Unit 2 Exam Individual nutrition

(Chapter 5) the lipid family includes:

triglycerides, phospholipids, and sterols; soluble in water and fats

(Chapter 5) triglycerides are made of

three fatty acids attached to glycerol in condensation reaction

(Chapter 5) saturated fatty acids

only single bonds between carbon atoms and fully loaded with hydrogens (most animal fats) (solid)

(Chapter 5) unsaturated fatty acids

with hydrogens missing and at least one double bond (most vegetable oils) (liquid)

(Chapter 5) What type of fat is solid at room temperature and liquid at room temperature?

saturated are solid at room temp, unsaturated are liquid at room temp.

(Chapter 5) characteristics of a phospholipid

soluble in both fat and water; hydrophilic (dissolves in water) heads and hydrophobic (dissolves in fats) tails; they help substances pass easily in and our of cells

(Chapter 5) digestion of lipids

starts in the mouth where hard fats begin to melt and moves to the stomach where strong muscle contractions grind the pieces to finer particles and moves to the small intestine where most lipid digestion occurs, and then moves to the large intestines where the fat and cholesterol trapped in fiber, exits in feces

best known phospholipid

lecithin

pancreatic lipases

major fat digesting enzyme; removes each of a triglyceride's two outer fatty acids one at a time, leaving a monoglyceride

CCK

signals the gallbladder to release bile

bile

is a digestive secretion that is made the liver, stored in the gallbladder and released into the small intestine when needed

mouth digestion of phospholipids

some hard fats begin to melt as they reach body temperature. The sublingual salivary gland in the base of the tongue secretes lingual lipase. The degree of hydrolysis by lingual lipase is slight for most fats but may be appreciable for milk fats

stomach digestion of phospholipids

the stomach's churning action mixes fat with water and acid. A gastric lipase accesses and hydrolyzes (a very small amount of) fat.

small intestine digestion of phospholipids

Cholecystokinin (CCK) signals the gallbladder to release bile (via the common bile duct): fat-----> Bile---> emulsified fat Pancreatic lipase flows in from the pancreas (via the pancreatic duct): emulsified fat (triglycerides)---> Pancreatic (and intestinal) lipase---> monoglycerides, glycerol, fatty acids (absorbed)

large intestine digestion of phospholipids

some fat and cholesterol, trapped in fiber, exit in feces

(chapter 5) the 4 types of lipid transport

chylomicrons, VLDL, LDL, HDL

chylomicrons

largest and least dense of the lipoproteins, transport diet-derived lipids from small intestine to the body

VLDL (very low-density lipoproteins)

lipids made in the liver and those collected from chylomicron remnants are packaged with proteins known as VLDL and shipped to other parts of the body

LDL (low-density lipoproteins)

circulate throughput the body, making their contents available to the cells of all tissues. Lipoproteins that derive from the VLDL and transport lipids in the blood, delivers cholesterol to tissues; high levels increase heart disease risk

HDL (high-density lipoproteins)

livers makes this to remove cholesterol from the cells and carry it back to the liver fro recycling or disposal, returns cholesterol to the liver fro excretion (reverse trasnpor); high levels reduce heart disease risk

which types of foods contain cholesterol?

meats, eggs, and dairy; only animal products contain cholesterol

recommendations to include date in your diet

Most nutrient dense foods, fewer or smaller portions, checking nutrient labels

what is the role of fat in the body?

