Chapter 3 - The Cell Flashcards
how big is a micrometer?
um (symbol), a unit of length equal to one millionth of a meter, or about the tenth the size of a droplet of fog/mist, or the size of an average mitochondrion (used to be referred to as a micron)
light microscopes
can see things the human eye cannot see, including most bacteria.
electron microscopes
can see a wide variety of the structures light microscopes can see, incl. viruses, ribosomes, all bacteria, proteins, lipids, and small molecules.
what is the least amount of cells an organism can have?
1
____ are the fundamental units of life.
cells
ALL cells on earth can be categorized into these two groups:
Prokaryotic and Eukaryotic
characteristics of prokaryotic cells
comprise single celled organisms, bacteria, and are very simple. cells may contain plasmids, pili, a capsule, and nucleoid.
characteristics of eukaryotic cells
larger, more complex cells, comprise single-celled or multicellular organisms, make up animals, fungi, plants, and protists
What are the two categories of prokaryotes?
Archaea and Bacteria
About how long have prokaryotes been around?
prokaryotic fossils date back 3.5 billion years
nucleoid
coiled DNA found in prokaryotic cells only unbound by any membrane
pili
short projections on the outside of prokaryotic cells, can attach to other prokaryotes
capsule
a sticky outer coat on prokaryotic cell walls, provides protection and helps the cell stick to surfaces
plasmids
small rings of DNA found in prokaryotes that duplicate independently and can be exchanged among cells
what structures do eukaryotic cells and prokaryotic cells have in common?
cytoplasm, cell wall, ribosomes, flagellum, plasma membrane
about how long ago did eukaryotic cells evolve from prokaryotic cells?
3 billion years ago
organelles are…
membrane-enclosed structures that perform specific functions
true or false: Prokaryotes contain organelles
False
what cell structures are unique to animal cells?
lysosomes
what are lysosomes?
membrane-enclosed bubbles of digestive enzymes (a type of vesicle) that break down and recycle foreign or worn-out cellular substances
what structures are unique to plant cells?
central vacuole, cell wall, chloroplasts
ribosomes
are free-floating or attached to the rough ER. They make protein that is necessary for usage in the cell.
mitochondria
where the cell harvests energy from food molecules and converts it into ATP
nucleus
location of much of a cell’s DNA