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CNS Exam 2024 > Macronutrients > Flashcards

Macronutrients Flashcards

1
Q

Carbohydrates (functions)

A
  • chemical properties consist of carbon, hydrogen, and oxygen atoms
  • Functions
    1. Energy production
    2. Regulation of fat metabolism
    3. protein sporing action

A. In the mouth: (AMYLASE enzyme) AMYLOSE AND AMYLOPECTIN: salivary glands release AMYLASE which hydrolyzes amylose forming DEXTRINS.

B. stomach: no further digestion here. acidity of gastric juices destroys enzymes.

C. small intestine: (AMYLASE enzyme) AMYLOSE AND AMYLOPECTIN pancreas releases pancreatic amylase into the SI. DEXTRINS are broken down into MALTOSE.
2. pancreatic enzymes amylase hydrolysizes glycosidic bonds into AMYLOPECTIN.

D. BRUSH BORDER OF SI:( MALTASE enzyme and DEXTRINASE enzyme) AMYLOSE AND AMYLOPECTIN: MALTOSE is hydrolyzed by MALTASE forming free glucose.

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2
Q

Types of carbohydrates

A
  1. Monosaccharides
    a. Glucose
    b. Fructose
    c. Galactose
  2. Disacharides
    a. Lactose (glucose and galactose)
    b. Sucrose (glucose and fructose)
    c. Maltose (galactose and glucose)
  3. Polysaccharides
    a. starch
    b. cellulose
    c. pectin
    d. Glycogen
    e. Dextrin
    F. sorbitol
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3
Q

Ranking of sweetness

A

Fructose (sweetest)
Invert sugar
scurose
glucose
sorbitol
mannitol
galactose
maltose
lactose (last in sweetness)

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4
Q

absorption of circulation of monosacharides (glucose, galactose, fructose)

A

Glucose and galactose: carrier dependent, energy required ACTIVE TRANSPORT:
-move from a lower to a higher concentration by a transport protein.

Fructose: transported into enterocytes via FACILITATED DIFFUSION. higher concentration to lower concentration with assistance of transport protein.

Circulated to the Liver via the hepatic portal system.

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5
Q

sucrose

A

glucose + fructose = table sugar

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6
Q

Maltose

A

glucose + glucose (very few foods contain maltose)

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7
Q

Lactose

A

Galactose + glucose = milk sugar

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8
Q

simple carbs vs complex carbs

A

A. simple (monosacharide and disaccharides)
1. Mono (1 sugar) : glucose, fructose, galactose
2. Disaccharides (2 sugar): lacotse, sucrose, maltose.

B. complex carbohydrates
1. Oligosaccharides (3-10 sugar units) : Raffinose, stachyose
2. Polysaccharides (>10 sugar units) :
Glycogen, starch, dietary fiber

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9
Q

Role of insulin in cellular uptake of glucose

A
  1. in response to a rise in blood glucose, the pancreas releases more insulin into the blood
  2. Insulin binds to a membrane bound receptor.
  3. The binding of insulin to its receptor signals glucose transporters to move from the cytoplasm to the cell membrane.
  4. Glucose transporters enable glucose to move from the extracellular space into the cytoplasm.
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10
Q

Insulin (hormone) Promotes energy storage

A

the pancreas increases its release of the hormone insulin in response to high blood glucose. Insulin stimulates glucose transport into cells and promotes energy storage.

HOMEOSTASIS DISTURBED: RISE IN BLOOD GLUCOSE: Beta cells release insulin

a. promotes uptake of glucose into some cells (muscle and adipose tissue)
b. promotes conversion of glucose to glycogen in liver and skeletal muscle cells (glycogenesis)
c. promotes protein synthesis in muscle cells
D. promotes fat synthesis in adipose tissue

BLOOD GLUCOSE DECLINES

HOMEOSTASIS RESTORED
normal blood glucose

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11
Q

Protein

A

Chemical properties: Composed of carbon, hydrogen, oxygen, nitrogen, some contain sulfur (cysteine and methionine)
-Building blocks are amino acids which contain an amino group and carboxyl group.
-Essential amino acids cant be synthesized by the body and must be obtained in the diet.(9)
-Tryptophan serves as a precursor to serotonin and niacin
-Phenylalonine can convert to tyrosine
-Methionine convert to cysteine
-Complete proteins contain sufficient levels of all essential amino acids, incomplete proteins lack one or more essential amino acid.

