Histology Organelles

Front 1

Nucleaus

Back 1

Bounded by nuclear envelope; contains chromatin, nucleolus, and nucleoplasm

Front 2

Chromatin, nucleolus, nucleoplasm

Back 2

genetic material of the cell; where ribosomal RNA sysntehsis occurs; and everything except the first two

Front 3

Nuclear Envelope

Back 3

Inner and outer nuclear membranes; outer membrane is continous and can have polyribosomes attached (causing it to function as rough ER).

Front 4

Nuclear pore complex

Back 4

Pores are 80-100 nm in diameter; complex occupies a large portion of each pore. The configuration of the nuclear pore complex is such that ions and molecules up to 10nm can freely diffuse across the pore. Larger molecules and structures are selectively transported in an energy-requiring process.

Front 5

Nuclear Lamina

Back 5

Fibrous network always closely associated with the nucleoplasmic side of the inner membrane. The fibers are polymers of proteins called lamins.

Front 6

Lamins

Back 6

Stabilize the nuclear envelope and are involved in the functional organization of the interphase nucleus. This has been shown by experiments in which antibodies to lamins were injected into cells during mitosis. The cells divided, but daughter cells had abnormal nuclei; the chromatin remained condensed and inactive, and nucleoli were not reformed

Front 7

Chromatin: Euchromatin and Heterochromatin

Back 7

Euchromatin is active form of used for transcription from DNA to RNA; Heterochromatin is inactive, portion not being transcribed; highly condensed and visible as dark clumps under light microscope, and can inactivate nearby genes

Front 8

Nucleolus

Back 8

non-membrane-bound spherical structure present in the interphase nucleus. The nucleolus is involved in transcription of genes coding for ribosomal RNA (rRNA), processing of RNA-precursor molecules, and assembly of ribosomal subunits; bigger in more active cells

Front 9

Nucleoplasm

Back 9

portion of the nucleus within the nuclear envelope that excludes the chromatin and nucleolus. Major components of this include ribonucleoprotein particles (RNPs) and the nuclear matrix.

Front 10

ribonucleoprotein particles (RNPs)

Back 10

condensation of newly-formed RNA (heterogenous or hnRNPs); RNA splicing, a process of removing introns (RNA not involved in protein coding) (small nuclear or snRNPs).

Front 11

Nuclear Matrix

Back 11

Fills the space between the chromatin and nucleoli and is composed of a variety of proteins and fibrillar elements; the nuclear lamina and portions of the nuclear pore complex are part of this. The filamentous network may form a nuclear structural support system; posses binding sites for other molecules

Front 12

Mitochondria

Back 12

cellular power plants" because they generate most of the cell's supply of adenosine triphosphate (ATP), used as a source of chemical energy.[2] In addition to supplying cellular energy, mitochondria are involved in a range of other processes, such as signaling, cellular differentiation, cell death, as well as the control of the cell cycle and cell growth

Front 13

Mitochondria Membranes

Back 13

smooth outer membrane and folded
inner membrane. Both membranes are typical lipid bilayers with
embedded proteins;

Front 14

Outer Membrane

Back 14

Porin: A multipass protein present in high numbers in the outer
membrane lipid bilayer. Each porin forms a large channel through
which molecules as large as 10kD can pass, resulting in the
intermembrane space having a composition similar to the cytosol

Front 15

Inner Membrane

Back 15

ATP synthase; electron transport chain

Front 16

Cristae

Back 16

Numerous inner membrane folds that increase inner membrane surface area thereby increasing its energy-producing capabilities; directly proportional to the metabolic activity of the cell.

Front 17

Cardiolipin

Back 17

Unusual phospholipid prevalent in the inner membrane; has four fatty acid chains per molecule instead of the usual two; Its high concentration makes the inner membrane virtually impermeable to ions, electrons, and protons.

Front 18

Apoptosis

Back 18

"programmed” cell death; regulation of cell turnover. It is especially important a) during normal development and b) in preventing proliferation of damaged cells.

