Test 2 Objectives Flashcards
discuss the availability of fresh water on earth
less than 1% of water on earth is fresh water available for consumption
list the top three uses of water in the United States
- thermoelectric power
- irrigation
- public supply
explain the water cycle by describing the movement of water between major reservoirs
-starts in ocean
-heat energy from the sun, evaporates and enters atmosphere
-cooler temperates in air, condense into clouds
-clouds get bigger and moist enough to release water, precipitates into ice caps and glaciers
-ice caps melt, runoff back into ocean
discuss the benefits that floodplains provide for humans and ecosystems
store excess water, very fertile soils, reduce flood impact, filter stormwater, protect water quality
compare groundwater and surface water as sources of fresh water for humans, including the methods used to extract water from these sources
groundwater: most of available freshwater, stored in aquifer pores and extracted by drilling and pumping, high to low energy
surface water: already on surface, high to low elevation
describe how agriculture contributes to physical and chemical water pollution
fertilizers high in N and P
explain the process of eutrophication and describe the harm that occurs as a result
nitrogen and phosphorous act as fertilizers and promote algae bloom.
as algae dies, it is decomposed by aerobic bacteria in water. bacteria use up oxygen in water and low dissolved oxygen (DO) levels result in dead zones (areas where large numbers of aquatic life have died from suffocation)
explain how agricultural practices can be adjusted to reduce the amount of agricultural water pollution
changing fertilizer concentration or otherwise monitoring use
name the six basic tastes and explain why each is important for humans to detect
- sweet: sugar=quick energy
- salty: maintaining body fluid levels
- bitter: detecting toxic substances
- sour: vitamin c
- umami: protein and amino acids
- fat: energy storage and essential fatty acids
discuss how sensory information contributes to the formation of flavor images in our brains
smell and taste receptors send information to brain
name the two types of starch produced in plants and discuss the role they play in staling bread
amylose: smaller, linear
amylopectin: larger, branched
dough is wet, water absorbed into crystalline structure of starch, bread dries
name the four macronutrients that humans need to survive
- water
- carbs
- proteins
- fats
describe the digestive process that occurs in the small intestine
accepts stomach contents, macros broken down by digestive enzymes and absorbed
4-hour process
describe the digestive process that occurs in the large intestine
accepts small intestine contents, absorbs water and water-soluble salts, bacteria metabolize remaining nutrients and produce gas
week-long process
name the three earliest cooking methods used and discuss the advantage of cooking food
- dry roasting with fire
- earth ovens (pits lined with stones)
- boiling in water
cooking kills pathogens, enhances flavor and texture
discuss the advantages and disadvantages of the farming lifestyle compared to the hunter-gatherer lifestyle
hunter-gatherer: pros– consume less energy, work less; cons–more effort, unpredictable
farming: pros– all dietary needs met, consistent; cons–higher energy demands, physical labor
explain the hypothesis that past climate may have influenced the shift away from hunting and gathering and toward farming
because hunter-gatherers followed food, they had no central settlement and were at the mercy of the climate, in terms of protection as well as food source. with farming they could store food for when sources were low, and could have permanent settlements to protect them from the elements
describe the benefits and drawbacks of slash-and-burn agriculture in the neolithic era
Initially very fertile, but decline in fertility over time so they have to move and start over until the previous land is restored
list three factors that influenced the ease with which agriculture was adopted by various societies
- increased availability of farmland
- food security
- ability to settle
name the innovations that led to a widespread adoption of agriculture ~5,000 years ago
discovery of metals, and subsequent availability of plows and other tools
define landrace and explain how they arise and why they are valuable
landrace is variety of crop that is adapted to environmental conditions and agricultural practices of a specific geographic area
arise from selective breeding
help against pests, diseases, etc
explain the process that Nikolai Vavilov used to identify the origins of diversity of modern crops
collected germplasm of domesticated plants and their wild relatives from all over the world
explain how diversity in crops arises, why it is valuable to humans, and how seed banks protect crop biodiversity
develops via mutation or hybridization, promotes desirable traits, seed banks keep a supply of genetic material which can be used to breed
describe the difference between wild wheat and domesticated what and explain how these differences helped humans
wild has smaller seeds, slower growth, lower yields, less gluten, and seeds detach easily
domesticated has larger seeds, faster growth, higher yields, more gluten, and retains seeds (which make them easier to harvest)
describe the technological innovations that were required to make bread, and name their countries of origin
Egypt: yeast to leaven bread, flat-top ovens to bake
Greece: sifting to remove bran and make white flour, grindstones to make meal, domed ovens to bake
name the two major cookware innovations that facilitated frying of foods, and name their countries of origin
Greece: ceramic pots and pans made of finer clay and fired at higher temperatures (withstand heat better); olive oil
China: cast iron from raw iron ore; sesame oil
list two contributions of Jan Baptist van Helmont to cooking science
- coined term “gas” in reference to “gas of wines” from fermenting grapes (same as CO2 from burning charcoal)
- Suggested presence of digestive enzymes (“ferments”)
explain how Robert Boyle’s research into air and pressure led to invention of pressure cookers by Dennis Papin
Boyle’s Law–inverse proportionality of pressure and volume
Pressure cookers–when temperature rises so does pressure and foods cook faster; added safety valve to release pressure before explosion
describe the purpose of emulsifiers and explain how they work
purpose: stabilize emulsions
how: hydrophilic heads and lipophilic tails, create a barrier between hydrous molecules and fat molecules
explain how the law of conservation of matter is demonstrated by Lavoisier’s formula “must of grapes=alcohol+carbonic acids”
mass lost by fermenting grapes is equal to mass of alcohol and carbonic acids released in the process
(mass of grapes before=mass of fermented grapes+products after)
describe the food culture in 17th century Chine and how it differed from food culture in Europe
- best chefs cooked for elite (same as Europe)
- chefs also worked in tearooms, restaurants, etc (unique to China)
- food and cooking as an art (lacked scientific influence of Europe)
