A&P II Chapter 24

Cellular respiration purpose/goal

To produce ATP in cells by catabolic breakdown of food fuel (mainly glucose). Its goal is to trap chemical energy in ATP

What are the pathways in cellular respiration?

Glycolysis, citric acid cycle (Krebs cycle), and oxidative phosphorylation

What is glycolysis (AKA glycolytic pathway), and where does it occurs

It is the breakdown of glucose into pyruvic acid. Occurs in the cytosol of the cells

Where does the Citric acid cycle( AKA Kreb Cycle) occur

mitochondrial matrix.

Oxidative phosphorylation and where it occurs

Produces the most ATP via the electron transport chain. It occurs in the inner mitochondrial membrane

Does Glycolysis require oxygen

no

Does citric acid cycle require oxygen

Yes but only to run the cycle (indirect usage)

Does Oxidative phosphorylation require oxygen

yes ( direct usage)

What are carbohydrate reactions?

Glycolysis, Glycogenesis, Glycogenolysis, and Gluconeogenesis

Glycolysis

Converts glucose to pyruvic acid 

Glycogenesis

Polymerizes glucose to form glycogen (means it forms glycogen from excess glucose) 

Glycogenolysis

Hydrolyzes glycogen to glucose monomers (means the breakdown of glycogen to glucose)

Gluconeogenesis

Forms glucose from non-carbohydrate precursors (it means that it is the process of forming new (neo) glucose from non-carbohydrate sources)

What are the amino acid reactions

Transamination, Oxidative deamination, and Keto acid modification

Transamination

Transfer an amine group from an amino acid to 𝛼 -ketoglutaric acid, generating glutamic acid

Oxidative deamination

Removes an amine group (as ammonia) from glutamic acid and regenerates

𝛼 -ketoglutaric acid 

Keto acid modification

when transaminations are altered to produce metabolites that can enter the citric acid cycle.

What are the Lipid reactions?

Beta oxidation, lipolysis, and lipogenesis

Beta oxidation

Converts fatty acids into acetyl CoA.

Lipolysis

Breaks down lipids (stored fats) to fatty acids and glycerol (reverse of lipogenesis)

Lipogenesis

Forms lipids from acetyl CoA and glyceraldehyde 3-phosphate (triglyceride synthesis from glycerol and fatty acids)

What is the importance of vitamins

Act as coenzymes meaning that vitamins works with an enzyme to accomplish some body function. 

What is the preferred fuel for the brain

glucose

What is the preferred fuel for the Kidney

fatty acid and glucose

What is the preferred fuel for the adipose tissue, liver, and skeletal and cardiac muscle 

Triglycerides ( fatty acid)

Which macromolecules are stored in the body

Lipids (triglycerides) and carbohydrates (glycogen)

Which macromolecules are not stored in the body

Proteins

What macromolecules have the highest energy yield

Lipids (9 kcal/mol)

What macromolecules have the lowest energy yield

Protein and carbohydrate (4 kcal/mol) 

What are the structural materials made from lipids

phospholipids for cell membranes, myelin sheath for neurons, steroids for hormone synthesis, and cholesterol for cell membranes

Absorptive state

Metabolic state focused on anabolism after eating.

Postabsorptive state

Metabolic state focused on catabolism during fasting.

What is Absorptive state's main hormone

Insulin (hypoglycemic hormone)

What is Absorptive state's main hormone affect on the body

it lowers blood glucose, and it inhibits glucose from being released from the liver and gluconeogenesis

What is postabsorptive state's main hormone

Glucagon (hyperglycemic hormone)

What is postabsorptive state's main hormone affect on the body

It raises blood glucose levels using Glycogenolysis and gluconeogenesis

In the postabsorptive state, some organs shift the fuel they use for metabolism. Why? 

To make sure some glucose can be saved for the brain to use. 

Nitrogen balance

the homeostatic state where rate of protein synthesis equals rate of breakdown and loss 

Positive nitrogen balance

Synthesis exceeds breakdown, common in children and pregnant women, and tissue repair

Negative nitrogen balance

Breakdown exceeds synthesis, (examples : stress, burns, infection, injury, poor dietary proteins, starvation) 

Heat-promoting mechanisms

• Constriction of cutaneous blood vessels

• Shivering

• Increases in metabolic rate (chemical (nonshivering)thermogenesis)

• Enhanced release of thyroxine

What are the voluntary measure of heat promoting mechanism

• Putting on more clothing 

• Drinking hot fluids 

•  Changing posture (clasping arms across chest) 

•  Increasing physical activity (jumping up and down)

What are the voluntary measure of heat loss mechanism

• Reducing activity and seeking a cooler environment 

• Wearing light-colored, loose-fitting clothing 

Heat-loss mechanisms

• Heat-promoting center is inhibited 

• Dilation of cutaneous blood vessels 

• Enhanced sweating