Chapter 4 Flashcards
who discovered cells and when?
Robert Hooke in 1665
who proposed cell theory and when?
Schleiden and Schwann in 1840
list the three rules of cell theory
- all living things are composed of cells
- cells are the smallest living things
- cells arise only from other cells
can cells be any size?
no, cell size is limited
why is cell size limited?
as size increases, the surface area to volume ratio decreases, and diffusion becomes less efficient, this is why cells are microscopic
what are the three structures that all cells have in common?
- plasma membrane; cell boundary
- cytoplasm; also called cytosol
- DNA; requirement for life
what is the primary characteristic of prokaryotic cells?
they lack membrane bound organelles
what are the two types of prokaryotic cells and where are they found?
- acteria; everywhere
2. archaebacteria; found in limited, extreme environments, likely the first cells to evolve
what structures do prokaryotic cells possess? Don’t put Cheese on your PopCoRN
DNA Cytoplasm Plasma membrane Cell wall Ribosomes No membrane bound organelles
what are two extracellular structures that some, but not all prokaryotic cells have?
flagella and pili
what do prokaryotic cell walls do?
protect and maintain structure/shape
what are prokaryotic cells composed of?
combination of proteins and sugars called glycoproteins
what do the flagella of prokaryotic cells do?
allows cell to move and change location
what do the pili of prokaryotic cells do?
anchors cell in place
what does the envelope of prokaryotic cells do?
further protects cell from harsher environment, is typically gelatinous, can be glycoprotein structure
what is the biggest difference between prokaryotic and eukaryotic cells?
eukaryotic cells possess membrane bound organelles, they are also more complex, compartmentalized, and have more support and structure, they also have mitochondria
what does the nucleus do?
stores DNA
what is the nucleus surrounded by?
nucleoplasm, a phospholipid bilayer
what is chromatin?
DNA’s less organized form, an unwound loose chain for the cell to use easily
what is the endoplasmic reticulum?
Rough ER and Smooth ER, right outside the nucleus, protein and lipid synthesis
what is the nuclear membrane/envelope?
it surrounds the nucleus and has NUCLEAR PORES to allow DNA info out
what is the nucleolus?
where RNA baker is stored and organized, darker region in nucleus
what is special about cancer cells?
they have multiple nuceoli to handle cell divisions
what are ribosomes?
OVENS!
site of protein synthesis
composed of RNA
large and small part joined together (oven and oven door?)
where are the ribosomes located?
embedded in the ER and floating free in the cytoplasm
where is the endomembrane system located?
nuclear pores, through endoplasmic reticulum, inside cell cytoplasm
what does the endomembrane system do?
synthesizes protein, gets it into correct form, moves it through ER, synthesizing and folding, packages it to move to golgi, where it is folded and packaged into its final form, and expelled out through vesicles
what composes the endomembrane system?
- nuclear membrane
- ER
- golgi body
- transport vesicles
- plasma membrane
Are ribosomes part of the endomembrane system?
No
What does the rough endoplasmic reticulum do?
Protein synthesis
Where is the rough ER located?
Closest to the nucleus