1.1 General Properties of cells Flashcards
criteria for self-replication
- be able to obtain and use energy from environment
- other building blocks
- DNA (instructions)
○ a way to read and replicate the DNA/pass on to next generation - machinery to undergo division (proteins)
- plasma membrane (container)
Cell theory
- all living organisms are made of cells
- cells arise from pre-existing cells
- cells are the basic unit of life
DNA in bacterial cell
- single circular chromosome
- also carry additional DNA in the form of plasmids
plasmids
small circles of DNA that replicate independently of the cell’s circular chromosome
not essential for cell’s survival but may have adaptive value!!
organelles in bacterial cell
- non membrane-bounded organelles
- cell processes are carried out by proteins that float freely in cytoplasm or are embedded in the plasma membrane
- does contain internal membranes similar to chloroplasts and mitochondria
structural support in bacterial cell
- Cell wall made of peptidoglycan
- Can have thick wall made of multiple ^ layers
- Or thin wall with an outer layer of lipids
- Bacteria DO possess internal scaffolding of proteins that play role in determining shape, polarity, and other spatial properties of bacterial cells
how does diffusion limit cell size in bacteria
- Small cell has more surface area in proportion to its volue
○ Interior parts of a small cell are closer to the surrounding environment than those of a larger cell- So!!! Slowly diffusing molecules do not have to travel far to reach every part of a small cell’s interior
- As cell size increases, It becomes harder to supply the cell with the materials needed for growth
Unicellular
one cell
- Multicellular
– billions to trilion of cells that function in a coordinated function
Plasma membrane
separates the living material within the cell from the nonliving environment around it
○ Controls movement of materials into and out of the cell
Nuclear membrane
selectively controls movement of molecules into and out of it
what are the 3 domains of life
○ Bacteria & Archaea
§ Mostly single celled microorganisms
§ Lack nucleus
§ prokaryotes
○ Eukarya
§ Have a nucleus
§ Eukaryotic
Organisms acquire energy from 2 sources
○ Sun
Chemical compounds
Metabolism
chemical reactions by which cells convert energy from one form to another and build and break down molecules
adenosine triphosphate (ATP)
Molecule that carries energy within cells
Many metabolic reactions are highly conserved between organisms, meaning…
the same reactions are found in many different organisms
internal organization in eukaryotes
- Has a nucleus
- Allows for Transcription and Translation to be separated in time and space
- Allows for more complex ways to regulate gene expression than is possible in prokaryotes
Has organelles – divides cell contents into smaller spaces specialized for different functions
lipids in eukaryotes
Cholesterol (part of the sterol group)
lipids in prokaryotes
- Do noy synthesize sterols
Some synthesize compounds called hopanoids
nucleoid
- DNA concentrated in discrete region of cell
because prokaryotes have no nucleus!!
eukaryote internal scaffolding
- rely on these to organize the cell
- different from protein framework of bacteria in that it can be remodelled quickly, enabling cells to change shape!!
endomembrand system
are all interconnected, many are capable of changing shape rapidly. are in dynamic continuity!
- dynamic network of membranes
- nuclear envelop
- endoplasmic reticulum
- Golgi apparatus
- plasma membrane
endocytosis
engulfing molecules or particles
enabled by cytoskeleton and membrane system
prokaryotic cells cannot perform this activity!!
phagocytosis
specific form of endocytosis in which eukaryotic cells surround food particles and package them in vesicles that bud off from the cell memrane
exocytosis
molecules or cytoplasmic waste formed within the cell are packaged in vesicles and moved to the cell surface for removal
how are intracellular vesicles and the molecules they carry transported?
molecule motors associated with the cytoskeleton!!
the speed means that EUK cells can be larger than most bacteria
mitochondrion
where aerobic respiration
chloroplast
where photosynthesis
