Biology Chapter 3 (part 1) Flashcards
Cells are small becasue…
nutrients need to diffuse across the cell
the largest a cell can be is…
~100 micrometers in diameter
some cells have special modifications that…
increase surface area relative to their cell volume
neurons are
very long and thin
cells lining the digestive tract have
microvilli (finger-like projections that increase surface area)
in order for organisms to become larger, they must become…
multicellular
all living organisms are composed of…
cells
the cell is a basic unit of…
all living organisms
cells are the ___________ that can survive independently
smallest single unit
all cells come from…
pre-existing cells
all cells contain ___________ which is passed through to new cells through __________
genetic material (DNA), cell division
all cells are either…
prokaryotic or eukaryotic
Plasma Membrane
forms the boundary of the cell, controls the permeability of the cell to water, and dissolves substances
cytoplasm fills the…
interior of the cell
the plasma membrane is a sheet of…
lipids with embedded proteins
the molecules comprising the lipid layers are called…
phospholipids
structure of phospholipids
polar head (hydrophilic), non-polar tails (hydrophobic)
polar regions consist of…
phosphate group
non-polar regions consist of…
fatty acids
receptor proteins
binds substances outside the cell that affect the function of that cell
antigens
they act as markers, such as blood type proteins
transport proteins
allow substances to cross the membrane
Prokaryotic
- Lack a nucleus and do not have an extensive system of internal membranes.
- All eubacteria and archaea are prokaryotic
Eukaryotic
- Have a nucleus and have internal membrane-bound compartments.
- All organisms other than bacteria are eukaryotic.
Prokaryotes are the _________ cellular organisms
Simplest
prokaryotes have no or few…
interior compartments
prokaryotes cell wall
combination of disaccharides and amino acids known as peptidoglycans confer a rigid structure
Capsule
may surround the cell wall
cytoplasm
uniform with little or no internal
support framework
ribosomes
scattered throughout the cytoplasm
Nucleoid region
area of the cell where DNA is localized.
→ It is not membrane-bound, so not a true nucleus