Exam 2 Flashcards
Cell Theory
Unifying principle of biology:
- Cells are fundamental unit of life
- All organisms are made of cells.
- All cells come from preexisting cells
- Modern cells evolved from a common ancestor
Site of cellular transport of nutrients and waste for all cells
Cell membrane
Cellular intake of nutrients and release of waste products happens faster when what ratio is higher
Surface area to volume
What limits how big a cell can get
Surface area
Components of all cells
- Cell Membrane: Outer boundary of every cell; phospholipid bilayer with embedded proteins
- Cytoplasm: Everything in cell (except nucleus if applicable)
- Cytosol: Fluid cytoplasm not contained inside other compartment.
What organelles do prokaryotic cells have that eukaryotic cells don’t
Nucleoid, cell wall, capsule (not in all prokaryotes)
Prokaryotic cell walls are polymers of
Peptidoglycan
Difference between gram negative and positive bacteria
Gram negative bacteria have a thin peptidoglycan cell wall surrounded by a polysaccharide-rich outer membrane (rod-shaped) vs positive bacteria that have no outer membrane but have layers of thick peptidoglycan cell wall (spherical)
Hairlike structures that help bacteria adhere to other cells
Pili
Used by prokaryotes to swim, made from protein flagellin
Flagella
Function of slimy capsule that some bacteria have outside their cell wall
- Prevents detection by host immune cells
- Keeps cells from drying out
- Sometimes help with adhesion to other cells
- Mostly made of polysaccharides
Steps of cell fractionation
- Break cells open through homogenization; amphipathic cells could do this
- Separate homogenate using centrifugation; organelles with greatest density would fall first (nuclei first)
Nucleus in DNA
- Stores DNA
- Site of DNA replication, transcription, ribosome assembly
How is DNA packed in the nucleus?
Chromatin+chromosomes (compacted chromatin)
Chromatin
DNA and the histone proteins it wraps around
Where is DNA stored in prokaryotes
Nucleoid
Where does transcription and translation occur in prokaryotes
In cytoplasm (happens at the same time and place)
Mitosis
Process of nuclear division in eukaryotic cells
How did nucleus form
Through invagination of the cell membrane
Mitochondria
- Powerhouse of cell
- Uses glucose to produce ATP
- Next dense organelle after nucleus
- Many layers of membrane
- Has own DNA and can divide separately from cell division but can’t divide or grow outside cell
Which cells have the most mitochondria
Cells that require a lot of ATP (e.g muscle cells)
Endosymbiotic Theory
Some eukaryotic organelles are a result of our ancestors engulfing from ancient bacteria
Chloroplasts
- Helps provide plants cells with energy
- Has own DNA and can divide separately from cell division but can’t grow outside of cell
Plant Vacuoles
May provide structure, hold pigment, aid in digestion, and/or store water or waste