ch 8 - [CARB METABOLISM ONLY] cellular respiration, energy metabolism

metabolism: the ____ of all chemical reactions involved in ______ and ______

[sum] [catabolism] [anabolism]

catabolic reactions

break down food to obtain energy

anabolic reactions

synthesizes larger mlcs from smaller ones using energy released by catabolic reactions

[…] drives all bodily functions

[energy gained from ATP]

most common energy source for the body

carbohydrates

most common carb mlc used as fuel for body cells’ ATP production

glucose

fill in the diagram detailing how ATP is sourced from food intake. also specify which pathways are anabolic and catabolic

monosaccharides

a monomer of carbohydrates absorbed by SI, transported through circulatory system

process of generating ATP in the cytoplasm and mitochondrion, using monosaccharides in body’s tissues

cellular respiration

process of cellular respiration (4)

1. Glycolysis in cytoplasm: converts 1 glucose mlc to 2 pyruvate mlcs

   1. lactic acid fermentation (pyruvate enters anaerobic pathway)

2. Conversion in mitochondrial matrix: each pyruvate mlc converted to 1 acetyl co-a mlc

3. Krebs cycle in mitochondrial matrix: acetyl co-a is processed by krebs cycle

4. Oxidative phosphorylation in mitochondrial inner membrane: electrons removed from glucose, pyruvate, and acetyl CoA (ELECTRON CARRIERS) are passed through electron transport chain → undergo redox reactions and using energy to make ATP through oxidative phosphorylation

glycolysis (1/4 cellular respiration)

• what occurs

• what is produced

• 2 phases

step 1 of cellular respiration in cytoplasm: converts 1 glucose mlc → 2 pyruvate mlcs

glyco = sugar, lysis = break apart

• produces ATP (cellular energy)

• produced NADH (electron carrier)

phases:

1. energy-consuming phase

2. energy-yielding phase

phases of glycolysis

step 1 of cellular respiration in cytoplasm: converts 1 glucose mlc → 2 pyruvate mlcs

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1. energy-consuming phase: 2 ATP used to split glucose into → 2 G3P mlcs

2. energy-yielding phase: each G3P mlc split into → pyruvate → generating 4 ATP, 2 NADH

= net gain of 2 ATP

describe what pyruvate does after glycolysis pccurs (2 possible pathways)

1. with oxygen: enters aerobic pathway, 2 pyruvates travel to mitochondrial matrix to convert to acetyl-CoA

2. without oxygen: enters anaerobic pathway when oxygen is limited & converts into lactic acid (fermentation, kind of like backup plan b/c without oxygen you can’t have good power efficiency)

lactic acid fermentation

• when it occurs

• enzyme catalyzing its reaction

• what it generates

• what happens with lactic acid buildup

occurs after glycolysis when pyruvate converts into lactic acid

occurs with insufficient oxygen supply (anaerobic pathway) in RBC and skeletal muscle so that ATP can continue being produced

pyruvate is converted into lactic acid: enzyme catalyzing reaction = lactate dehydrogenase

• lactic acid conversion uses up electron carried by NADH → generating NAD+

  • NAD+ used again in glycolysis

• lactic acid builds up and causes muscle stiffness and fatigue - buildup gets removed from muscle and brought back to liver to be converted back to pyruvate

conversion of pyruvate (2/4 cellular respiration)

• what occurs

• what is produced, byproducts produced

• what happens to the new product after it is formed

(step 2/4 cellular respiration)

• pyruvate → converted to acetyl (COCH3 group) → carrier compound coenzyme A (CoA) picks up acetyl group

• produces: acetyl CoA

  • byproducts: 1 CO2, 1 NADH

• after conversion: acetyl CoA is delivered to krebs cycle

krebs cycle / citric acid cycle (3/4 cellular respiration)

• what occurs

• what is produced in the cycle

occurs in mitochondrial matrix

• 8 step closed loop cycle; last part regenerates compound used in the first step

• produces:

  • 2 CO2

  • 3 NADH

  • 1 FADH2

  • 1 ATP

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oxidative phosphorylation (4/4 cellular respiration)

• what occurs

• where it occurs

• byproducts produced

• what the product is used for

(step 4/4 cellular respiration)

•  electrons removed from glucose, pyruvate, and acetyl CoA (ELECTRON CARRIERS) are passed through electron transport chain

  • undergo redox reactions and using energy to make ATP

• occurs in mitochondria’s inner membrane

• byproduct: water

gluconeogenesis

• what it is

• when it occurs

synthesis of glucose (body creating new glucose) from: pyruvate, lactate, glycerol, some amino acids

• occurs during fasting, starvation, and low carb diets

what body cells are permitted to use glucose as an energy source?

• brain cells

• erythrocytes

• adrenal medullary cells

• sperm cells