Chapter 14 A (Cell Bio)

1. Cytoplasmic streaming

2. Amoeboid movements

3. Contraction

4. Assembly motion

5. Cell migration

What are the five examples of microfilament-based cell movements ?

Cytoplasmic Streaming

the directional flow of the cytoplasm; also known as cyclosis

It moves particles, organelles, and molecules

What is the importance of cytoplasmic streaming ?

It pushes cell borders into extensions.

What is the mechanism of amoeboid movement ?

Cell migration

Phagocytosis

What are two examples of amoeboid movement ?

Muscle contraction

microfilaments slide over each other and forcibly shorten a cell segment or whole cells.

Contraction of smooth muscles

Contraction of striated muscles

Cytokinesis

What are examples of muscle contraction ?

Assembly motion

rapid assembly causes microfilaments to lengthen, pushing attached structures forward.

The acrosome reaction, or rapid extension of the sperm tip during fertilization.

What is an example of assembly motion ?

Actin

Myosin

Tropomyosin

What are the three major components of microfilaments ?

Actin

This protein forms the filaments.

Myosin

This protein acts as a motor protein

Tropomyosoin

This protein forms fibrous reinforcement

Through myosin decoration, where microfilaments are reacted with myosins.

How are microfilaments highlighted for study ?

Highlighting microfilaments for study

Isolating microfilaments for study

Determining the polarity of microfilaments

What are the three purposes of myosin decoration ?

They are ancient, highly conserved proteins prevalent in all eukaryotic cells.

Where are actins found ?

A polypeptide containing either 374, 375, or 376 amino acids

What is the structure of actin ?

A globular protein with two lobes and a cleft

What is the tertiary structure of actin ?

MG²⁺, ATP, and ADP

What are the binding sites on globular actin ?

Alpha (α), beta (β), and gamma (γ) actins.

What are the three types of actins ?

α-skeletal: Skeletal muscles

α-cardiac: Cardiac muscles

α-smooth: Smooth muscles

Where are alpha-actins found ?

Non-muscle cells

Where are beta-actins found ?

Non-muscle cells

Where are gamma-actins found

Arps

____ are widely distributed in organisms.

Arps

____ show 50% similarity to a variety of actins