Wednesday, April 19, 2023Wednesday, April 19, 2023

Macro: provide the body with energy

Micro: provide the body with small amounts of chemicals needed in biochemical reactions

What is the difference between macronutrients & micronutrients?

Kilocalories

1 kcal = amount of energy needed to raise 1 kg of H2O by 1oC

Kilocalories are known as Calories to consumers. 1 kcal = 1 Calorie

So… The number of Calories in a food indicates how much energy the food provides.

Which units do we use to measure energy from macronutrients?

1. Carbohydrates: C,H,O in a 1:2:1 ratioa. Basic unit is the monosaccharide b. Sugars:

a. Simple carbs that are absorbed by the body quickly

c. Starches: a. Complex carbs that provide the body with

steadier, long lasting energy

d. Carb Energy a. Most carbs provide the body with 4kcal per gram

3 major groups of macronutrients.

Simple Sugars

s

Complex Starches

d

Basic unit = amino acids 4kcal per gram

Proteins

20 different amino acids arrange in numerous

ways to make proteins. Protein structure and function depend on this

arrangement.

Amino Acids

d

The human body can make many of the amino

acids.

The remaining amino acids are obtained from food. essential amino acids = amino acids that must

be obtained from food.

Where do we get our Amino Acids

Basic unit is the Lipid

fatty acids attached to glycerol 9kcal per gram

Fats

Phospholipid Bilayer of Your Cells

Lipid Functions

Energy Storage

Lipid Functions

Vitamins & Minerals

Do not provide energy directly Play key roles in biochemical reactions

responsible for: releasing energy structural formation

Micronutrients

Adult nutritional requirements

2000-2800 kcal per day 500 million people worldwide are nutritionally

deficient 13 million people die of starvation each year

Undernourishment

World Hunger

Lack of a specific type of nutrient Examples:

Kwashiorkor (lack protein) Scurvy (lack Vit. C) Beri beri (lack Vit. B1) Rickets (Lack Vit. D) Goiter (Lack iodine)

Malnutrition

Food supplies worldwide are increasing.

More food available per person Why are so many people starving.

Food increases are in countries that already produced enough food

Long drought, civil war, political stability make it difficult for the neediest countries to improve food production.

World Food Supply

1. Green Revolution: 1960’s

• Developments of new strains of wheat & rice• More response to fertilizers and irrigation• Resistant to disease, grow faster, survive in

variety of climates• Modern farming methods and machinery

increased efficiency• Greater crop yields

• Increase gains, decreases price

Food Production and Economics

Intended to help underfed nations feed themselves

However, farmers in developing nations: do not adequate water supply to maintain the new

crops Do not have money to buy fertilizers Do not own modern machinery

Side effect of Green Revolution: Huge crop yields in developed nations drive down

prices, resulting in poorer farmers receiving lower profit for their crops.

Green Revolution (cont)

crops grown for purpose of selling Poor farmers in developing nations can’t sell

crops to other poor people in their own country

These farmers choose crops that can be exported

Cash Crops

d

d

Oceans can provide approximately 100 million

metric tons of food per year without damaging marine biomes.

Currently, over 90 million metric tons per year are harvested

Food from the Water

Aquaculture: commercially grown food in

controlled water environment Reduces the overfishing of oceans Produces over 21 million metric tons of food

Fish, clams, oysters

Aquaculture

d

Aquaculture

Historically, Preparing soil, planting seeds, and maintaining crops were done by hand

Industrialized Agriculture (mid-20th Century) Equipment powered by fossil fuels replaced

human-powered tools

Modern Farming Techniques.

Able to feed 5 people in 1850 per farmer; now

able to feed 78 people after industrialized agriculture

Industrialized agriculture’s positive impact on food production

Requires a large amount of energy, pesticides,

and fertilizers

Industrial agriculture’s negative

impact on environment?

Pesticides kill most pests, but a small portion of

the pest population is genetically resistant and will survive.

These resistant pests are able to reproduce, passing on the gene that is resistant to pesticides.

Result: more resistant individuals within the population.

Pesticide Resistance

Homozygous Dominant: TT Heterozygous: Tt Homozygous Recessive: tt

Revisiting Mendelian Genetics

Grow 1 or 2 crops that get highest prices Problems:

No genetic diversity Vulnerable to disease

soil becomes depleted of nutrients

What is monoculture farming? Does this have a positive or negative impact on environment?

Driven by economics and international trade Negative Results

Soil erosion Deforestation Hunger War Desertification

Modern Agriculture

1. Crop Rotation: changing your crops on a

regular cyclea. Prevents soil from becoming depleted of

nutrientsb. Prevents the need for nitrogen-based fertilizers

3 main components of Sustainable Agriculture

s

Nitrogen Fixing Legumes

Wind and Flowing Water are main agents of

erosion

When topsoil is eroded, organic and mineral nutrients are lost.

This is bad news for farmers.

2. Erosion

Cover Crops

Non food crops planted between growing seasons.

Drip irrigation Delivers small quantities of water directly to

roots of plants No drain off

Reduce tillage Process of turning the soil so that lower layers

are brought to the surface. Excessive tillage causes erosion.

Reducing Erosion

d

Drip Irrigation vs

Flood Irrigation

IPM: integrated pest management

Alternative to pesticides Use natural predators to control pest

populations Bats, lady bugs, wasps, viruses, bacteria

3. Pest Management

d