Question | Answer |
Cells | -Smallest living unit
-Most are microscopic |
Who discovered cells? | Robert Hooke |
When were cells discovered? | Mid-1600 |
When/ who was the term "all living things are made of cells" discovered? | In 1839 by Theodor Schwann & Matthias Schleiden |
When/ who was the term "all cells come from cells" discovered? | In 1889 by Rudolf Virchow |
What are some principles of cell theory? | -All living things are made of cells
-Smallest living unit of structure and function of all organisms is the cell
-All cells arise from preexisting cells (this principle discarded the idea of spontaneous generation) |
Do cells have large surface area-to-volume ratios? | Yes |
What are the characteristics of all cells? | -A surrounding membrane
-Protoplasm; cell contents in thick fluid
-Organelles; structures for cell function
-control center with DNA |
What are the two types of cells? | 1. Prokaryotic
2. Eukaryotic |
Prokaryotic Cells | -First cell type on earth
-Cell type of bacteria and archaea
-No membrane bound necleus
-Nucleoi = region of DNA concentration
-Organelles not bound by membranes |
Eukaryotic Cells | -Nucleus bond by membrane
-Include fungi, protists, plant, and animal cells
-Possess many organelles |
Organelles | -Cellular machinery
-Two general kinds; derived from membranes, bacteria-like organelles |
Bacteria-like organelles | -Derived from symbiotic bacteria
-Ancient association
-Endosymbiotic theory; evolution of modern cells from cells & symbiotic bacteria |
Plasma membrane | -Contains cell contents
-Double layer of phospholids & proteins |
Phospholipids | -Polar; hydrophylic head, hydrophobic tail
-Interacts with water |
Movement across the plasma membrane | -A few molecules move freely; water, carbon dioxide, ammonia, oxygen
-Carrier proteins transport some molecules; proteins embedded in lipid bilayer, fluid mosaic model (describes fluid nature of a lipid bilayer with proteins) |
Membrane Proteins | 1. Channels or transporters
-move molecules in one direction
2. Receptors
-Recognize certain chemicals
3.Glycoproteins
-identify cell type
4.Enzymes
-catalyze production of substances |
Cell walls | -Found in plants, fungi, & many protists
-Surrounds plasma membrane |
What are the two different cell walls? | 1. Plants- mostly cellulose
2. Fungi- contain chitin |
Cytoplasm | -Viscous fluid containing organelles components of cytoplasm
-Components of cytoplasm; interconnected filaments & fibers, fluid = cytosol, organelles (not nucleus), storage substance |
Membranous organelles | -Functional components within cytoplasm
-Bound by membranes |
Nuclear envelope | -Separates nucleus from rest of cell
-Double membrane
-Has pores |
DNA | -Hereditary material
-Chromosomes; DNA, proteins, form for cell division |
What do bacteria-like organelles do? | -Release and store energy |
Types of bacteria-like organelles | -Mitochondria (release energy)
-Chloroplasts (store energy) |
Chloroplasts | -Derived from photosynthetic bacteria
-Solar energy capturing organelle |
Photosynthesis | -Takes place in the chloroplast
-Makes cellular food; glucose |
Molecule movement and cells | -Passive transport
-Active transport
-Endocytosis
-Exocytosis |
Passive transport | -No energy required
-Move due to gradient; differences in concentration, pressure, charge
-Move to equalize gradient; high moves toward low |
Types of passive transport | 1. Diffusion
2. Osmosis
3. Facilitated diffusion |
Diffusion | -Molecules move to equalize concentration |
Osmosis | -Special form of diffusion
-Fluid flows from lower solute concentration
-Often involves movement of water; into cell, out of cell |
Solution differences and cells | -Solvent + solute = solution
-Hypotonic; solutes in cell more than outside, outside solvent will flow into cell
-Isotonic; solutes equal inside and out of cell
-Hypertonic; Solutes greater outside cell, fluid will flow out of cell |
Facilitated diffusion | -Differentially permeable membrane
-Channels help molecule or ions enter or leave the cell
-Channels usually are transport proteins
-No energy is used |
Process of facilitated transport | -Protein binds with molecule
-Shape of protein changes
-Molecule moves across membrane |
Active transport | -Molecular movement
-Requires energy
Ex: sodium-potassium pump |
Endocytosis | -Movement of large material; particles, organisms, large molecules
-Movement is into cells
-Types of endocytosis; bulk-phase and receptor-mediated |
Process of endocytosis | -Plasma membrane surrounds material
-Edges of membrane meet
-Membranes fuse to form vesicle |
Forms of endocytosis | 1. Phagocytosis - cell eating
2. Pinocytosis - cell drinking |
Exocytosis | -Reverse of endocytosis
-Cell discharges material
-Vesicle moves to cell surface
-Membrane of vesicle fuses
-Materials expelled |