Plasma Membrane
all cells are bounded by
Double Layer
phospholipid bilayer, with various proteins attached to or embedded
hydrophobic parts
phospholipids and proteins are foundf in the interior of the membrane where the fatty acid tails are
hydrophilic parts
are in contact with the aqueous solution on either side; water loving region
carbohydrate chain
may be attached to proteins or lipids in the outer surface of the plasma membrane
cytosol / cytoplasm
semi-fluid or jelly-like substance inside the cell; where subcellular components are suspended
Nucleus
contains most of the cell’s genes and is usually the most conspicuous organelle
Nucleus
has several parts: nuclear envelope, nuclear pores and nuclear lamina
Nucleus
where DNA replication occurs
Nuclear envelope
encloses the nucleus, separating it from the cytoplasm
Pores
regulate the entry and exit of molecules from the nucleus
Nuclear Lamina
lines the nuclear envelope
Nuclear Lamina
composed of proteins and maintains the shape of the nucleus
Chrmosomes
In the nucleus, DNA is organized into discrete units
Chromatin
DNA and proteins of chromosomes
Nucleolus
located within the nucleus and site of ribosomal RNA (rRNA) synthesis
Nucleolus
usually in the middle of nucleus
Ribosomes
complexes made of ribosomal RNA and proteins
Ribosomes
build proteins into cytoplasmic regions at any given time
Ribosomes
protein synthesis (translation) takes place in ribosomes
Ribosomes carry out protein synthesis in two locations:
Cytosol (Free Ribosomes) and Outside the Endoplasmic Reticulum or the Nuclear Envelope (Bound Ribosomes)
Free Ribosomes
Cytosol
Bound Ribosomes
Outside the endoplasmic reticulum or the nuclear envelope
Endoplasmic Reticulum
accounts for more than half of the total membrane in many eukaryotic cell
Endoplasmic Reticulum
extensive network of membranes, accounts for more than half of the membrane in many eukaryotic cells
Endoplasmic Reticulum
consists of membranous tubules and sacs (cisternae)
Endoplasmic Reticulum
Continuous with the nuclear envelope
Two distinct regions of ER
Smooth ER and Rough ER
Smooth ER
outer surface lacks ribosomes
Smooth ER
synthesizes lipids, metabolizes carbohydrates, detoxifies drugs and poison, stores calcium ions
Rough ER
outer surface is studded with ribosomes
Rough ER
membrane factory for the cell
Rough ER
has bound ribosomes which secrete glycoproteins
Rough ER
distributes transport vesicles, secretory proteins surrounded by membranes
Golgi Apparatus
consists of cisternae
Cisternae
flattened membranous sacs
Golgi Apparatus
modifies products of the ER
Golgi Apparatus
manufactures certain macromolecules
Golgi Apparatus
sorts and packages materials into transport vesicles
Lysosomes
membranous sac of hydrolytic enzymes that digest macromolecules
Lysosomes
carry out intracellular digestion in a variety of circumstances
Lysosome enzymes
work best in the acidic environment inside the lysosome
Hydrolytic enzymes and Lysosomal membranes
are made by rough ER and then transferred to the Golgi apparatus for further processing
Phagocytosis
which cells engulf other cells; forms food vacuole
Lysosomes
fuse with the food vacuole and digests the molecules
Nutrients
Once it enters plasma membrane, it is enclosed in a food vacuole then fuses with lysosomes and digest molecules
Lysosmes
use enzymes to recycle the cell’s own organelles and macromolecules through autophagy
Lysosomes
digest organelles that are no longer functioning
Molecular Composition and Metabolic Functions
are modified as molecules move from ER to Golgi Apparatus
Mitochondria
nearly all eukaryotic cells have one
Mitochondrion and Chloroplast
organelles that convert energy to form stem cells for work
Mitochondria
sites of cellular respiration
Cellular Respiration
metabolic process that uses oxygen to drive the generation of ATP by extracting energy from sugars, fats and other fuels
Mitchondria
have smooth other membrane and inner membrane folded into cristae
Cristae
large surface area for enzymes that synthesize ATP
Intermembrane Space and Mitochondrial Matrix
Inner membrane of mitochondria creates two compartments
Mitchondrial Matrix
where some metabolic steps of cellular respiration are catalyzed
Peroxisomes
specialized metabolic compartments bounded by a single membrane
Peroxisomes
produce hydrogen peroxide and convert it to water
Peroxisomes
perform reactions with many different functions
Peroxisomes
some use oxygen to break fatty acids into smaller molecules to transport it to mitochondria and use as fuel for cellular respiration
Peroxisomes
in the liver, it detoxifies alcohol and other harmful compounds by transferring hydrogen from the poisonous compounds to oxygen
Cytoskeleton
network of fibers that organizes structures and activities in the cell
Cytoskeleton
a network of fibers extending throughout the cytoplasm
Cytoskeleton
composed of three types of molecular structures: microtubules, microfilaments (actin filaments), and intermediate filaments
Cytoskeleton
most obvious function is to give support to the cell and maintain it shape which is important in the animal cells which lack cell walls
Cytoskeleton
is involve in some cell motility and movement
Cytoskeleton
helps to support the cell and maintain its shape
Cytoskeleton
interacts with motor proteins to produce motility
Vesicles
can travel along the tracks provided by the cytoskeleton
Microtubules
function as compression resisting girders of the cytoskeleton
Microtubules
in animal cells it grows out from a centrosome near the nucleus
Centrosome
has a pair of centrioles, each with nine triplets of microtubules arranged in a ring
Microtubules
control the beating of flagella and cilia
Cilia and Flagella
microtubule-containing extensions that project from some cells
Cilia and Flagella
differ in their beating pattern but share a common structure
Plasma Membrane
sheathes the core of microtubules
Basal Body
anchors the cilium or flagellum
Dynein
motor protein that drives the bending movements of a cilium or flagellum
Dynein
has two feet that walk along the microtubule the adjacent doublet using ATP for energy
Dynein
Cross-links
prot
Microfilaments
function in cellular motility contain the protein myosin in addition to actin
Actin Filaments
in muscle cells, thousands of it are arranged parallel to one another
Thicker Filaments (Myosin)
initerdigitates with thinner actin fibers
Intermediate filaments
formation of nuclear lamina
Intermediate Filaments
Fibrous proteins coiled into cables
Intermediate Filaments
anchorage of nucleus and certain other organelles
Intermediate Filaments and Microfilaments
maintenance of cell shape (tension-bearing elements)
Microfilaments
Two intertwined strands of actin
Microfilaments
functions in changes in cell shape
Microfilaments
function: cell motility (as in amoeboid movement)
Microfilaments
function: muscle contraction
Microtubules
hollow tubules
Tubulin
a dimer consisting of a-tubulin and B-tubulin
Microtubules
maintenance of cell shape (compression-resisting “girders”)
Microtubules
functions in cell motility (as in cilia or flagella)
Microtubules
function: chromosome movements in cell division
Fibroblasts
in each structure of interest has been tagged with fluorescent molecules
Extracellular Components
connection between cells that help coordinate cellular activities