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76 Cards in this Set

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  • Back
Use specific examples to illustrate how cells vary in size
Nerve cells have long, threadlike extensions to transmit impulses. Epithelial cells are smaller and flattened for gas exchange. Muscle cells are slender and rod-like.
Describe how the shapes of nerve cells are well suited to their functions.
Nerve cells are long with threadlike extensions that can be used to transmit motor or sensory information.
Describe how the shapes of epithelial cells are well suited to their functions.
Epithelial cells, specifically simple squamous, are thin and flattened for gas exchange.
Describe how the shapes of muscle cells are well suited to their functions.
Muscle cells are slender and rod-like which contract to move parts of the body
Name the major components of a cell, and describe how they interact.
The two major components are the nucleus and the cytoplasm. The nucleus is the innermost part and controls the overall activities of a cell. The cytoplasm is a mass of fluid that surrounds the nucleus and is enclosed by the cell membrane. It holds the organelles.
Discuss the structure and functions of a cell membrane
The basic structure of the cell membrane consists of a phospholipid bilayer. It contains embedded protein molecules. It functions to keep the inner portion of the cell intact. It controls the entrance and exit of substances.
How do cilia molecules move cells?
Cilia, small hair like projections that occur in groups, move together in a uniform, wavelike motion. This is used to propel substances along to a certain destination. An example is the uterine tube where the cilia move the egg from the ovary to the uterus.
How do flagella molecules move cells?
Flagella, which occur singularly, have a whip-like motion to propel the object forward. An example is the sperm cell moving up the vagina toward the cervix.
How do cell adhesion molecules move cells?
Cell adhesion molecules (CAMS) occur on the cell membrane. The resulting interactions can slow the cell and allow it to move in certain ways.
Distinguish between organelles and inclusions
An organelle is a structure within the cytoplasm that has a specific function. Inclusions are masses of lifeless chemicals such as pigments or glycogen.
Selectively permeable
the cell membrane allows some substances to pass through easily while excluding other substances.
Describe the chemical structure of a membrane.
The basic framework consists of a phospholipid bilayer with embedded proteins throughout.
Explain how the structure of a cell membrane determines which types of substances it is permeable to.
As the cell membrane is comprised chiefly of fatty acid portions of the phospholipid molecule, it allows
substances that are soluble in lipids to pass through easily. It is impermeable to water soluble molecules.
Explain the function of membrane proteins.
The functions of membrane proteins include acting as a receptor to combine with a specific substance such as a hormone, while some form narrow passageways, or channels, through which various molecules and ions can cross the cell membrane. Others function as enzymes in signal transduction.
Describe three kinds of intercellular junctions.
Tight junctions –The membranes of adjacent cells converge and fuse. The area of fusion surrounds the cell like a belt. This then closes the junction between cells. These are the types of junction found in the lining of the digestive tract.
Desmosome –This is where rivets or “spot welds” are placed between adjacent skin cells.
Gap junctions –This is where tubular channels interconnect the membranes of certain cells.
PEROXISOMES
Membranous sacs filled with oxidase enzymes (catalase)
detoxification of harmful substances (i.e. ethanol, drugs, etc.)
CENTROSOMES
paired cylinders of microtubules at right angles near nucleus

aid in chromosome movement during mitosis
CILIA
short, eyelash extensions;human trachea & fallopian tube

to allow for passage of substances through passageways
FLAGELLA
long, tail-like extension; human sperm

locomotion
MICROVILLI
microscopic ruffling of cell membrane

increase surface area
CYTOSKELETON
Protein strands that makeup cellular frame

Provide shape of cell, locomotion
OTHER STRUCTURES
Accumulations of substances

storage
NUCLEUS
Central control center of cell; bound by lipid bilayer membrane; contains chromatin (loosely coiled DNA and proteins)

controls all cellular activity by directing protein synthesis (i.e. instructing the cell what proteins/enzymes to make).
NUCLEOLUS
dense spherical body(ies) within nucleus; RNA & protein

Ribosome synthesis
CHROMATIN
DNA wrapped in protein forming nucleosomes

Protection of genetic material
INTERPHASE
Cell is growing and duplicates (replicates) centrioles during G1, replicates DNA during S phase;DNA appears as chromatin in nucleus.
PROPHASE
Distinct chromosomes become apparent (i.e. sister chromatids held together by a centromere);Centrioles migrate to opposite poles of cell and spindle fibers form between them;nucleolus disintegrates;nuclear envelope disintegrates
METAPHASE
Chromosomes line up in an orderly fashion in the middle of the cell (on metaphase plate);Each centromere holding chromatids of the chromosome together attaches to a spindle fiber.
ANAPHASE
The centromere holding the chromosome together splits;Resulting chromosomes migrate toward opposite poles of the cell being pulled by spindle fibers;Cytokinesis begins.
TELOPHASE
Cleavage furrow between daughter cells is apparent (i.e. dumb-bell shaped);Chromosomes complete migration to poles;Nuclear envelope & nucleolus reappear;Cytokinesis is completed
STEM AND PROGENITOR CELLS
Allow for continued growth and renewal of cells
Stem cell
divide by mitosis

may partially specialize producing a
Progenitor cell
committed to a specific cell line
· epithelial
· connective
· muscle
· nervous
Totipotent
can become every cell type
Pluripotent
can become many cell types, but not all
Differentiation
process of specializing cell types; occurs due to gene activation
CELL MEMBRANE
Bilayer of phospholipids with proteins dispersed throughout

cell boundary; selectively permeable (i.e. controls what enters and leaves the cell; membrane transport)
CYTOPLASM
jelly-like fluid (70% water)
suspends organelles in cell
RIBOSOMES
RNA & protein; dispersed throughout cytoplasm or studded on ER

protein synthesis
ROUGH ER
Membranous network studded with ribosomes

protein synthesis
SMOOTH ER
Membranous network lacking ribosomes

lipid & cholesterol synthesis
GOLGI
“Stack of Pancakes”; cisternae

modification, transport, and packaging of proteins
VESICLE
Cylindrical membrane sacs

Storage and transport
MITOCHONDRIA
Kidney shaped organelles whose inner membrane is folded into “cristae”.

