Cell: The Unit of Life

Biology · Class 11

Simulation · Biology · Class 11

The secretory route

"The secretory route" is a free, interactive Class 11 Biology simulation for NEET, built on the NCERT section "Endomembrane system: ER and Golgi apparatus" in Cell: The Unit of Life. Route a protein from a ribosome on the rough ER through the lumen, a vesicle, the Golgi cis face to trans face (glycosylation) and out by secretion or into a lysosome; lipids start on the smooth ER. NEET has asked about this idea 10 times in 10 years of papers.

From the lesson Endomembrane system: ER and Golgi apparatus in Cell: The Unit of Life. Change the values and watch what happens.

The secretory routeBiology · Class 11

What it shows

NCERT §8.5.3

Route a protein from a ribosome on the rough ER through the lumen, a vesicle, the Golgi cis face to trans face (glycosylation) and out by secretion or into a lysosome; lipids start on the smooth ER.

Controls

4 to try

  • Segmentedcargo secreted protein / lysosomal enzyme / membrane lipid
  • Dragvesicle to the next organelle
  • Toggleadd sugar in Golgi
  • Buttonrelease

Try this

Deliver a secreted glycoprotein outside the cell in the right order; the check refuses any route through a mitochondrion or peroxisome.

Common mistake

Mitochondria/chloroplasts belong to the endomembrane system; cis and trans faces swapped.

In NEET

10 years of papers

Asked 10 times in 10 years of NEET.

See the past questions: Cell: The Unit of Life (chapter)

The idea behind it

NCERT §8.5.3–§8.5.3.2

  • The endomembrane system groups organelles whose functions are coordinated: endoplasmic reticulum, Golgi complex, lysosomes and vacuoles. Mitochondria, chloroplasts and peroxisomes are NOT part of it because their functions are not coordinated with these.
  • The ER is a network of tiny tubular structures in the cytoplasm that splits it into a luminal (inside ER) and an extra-luminal (cytoplasm) compartment.
  • ER carrying ribosomes on its surface is rough ER (RER); ER without ribosomes is smooth ER (SER). RER is abundant in cells busy making and secreting proteins and is continuous with the outer nuclear membrane.
  • Lipids are synthesised mainly in the SER, which in animal cells also makes the lipid-like steroidal hormones.
  • Camillo Golgi first saw the Golgi apparatus in 1898 as densely stained reticular structures near the nucleus.
  • It is a stack of flat, disc-shaped sacs called cisternae, about 0.5–1.0 μm in diameter, arranged parallel to one another in stacks, with cisternae varying in number.
  • The stack has two faces: the convex cis (forming) face and the concave trans (maturing) face. They are entirely different but interconnected.
  • Materials packed in ER vesicles fuse with the cis face and travel towards the trans face, which explains why the Golgi lies close to the ER.
  • The Golgi packages materials for intracellular targets or for secretion. Proteins made on ribosomes of the ER are modified in its cisternae before release from the trans face, and it is an important site for forming glycoproteins and glycolipids.

Questions

4 answers

What does the "The secretory route" simulation show?
Route a protein from a ribosome on the rough ER through the lumen, a vesicle, the Golgi cis face to trans face (glycosylation) and out by secretion or into a lysosome; lipids start on the smooth ER.
What mistake does the "The secretory route" simulation fix?
A common mistake it clears up: mitochondria/chloroplasts belong to the endomembrane system; cis and trans faces swapped.
Has NEET asked about this idea?
Yes. NEET has asked about this idea 10 times in 10 years of papers.
Is this simulation free?
Yes. It is free and runs in the browser on a phone or a laptop. It belongs to the lesson "Endomembrane system: ER and Golgi apparatus" in Cell: The Unit of Life (Class 11 Biology).

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