Front 19

How to kill cell:

Back 19

inability of the mitochondria to meet the cell’s energy demands and b) release of apoptotic factors into the cytoplasm

Front 20

Mitochondria and Mendelian Genetics

Back 20

mitochondria do not follow typical Mendelian genetics. Mitochondria are self-replicating and each cell has hundreds, and often thousands, of mitochondria. Thus a mutation arising in mitochondrial DNA results in a cell with a mixture of normal and mutated mitochondria. These are randomly distributed to daughter cells and, after many cell divisions, some cells will have predominantly normal mitochondria

Front 21

RIbosomes

Back 21

organelle, the function of which is to assemble the twenty specific amino acid molecules to form the particular protein molecule

Front 22

Poly-ribosomes

Back 22

Free polyribosomes synthesize proteins that remain diffusely distributed in the cytoplasm.
 Polyribosomes bound to endoplasmic reticulum (ER) produce both proteins enveloped in membrane-bound vesicles and most integral membrane proteins. The cell produces vesicular proteins either for secretion (e.g. salivary enzymes) or storage (e.g. lysosome enzymes).

Front 23

Rough Endoplasmic Reticulum

Back 23

synthesizes proteins

Front 24

Smooth ER

Back 24

synthesize lipids and steroids, metabolize carbohydrates and steroids (but not lipids), and regulate calcium concentration

Front 25

SER vs RER differences

Back 25

a) SER has a smooth surface due to a lack of attached polyribosomes and b) it generally consists of interconnected tubules rather than flattened cisternae.

Front 26

Golgi Apparatus

Back 26

processes and packages macromolecules, such as proteins and lipids, after their synthesis and before they make their way to their destination; it is particularly important in the processing of proteins for secretion

Front 27

Endocytosis: Phagocytosis and Pinocytosis

Back 27

The means by which cells ingest extracellular molecules and fluid. Phagocytosis involves uptake of large particles such as cell debris or microorganisms; the typically nonselective process of ingestion of fluids and small particles

Front 28

Endosomes

Back 28

It is a compartment of the endocytic membrane transport pathway from the plasma membrane to the lysosome. Molecules internalized from the plasma membrane can follow this pathway all the way to lysosomes for degradation, or they can be recycled back to the plasma membrane

Front 29

Early and late Endosomes

Back 29

1. Early endosomes – adjacent to the cell membrane. Where pinocytotic vesicles first arrive.
2. Late endosomes – lie closer to the nucleus. Material to be digested is sent to this portion of the endosomal compartment.

Front 30

Lysosomes

Back 30

contain acid hydrolase enzymes to break down waste materials and cellular debris; digest excess or worn-out organelles, food particles, and engulfed viruses or bacteria. The membrane around a lysosome allows the digestive enzymes to work at 4.5 pH

Front 31

Cytoskeleton

Back 31

contained within the cytoplasm and is made out of protein; structures such as flagella, cilia and lamellipodia and plays important roles in both intracellular transport (the movement of vesicles and organelles, for example) and cellular division

Front 32

Functions of the Cytoskeleton

Back 32

structural support; intracellular organization (transport of organelles and other structures to specific sites, and retention of the structures at their final destination); cell motility (responsible for muscle cell contraction, changes in cell shape, cell migration, and the actions of cilia and flagella)

Front 33

Components of Cytoskeleton

Back 33

Intermediate filaments; Actin filaments (thin filaments; microfilaments); Microtubules

Front 34

Intermediate Filaments

Back 34

Primary function: Protect the cell from mechanical stress during stretching or shearing

Front 35

Actin Filaments

Back 35

(contained in cell cortex) participates cell motility, cell division and cytokinesis, vesicle and organelle movement, cell signaling, and the establishment and maintenance of cell junctions and cell shape

Front 36

Myosin

Back 36

Actin binding protein; makes up thick filaments that interact with actin-based thin filaments in contractile units of muscle.

Front 37

Microtubulues

Back 37

inside of the microtubule, called the lumen, important for maintaining cell structure, providing platforms for intracellular transport, forming the spindle during mitosis, as well as other cellular processes.[2] There are many proteins that bind to the microtubule, including motor proteins such as kinesin and dynein, severing proteins like katanin, and other proteins important for regulating microtubule dynamics

Front 38

Flagellum

Back 38

generally propels entire cell, such as the flagellum on each sperm cell

Front 39

Cilium (cilia)

Back 39

two types of cilia: motile cilia (assist in transport) and non-motile, or primary cilia, which typically serve as sensory organelles