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12
Q

Protein digestion

A

Occurs in stomach and small intestine
1. gastric cells release the hormone GASTRIN, which enters the blood causing release of gastric juices.
2. Hydrochloric acid in gastric juice denatures proteins and converts PEPSINOGEN TO PEPSIN, which begin to digest proteins by hydrolyzing peptide bonds.
3. partially digested proteins enter the SMALL INTESTINE and cause release of the HORMONE SECRETIN AND CCK.
4. SECRETIN stimulates the pancreas to release BICARBONATE which neutralizes chyme. CCK stimulates the pancreas to release pancreatic proenzyme (TRYPSINOGEN) into the small intestine.
5. IN SI: TRYPSINOGEN converted to TRYPSIN ( active enzyme)
a. TRYPSIN digest polypeptides into
1. tripeptides
2. dipeptides
3. free amino acids
6. intestinal enzymes in the lumen of the SO and within the mucosal cells complete the protein digestion.

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13
Q

Essential amino acids. (PVT TIM HaLL)

A

Phenylalanine—-Tyrosine
Valine
Threonine
Tryptophan
Isoleucine
Methionine—Cysteine
Histidine
Leucine
lysine

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14
Q

Protein functions and properties

A

Tissue synthesis:
a. formation and construction of body tissues
b. Building and repairing of cells and organs

Growth:
-supports and sustains physical development and growth

Regulation: Helps in controlling and coordinating various bodily functions

Inefficient energy source:
-protein is not an efficient source of energy compared to carbohydrates and fats.
-Before protein can be used as an energy source, nitrogen needs to be removed through metabolic processes.

requirements: Recommended daily protein intake is approximately .8 g per kilogram body weight.
- protein should make up around 10-15 % of the total energy intake in a diet.

Other facts:
-soybeans have low levels of methionine
-Legumes have low levels of cysteine, tryptophan and methionine
-Gelatin is deficient in methionine and lysine and does not contain tryptophan

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15
Q

Conditionally essential amino acids include:

A

Tyrosine
Cysteine
Arginine
Glutamine
Glycine
Proline
Serine

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16
Q

Types of proteins (simple, conjugated, derived)

A

Simple: amino acids exist in their individual form, not chemically bound.

Conjugated proteins:
composed of simple proteins combined with non-protein substances (lipoproteins)

Derived proteins: fragments derived from the breakdown or modification of simple and conjugated proteins. (peptides)

Simple: amino acids
conjugated: lipoproteins
derived: peptides

17
Q

Alcohol

A

automatically absorbed through the stomach or small intestine lining without digestion
-transported into the blood stream
-food can interfere with absorption
-Calories from alcohol = .8 x ounces x proof
-proof = % alcohol x2

18
Q

Fats (lipids/triglyceride digestion)

A

Mouth: Triglycerides digest by LINGUAL LIPASE produced in salivary glands.
into triglycerides, diglycerides, and fatty acids

Stomach: additional digestion from GASTRIC LIPASE produced in stomach

Small Intestine :
Phase 1 : emulsification from BILE
Phase 2: Enzymatic digestion (pancreatic lipase produced in the pancreas)

End product: monoglycerides and fatty acids.

19
Q

Absorption and circulation of lipids in the small intestine

A

It is easier to absorb hydrophylic lipids ( short and medium chain fatty acids)

Hydrophobic lipids (long chain fatty acids and monoglycerides) Harder to absorb.

