3.2.1 Cellular Function: Endoplasmic Reticulum Flashcards
endoplasmic reticulum
- is a series of interconnected membranous channels in the cell’s cytoplasm. The structure is a network of cisternae, or flattened sacs, consisting of an outer membrane and an inner space, or lumen. The illustration shows that the outside portion of the structure is studded with ribosomes (the dark bumps).
After a polypeptide chain is formed on a ribosome, it moves into the lumen (inner space) of the ER.
rough endoplasmic reticulum
- connected to ribosomes. The rough ER is responsible for processing and altering proteins:
· The proteins are converted from primary to tertiary structure.
· Portions of carbohydrate can be added to the proteins.
· The proteins can be incorporated into the ER itself.
smooth endoplasmic reticulum
- lacks ribosomes and functions in the synthesis of phospholipids and steroids. Cells that have a lot of smooth ER can detoxify cells exposed to chemicals of the body
Which organelle will produce steroid hormones in the testes and adrenal cortex while detoxifying alcohol in the liver?
- smooth endoplasmic reticulum
The folds of the ER are
- cisternae
You might expect that pancreatic cells would contain large amounts of
- rough endoplasmic reticulum
Which of the following statements is false?
a. The ER is continuous with the nuclear envelope.
b. Rough ER is rough because of the presence of ribosomes.
c. Smooth ER functions in lipid synthesis.
d. Proteins manufactured in the rough ER are secreted into the cytoplasm.
- d. proteins manufactured in the rough ER are secreted into the cytoplasm
True or false?
Proteins are present in both the smooth and rough ER.
- true
The ER is involved in the synthesis of all but which of the following?
- carbohydrates
A cell that is actively involved in synthesizing proteins for export from the cell contains large amounts of
- rough endoplasmic reticulum
