Download Chapter 3 Cells Cell: A cell consists of three main parts--

Chapter 3 Cells
Cell:
A cell consists of three main parts---the __organelles, the cell “stuff” called __cytoplasm__, and the
outer ____membrane_.
Cell
Membrane:
The
cell membrane is extremely thin_________and is _selectively
permeable________________ permeable.
function: The cell membrane regulates the_____homeostasis______, participates in signal
transduction, and helps cells adhere to other cells
structure: The basic framework of the cell membrane consists of a double layer of
_phospholipids________________
_proteins________________ are found in the cell membrane, including some which are
transmembrane and some that are peripheral membrane.
Cytoplasm: The cytoplasm consists of a clear liquid called ___cytosol___________________, a
supportive ____cytoskeleton________________________,
and networks of membranes
and organelles.
endoplasmic reticulum: provides a tubular __transporation_________ system inside the cell.
rough: why does it appear rough? ribosomes
What does it function in the synthesis and transport of? Proteins and lipids
smooth: Why does it appear smooth? No ribosomes
What does it function in the transport of?
Important in lipid synthesis and absorption of fats
ribosome: Where are they found? On the rough endoplasmic reticulum
What are they composed of? 60% RNA and 40% protein
What do they help in the production of? proteins
golgi apparatus: is composed of flattened _membraneous sacs ( cisternae )________and it
packages the cells products. These packages are released in the form of glycoprotein_
lysosomes: contain _powerful_____ enzymes to break up old cell components and bacteria.
They are sometimes called the "__garbage disposal " of the cell.
microfilaments and microtubules:
are thin threadlike structures that serve as the
____cytoskeleton_________of the cell.
Microfilaments, made of the protein _____bundles___, cause various cellular movements.
Mictotubules, made of the globular protein ____tubulin__.
centrosome: is a structure made up of two hollow cylinders called __centrioles_________. What
is their function? Dring mitosis they distribute chromosomes.
cilia & flagella: are motile extensions from the cell. Which one is shorter?
cilia
What is its function in the human body? They provide waves of motions moving fluid over the cells.
What is the only flagellated cell in the body? sperm
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Nucleus: is bounded by a _double____-layered nuclear membrane containing relatively large nuclear
_____pores____that allow the passage of certain substances.
nucleolus: Where is it found?
membrane? No
In the nucleus
Does it have its own
What chemicals is it made of? RNA and protein
chromatin: What chemicals is the chromatin made of? Protein and DNA
Movement Through Cell Membrane: The cell membrane controls what passes through it.
PASSIVE TRANSPORT: Mechanisms of movement across the membrane may be passive, requiring no
energy_____________ from the cell (diffusion, facilitated diffusion, osmosis, and
filtration).
diffusion: from area of _high_____ concentration to area of _low______ concentration to reach
_equilibrium_______.
osmosis: Only substance that is moved by osmosis is water__________________.
What substances diffuse in the human body? Alcohol, fatty acids, steroids, and dissolved
gasses, such as carbon dioxide and oxygen.
What pressure results from osmosis? Osmotic pressure
Facilitated Diffusion:
Facilitated diffusion uses membrane proteins that function as
_______channel______ to move molecules (such as glucose) across
the cell membrane.
Filtration: Filtration forces molecules through ___membrane pores___________ and is commonly
used to separate solids from _____water_____________________
Active Transport: moves from area of __low_____ concentration to area of __high________
concentration. Requires _____carrier________ proteins: (pumps). Also requires energy in
the form of ___ATP_.
Endocytosis and Exocytosis: In __endocytosis__ molecules that are too large to be transported by
other means are engulfed by an invagination of the cell membrane and carried into the cell surrounded by
a vesicle.
Pinocytosis is a form in which cells engulf liquids.
Phagocytosis is a form is which the cell takes in larger particles, such as a white blood cell
engulfing a bacterium.
In ____exocytosis___molecules are pushed out of the cell
Cell Cycle: The series of changes a cell undergoes from the time it is formed until it _divides is called the
cell cycle.
The cell cycle consists of what four stages? Prophase, metaphase, anaphase, telephase
The cell cycle is highly regulated. Most cells do not divide continually. Cells have a maximum number of
times they can divide because of built-in “clocks”called _telemers____________ on the tips of
chromosomes.
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