It is the simplest structure that shows all the characteristics of life, including organization, metabolism, responsiveness, homeostasis, growth, and reproduction
The study of cells
Formerly called the cell membrane
not only encloses the cell contents but also participates in many cellularactivities, such as growth, reproduction, and interactions between calls, and is especially important in regulating what can enter and leave the cell.
Main substance of this membrane is a double layer of lipid molecules called a bilayer
Cholesterol strengthens the plasma membrabe
a complex lipid containing phosphorus
an organic catalyst
speeds the rate of a chemical reaction but its not changed in the reaction
(Plasma membrane) Channels
pores in the membrane that allow specific substances to enter or leave. Certain ions travel through channels in the membrane
(plasma membrane) Transporters
shuttle substances from one side of the membrane to the other.
(plasma membrane) Receptors
points of attachment for materials coming to the cell in the blood or tissue fluid.
some hormones, for example, must attach to receptors on the cell surface before they can act upon the cell
give structure to the cell membrane and help attach cells to each other
Cell identity markers
proteins unique to an individual's cells. these are important in the immune system and are also a factor in transplantation of tissue from one person to another
small projections of the plasma membrane that increase surface area, allowing for greater absorption on materials from the cell's environment
the cell's specialized structures that perform specific tasks
the largest of the organelles
The "brain" or "control center" of the cell
contains the chromosomes
threadlike units of heredity that are passed on from parents to their offspring. It is information contained in the chromosomes that governs all cellular activities.
the job of the nucleolus is to assemble ribosomes
small bodies outside the nucleus that are involved in the manufacture of proteins
the material that fills the cell from the nuclear membrane to the plasma membrane
the liquid part of the cytoplasm
a suspension of nutrients, minerals, enzymes, and other specialized material in water.
a network of membranes located between the nuclear membrane and the plasma membrane.
Smooth ER - involved in the synthesis of lipids
Rough ER - has ribosomes
attatched to the rough ER
necessary for the manufacture of proteins
large organelles with folded membranes inside
converts energy from nutrients into ATP
Layers of membrane sacs involved in sorting and modifying proteins and packaging them for export from the cell.
small sacks of digestive enzymes in the cytoplasm
contain digestive enzymes, remove waste and foreign materials from the cell. Also involved in destroying old and damaged cells as needed for repair and remodeling of tissue.
membrane enclosed organelles containing enzymes
have enzymes that destroy harmful substances produced in metabolism
Small membrane-bound sacs used for storage. can be used to move materials into or out of the cell.
rod shaped bodies near the nucleus that function in cell division
help separate the chromosomes during cell division
small hair like projections that wave, creating movement of the fluids around the cell
long whip like extension from the cell
moves the cell
portion of the DNA on a chromosome
genetic material of the cell
makes up the cell's chromosomes in the cell's nucleus
building block of DNA and RNA
substance neededfor protein manufacture in the cell
cells that form sex cells (egg and sperm) divide by the process of meiosis, which cuts the chromosome number in half to prepare for union of the egg and sperm in fertilization.
All body cells except sex cells divide by mitosis
each cell splits in half and becomes two daughter cells
any cell that is not a sex cell - egg or sperm
Phases of Mitosis
The period when the cell is not in active mitosis
the stage in a cell's life between one mitosis and the next
DNA replicates during this phase
where the DNA strands are held together
separates during mitosis
First stage of mitosis, during which the chromosomes become visible and the organelles disappear
Second stage of mitosis in which the chromosomes line up across the equator of the cell attached to spindle fibers
The third stage of mitosis in which the chromosomes separate and move to opposite sides of the cell
The fourth stage of mitosis in which during which the new nuclei form and the cell contents usually divide. A membrane forms around each new cell
movement through the plasma membrane that does not require energy output by the cell
depends on the internal energy of moving particles or some outside source of energy such as diffusion , osmosis, filtration or facilitated diffusion
The movement of particles from a region of a relatively higher concentration to an area of lower concentration
diffusion of WATER membranes through a semi permeable membrane
the passage of water and dissolved material through a membrane as a result of a mechanicla ("pushing") force on one side
the movement of materials across the plasma membrane inthe direction of the concentration gradient (from higher concentration to lower concentration) but using transporters to move the material at a faster rate
movement through the plasma membrane that requires energy
regulates what can enter and leave the cell based on the needs of the cell
the bulk movement of materials into the cell
phagocytosis - relatively parge particles are engulfed by the plasma membrane and moved into the cell. "cell eating"
pinocytosis - the plasma membrane engulfs dropletts of fluid. "cell drinking"
the cell moves materials out in vessicles
a solution that has the same concentration as the fluid within the cell
a solution that is less concentrated than the fluids with in the cell
when a fluid is more concentrated than the fluids in the cell
Cancer Risk Factors
Chemicals - carcinogens are chemicals that cause cancer