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67. What are the major processes that use energy? 2. 3. What is the unit of ener

ID: 3483799 • Letter: 6

Question

67. What are the major processes that use energy? 2. 3. What is the unit of energy? What is its definition? * 68. What is the difference between brown fat and white fat? 69, What is the definition of digestion vs. absorption? What kinds of molecules/ proteins do each process? 70. What are reactive oxygen species (ROS)? Why are they dangerous? Why are the necessary? What molecules inactivate them? 71. Distinguish autoscine vs paracrine vs endocrine vs exocrine signaling. Signal autocrine paracrine endocrine exocrine Long or short distance Si Relationship b/t sender and receiver

Explanation / Answer

67. 1. Glycolysis : Glucos converted to pyruvate

2. Kerbs cycle/citric acid cycle : Acetyl CoA is cycled several times to give NADH, FADH2, GTP

3. Electron transport chain in mitochondria

The energy obtained by these pathways are termed ATP which stands for adenosine triphosphate. This molecule is made of a nitrogen base (adenine), a ribose sugar, and three phosphate groups. The word adenosine refers to the adenine plus the ribose sugar. The bond between the second and third phosphates is a high-energy bond.

68.

69.

Digestion is when the ingested food is broken down into smaller building blocks. This may be achieved by mechanical methods (chewing, churning) and chemical methods (digestive enzymes of stomach and intestines).

Molecules/proteins involved :

Carbohydrate - Amylase

Protein - pectin, trypsin and chymotrypsin

Fat/lipids - lipase

Absorption is when the digested materials are absorbed into the bloodstream or lymphatic system through the intestines and then transported to various cells, tissues, organs in the body.

Carbohydrate - microvilliof epithelial cells

Lipids - simple diffusion through plasma membrane of small intestine

Protein - peptide carrier in brush border membrane

70. ROS is a chemically active oxygen species produced by reduction of oxygen. E.g. Superoxide, peroxide. It has an unpaired electron.

At low level it is useful in many signalling pathway and participate in immune function and cell proliferation. At high levels, it will damage macromolecules like DNA, RNA and take part in apoptosis (cell death).

Antioxidants will inactivate ROS by donating an electron to the unpaired electron in ROS.

71.

Brown fat white fat Contains small lipid droplets with mitochondria and iron Contains a single large droplet with less mitochondria Burn calories to generate heat and is a good fat Energy reserve of our body. Will not burn easily. Hence bad fat. Derived from muscle tissue Derived from connective tissue Found in hibernating animals and infants. Decreases in increasing age Seen after infancy is over. Seen near neck and shoulder in infants Seen in subcutaneous layer of skin and around organs.