Ch.2 Cell Structure
Terms
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- Plasma membrane
- sep. the cel from the extracellular fluid.
-
Nucleus
Cytoplasm -
What are the main components of a cell?
(2) - Nucleus
-
Chromatin
Nuclear envelope
Nuclear pores
Nucleolus - Cytoplasm
- everything inside the cell, except the nucleus.
-
cytosol
organelles - What are the 2 components of cytoplasm?
- Cytosol
- gel-like fluid
- Organelles
- structures made up of a varity of biomolecules, carry out specific functions in the cell
- Membranous organelles
- separated from cytosol by one or more membranes
- Nonmembranous organelles
- have no such boundary with the cytosol
- Nuclear envelope
- separates the nucleus and the cytoplasm
- fluid mosaic
-
structure of the plasma membrane is described as _____ ______.
phospholipids
cholesterol
Proteins
Carbohydrates - Phospholipid bilayer
-
forms basic structure of the membrane
membrane considered fluid because molecules are NOT chemically bonded together and THEREFORE can move laterally and even from one side of bilayer to other. - Integral membrane proteins
-
embedded within the lipid bilayer, and therefore they can be dissociated from the membrane only by physically disrupting the bilayer.
amphipathic molecules (hydrophilic & hydrophobic) - Transmembrane proteins
-
A branch of Integral membrane proteins
include channels that allow ions to permeate the membrane, and carrier proteins that transport molecules from one side of the membrane to the other - Peripheral membrane proteins
-
loosely bound to the membrane by associations with integral membrane proteins or phospholipids.
can be dissociated from the membrane and still leave the membrane intact.
most on cytosol side of membrane - Membrane carbohydrates
-
located on extracellular side of membrane
They form glycocalyx & function in cell recognition - glycocalyx
- a protective layer that also functions in holding cells together
- cell recognition
-
helps label the cell as part of the body
important in immune response and tissue growth - Chromatin
-
the form in which DNA, along eith its associated proteins, exists througout most of the cell cycle
loosely coiled DNA and proteins scattered throughout the nucleus - Nuclear pores
- membranes that fuse intermittently leave gaps that allow selective movement of molecules btwn. the nucleus and the cytoplasm
- Nucleolus
- the site of synthesis of a type of RNA called rRNA.
- Inclusions
-
Energy in the form of triglycerides or glycogen is stored in masses
in the cytosol - Secretory vescicles
- membrane-bound sacs
- Endoplasmic Reticulum
-
an elaborate network of membrane enclosing an interior compartment called the lumen.
Rough & Smooth - Rough E.R.
-
continuous with the outer membrane of nuclear envelope.
closest to nucleus
has ribosomes
also attached to smooth E.R. - Ribosomes
- Protein synthesis
- Smooth E.R.
- In liver cells, contains detoxification enzymes that break down toxic substances in the blood.
- Rough E.R
- associated with the synthesis of proteins that will be secreted from the cell or incorporated into the plasma membranen or another organelle.
- Golgi Apparatus
- processes molecules that have been synthesized in the E.R.
- cisternae
- membrane-bound flattened sacs
- Cis face
- The Golgi Apparatus is closely assiciated with the E.R. on one side but are they are separate from one another
- Trans face
- Golgi Apparatus faces the plasma membrane
- Mitochondria
-
"powerhouse of the cell"
most usuable energy (ATP) is produced here. - Cristae
- inner membrane is foled into tubules to increase the area for the elceton transport system
- Electron transport chain
- a series of proteins and other molecules called a ____ ____ _____ in the inner mitochondria membrane.
- Lysosomes
-
Breakdown of cellular and extracellular debris
has enzymes that do this
Endocytosis
Breakdown of old organelles - Peroxisomes
-
often produce Hydrogen Peroxide, which is toxic
contains an enzyme called catalase
it breaks down hydrogen peroxide to form H20 and O2 - Vaults
-
Unknown
possible transport of molecules btwn. nucleus and cytoplasm
may be involved in development of resistance to chemotherapy - Centrioles
- Direction of mitotic spindle development during cell division.
- Cytoskeleton
-
Structural support of cell
cell movement and contraction - Microfilament
-
smallest in diameter
actin
muscle contraction
movement of cells
separation of cytoplasm during cell division
provide structural support for microvilli - Microvilli
- special cell projections found in epithelial cells that are specialized for the exchange of molecules
- Intermediate filaments
-
btwn microfilaments and microtubules.
stronger & more stable than microfilaments
keratin
myosin - Microtubules
-
largest in diameter
provide strength for cytoskeleton
hollow tube - tubulin
spindle fibers
cilia
flagella - spindle fibers
- aid in distribution of chromosomes during cell division