USC Bridge 2.3 cytoplasm
Cytoplasm
Cell forming material. All cellular material that is located between the plasma membrane and the nucleus
composed of:
- cytosol
- inclusions
- organelles
Cytosol
Gel like solution made up of water and soluable molecules such as proteins, salts, sugars.
Inclusions
Insoluble molecules, vary depending on the cell type. Ie: stored nutrients like glycogen in liver and muscle cells, lipid droplets present in fat cells, pigment or melanin, water containing vacuoles, crystals, and skin and hair cells.
Organelles
Metabolic machinery structures of cell. Each with specialized function. Either membranous or non membranous
Cytoplasmic organelles
Membranes allow compartmentalization which is crucial to cell function
- membranous: mitochondria, endoplasmic reticulum, golfing apparatus, peroxisomes, lysosomes
- Nonmembranous: ribosomes, cytoskeleton, centrioles
Mitochondria
Called the power plant of cells. Produce most of the cells energy molecules (ATP) via aerobic (oxygen-requiring) cellular respiration. Muscle cells have a lot of mitochondria cells
enclosed by double membranes. Has many folds called cristae
contain their own DNA, RNA, and ribosomes
resemble bacteria capable of same type of cell division that bacteria use called fission
Endoplasmic reticulum
(ER) Consists of series of parallel, interconnected cisterns- flattened membranous tubes that enclose fluid-filled interiors.
Is continuous with the nuclear membrane
rough ER is studded with ribosomes to manufacture proteins secreted from cells
smooth ER is continuous with rough ER and makes lipids (fats)
Golgi apparatus
Principal traffic director for cellular proteins.
Stacked and flattened membranous cistern sacs
modifies and packages proteins and lipids received from rough ER
Sequence of events in protein synthesis
Peroxisomes
Membranous sacs containing powerful detoxifying substances that neutralize toxins
- free radicals-toxic, highly reactive molecules that are natural by-products of cellular metabolism. Can cause havoc to cell if not detoxified
- two main detoxifiers: oxidase and catalase that converts H2O2 to H2O
peroxisomes also play a role in breakdown and synthesis of fatty acids
Lysosomes
- Spherical membranous bags containing digestive enzymes. Considered safe sites because they isolate digestion from the rest of the cell
- digest ingested bacteria, viruses and toxins
- degrade nonfunctional organelles
- intracellular release in injured causes cells to digest themselves (autolysis)
- release ionic calcium from bones
Lysosomal storage disease
Result when one or more lysosomal digestive enzymes are mutated and do not function properly
tay sachs disease
Nucleus
The control center of the cell. Have pores to allow transport in and out of the nucleus
Largest organelle
contains genetic instructions for synthesis of nearly all cellular proteins
most cells are uninucleated, but some can be multinucleated in ex: are skeletal muscle, some bone cells, liver cells
RBC are anucleated
Chromatin
Strands of DNA, histone proteins and some RNA in the nucleus
chromosomes are compacts chromatin
What cell does not possess a nucleus at maturity?
RBC
In a cell proteins are synthesized at the _______
Ribosomes
In a cell ATP is produced by______
Mitochondria