Q1. Which of the following is not matched correctly?

A) Lysosome- Autophagy

B) Endosomal vescicles- shuttle internalized materials outside the cell

C) Proteosome- Degrades tagged proteins

D) Peroxisomes- Breaks down very long chain fatty acids.

Answer: B- Endosomal vesicles- shuttle internalized materials to other organelles inside the cell

2. Identify the cytoskeletal protein shown in the image

Clues: Most abundant and 5-9 nm in diameter

A) Actin

B) Myosin

C) Desmin

D) Laminin

Answer: A –

Actin microfilaments are 5- to 9-nm diameter fibrils formed
from the globular protein actin (G-actin), the most abundant cytosolic protein in cells. G-actin monomers noncovalently polymerize into long filaments (F-actin) that intertwine to form double stranded helices with a defined polarity

3. All are true regarding protein synthesis except?

A) Membrane bound ribosomes in the RER translate mRNA.

B) Chaperones assist folding of proteins.

C) From the RER, proteins and lipids destined for other organelles or extracellular export are shuttled into the Golgi apparatus

D) O- linked oligosaccharides are converted into N- linked Oligosaccharides in golgi apparatus.

Answer: D –

N-linked oligosaccharides are pruned and extended in a stepwise fashion into O-linked oligosaccharides in the golgi . Some of this glycosylation is important in sorting molecules
to lysosomes (via the mannose-6-phosphate receptor); other glycosylation adducts are important for cell-cell or cell-matrix interactions or for clearing senescent cells (e.g., platelets and erythrocytes).

References: Robbins and cotran pathologic basis of disease 10 th edition.


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