Experimental Plant Science Test 3

Define Transpiration

Movement of water and mineral nutrients from soil to atmosphere in plants

Define Evapotranspiration

Landscape-level movement of water from soil to atmosphere

What is controlling transpiration

Turgid guard cells

Why are stomates open during the day?

It is open for photosynthesis and closed at night to conserve water.

Xerophytes photosynthesis type

CAM photosynthesis

How does H2O move through guard cells

When potassium enters, water enters, opening the cell; when potassium is released, the cell closes with less water.

Leaf adaptations in arid environments

Thick cuticle, long dermis, hairs, and sunken stomates for water conservation.

Composition of cortical cells

Cellulose; function is to absorb water.

Transpiration-cohesion theory

Water has cohesive and adhesive properties due to its polarity.

Water’s free energy components

Solute and pressure potential.

Sign of solute potential

0 or negative.

Effect of increased solute concentration

Decreases solute potential, making it more negative.

Sign of pressure potential

Positive; known as turgor pressure.

Major essential nutrients

Nitrogen, phosphorus, potassium, magnesium, sulfur.

Function of nitrogen in plants

Forms proteins, nucleic acids, and chlorophyll.

Function of phosphorus (P) in plants

Forms nucleotides, nucleic acids, and phospholipids.

Function of potassium (K) in plants

Regulating guard cells.

Function of magnesium (Mg) in plants

Component of chlorophyll.

Function of sulfur (S) in plants

Forms certain amino acids.

Function of calcium (Ca) in plants

Component of plant cell walls.

Importance of hydroponic tomatoes

Better pest control and less heavy and expensive.

Phytoremediation use

Using plants to clean up contamination from soils, sediments, and water.

Location of sugar translocation

In living phloem sieve tube members.

Is ATP required for sugar translocation?

Yes.

Function of sugar translocation

Moves sucrose and other organic compounds from source (where photosynthesis occurs) to sink (where no photosynthesis occurs).

Pressure flow hypothesis

Explains the translocation of sugars from source to sink.

Water vs. sugar transport in plants

Water/mineral transport relies on solute/pressure potential without ATP, transported via xylem; sugar transport requires ATP and is transported via phloem.

Plants providing commercial sucrose

Sugar cane and sugar beet.

Light range used by plants

400-700 nm.

Primary pigments in plants

Chlorophyll a P680/P700.

Accessory pigments

Rest of chl a, chl b, carotenoids (carotenes, xanthophylls).

Location of pigment and protein complexes formation

Thylakoid membrane.

Hydrophobic and hydrophilic portions of chlorophyll

Tail is hydrophobic, body is hydrophilic.

Carotenoids' solubility

Mainly hydrophobic.

Reason for chlorophyll breakdown in fall

Lower nitrogen levels lead to breakdown, while carotenoids survive.

Limiting growth nutrient in plants

Nitrogen.

Carotenoids during fall

Do not break down as CO2 is easily accessible.

Two phases of photosynthesis and their locations

Light reactions (thylakoid membrane), Calvin Cycle (stroma).

Process during carboxylase phase

CO2 enters the plant.

Process during oxygenase phase

O2 fits into the active site.

Enzyme for carbon fixation in C3 cycle

Rubisco.

Process and efficiency of photorespiration

Rubisco combines O2 with RuBP; it's inefficient as O2 takes the spot of carbon.

Location of Rubisco 4mM

In the stroma.

Uniqueness of Rubisco 4mM

Abundant enzyme while being slower than substrates, needs abundance for carbon fixation.

Most abundant protein on earth

Carbon, makes up 25% of the leaf.

Rubisco's CO2 fixation rate compared to O2

80 times faster.

CO2 to oxygenation ratio

3:1.

Environments using the C4 Cycle

Tropical and warm season grasses.

Reason for C4 over C3 cycle

Warmer climates.

