Chapter 4 Cell Structure and Function Flashcards
Most cells are much smaller than one _____________
millimeter
-some are as small as one micrometer
______ _________ states all organisms are composed of cells and that cells come only from preexisting cells.
Cell theory
Everything that enters or leaves the cell must cross the _______ ____________ that forms the cell surface
plasma membrane
The smaller the cell the larger the ________ of the surface are to volume
ratio
Small cells are likely to have an adequate ________ ____ for exchanging wastes and nutrients.
surface area
All cells have
- plasma membrane
- nuclear region
- cytoplasm
Organelle
-membrane bound sub cellular structures found only in eukaryotes
prokaryotic cells
- lack a membrane-bounded nucleus
- structurally simple
- can be divided into two domains
- Bacteria
- Archaea
Cell envelopes
-includes plasma membrane, cell wall, and glycocalyx
capsule-well organized compact layer
slime layer-diffuse layer
Plasma membrane may fold in to form internal pouches (_________)
mesosomes
-not a true membrane-bound organelle
Cytoplasm
-semifluid solution encapsulated by plasma membrane
(water, proteins, dissolved salts, ribosomes, etc)
inclusion bodies-stored granules of various substances
Appendages
flagella-
-rotating filament for locomotion
Fimbriae
-small bristles used to attache to surfaces
Sex Pili
-hollow tube used in exchange of genetic material with other cells
Organelles of ______________ _________ communicate with one another
endomembrane system
Nucleus
- contains chromatin (uncondensed DNA & protein) in semifluid nucleoplasm.
- separated from cytoplasm by double-membrane nuclear envelope
- nuclear pores permit passage in and out of the nucleus
nucleolus
-site of manufacture of ribosomes, move to cytoplasm
ribosomes
- make proteins from instructions coded in the DNA of the chromosomes
- RNA and proteins
Ribosomes are composed of large and small subunits that serve in ______ ________
protein synthesis
Endomembrane system consists of nuclear envelope, membranes of endoplasmic reticulum, Golgi apparatus, and several types of ________
vesicles
Endoplasmic Reticulum
- produces enormous variety of molecules for the cell
- Rough E.R-studded with ribosomes
- Smooth E.R-no ribosomes
Rough E.R
- makes proteins and other substances
- makes new plasma membrane
Smooth E.R
-makes lipids, including steroids
molecules may leave the ER in transport vesicles, which bud off from the membrane of the ER
Golgi Apparatus
- consists of flattened, curved saccules
- works in partnership with the ER
- Refines, stores, and distributes the products of cells
Lysosomes (not found in plants)
- Membrane-bounded vesicles produced by the Golgi apparatus
- contains digestive enzymes to break down macromolecules (hydrolysis)
Peroxisomes are membrane-bounded vesicles that enclose enzymes.
- enzymes are cell-specific
- all make H2O2, often from the oxidation of lipids
Vacuoles are membranous sacs that are larger than vesicles
- stores substances
- Plant cells typically have a central vacuole that functions in storage of nutrients and waste products
- Many protists have a contractile vacuole that rids the cell of excess water
Chloroplasts use solar energy to synthesize carbohydrates-found in plants and some protists
-Photosynthesis:stores light energy in glucose
Cellular Respiration-both plant and animal cells use this process to get the energy out of molecules
-Produces Adenosine triphosphate:used for all energy-requiring processes in cells
Chloroplasts are partitioned by membranes into three major compartments
- outer and inner membranes
- within the inner membrane is the Stroma
- The stroma is a thick fluid that fills the second compartment
Mitochondria are involved in cellular respiration
- found in almost all eukaryotic cells
* both plant and animal cells
The mitochondria produces most of ATP utilized by the cell
- Cristae-inner memberane that encloses matrix
* Deeply folded to increase surface area
Matrix
-has enzymes that break down nutrient molecules
_____________ serves as internal skeleton that maintains cell shape and assists in movement of its parts
Cytoskeleton
Actin Filaments
-movement
(two twisted chains of actin monomers
*Pseudopods & Cell Division
Intermediate Filaments
-support
(Fibrous, thin, and rope-like
*supports membrane and cell-to-cell junctions
Microtubules
-cell shape and organelle movement
smallest of the three, hollow cilinders
Centrioles
-special organization of microtubules
(equivalent to a basal body)
9+0 pattern and are found at the base of cilia and flagella
______ and __________ are hairlike projections with a 9+2 pattern of microtubules that aid in cell movement.
Cilia; Flagella
In ____________, cilia are much shorter than flagella.
eukaryotes
