bio muscles pray for me

Define movement

Change of position for an organism or a body part

Tropism Definition

plants response towards external stimuli

Sessile Definition

Barnacles attach to rocks and don’t move place to place

How does amoeba portray movement?

Amoeba moves body parts to engulf other tiny organisms

Structure of muscle fibers

Fused together by many cells and multinucleated

Parts of the muscle fiber

Sarcolemma, sarcoplasm, sarcoplasmic reticulum, many mitochondria, myofibrils, and sarcomeres

Sarcolemma definition and function

plasma membrane of muscle fibers controls what enters and exits the muscle fiber. The sarcolemma contains protein receptors for the neurotransmitter acetylcholine

Sarcoplasm definition and function

cytoplasm of the muscle fibre this is where the metabolism required for muscle contraction occurs

Sarcoplasmic reticulum definition and function

stores calcium ions for muscle contraction

Mitochondria are used for?

Generating ATP. The more mitochondria a muscle has, the stronger it grows.

Myofibrils are made of ___

Sarcomeres

Sarcomeres are

strands of actin and myosin proteins

What happens when Troponin and Tropomyosin are in place? (hint: what do they prevent?)

They prevent actin and myosin from interacting.

What needs to be received in order for actin and myosin to interact? What happens?

Once calcium is received, the troponin and tropomyosin change shapes and now actin and myosin

Stage 1 of sarcomere contraction:

Calcium ions release from sarcoplasmic reticulum

Stage 2 of sarcomere contraction:

Actin and myosin cross bridges and are now free to interact. Myosin head binds to actin binding sites.

Stage 3 of sarcomere contraction:

ATP breaks myosin heads to break the cross bridge and they swivel back

Stage 4 of sarcomere contraction:

Sarcomere shortens

Why are antagonistic muscle pairs required for function?

As one muscle shortens, the other pulls it back into its original place.