Rough and smooth
Ribosomes on the ER change how it looks and what it does.
Two kinds of ER
Under an electron microscope, some ER looks bumpy and some looks smooth.
What could make the bumpy kind look bumpy?
What this lesson covers
The idea
Rough ER has ribosomes on its surface and is mainly involved in protein synthesis and secretion; smooth ER has no ribosomes and synthesises and stores fats and hormones.
Two kinds of ER
Under an electron microscope, some ER looks bumpy and some looks smooth.
What could make the bumpy kind look bumpy?
- Ribosomes attached to its surface
- It is covered with fat
- It has a cell wall
Rough or smooth?
Choose each type. See what is on its surface.
Two types of ER
Rough ER (RER) has ribosomes on its surface and is mainly involved in protein synthesis and secretion (for example in pancreatic gland cells). Smooth ER (SER) has no ribosomes and is involved in the synthesis and storage of fats and hormones.
A cell makes more rough or smooth ER depending on its function.
- Rough ER | Smooth ER
- Ribosomes | attached | none
- Appearance | rough | smooth
- Job | protein synthesis and secretion | fats and hormones: synthesis and storage
Notes
Rough ER has ribosomes and mainly makes and secretes proteins. Smooth ER has none and makes and stores fats and hormones.
Check yourself
Why does rough ER look rough?
Pancreatic gland cells secrete proteins. They have a lot of…
Smooth ER is involved in…
- Ribosomes are attached to its surface — correct. Yes.
- It is covered in a cell wall. The ER has no wall.
- It stores starch. Ribosomes cause the rough look.
- rough ER — correct. Yes. Rough ER is involved in protein synthesis and secretion.
- smooth ER only. Smooth ER is mainly for fats and hormones.
- chloroplasts. Animal cells have no chloroplasts.
- synthesis and storage of fats and hormones — correct. Yes.
- protein synthesis with ribosomes. That is rough ER.
- photosynthesis. That happens in chloroplasts.