Intermediary Metabolism 1-Exam 1

Carbohydrates

½ of caloric intake in form of polysaccharides and simple sugars

Hexose

major energy source consisted of glucose, fructose, and galactose and is for energy and storing

Pentose

made from hexoses and is found in ribose which consists of ATP, DNA, and RNA

Glucose

most abundant monosaccharide and regulates blood sugar

Galactose

very similar to glucose so they use the same receptors and transporters

Disaccharides

formed from the condensation of 2 monosaccharides

maltose

glucose+glucose

Sucrose

glucose+fructose

Lactose

glucose+galactose

Sucrose

is table sugar and made of 50/50 glucose and fructose

High Fructose Corn Syrup

is 45/55 glucose and fructose and is a processed food

Oligosaccharides

3-10 monosaccharides

Digestible Oligosaccharides

dextrins (glu-glu)

Non-Digestible Oligosaccharides

raffinose (gal-glu-fruc), stachyose (gal-gal-glu-fruc) and is encompassed under fiber

Polysaccharides are

starches, glycogen, and fiber

Starches are

the storage form of CHO in plants

what are the types of starch

amylose and amylopectin

Amylose

glucose linked by alpha 1-4 bonds and is linear

Amylopectin

branched chain polymer with glucose linked by alpha 1-4 and alpha 1-6 bonds

Glycogen is

the storage form of CHO in animals

glycogen is stored in

the liver and muscle

Fiber is

non-digestible plant polysaccharide

fiber can be used as energy by

bacteria

Dietary Fiber

is found intact and is natural (intrinsic in plants)

Functional Fiber

has been isolated, extracted, or manufactures, and has beneficial effects (supplement)

Insoluble Fiber

doesn’t dissolve in water, decreases transit time, and increases fecal bulk

Examples of insoluble fiber

lignans, celluloses, some hemicelluloses

Soluble FIber

dissolves in water and increases transit time

Examples of soluble fiber

pectins, gums, some hemicelluloses

Digestive enzyme

an enzyme that breaks a bond and is specific

Since fiber has molecules and bonds that don’t have corresponding enzymes

they are fermented by bacteria in the colon

Short chain fatty acids

acetic acid, butyric acid, propionic acid

Short chain fatty acids help

create a healthy gut and enhanced immune function

where does fiber go?

fiber is excreted as fecal matter

Fiber is found in

fruits, vegetables, and whole grains

FOD MAPS

are carbs that can be difficult for some to digest or absorb

Those with GI disorders may benefit from

eating a low FOD MAP diet

Digestion of Carbohydrates begin in

the mouth

Salivary glands produce

salivary amylase which digests alpha 1-4 bonds

The second step of digestion of carbs happens in

the stomach

What is the purpose of HCl in the stomach

it inactivates salivary amylase and denatures proteins

The third step of carb digestion happens in the

small intestine

What are the two pancreatic secretions?

bicarbonate and pancreatic amylase

Bicarbonate

neutralizes stomach acid

Pancreatic Amylase

breaks down glucose units

Brush border enzymes are

released from enterocytes

Brush border enzymes break down

sucrase, lactase, and maltase

Sucrase

sucrose→glucose + fructose

Lactase

lactose→ glucose + galactose

Maltase

maltose→ glucose + glucose

Absorption and transport of carbs happens in

the small intestine

Passive Diffusion

no energy required, limited by concentration gradient, small molecules & solutes, lipids

Facilitated Diffusion

needs carrier protein which is an integral membrane protein that functions as a transporter

The rate of Facilitated Diffusion is determined by

the concentration gradient, the amount of carrier available, and the rapidity of solute/carrier interaction

Active Transport

needs a carrier protein and requires energy (Sodium Potassium Pump)

What diffusion does Fructose use?

Facilitated Diffusion

GLUT 2

movement across the basolateral membrane of enterocytes, fructose and glucose transport at liver

GLUT 4

insulin-stimulated uptake of glucose at muscle, heart, adipocytes

GLUT 5

absorption of fructose at small intestine, fructose at muscle, adipose, brain

SGLT 1

uptake of glucose and galactose from lumen

The liver mainly takes up

fructose and galactose

What is better for the rest of tissues and is not primarily taken up in the liver?

Glucose

Portal Circulation happens in the

Liver

Glucose that is facilitated and insulin-dependent goes to

the skeletal muscle and adipose tissue

Glucose that is facilitated and insulin-independent goes to the

kidney and brain

Glycolysis is

the oxidation/breakdown of glucose and produces energy

Glycolysis happens in the

cytosol

What are the two types of Glycolysis?

aerobic and anaerobic

Anaerobic Glycolysis

happens without oxygen, produces lactate, and less ATP is produced

Anaerobic Glycolysis is seen

with intense exercise of the muscle and in red blood cells

Aerobic Glycolysis

happens with oxygen, produces Acetyl CoA, and more ATP is produced

Glucokinase

functions in the liver and pancreas and is up regulated by insulin

When does the liver remove large quantities of glucose form the blood?

when blood glucose levels are high

Hexokinase functions in the

muscle, adipose, and brain

hexokinase is

down regulated by Glucose-6-Phosphate and has max enzyme activity at normal blood glucose levels

The Krebs cycle happens in the

mitochondrial matrix

The Krebs cycle is

an amphibolic pathway where CHO, fats, and proteins can all enter and be completely oxidized

What are the products of the Krebs Cycle?

CO2, H2O, and energy

NADH equals how much ATP?

3 ATP

FADH equals how much ATP?

2 ATP

GTP equals how much ATP?

1 ATP

How much energy is produced from the Krebs cycle starting at Acetyl CoA?

12 ATP

How much energy is produced from the Krebs cycle starting at Pyruvate?

15 ATP

Malate-Aspartate Shuttle

moves NADH into the mitochondria via the ETC

The Malate-Aspartate Shuttle is active in

the liver, kidney, and heart

Gylcerol-3-Phosphate Shuttle

NADH is converted into FADH and enters at complex II of the ETC

The Gylcerol-3-Phosphate Shuttle is active in

the muscle and brain

What is the overall purpose of shuttle systems?

to move hydrogens into the mitochondria to make energy/ATP

What is the purpose of the Electron Transport Chain?

to produce mitochondrial ATP

Oxidation reaction in the ECT

loss of electrons or hydrogen

Phosphorylation in the ETC

addition of phosphorus

Uncoupling in ETC

it is not a perfect system so at some point uncoupling of proteins occurs

Proton Gradient

particles diffuse from an area of higher concentration to lower concentration but we must maintain a higher concentration of protons in the outer mitochondrial space

Proton Pumps

complexes which remove electrons from coenzymes located in the inner mitochondrial space and/or pump protons into the outer mitochondrial space

Complex I Proton Pump

NADH dehydrogenase complex

Complex III Proton Pump

Cytochrome B-C complex

Complex IV Proton Pump

Cytochrome Oxidase complex

Electron transporters

transport electrons between complexes in the ETC

What are the two electron transporters for the ETC?

Ubiquinone and Cytochrome C

Uiquinone

transports electrons between complex I and III