- virtually unlimited ability to store fat energy; adipose tissue stores body fats; secretes hormones (adipokines) with help regulate energy balance and influence several body functions

what happens when deficient in a fatty acid?

impaired growth, reproductive failure, skin lesions, kidney and liver disorders, and subtle neurological and visual problems

What differentiates one amino acid from another?

they all have a central carbon atom, with a hydrogen atom, an amino group, an acid group, and a side group that make them each unique.

essential amino acids

human body either cannot make at all, or not in sufficient amounts; must be supplied by the diet

nonessential amino acids

an amino acid that the body can make

denaturation

that change in a protein's shape and consequent loss of its function brought about by heat, agitation, acids, bases, alcohol, heavy metals, or other agents (in the body proteins are denatured during digestion when they are exposed to stomach acid)

deamination

removal of nitrogen as part of the breakdown of an amino acid

what is nitrogen balance?

compares nitrogen intake (diet) with nitrogen excretion (urine, feces, sweat)

postive nitrogen balance

building or net positive of body proteins ex: infants, growing kids, pregnancy

negative equilibrium

net zero: protein intake = protein loss ex: average, healthy adults

negative nitrogen balance

net loss of body protein ex: starvation, critical condition (injury, illness, burns)

What is the RDA for protein in healthy adults?

0.8g/kg body weight/day for healthy adults

calculate this person's RDA ex: 165lb "5'9" BMI= 24.3 kg/m2 (1kg= 2.2lb)

165lb/2.2= 75kg then 75kg X 0.8g/kg = 60g protein per day

structural proteins

proteins form integral parts of most body tissues and provide strength and shape to skin, tendons, membranes, muscles, organs, and bones

enzyme proteins

proteins facilitate chemical reactions

hormone proteins

proteins regulate body processes (some hormones are proteins)

fluid balance proteins

protein help maintain the volume and composition of body fluids

acid-base proteins

proteins help maintain the acid-base balance of body fluids by acting as buffers

transportation proteins

proteins transport substances such as lipids, vitamins, minerals, and oxygen around the body

antibody proteins

proteins inactivate forge in invaders, thus protecting the body against diseases

energy and glucose proteins

proteins provide some fuel, and glucose if needed, for the body's energy needs

blood clots

protein fibrin forms blood clots

scars

protein collagen forms scars

vision

protein opsin participates in vision

digestibility of animal proteins

90 to 99%

digestibility of plant proteins

70 to 90%

protein digestion in stomach

partial breakdown of proteins, hydrochloric acid uncoils protein's strands so that digestive enzymes can attack the individual peptide bonds, pepsin breaks down protein to smaller polypeptides

protein digestion in small intestines

pancreatic and intestinal proteases hydrolyze polypeptides, peptidase enzymes function on the intestinal cell surfaces, polypeptides are broken down to tripe-tides, dipeptides, and single AA

what are some health effects of excess protein intake?

protein deficiency, heart disease, cancer, adult bone loss (osteoporosis), body weight, kidney disease

catabolic reaction

reactions in which large molecules are broken down to smaller ones, release of energy, ex: breakdown of glycogen to glucose , triglycerides to glycerol and fatty acids, and proteins to amino acids

anabolic reaction

reactions in which small molecules are put together to build larger ones, require energy, ex: making of glycogen from two glucose, triglycerides from glycerol and fatty acids, and protein from two amino acids

What are the four steps of converting a macronutrient into energy?

glycolysis, intermediate step, TCA cycle (citric acid cycle), and electron transport chain

protein breaks down to?

amino acids (glycogen- pyruvate, acetyl-CoA, TCA cycle, make glucose)

carbohydrates breaks down to?

glucose (glucose goes to pyruvate, acetyl-CoA)

fats break down to?

glycerol to pyruvate and fatty acids to acetyl CoA but cannot make glucose

reversible reaction

Changing glucose to pyruvate

irreversible break down

pyruvate to acetyl-CoA

What must happen to protein before it can enter energy metabolism?

deamination must occur when nitrogen-containing amino group is removed

how can protein provide energy?

amino acids convert to pyruvate to make glucose and acetyl-CoA to provide energy or be stored as fat

How can fat provide energy and what can it not make for energy?

convert the small glycerol portion of a triglyceride to either pyruvate (and then glucose) or acetylene-CoA, fatty acids of a triglyceride cannot make glucose

glycolysis

anabolic process in which glucose is broken down to pyruvate, hydrogen atoms with their electron are released and carried to the electron transport chain by coenzymes

