Keratin, the protein that strengthens hair and nails, belongs to which group of cytoskeletal fibers?
AThe narrow microfilaments
BThe hollow microtubules
CThe strands of actin
DThe intermediate filaments
Answer & Solution
Correct answer: D. The intermediate filaments
1. The cytoskeleton has three fiber types: microfilaments, intermediate filaments, and microtubules.
2. Intermediate filaments are made of several strands of fibrous proteins wound together.
3. Keratin, familiar from hair, nails, and the epidermis of the skin, is one of those fibrous proteins.
4. Microfilaments are built from actin, so the actin option and the microfilament option name the same wrong fiber twice.
5. Microtubules are hollow tubes of tubulin that partner with cilia and flagella instead.
_Source: OpenStax Biology (1st ed., CC BY 4.0), Ch 4 "Cell Structure", section 4.5 The Cytoskeleton_
Related questions
The earliest fossil evidence for life on Earth, microbial mats, dates back about:A gap junction channel is built when six connexin proteins arrange into a structure calledRanking the cytoskeletal fibres from narrowest to widest gives:Lysosomes can digest material because their internal pH is:Removing the centrosome from a cell shows that centrioles:Which pair of structures is found in animal cells but generally not in plant cells?Structures found in plant cells but not in animal cells include chloroplasts, a large centThe material cells secrete around themselves, holding a tissue together, is the: