Food

food provides ____ and _____

energy and chemical building blocks

energy content of food can be measured by the

amount of heat the food produces when completely burned in the presence of o2, producing co2 and h2o

measures of heat energy (3)

calorie, kilocalorie, joule

calorie

amount of heat needed to raise 1 gram of water 1 degrees Celsius

kilocalorie

1000 calories, food lable calories

joule

0.239 calories

_____ is the amount of energy an animal converts to heat per day

metabolic rate

three types of food molcules

lipids (fats and oils), carbohydrates, proteins

lipids are ___ kcal/g

9.4

carbohydrates are ____ kcal/g

4.1

proteins are ____ kcal/g

4.5

most energy is stored as _____, they store the most energy per gram and with little ____

lipids, water

animals store _____, which is a ____, with water bound to the molecules. energy density is only about ___ kcal/g

glycogen, carbohydrate, 1

glycogen yields ____ when broken down, needed for the brain and _____

glucose, anaerobic glycolysis

the molecules in an animal’s body are made from

the molecules in the animal’s food

the molecules in an animal’s body are made from the molecules in the animal’s food:

for carrying out this process, animals have _____ to _____. for example, _____ can be converted to _____

enormous capacities to interconvert molecules, lipid molecules, carbohydrates

_____ control both anabolic and catabolic metabolism

hormones

the chemical reactions underlying metabolism involve the ______ by processes catalyzed by _____ through _____ reactions

transfer of electrons from one compound to another, enzymes, redox

ketogenesis:

excess _____ is diverted to create ____ that serve as a ______ if _____levels are too low in the body

acetyl coa, ketone bodies, fuel source, glucose

ketogenesis:

ketones serve as fuel in times of ______ or when patients suffer from _____ and cannot utilize most of the _____

prolonged starvation, uncontrolled diabetes, circulating glucose

ketogenesis:

fat stores are liberated to generate energy through the _____ and will generate ketone bodies when too much _____ accumulates

krebs cycle, acetyl coa

lipogenesis:

when glucose levels are plentiful, the excess _____ generated by glycolysis can be converted into (5)

fatty acids, triglycerides, cholesterol, steroids, bile salts

lipogenesis:

takes place in the

cytoplasm of adipocytes (fat cells) and hepatocytes (liver cells)

lipogenesis:

lipogenesis occurs in the _____, the necessary acetyl CoA is created in the _____ and (can/cannot) be transported across the mitochondrial membrane

cytoplasm, mitochondria, cannot

lipogenesis:

_____ and acetyl CoA combine to form _____, which can cross the mitochondrial membrane and enter the _____

oxaloacetate, citrate, cytoplasm

lipogenesis:

in the cytoplasm, citrate is converted back into

oxaloacetate and acetyl coa

lipogenesis:

in the cytoplasm, oxaloacetate is converted into _____ and then into _____

malate, pyruvate

lipogenesis:

_____ crosses back across the mitochondrial membrane to wait for the next cycle of lipogenesis

pyruvate

lipogenesis:

the _____ is converted into _____ that is used to synthesize fatty acids

acetyl coa, malonyl coa

______ are required but cannot be synthesized by the animal

essential nutrients

standard amino acids

20 amino acids to build protein

animals can synthesize ______ amino acids

nonessential

______ amino acids cannot be synthesized and must come from _____

essential, food

common food combination that provides all eight essential amino acids

corn in tortilla chips, legumes, mac and cheese

animals must also obtain ______ fatty acids

essential

humans require _____ and ____ and must get these or similar molecules in their diet via omega-3 and omega-6 fatty acids

linoleic acid, alpha-linoleic acid

_____ are also essential nutrients

vitamins

vitamin A is required for

vision and other functions

vitamins are all _____ compounds, needed in _____ amounts

carbon, small

vitamins are either ____ or ____ solule

water or lipid

some animals can synthesize some vitamins. most mammals can make ______, but not primates

vitamin C (ascorbic acid)

humans can synthesize _____ if the skin is exposed to sunlight

vitamin D

some essential minerals are required in large amounts, such as

calcium for bones, teeth, nerve, and muscle function

other essential minerals are needed in very small amounts, such as

iron for o2 binding in hemoglobin/myoglobin and part of enzymes in etc

nutrient deficiency leads to

malnutrition

chronic malnutrition leads to a

deficiency disease

two types of deficiency diseases

scurvy and beriberi

scurvy

lack of vitamin C

beriberi

lack of vitamin B1

the digestive system plays a key role in determining

the nutritional value of foods

most animals have _____ guts:

foods enter at the _____ while indigestible materials exit at the _____

tubular, mouth, anus

the digestive tract is lined with

epithelium

digestive system’s principle functions (2)

digestion and absorption

digestive system’s principle functions:

____ is the breakdown of large food molecules by ____ in ____ to produce smaller molecules

digestion, enzymes, gut lumen

digestive system’s principle functions:

absorption is the

transport of small molecules from gut lumen into the blood

_____ determine which foods have nutritional value.

for example, humans cannot digest ______. the molecules are too _____ to cross the gut epithelium, and we have no _____ to break it down

digestive abilities

cellulose, large, enzymes

digestive abilities determine which foods have nutritional value:

cellulose in plant materials stays in the _____ and passes out with the ____

gut lumen, feces

digestive enzymes are specific in the

types of chemical bonds they can break

an animal’s ability to digest foods is strictly determined by the

particular digestive enzymes the animal synthesizes

the ability to digest _____ varies among human populations

lactose (milk sugar)

human infants produce _____, but most populations lose this ability as adults

lactase

______ rapidly evolved lactase production in adults; it has evolved _____ several times. the gene responsible appeared only about ____ years ago.

cattle-raising tribes in africa, independently, 5000

_____ also make lactase as adults. the gene mutations arose after their ancestors ______, indicating that it arose independently

northern europeans, migrated out of africa

individual animals can _____ to adapt to available foods

modify digestive enzyme production

if a rat is switched from a low-protein to a high-protein diet, the digestive tract starts increasing production of _____ within ____ hours

protein digesting enzymes, 24