| Question | Answer |
| Key Points of the Cell Theory | 1.All organisms are composed of cells
2.
3. All cells come from preexisting cells |
| Explain why cells must be small. | Small cells are likely to have an adequate surface area for exchanging wastes for nutrients.
B. Cells that specialize in absorption have modifications that greatly increase the surface area
per volume of the cell. |
| prokaryotic | Lack a membrane-bounded nucleus |
| List every component of a prokaryotic cell and explain the function of
each component. | Cell Envelopes
plasma membrane
cell wall
glycocaly
Capsule
Cytoplasm
Nucleoid
Plasmid
Inclusion Bodies
Cyanobacteria
Ribosomes
Appendages
Flagella
Fimbriae
Sex Pili |
| eukaryotic | Contain membrane-bounded nucleus.
Contain plasma membrane. |
| Describe the structure and function of each organelle in a eukaryotic cell | Compartmentalization:Allows eukaryotic cells to be larger than prokaryotic cells
Isolates reactions from others
B. Two classes:
1. Endomembrane system:
Organelles that communicate with one another
Energy related organelles
Mitochondria & chloroplast |
| Describe how ribosomes are notably different in prokaryotic and eukaryotic cells | Prokaryotic cells: protein synthesis
Eukaryotic cells:Composed of rRNA
Consists of a large subunit and a small subunit
Subunits made in nucleolus |
| endomembrane system | Endoplasmic Reticulum
Golgi Apparatus
Lysosomes |
| Energy-Related Organelles | Chloroplasts
Mitochondria |
| Describe the relationship between the endoplasmic reticulum and the Golgi apparatus | Both form vesicles that transport materials to the Golgi apparatus for modifications
and packaging |
| vesicles | Peroxisomes are membrane-bounded vesicles that enclose enzymes. |
| vacuoles | Membranous sacs that are larger than vesicles. |
| Describe the role of a central vacuole in a plant | functions in storage of nutrients and waste products; provides support and is a
reservoir for water |
| mitochondria | involved in cellular respiration
Produce most of ATP utilized by the cell
Cristae – Folds of inner membrane that encloses matrix.
Matrix - Enzymes that break down nutrient molecules. |
| List the 6 components of the cytoskeleton and the overall function of the cytoskeleton. | Actin Filaments
Intermediate Filaments
Microtubules
Centrioles
Basal body
Cilia and flagella |
| actin filaments | Pseudopods
b. Motor molecules |
| Intermediate Filaments | Supports nuclear envelope |
| Microtubules | Interact with proteins to cause movement of organelles
b. Centrosome |
| function and movement of cilia and flagella | are hairlike projections with a 9 + 2 pattern of microtubules that aid in cell
movement.
In eukaryotes, cilia are much shorter than flagella |
| basal bodies | organelle that is found at base of cilia and flagella and may direct
organization of microtubules |
| phospholipid bilayer | 1.External surface and cytoplasmic surface lined with hydrophilic polar phosphate
heads
2. Sandwiched in between are Nonpolar, hydrophobic, fatty-acid tails |
| Describe the structure of cholesterol in the plasma membrane and explain its importance to
the plasma membrane. | 1. Modifies fluidity of membrane
a stiffens membrane at higher temperatures
b. at lower temperatures, helps prevent membrane from freezing by not allowing
phospholipid tails to come in contact with each other
2. Lipid structure |
| glycolipid | carbohydrate chain attached to lipid |
| Glycoprotein | carbohydrate chain attached to protein |
| Describe the reason each cell has a unique “fingerprint”. | Accounts for tissue rejection and blood groups |
| peripheral protein | found on the inner membrane surface |
| integral protein | embedded in the membrane |
| Describe the functions of the six types of
integral proteins of the plasma membrane | Channel Proteins
Carrier Proteins
Cell Recognition Proteins
Receptor Proteins
Enzymatic Proteins
Junction Proteins |
| Channel Proteins | Involved in passage of molecules through membrane. |
| Carrier Proteins | Combine with substance to aid in passage through membrane. |
| Cell Recognition Proteins | Help body recognize foreign substances. |
| Enzymatic Proteins | Carry out metabolic reactions directly |
| differentially (selectively) permeable | Only certain substances can move across the membrane and others cannot |
| factors that determine whether a molecule can pass through the plasma membrane of a cell | Size, shape, charge, lipid solubility, temperature, pressure, electrical currents |
| concentration gradient | Particles move from area of high concentration to an area of low
concentration |
| solution | contains a solute (solid) and a solvent (liquid) |
| solute | solid |
| solvent | liquid |
| Describe the two methods of passive transport of materials across a membrane. | Diffusion - Movement of molecules from a higher to a lower concentration until
equilibrium is reached.
Facilitated Transport-Allows rapid passage of solutes |
| Osmosis | Diffusion of water across a differentially (selectively) permeable membrane due to concentration differences. |
| Osmotic pressure | is the pressure that develops due to osmosis |
| Tonicity | refers to the strength of a solution |
| Isotonic Solution | Solute and water concentrations both inside and
outside the membrane are equal. |
| Hypotonic Solution | Solution with a lower concentration of solute
than the solution on the other side of the membrane |
| Cytolysis | disrupted cells which may burst; animal cells only |
| Turgor pressure | plant cells do not burst due to cell wall;
provides water to allow plant to remain erect |
| Hypertonic Solution | Solution with a higher concentration of solute than the solution on the other side of the membrane. |
| Crenation | animal cells shrivel |
| Plasmolysis | plant cells the cytoplasm shrinks and the plasma membrane pulls away from the cell wall |
| Describe the two methods of active transport of materials across a membrane | Move against concentration gradient (toward high concentration)
B. Combining with carrier proteins
Bulk transport- macromolecules transported into or out of the cell inside vesicles |
| exocytosis | Vesicles fuse with plasma membrane and secrete contents out |
| Endocytosis | Cells engulf substances into pouch which becomes a vesicle |
| Phagocytosis | Large, solid material into vesicle |
| Pinocytosis | Liquid or small, solid particles go into vesicle |
| Receptor-Mediated | Specific form of pinocytosis using a coated pit |
| extracellular matrix | Meshwork of polysaccharides and proteins in close association with the cell that
produced them |
| List the major components of extracellular matrix | a. Collagen
b. Elastin- gives resilience
c. Fibronectin- binds to integrin and assist communication between ECM and
cytoskeleton
d. Proteoglycans- resists compression of ECM and assist cell signaling |
| Adhesion Junctions (desmosomes) | Intercellular filaments between cells |
| Tight Junctions | Form impermeable barriers |
| Gap Junctions | Plasma membrane channels are joined (allows communication) |
| Describe plant cell wall structure and its function | Plants have freely permeable cell wall, with cellulose as the main component. |
| plasmodesmata | 1. spans cell wall and contains strands of cytoplasm
2. Allows passage of water and small solutes between cells |
