NUTR 9 (test review)

energy metabolism?

body source of energy are macronutrients like…

obtain energy from macronutrients

carbs (4 kcal/g), protein (4 kcal/g), fat (9 kcal/g), alcohol (7 kcal/g)

Metabolic pathways

catabolic pathway (ex: lipolysis) =

anabolic pathway (ex: protein synthesis) =

amphibolic pathway (ex: citric acid cycle) =

breaks down large molecules to release energy

uses energy to build larger molecules

is both catabolic and anabolic

food into energy is a series of catabolic reactions which begins with ___ then units go through ___

digestion (breaking food in smaller absorbable units)

metabolic pathways

units from digestion that sent through metabolic pathways?

(key metabolic pathways: anabolic, catabolic, amphibolic)

amino acids

monosaccharides (fuel for ATP production)

free fatty acids (long-term energy)

glycerol (3 fatty acids + glycerol = triglycerides)

alcohol (later converted to acetyl-CoA)

A metabolic pathway for energy metabolism is a series of connected,

enzyme-catalyzed chemical reactions that transform nutrients into usable cellular energy (ATP)

intermediates

molecules formed in between steps

metabolism steps:

step 1: digestion = food broken down into absorbable small units

step 2: conversion =

step 3: energy use

absorbed nutrients converted into ATP, storage forms (glycogen, fat), and metabolic intermediates

metabolism steps:

step 1: digestion

step 2: conversion

step 3: energy use = ATP used for…

muscle contraction, pump ions across membranes, condensation reactions, making new compounds

energy stored as ATP and creating ATP releases

heat (about 60% of energy from glucose is released as heat)

carbon dioxide (Krebs cycle)

water (electron transport chain)

redox reactions =

transfer electrons (hydrogen ions) to release and store energy

redox reactions are controlled by ___ and directly make ___

enzymes, ATP

Oxidation:

Reduction:

Oxidation: loses electrons or hydrogen OR gains oxygen

Reduction: gains electrons or hydrogen OR loses oxygen

important enzymes for redox reactions is dehydrogenases which…

remove hydrogens from energy-yielding compounds to form water

vitamins that help aid dehydrogenases?

niacin (B3) and riboflavin (B2)

niacin (B3) oxidized and reduced form =

riboflavin (B2) oxidized and reduced form: =

oxidized form: NAD (nicotinamide adenine dinucleotide)

reduced form: NADH

---

oxidized form: FAD

reduced form: FADH₂

Niacin (B3) and riboflavin (B2) in energy metabolism are

coenzymes that act as electron carriers to convert carbohydrates, fats, and proteins to energy

how many ATP produced at each stage of aerobic cellular respiration (glycolysis, pyruvate to acetyl-CoA, citric acid cycle, electron transport chain)

glycolysis: net 2 ATP (4 produced - 2 invested)

pyruvate to acetyl-CoA: 0 ATP

citric acid cycle: 2 ATP

ETC: 28 ATP

(leave out ATP) end results of each stage of aerobic cellular respiration (glycolysis, pyruvate to acetyl-CoA)?

glycolysis: 2 pyruvate (3 carbon compound), NADH

pyruvate to acetyl-CoA: acetyl-CoA (2 carbon compound), CO₂, NADH

(leave out ATP) end results of each stage of aerobic cellular respiration (citric acid cycle, electron transport chain)?

citric acid cycle: 6 NADH, 2 FADH₂, CO₂ (most CO₂ released here)

ETC: water, NAD, FAD

location of each stage of aerobic cellular respiration (glycolysis, pyruvate to acetyl-CoA, citric acid cycle, electron transport chain)

glycolysis = cytosol (fluid in cytoplasm)

pyruvate to acetyl-CoA = mitochondrial matrix

citric acid cycle = mitochondria

ETC = mitochondria

stages that require oxygen and don’t in aerobic cellular respiration ?

need oxygen: ETC

don’t need oxygen: glycolysis, citric acid cycle

gluconeogenesis (makes glucose from some amino acids and other compounds) location?

occurs in liver and kidneys

gluconeogenesis begins in ___ (specifically where in hepatocytes) with _____ (hint: acetyl-CoA)

mitochondria (& later cytoplasm) with oxaloacetate

oxaloacetate?

combines with acetyl-CoA to form citrate, which improve ATP production

ketogenesis is process where

acetyl-CoA build up and forms ketone bodies in liver

Ketosis (state) happens when…

(ketogenesis is the process)

low carbs. low insulin, fasting, type 1 diabetes (autoimmune)

Gluconeogenesis starts around ___ after fasting and depletes around ___

4-6 hours, 24 hours

ketones (Ketosis) begins ___ after fasting with major production around ___ (also spares body proteins by reducing need of gluconeogenesis)

24 hours, 2 days

Insulin promotes:

glycogen synthesis, fat storage, protein synthesis

Low insulin promotes:

gluconeogenesis. lipolysis (breaking down stored triglycerides into glycerol and free fatty acids for energy), protein breakdown

cori cycle (aka lactic acid cycle) is a metabolic pathway connecting….

muscle and liver

cori cycle is where…

anaerobic lactate production in muscles is converted back into glucose in the liver (to sustain energy production)

beta-oxidation is the metabolic process of…

breaking down fatty acids in mitochondria to make energy

beta-oxidation produces…

acetyl-CoA, NADH, and FADH₂

location of protein metabolism?

liver

urea cycle (or ornithine cycle) is a metabolic pathway location?

the liver (the same with deamination and synthesis of blood proteins)

urea cycle (or ornithine cycle) converts…

highly toxic ammonia, produced from protein metabolism, into urea for safe excretion by the kidneys

location of the synthesis of blood proteins (like albumin)

liver (same place for deamination, ammonia to urea)