  1. Short and medium chain fatty acids absorbed esily and circulated in the blood bound to ALBUMIN.
  2. Long chain fatty acids (lysophospholipids, cholesterol, monoglycerides ) are packaged into micelles and then taken up by the enterocyte.
  3. Triglycerides, phospholipids and cholesteryl esters are reformed.
  4. Cholesteryl esters, triglycerides, and phospholipids are then packaged into chylomicrons and circulated in the LYMPH.
20
Q

Types of fatty acids

A
  1. Saturated fatty acids:
    a. all carbon atoms in the chain are bonded to hydrogen atoms.
    b. solid at room temperature
    c. in order of most saturated to least saturated:
  2. coconut oil (most saturated)
  3. palm kernel
  4. cocoa butter
  5. butter
  6. palm oil
  7. canola (least saturated)
  8. Unsaturated fatty acids:
    Contains one or more double bonds in their carbon chain.
    a. monounsaturated fatty acids:
    1. olive (most monounsaturated)
    2. canola
    3. peanut
    4. sunflower
    5. coconut ( least monounsaturated)
      b. polyunsaturated fatty acids (2 or more)
    6. safflower (most polyunsaturated)
    7. corn
    8. soybeans
    9. cottonseed
  9. palm kernel
21
Q

Essential fatty acids:
Linoleic acid (omega 6)
(not made in body)

A

Linoleic acid (omega 6): C18:2w6
18 carbon, 2 double bond, first double bond located on the 6th carbon.
- deficiency can cause: eczema, poor growth rate and red or purple skin spots (petichae)
- If linoleic acid replaces carbs in the diet it can result in decrease of LDL cholesterol and increase in HDL cholesterol.
-SAFFLOWER OIL (BEST SOURCE)

22
Q

Essential Fatty acids (Linolenic acid) (omega 3)

A

C18:3w3
A. deficiency: neurological changes such as numbness and blurred vision.
B. Found in fish oils (EPA and DHA) , walnuts, flaxseed, and canola oil.
-Decreases the production of triglycerides in the liver (inhibits VLDL synthesis) but it has little effect on total cholesterol levels.

23
Q

Other FATS
1. medium chain Triglycerides
2. phospholipids

A

Medium chain Tryglycerides (MCTs)
a. bw 6 & 12 carbons,
b. found in milk fat, coconut oil and palm kernel oil.

Phospholipids
a. found in cell membranes and control the movement of compounds in and out of cells.
B. Lecithin contains choline

24
Q

Energy : calories per carb, protein, fat

A

Carbohydrates: 4 calories/gram
Protein: 4 calories/gram
Alcohol: 7 calories/gram
fat: 9 calories/gram

Brain primarily uses glucose for energy
During starvation ketone bodies are used.

Anabolism: Builds complex molecules from simpler ones, requires energy input.

Catabolism: Breaks down complex molecules into simpler ones, releases energy

25
Q

Hydrogenation

A
  1. Chemical process that involves adding hydrogen atoms at the double bond of unsaturated fats or oils, creating solid or semi solid fats, increases shelf life and stability of fats.
  2. Trans fats are formed during partial hydrogenation, hydrogens are packed tightly across from each other in membranes. Harmful to cells and overall health.
  3. found in shortening, margarines, fried foods, fast foods.
  4. Many food manufactures have eliminated the use of trans fats due to health concerns.
26
Q

Basal Metabolic Rate (BMR)

A

The most minimum amount of energy expended by an individual at rest., when awake, several hours after exercise, in a post absorptive state (12-18 hours after the last meal) in a thermal neutral environment.

It represents the energy required for essential bodily functions

Affected by gender and age: Males have a higher BMR than Women whereas children aged 0-2 years old have the highest BMR.

Uses the Harris Benedict formula

27
Q

Resting MEtabolic Rate (RMR)

A

similar to BMR but measured using slightly less strict criteria compared to BMR.
Higher than BMR and is used more often.

Uses the Mifflin-St Jeor formula

28
Q

Thermic effects of food (TEF)

A

The energy expenditure associated with the digestion, absorption and metabolism of food.

29
Q

Respiratory Quotient

A

Relationship between the amount of Carbon Dioxide (CO2) produced and the amount of oxygen (O2) consumed during cellular metabolism: Serves as the measure of the type of fuel (carbohydrates, fats, or proteins)

RQ of .7: fat is the source
RQ 0.82 : protein is the primary fuel
RQ of 0.85 : Indicates a mixed fuel source
RQ of 1.0: carbohydrates

CNS Exam 2024 (41 decks)

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