Question

1. List the major structural differences between a generalized cell and the modifications that are found in a muscle cell.

2. Describe how lactic acid fermentation differs form aerobic respiration, including the amount of ATP energy is produced in each.

3. Explain how the mechanism of striated muscle contraction differs from smooth muscle contraction.

  

Answer 1

1.

Generalised cells	Other cells in a muscle
Cells are closely packed together No blood capillaries are found They are formed mainly by cells. Cellular component is maximum. Innervated by lots of nerves. .	Cells are Scattered throughout an extracellular matrix Encompassed of blood capillaries which absorb nutrients. Major component is extra cellular matrix Cellular component is minimum Innervated by nerves, blood vessels and other connective tissue.

2.

Lactic acid fermentation	Aerobic respiration
Does not use oxygen Lactic acid and alcohol are produced CO2 produced only in alcoholic fermentation 2 ATP produced Steps : glycolysis only Seen only in some bacteria, fungi and human body	Uses oxygen CO2 and H2O are produced CO2 always produced 38 ATP produced Steps : glycolysis, pyruvate oxidation, Krebs cycle, electron transport chain Seen in most organisms

3.

Skeletal muscle contraction

Smooth muscle contraction

Activation of the tension generating sites within skeletal muscle Fibres The release of calcium in the sarcoplasmic reticulum Contraction is initiated by Calcium mediated change in the thick filaments Skeletal muscle contraction begins with electrochemical stimulation of a muscle fiber by a motor neuron. That occurs at chemical synapse called neuromuscular junction. The neurotransmitter acetylcholine diffuses across the synaptic cleft and binds to receptors on the muscle fiber. It is a type of voluntary muscle contraction. Regulated through the somatic nervous system

The activation of the tension generating sites within smooth muscle Intracellular calcium in the sarcoplasmic reticulum and extracellular calcium entered in to the cell through calcium channels. Uses actin and myosin filaments for contraction. It is initiated when the Calcium binds to intracellular calmodulin, which then activates an enzyme called myosin kinase that phosphorylates myosin heads so they can form the cross bridges with actin and then pull on the filaments. It is a type of involuntary muscle contraction. Regulated through the autonomic nervous system