Tour of the Cell Flashcards
all organisms are made up of?
cells
what are some examples of single celled organisms?
bacteria and archaea
what are some examples of multicellular organisms?
fungi, plants, animals, protists
what is the cell theory?
- every living organism is made up of one or more cells.
- the smallest living organisms are single cells and cells are the functional units of multicellular organisms.
- all cells arise from preexisting cells.
what are the two types of cells?
prokaryotic and eukaryotic cells
some information about prokaryotic cells?
- do not have a nucleus
- small
- lack other membrane bound organelles
some information about eukaryotic cells?
- has a nucleus
- larger
- have other membrane bound organelles
size of cells: prokaryotic vs eukaryotic cells?
prokaryotic: 1-5um
eukaryotic: 10-100um
do larger organisms have larger cells?
no they just have more cells.
basic components of any cell?
ribosomes, genetic material, plasma membrane, cytoplasm
all organisms can be placed into one of three?
domains: bacteria, archaea, eukarya
how are cells studied?
with the use of microscopes
the most commonly used microscope in the lab is?
light microscope
what are the 4 light microscopes that are commonly used?
- bright field microscope
- dark field microscope
- phase contrast microscope
- fluorescence microscope
most modern microscopes are?
compound microscopes meaning they use several lenses in combination to enlarge an image.
what are bright field microscopes useful for?
- looking at dead stained cells
- one will see a dark object on a light background
which microscopes allow one to see living organisms?
darkfield and phase contrast
what are electron microscopes?
electron microscopes use electrons as the source of illumination.
1. transmission electron microscope
2. scanning electron microscope
what is the transmission electron microscope used for?
forms an image from electrons transmitted from the specimen. it is used to look at INTERNAL STRUCTURES
what is the scanning electron microscope used for?
forms an image from electrons that are deflected from the specimens outer surface.
it is used to look at the SURFACE TOPOLOGY OF A CELL: gives 3D SHAPE
strength and weakness of electron microscope?
strength: great magnification
weakness: cant look at living specimens, specimen prep is time consuming and difficult, needs a lot of technical expertise, machine is very large and expensive.
what is an organelle?
a membrane bound structure with a specialized function within the cell.
examples: golgi apparatus.
what is the endomembrane system?
a collection of membranes inside and surrounding the cell.
what are some components of the endomembrane system?
nuclear envelope, endoplasmic reticulum, golgi apparatus, lysosomes, plasma membrane, vesicles, vacuoles.
the membranes of the endomembrane system are related by?
direct physical continuity or by the transfer of content via vesicles.
what structures are found in animal cells but not plant cells?
flagellum, centrioles, lysosomes
what structures are found in plant cells but not animal cells?
chloroplast, central vacuole, cell wall
animal cells do not have?
a cell wall.
what do animal cells have instead of a cell wall?
they have a plasma membrane and outside of the plasma membrane is the extracellular matrix.
what does the extracellular matrix consist of?
- protein fibers
- the most abundant protein found in the ecm is collagen
- plays a role in structural support
collagen is embedded in?
a network of proteoglycan complexes
what is a proteoglycan?
protein with many carbohydrate chains attached.
what does a proteoglycan complex consist of?
a proteoglycan complex consists of many proteoglycans noncovalently attached to a single polysaccharide molecule.
collagen is embedded in?
a network of proteoglycan complexes
what are the functions of the ecm?
- provides structural support
- helps to keep individual cells in place
- keeps adjacent cells in contact with one another
- plays a role in communicating with the cell
plant cell communication?
plant cells have cell walls surrounding them, they have plasmodesmata which are channels that connect the cytoplasm of two plant cells.
animal cell communication?
in animal cells, communication occurs through gap junctions. gap junctions consist of specialized membrane proteins that surround a pore thereby allowing certain molecules to pass through.
