Passive mechanisms Active mechanisms Cell diffusion Cut along the dotted lines then fold Mechanisms that do not require cellular energy such as: Passive mechanisms Diffusion Facilitated diffusion Osmosis Filtration Mechanisms that do require cellular energy such as: Active mechanisms Active transport Endocytosis Exocytosis A substance can only diffuse into or out of a cell if the cell membrane is permeable to the substance and if a concentration gradient exists Cell diffusion

Facilitated diffusion Cut along the dotted lines then fold A chemical technique that uses diffusion to separate small molecules from larger ones in a liquid Dialysis A process that moves molecules from regions of higher concentration toward regions of lower concentration Facilitated diffusion A hormone that promotes facilitated diffusion of glucose through the membrane of certain cells Insulin

Osmosis Osmotic Pressure Isotonic Cut along the dotted lines then fold A special case of diffusion that occurs whenever water molecules diffuse from a region of higher water concentration to a region of lower water concentration across a selectively permeable membrane Osmosis The ability of osmosis to generate enough pressure to lift a volume of water Osmotic Pressure Refers to a solution that has the same osmotic pressure as body fluids Isotonic

Hypertonic Hypotonic Hydrostatic pressure Cut along the dotted lines then fold Refers to a solution that has a higher osmotic pressure than body fluids causing the cells to shrink as water moves out of the cell Hypertonic Refers to a solution that has a lower osmotic pressure than body fluids causing the cells to swell and possibly burst as water moves into it Hypotonic Hydrostatic pressure Pressure created by the weight of water

Cut along the dotted lines then fold Process that occurs when particles move from a region of lower concentration to a region of higher concentration Active transport Process by which particles that are too large to enter a cell by diffusion, facilitated diffusion, or active transport are conveyed with a vesicle formed from a section of the cell membrane Endocytosis Process by which particles stored in vesicles are secreted from the cell Exocytosis

Cut along the dotted lines then fold Process by which cells engulf tiny droplets of liquid from their surroundings as a small portion of the cell membrane indents Pinocytosis Process by which cells engulf particles from their surroundings as a small portion of the cell membrane indents Phagocytosis Process that combines endocytosis and exocytosis to transport a particle or structure across a cell Transcytosis

Interphase S phase of interphase G1 and G2 phases Cut along the dotted lines then fold The stage in the cell cycle where young cells grow, manufacture compounds, new organelles are made, and the chromosomes and centrioles replicate Interphase S phase of interphase The phase when the DNA of the cell is replicated in preparation for cell division G1 and G2 phases The phase when the cell grows and other structures are duplicated

Cut along the dotted lines then fold Division of the cell nucleus Each daughter cell receives an exact copy of the mother’s genetic material Described as a series of four stages but the process is actually continuous Mitosis The division of sex cells resulting in two, and then four, daughter cells each containing the haploid number of chromosomes which is half of the parent cell’s genetic information; mitosis is a phase of meiosis Meiosis The first stage of mitosis when the DNA condenses into chromosomes, the nuclear envelope and the nucleolus disperse, and a spindle-shaped group of microtubules forms between the centrioles as they move apart Prophase

Cut along the dotted lines then fold The second stage of mitosis when the chromosomes line up in an orderly fashion about midway between the centrioles, and spindle fibers become attached to the centromere of the chromosome Metaphase The phase when the centromere of the chromatids separate and the chromatids become chromosomes, which are pulled apart toward opposite sides of the cell Anaphase The final stage of mitosis when the chromosomes complete their migration toward the centrioles, the nuclear envelope reforms, and the chromosomes become invisible Telophase

Cut along the dotted lines then fold This phase begins during anaphase; cell membrane develops a cleavage furrow Contraction of a ring of microfilaments divides cytoplasm Ring pinches inward, separating the two nuclei and distributing half of the organelles New cells may differ slightly but contain identical genetic info Cytokinesis The process by which cells develop specialized characteristics in structure and function to reflect genetic control of the nucleus as certain genes are turned on while others are turned off Cell differentiation Cells that retain the ability to divide repeatedly without specializing allow for continual growth and renewal; this cell divides mitotically to yield either two daughter cells like itself, or one daughter cell and one that becomes partially specialized Stem Cell

Apoptosis Scavenger Cell Cancer Cut along the dotted lines then fold A form of cell death that is a normal part of development (Ex: Skin cells peeling away after a sunburn) Apoptosis Scavenger Cell A cell that engulfs and destroys cells that are undergoing apoptosis A group of closely related diseases resulting from gene mutations that alter the cell cycle; characteristics include: Cancer Hyperplasia Dedifferentiation Invasiveness Angiogenesis Metastasis