ATP

most of the energy released during the breakdown of glucose, glycerol, fatty acids, and amino acids is captured in the high-energy compound adenosine triphosphate

What cells in the body are most metabolically active?

liver cells

protein synthesis

making proteins (DNA -> RNA -> protein)

cori cycle

the pathway of converting lactate from the muscles to glucose in the liver so that it can be returned to the muscles

lactic acid

product is made from pyruvate when oxygen is limited

the energy sources used for a short-term fast

the body draws on its glycogen and fat stores for energy

the energy sources used for a long-term fast

as glycogen stores dwindle, the body begins to break down its protein (muscle and lean tissue) to amino acids to synthesize glucose needed for brain and nervous system energy. The liver converts fats to ketone bodies, which serve as an alternative energy source for the brain, thus slowing the breakdown of body protein

hunger

physiological response to the need fro food triggered by nerve signals and chemical messengers originating and acting in the brain (primarily in the hypothalamus)

satiation

during the course of a meal, as food enter the GI tract and hunger diminishes, CCK becomes active, and the person begins to feel full- tells to "stop acting"

satiety

reminds us to "not start eating again", suppresses hunger and allows a person to not eat again for a while

What food provides the most satiety and satiation?

protein foods

Energy expenditure is measured through what 3 categories? Put them in order from greatest to least

basal metabolism, physical activity, and thermic effect of food

basal metabolism

the energy needed to maintain life when a body is at complete digestive, physical and emotional rest, about 2/3 of the energy the average person expends in a day

physical activity

voluntary movement of the skeletal muscles and their support systems, represents 25-50% of total energy expended

thermic effect of food

energy used and heat produced during digestion, absorption, and processing of nutrients after eating

calculating a man's BMR

(10 X wt) + (6.25 X ht) - (5 X age) + 5

calculating a woman's BMR

(10 X wt) + (6.25 X ht) - (5 X age) - 161

a person weigh 142 pounds, and spent 30 minutes in vigorous aerobic dance (0.062kcal/lb/min)

0.062 X 142+ 8.8 calories per minute and 8.8 X 30 minutes= 264 total calories expended

bicycling at 13 mph 0.045 calories per pound per minute. About how many calories will a 150-pound woman expend during a 60-minute ride?

0.045 X 150= 6.75 calories per minute

6.75 X 60= 405 total calories expended

calculating BMI

BMI= [weight (lb) / height (in.)^2] X 703

BMI= weight (kg) / height (m)^2

underweight BMI

< 18.5 kg/m

normal BMI

18.5-24.9 kg/m^2

overweight BMI

25.0-29.9 kg/m^2

obesity BMI

30.0 kg/m^2

body composition

the proportions of muscle, bone, fat, and other tissues that make up a person's total body weight

subcutaneous fat

fat stored directly under the skin generally not correlated with increased disease risk

visceral fat

central obesity, fat stored around the organs of the abdomen

recommended waist circumference for women

< 35"

recommended waist circumference for men

< 40"

metabolic syndrome

a combination of risk factors- elevated fasting blood glucose, hypertension, abnormal blood lipids, and abdominal obesity- that greatly increases a person's risk of developing heart disease

hormones associated with hunger and satiety

leptin and ghrelin

leptin

(associated with satiety hormone) suppresses appetite, enhances satiety, increases energy expenditure

ghrelin

(associated with hunger hormone) stimulates appetite, increases food intake, decreases energy expenditure

white fat cells

stores fat for other cells to use for energy, when oxidized (broken down for energy) a couple reaction: some energy provides heat some provides ATP

brown fat cells

released stored energy as heat only through uncoupled reactions, adults have little brown fat, and its activity decreases with age and obesity

brite fat cells

white fat cells converted to act like brown fat cells and help burn energy

Environmental contributors to overweight / obesity

industrialized food manufacturing, physical inactivity, social environment, economical environment