-
forms
outer boundary of cell
-
plasma membrane
Thin,two-layered membrane of phospholipids containing proteins
-
–May attach to rough ER or lie free
in cytoplasm
Ribosomes
-
–Manufacture proteins; often called protein
factories
Ribosomes
-
collects and transports
proteins made by ribosomes
–Rough ER
-
synthesizes chemicals; makes new membrane
Smooth ER
-
–Composed of inner and outer
membranes; contains one DNA molecule
mitocondria
-
–Involved with energy-releasing
chemical reactions; called power plants
of the cell
mitochondria
-
–Membrane-enclosed packets
containing digestive enzymes
Lysosomes
-
–Function in cell reproduction
Centrioles
-
–Fine, hairlike
extensions found on free or exposed surfaces of some cells
Capable
of moving in unison in a wavelike fashion
cilia
-
–Single projections extending from
cell surfaces; much larger than cilia
flagella
-
•Controls
cell because it contains the genetic code—instructions for making proteins,
which in turn determine cell structure and function
Nucleus
-
processes do not require added
energy and result in movement “down a concentration gradient”
passive transport
-
two forms of passive transport
diffusion and filtration
-
•Substances
scatter themselves evenly throughout an available space, the particles moving
from high to low concentration
diffusion
-
is diffusion of water
osmosis
-
movement of water and
solutes caused by hydrostatic pressure on one side of membrane
ØFiltration—
-
processes
occur only in living cells; movement of substances is “up the concentration
gradient”; this requires energy from ATP
active trasnport
-
use energy from ATP to move substances across cell membranes against
their concentration gradients
Ion pumps
-
are active transport mechanisms because they require cell energy
Phagocytosis and pinocytosis
-
•a
protective mechanism often used to destroy bacteria
phagocytosis
-
•used
to incorporate fluids or dissolved substances into cells
pinocytosis
-
•occurs
in cytoplasm, thus genetic information must pass from the nucleus to the
cytoplasm
Protein synthesis
-
what is happening when Double-stranded
DNA separates to form messenger RNA (mRNA)
ØTranscription
-
•Involves
synthesis of proteins in cytoplasm by ribosomes
ØTranslation
-
reproduction
of cell involving division of the nucleus (mitosis) and the cytoplasm; period
when the cell is not actively dividing is called interphase
-
process in cell division that distributes identical chromosomes (DNA molecules) to each
new cell formed when the original cell divides; enables cells to reproduce
their own kind; makes heredity possible
mitosis
-
Stages of mitosis
- Prophase—first stage
- Metaphase—second stage
- Anaphase—third stage
- Telophase—fourth stage
-
•Chromatin
granules become organized
•Chromosomes
(pairs of linked chromatids) appear
•Centrioles
move away from nucleus
•Nuclear
envelope disappears, freeing genetic material
•Spindle
fibers appear
prophase
-
•Chromosomes
align across center of cell
•Spindle
fibers attach themselves to each chromatid
metophase
-
•Centromeres
break apart
•Separated
chromatids then called chromosomes
•Chromosomes
are pulled to opposite ends of cell
•Cleavage
furrow develops at end of anaphase
anaphase
-
•Cell
division is completed
•Nuclei
appear in daughter cells
•Nuclear
envelope and nucleoli appear
•Cytoplasm
is divided (cytokinesis)
•Daughter
cells become fully functional
telaphase
-
types of epi tissue
•Squamous
•Cuboidal
•Columnar
•Transitional
-
single layer of scalelike
cells adapted for transport
Simple squamous epithelium
-
several layers of closely packed cells specializing in
protection
Stratified squamous epithelium
-
tall, column-like cells arranged in a single layer; contain mucus-producing goblet cells; specialized for absorption
Simple columnar epithelium
-
up to 10 layers of roughly cuboidal-shaped cells that distort to squamous shape when stretched; found in body areas that stretch,
such as urinary bladder
- Stratified
- transitional epithelium
-
single layer of distorted columnar cells; each cell touches basement
membrane
Pseudostratified epithelium
-
single layer of cube like
cells often specialized for secretory activity; may secrete into ducts,
directly into blood, and on body surface
Simple cuboidal epithelium
-
Most abundant and widely
distributed tissue in body, with many different types, appearances, and
functions
connective tissue
-
attaches
to bones; also called striated or voluntary;
control is voluntary; striations apparent when viewed under a microscope
Skeletal tissue
-
also called striated involuntary;
composes heart wall; ordinarily cannot control contractions
Cardiac tissue
-
also called nonstriated (visceral)
or involuntary; no cross striations; found in blood vessels and other tube-shaped organs
Smooth tissue
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