C4 cycle process

Increases CO2 in bundle sheath cells, rescues photorespiration and reduces water loss at ATP cost.

CAM cycle environment

Arid environments.

Stomate opening time in CAM plants

At night.

Initial carboxylating enzyme of CAM cycle

PEP carboxylase.

Categories of macromolecules in organisms

Carbohydrates, nucleic acids, proteins, lipids.

Why only three macronutrients in human nutrition?

Nucleic acids are low in food amounts compared to others.

Kilocalories in carbohydrates and proteins

4 kilocalories per gram.

Kilocalories in fat per gram

9 kilocalories.

Common monosaccharides

Glucose and fructose.

Common disaccharide

Sucrose.

Common polysaccharide

Starch.

Cellulose as fiber

No energy input from plants but provides nutrient benefits.

Insoluble fibers

Cellulose and lignin.

Soluble fibers

Pectin and mucilage.

Gut bacteria's role

Fermenting soluble fiber to butyric acid, regulating glucose, reducing cholesterol, and colon polyp occurrence.

Essential amino acids definition

Amino acids that can't be produced by the body, obtained from food.

Why plant proteins aren't complete?

They lack all essential amino acids in a single plant.

Complete proteins

Meat, dairy, and mushrooms.

Vegan complete proteins source

Diverse plant consumption.

Disease triggered by gluten

Celiac disease leading to intestinal lining degradation.

Lipids solubility in water

Insoluble.

Lipid structure components

One glycerol and three fatty acids.

Differences in lipid types

Saturated has no double bonds, monounsaturated has one, polyunsaturated has two or more; plants typically have polyunsaturated oils.

Cholesterol definition

Steroids from animal sources or synthesized in the liver.

Function of HDL

Carries cholesterol from arteries; considered good cholesterol.

Function of LDL

Deposits cholesterol in arteries; considered bad cholesterol.

Trans fats definition and risk

Artificially produced by hydrogenation, increases CVD and T2DM risk.

Reason for trans fat production

Cheaper, easier to obtain, and improves food texture.

Micronutrients definition

Organic vitamins and inorganic minerals.

Vitamins role

Many act as coenzymes.

Fat-soluble vitamins

A, D, E, K.

Water-soluble vitamins

B-complex and C.

Effects of vitamin solubility

Fat-soluble vitamins can become toxic; water-soluble vitamins are easily excreted.

Consequences of vitamin D deficiency

High blood pressure, asthma, depression, muscle aches, osteoporosis.

More likely deficiency for vegans

Niacin and B12.

Mineral deficiency leading to osteoporosis

Calcium.

Importance of micronutrients despite quantity

They are still important despite being required in smaller amounts.

Overconsumption of processed carbohydrates effect

High blood pressure and cardiovascular disease.

Recommended fats to consume

Omega-3 fish oil.

U.S. diet concerns

Salt consumption, wrong fats, lack of phytochemicals, high glycemic index foods.

Michael Pollan’s 7 rules for eating

Don't eat unrecognizable food, avoid complex ingredients, shop perimeter, avoid non-perishable foods, leave a little hungry, eat with family, don't buy where you buy gas.

Homo sapiens evolution date

200,000 BP in eastern Africa.

Transition to permanent settlement and agriculture

End of the Paleolithic (10,000 BP).

Homo sapiens agriculture time span

5% of their existence.

Paleolithic diet description

Emphasizes foods from the paleolithic era.

Paleo diet hypothesis

Humans evolved to eat non-domesticated meats, fruits, and seeds.

Problems with grain-focused diets

Lack of proteins and nutrients from other food sources.

Importance of pollen, fiber, seeds, and phytoliths in archaeology

Indicates types of plants consumed historically.

Kung modern foragers location and duration

Near Kalahari Desert in southern Africa for 10,000 years.

Plant and animal species utilized by early foragers

100 plant and 50 animal species.

Foraging success as a survival strategy

Diverse diet provided necessary nutrients.