A&P2 Exam2 Ch18

A set of flashcards covering key concepts related to nutrition and metabolism, defined and formatted for effective study.

Nutrients

Chemical substances supplied from the environment that an organism requires for survival.

Macronutrients

Nutrients needed in bulk, which include carbohydrates, fats, and proteins.

Micronutrients

Essential nutrients needed in small daily doses, which include vitamins and minerals.

Metabolism

The processes by which nutrients are altered chemically and used in anabolism and catabolism to support the activities of life

Essential nutrients

Nutrients that human cells cannot synthesize and must be obtained from diet.

Polysaccharides

Complex carbohydrates, such as starch from plant foods and glycogen from meats.

Disaccharides (double sugar)

simple carbohydrates such as milk sugar, cane sugar, beet sugar, and molasses.

Monosaccharides (single sugars)

simple carbohydrates, typically found in honey and fruits.

digestion breaks carbohydrates into monosaccharides that are small enough to be absorbed

What does digestion break carbohydrates down into?

cellulose

complex carbohydrate abundant in our food; not digested, but provides fiber

fructose (fruit sugar), galactose (milk sugar), and glucose

What are the 3 types of carbohydrates absorbed from the digestive tract?

liver enzymes

What converts fructose & galactose to glucose?

Glycogenesis

The process of converting excess glucose into glycogen for storage in the liver and muscles.

Glycogenolysis

The rapid conversion of glycogen back into glucose when energy is needed.

Lipogenesis

The process by which excess glycogen that cannot be stored is converted into fat.

glucose

What do neurons require for survival?

Gluconeogenesis

The formation of glucose from non-carbohydrates, like amino acids or glycerol when there is not enough glucose for neurons

used as starting material for vital biochemicals like DNA & RNA

Besides energy, what else is carbohydrates used for?

likely around 125 to 175 grams/day

The minimal dietary intake of carbohydrates is…

200-300g/day

How many g of carbohydrates does the average american intake a day?

Triglycerides

The most common dietary lipids, which are organic molecules including fats and oils.

Saturated fats

Fats found in foods of animal origin (lots of hydrogens, no double bonds)

Unsaturated fats

Fats found in seeds, nuts, and plant oils. (has double bonds)

Cholesterol

A type of lipid used to make bile salts; is found in liver and egg yolk; smaller amnts found in whole milk, butter, cheese, & meats; no plant origin

phospholipids, cholesterol, fats/triglycerides (most common)

What are the 3 types of lipids found in food?

1. supply energy

2. contains 2x as much energy than carbs/proteins

3. triglycerides broken down to glycerol & fatty acids to release energy

4. glycerol & fatty acids used to synthesize storage fats in adipose tissue

5. excess glucose/amino acids can be converted into fat

What are the 5 functions of lipids?

Beta oxidation

The process by which fatty acids are broken down in the mitochondria to generate Acetyl CoA.

Acetyl CoA

Molecule that enters the citric acid cycle for energy production.

ketone bodies

excess acetyl CoA is converted to ___, which can later be changed back into acetyl CoA

Lipoproteins

Large complexes of lipids and proteins that transport lipids in the bloodstream; vary in propoertions of the lipids they contain

1. triglycerides

2. lipoproteins (transport fatty acids)

3. fatty acids (- essential fatty acids)

4. cholesterol

5. phospholipids

What are the 5 products of fatty acid usage by the liver?

Very-low-density lipoproteins (VLDLs)

Lipoproteins with high concentration of lipids, low concentration of proteins

Low-density lipoproteins (LDLs)

Lipoproteins with high concentration of cholesterol, often referred to as 'bad' cholesterol.

High-density lipoproteins (HDLs)

Lipoproteins with high concentration of protein, low concentration of lipids; often referred to as 'good' cholesterol.

Cholesterol

used to make bile salts; provides structural material for cell and organelle membranes

1. shouldn’t exceed 30% of daily calories from fat

2. dietary fats must supply required amount of fat-soluble vitamins

What are the 2 main lipid requirements?

proteins

Nutrient that consists of chains of amino acids; has many functions; excess amino acids may be converted into glucose or fat

Deamination

process in which -NH2 groups from amino acids are converted into urea

meats, fish, poultry, cheese, nuts, milk, eggs, cereal, beans (less protein)

What are 9 protein food sources?

Essential amino acids

Amino acids that must be obtained from the diet for good health; 8 for adults, 10 for children

Complete proteins

Proteins that contain adequate amounts of all essential amino acids (milk, meat, eggs)

Incomplete proteins

Proteins that do not contain adequate amounts of essential amino acids

Nitrogen Balance

The state in which the amount of protein synthesized equals the amount of protein broken down.

negative nitrogen balance

develops from starvation (excretion exceeds dietary intake)

positive nitrogen balance

develops in growing children, pregnant women, or an athlete in training (protein being build into new tissue exceeds energy usage and excretion)

10% of a person’s body weight; 0.4g/lb of bodyweight

What is the recommended daily protein intake?

carbohydrates, fats, proteins

What 3 nutrients supply energy for all metabolic processes?

Calorie

amount of potential energy that food contains

Basal metabolic rate (BMR)

The amount of energy expended while at rest, necessary to maintain basic bodily functions; reflected energy needed to support activities of organs

1. to maintain BMR

2. support muscular activity

3. maintain body temp

4. growth in children & pregnant women

What are the 4 main reasons that energy is needed in the body?

women: 1400-1600

men: 1600-1800

What is the average calorie intake to maintain BMR per day for men and women?

Energy Balance

Exists when caloric intake equals caloric output, maintaining body weight.

positive energy balance

caloric intake exceeds output; tissues store excess nutrients; leads to weight gain

negative energy balance

caloric expenditure exceeds intake; tissues are broken down for energy; leads to weight loss

Body Mass Index (BMI)

A measure that assesses weight in relation to height.

overweight

according to BMI, is defined as exceeding desirable weight by 10% - 20%, or with a BMI of 25 and 30

Obesity

Defined as exceeding desirable weight by more than 20%, or with a BMI over 30.

Homeostasis

The body's ability to maintain stable internal conditions despite changes in the environment.