNA)

lysosomes found in

animal cells

vacuoles and vesicles found in

eukaryotes only

cytoskeleton found in

prokaryotes have similar structure, eukaryotes

ribosomes found in

ALL CELLS

ER found in 

eukaryotes only

Golgi apparatus found in 

eukaryotes only

chloroplast found in

some protists, plant cells

mitochondria found in

prokaryotes have reactions in cytoplasm instead, eukaryotes have them

cell wall

prokaryotes, plant cells

cell membrane exists in

all cells

all cells have 

DNA, cell membrane, cytoplasm, ribosomes

cell theory

• cells are the smallest unit of life

• all cells come from pre-existing cells

• all life is comprised of cells

only plant cells have

boxy/square shape, cell wall, large vacuole, chloroplast

only animal cells have

any shape, no cell wall, small vacuoles, lysosomes, centrioles

prokaryotes

• single celled organisms

• cell wall

• ex: bacteria

protists

• eukaryotic cells

• can be animal-like (eat and move), plant-like (photosynthesis) or fungi like(eat, cell wall, spores)

members only can come and go

cell membrane

brick wall

cell wall

sail through my plasma

cytoplasm

mighty powerhouse

mitochondria

I clean things up!

lysosomes

I’ll store anything

vacuole

I’m a “GOLden” packer

golgi bodies

make me something sweet to eat

chloroplast

I’m a transportER

endoplasmic reticulum

I make “some” nice proteins

ribosomes

control center

nucleus

little nucleus

nucleolus

I’m a “tin” of information

chromatin

archaea

single celled organisms w/structure similar to bacteria, form the 3rd domain of life