Site of Cellular Respiration; “Powerhouse”
LYSOSOMES
Membranous sac of digestive enzymes

destruction of worn cell parts (autolysis) and foreign particles
MITOTIC PHASE (M):
The mitotic phase (M) is divided into 2 parts that include mitosis and cytokinesis.
MITOSIS
division of nuclear parts; includes four parts:
PROPHASE
1. Distinct pairs of chromosomes become apparent (tightly coiled DNA and protein).

a. Each pair of chromosomes is made up of identical sister chromatids, held together by a centromere.

2. Pairs of centrioles migrate to opposite ends of the cell, spindle fibers form between them.

3. The nuclear envelope and nucleolus disappear.
METAPHASE
o Chromosomes line up in an orderly fashion midway between the centrioles (i.e. along equatorial plate);
o Centromere holding each pair of chromosomes together attaches to a spindle fiber between the centrioles.
ANAPHASE
o Centromere holding the chromosome pair together separates;
o Individual chromosomes migrate in opposite directions on the spindle fibers toward the polar centrioles;
o cytokinesis begins.
TELOPHASE
o Chromosomes complete migration toward centrioles;
o Nuclear envelope develops around each set of chromosomes;
o Nucleoli develop;
o Spindle fibers disappear;
o cleavage furrow nearly complete.
CYTOPLASMIC DIVISION (Cytokinesis_ =forming 2 daughter cells.
1. begins during anaphase, when the cell membrane begins to constrict (pinch) around the daughter cells.

2. is completed at the end of telophase when the nuclei and cytoplasm of the two newly formed daughter cells (in interphase) are completely separated by cleavage furrow.
CONTROL OF CELL DIVISION
Significance
1. to form a multi-celled organism from one original cell.
2. growth of organism
3. tissue repair.
Details of Cell Signaling
1. Maturation promoting factor (MPF) induces cell division when it becomes activated;

2. cdc2 proteins are a group of enzymes that participate in the cell division cycle.
a. They transfer a phosphate group from ATP to proteins to help regulate cell activities.

3.Cyclin is a protein whose level rises and falls during the cell cycle;
a.It builds up during interphase and activates the cdc2 proteins of MPF above.
Length of the Cell Cycle
1. varies with cell type, location and temperature;

2. Average times are 19-26 hrs;

3. Neurons, skeletal muscle, and red blood cells do not reproduce!
Abnormal Cell Division (CANCER)
When cell division occurs with no control (goes awry), a tumor, growth, or neoplasm results.
benign tumor
a non-cancerous tumor
malignant tumor
a cancerous growth

may spread by metastasis to other tissues by direct invasion, or through the bloodstream or lymph system.
oncologist
a physician who treats patients with tumors
Oncology
the study of tumors
INTERPHASE
cell growth and DNA replication
INTERPHASE
not considered part of mitosis.
2. represents the majority of a cell's life and includes:
a. cell growth and
b. duplication of DNA prior to prophase;

3. Interphase is divided into 3 parts:
a. G1 = rapid growth and replication of centrioles;
b. S = growth and DNA replication; and
c. G2 = growth and final preps for cell division
THE CELL CYCLE (NORMAL CELL DIVISION)
The life cycle of a cell is divided into two major portions that include interphase and a mitotic phase. Remember that the process of cell division is continuous. It is only divided into stages for convenience and to help you learn.
CELLS
The cell is the basic unit of structure and function in living things. Cells vary in their shape, size, and arrangement, but all cells have similar components, each with a particular function.
A COMPOSITE CELL or typical animal cell contains
A COMPOSITE CELL or typical animal cell contains four major cell parts
A COMPOSITE CELL or typical animal cell contains four major cell parts
o The CELL (or plasma) MEMBRANE, which is the outer boundary of the cell.
o The CYTOPLASM, which holds the cellular organelles.
o The CELLULAR ORGANELLES, which perform specific functions of the cell.
o The NUCLEUS, or control center of the cell.
The CELL (or plasma) MEMBRANE
is the outer boundary of the cell
CYTOPLASM
holds the cellular organelles
CELLULAR ORGANELLES
perform specific functions of the cell
NUCLEUS
control center of the cell.
Membrane Structure
Fluid Mosaic Model
Membrane Structure

description
Composed of a double layer (bilayer) of phospholipid molecules with many protein molecules dispersed within it
The surfaces of the membrane are
"hydrophilic" due to the polar phosphate heads;
The internal portion of the membrane is
"hydrophobic" due to the non-polar fatty acid tails;
The membrane proteins also have both hydrophilic and hydrophobic properties. There are two types
o Integral proteins are firmly inserted into and extend across the lipid bilayer.
1. Most are glycoproteins;

2. They serve as either channels (pores), transporters (carriers), receptors (recognition sites) or enzymes.
o Peripheral proteins lie loosely on the inner surface of the cell membrane.

1. They serve as cytoskeletal anchors.
Intercellular Junctions
a. Connect adjacent cell membranes
b. Three types
o Tight Junctions prevent movement of substances in between cells, like caulking between tiles
o Desmosomes are structural reinforcement, like superglue
o Gap Junctions allow ions to pass from cell to cell for communication, they are true cell phones