Section 22.3- The Life and Work of Cells Flashcards
cells were designed for one purpose:
to do work
the most pressing task that any living cells must accomplish is that of
staying alive
a stable internal environment
homeostasis
a major physical requirement of cells is maintain the proper
a property related to the concentration of dissolved substances inside a cell
osmotic pressure
necessary for a cell to maintain life
osmotic pressure
proper pH
temperature
food and wastes
maintenance and repair
the primary task of all cells is
to obtain energy
gives the cell its ability to work
energy
processed used in making and storing energy
photosynthesis
living cells break down chemimcal substances and combine them with oxygen to release energy through the process
cellular respiration (aerobic respiration)
the energy released by cellular respiration is used to synthesize the special compound
ATP
under anaerobic conditions, cellular respiration cannot take place, so cells rely on
fermentation
both ____________ and __________________ convert energy into a form the living cells can use
photosynthesis
cellular respiration
a few substances such as water, oxygen, and lipids can move in and out of cells from a place of higher concentration to a place of lower concentration by
simple diffusion
compounds that cannot pass directly through the cell membrane can move from higher to lower concentration in
uses channel or carrier proteins
facilitated diffusion
becuse the cell does not have to use energy for either simple diffusion or facilitated diffusion to occur, these processes are called
passive transport
the movement of molecules across the cell membrane from place of LOWER concentration to a place of HIGHER concentration with the expenditure of energy is
active transport
the process of transporting particles of material larger than molecules into and out of itself
the process of taking IN large substances
endocytosis
the basic methods used in endocytosis
phagocytosis
pinocytosis
a process of endocytosis used by certain cells to surround solid particles with the cell membrane and engulf them
phagocytosis
form of endocytosis that involves the intake of liquids
pinocytosis
cellular wastes products are eliminated from the cytoplasm by the process of
in this process, secretion-containing vesicles move to the surface of the cell and open, spilling their content to the exterior
exocytosis
biologists study the reproductive process of cells and summarize it as part of the
cell cycle
one of the most amazing aspects of the design of living cells is their ability to
reproduce
the cell cycle has ____________ phases
four (G1, S, G2, M)
the first three phases of the cell cycle are collectively called the
the stage between cell divisions
interphase
all of the cell’s normal activities occur during
interphase
during the S (synthesis) phase, each DNA molecule or _________________ is carefully replicated
chromosomes
a replicated chromosome consists of two identical DNA molecules, each of which is a
chromatid
small structure in the middle of the DNA molecules that fastens together the chromatids
centromere
controls the formation of microtubules in the cytoskeleton
centrosome
whiplike tails that extend from the cells
flagella
tiny hairlike projections that extend from the cell membrane
found in stationary cells
cilia
two movable appendages for cell movement
cilia
flagella
the cell divides during this phase
M phase
the two main processes of the M phase
mitosis
cytokinesis
the M phase process in which the nucleus of a cell divides to generate two nuclei with the same number of chromosomes as the original nucleus
mitosis
M phase process in which the cytoplasm separates to form two separate cells with their own nuclei, organelles, cell membranes, and cell walls
cytokinesis
very special propulsion system used by cells
electric motor
the process of mitosis consists of four stages:
- prophase
- metaphase
- anaphase
- telophase
the first stage of mitosis in which the cell packages its chromosomes into tightly packed structures that are visible through a microscope
prophase
the structure to which chromosomes attach during metaphase
spindle apparatus
as this mitosis stage begins, the nuclear envelope has completely disappeared, and the centrosomes are at the opposite poles of the cell
metaphase
as this mitosis stage begins, the chromatids en each replicated chromosome separate from each other and begin to move apart
anaphase
follows the anaphase and is in some respects the reverse of prophase
telophase
cytokinesis typically begins during _______________ and ends during or shortly after ________________-
anaphase
telophase
cell death through trauma such as disease or injury is
necrosis
programmed cell death that a cell can trigger once it is no longer needed or no longer ble to survive
apoptosis
