Botany II

Pericarp definition

Wall of the ovary that develops into the wall of the fruit

Fleshy pericarp examples

Guava, mango

Dry pericarp examples

Mustard, walnut

Epicarp definition

Outermost layer of pericarp; forms the peel

Mesocarp definition

Middle layer of pericarp; fleshy, edible portion of fruits

Endocarp definition

Innermost layer of pericarp; inner rough portion accommodating the seed

Seeds definition

Fertilized ovules found inside the pericarp

Seed coat function

Outermost seed layer; acts as protective barrier against drying out and damage

Endosperm composition & function

Nutritive tissue in seed; stores food reserves (starch, oil, protein) for embryo

Embryo composition & function

Developing plant in seed; contains epicotyl/hypocotyl giving rise to plumule and radicle

Simple fruits origin

Develop from a single ovary of a single flower

Simple fruits examples

Apple, mango, tomato

Dry fruit characteristic

Pericarp is dry at maturity

Dehiscent dry fruits definition & examples

Split open at maturity to release seeds (legumes, follicle, capsule); e.g., pea, bean, cotton, mustard

Indehiscent dry fruits definition & examples

Do not split open at maturity (achene, nut, samara); e.g., maize, rice, sunflower, wheat

Succulent (Fleshy) fruit characteristic

Pericarp becomes soft and juicy at maturity

Drupe definition & examples

One-seeded fruit with a hard inner layer (stone); e.g., mango, cherry, peach

Berry definition & examples

Fruit with entire pericarp fleshy and multiple seeds; e.g., tomato, guava, grape

Pepo definition & examples

Berry with a hard rind derived from an inferior ovary; e.g., pumpkin, cucumber, watermelon

Hesperidium definition & examples

Fruit with leathery rind and juicy segments inside; e.g., orange, lemon, lime

Pome definition & examples

Fruit developing from ovary and floral parts like receptacle; e.g., apple, pear

Aggregate fruits definition & examples

Develop from multiple ovaries of a single flower; e.g., raspberry, blackberry, strawberry

Multiple fruits definition

Formed from an entire inflorescence where flowers fuse into a single mass

Sorosis definition & examples

Multiple fruit formed from fused inflorescence flowers; e.g., pineapple, jackfruit, mulberry

Syconus definition & examples

Multiple fruit developing from hypanthodium inflorescence with enclosed flowers; e.g., fig

Accessory fruit (False fruit) definition

Fruit where the fleshy part is derived from tissue other than the ovary

Plant physiology definition

Study of plant function including photosynthesis, respiration, transpiration, nutrient uptake, and environmental responses

Photosynthesis definition

Anabolic process using chlorophyll and light energy to produce glucose sugar

Photosynthesis net equation

6CO2 + 6H2O + Sunlight -> C6H12O6 + 6O2

Photosynthesis major processes

Light Reaction and Dark Reaction

Absorbed light rays in photosynthesis

ROYBIV (absorbed by green pigment chlorophyll)

Light wavelength vs energy relation

Shorter wavelength means greater energy content

Pigments definition

Colored substances that absorb or reflect light

Fluorescence definition

Immediate emission or reflection of absorbed energy as light energy

Light reaction location

Thylakoid membranes (of chloroplasts)

Light reaction reactants

Light energy, H2O, ADP, NADP+

Light reaction products

O2, ATP, NADPH

Light reaction purpose

Convert light energy into chemical energy

Light reaction enzymes

Photosystems I & II, ATP synthase

Dark reaction other names

Calvin Cycle or Light-Independent Reaction

Dark reaction location

Stroma (of chloroplasts)

Dark reaction reactants

CO2, ATP, NADPH

Dark reaction products

Glucose (or G3P), ADP, NADP+

Dark reaction purpose

Fix carbon to form sugars

Dark reaction enzymes

RuBisCO (+ PEPC for some plants)

Photosystem definition

Multiprotein complex in thylakoid membrane that converts light energy to chemical energy

Photosystem II (PSII) electron source

Splitting of water (photolysis), which releases oxygen as waste

Photosystem I (PSI) electron source

Chloroplast electron transport chain

PSII mechanism

Captures light, performs water photolysis (H2O -> O2), excites electrons, transfers via ETC (Pq to cytochrome b6f to plastocyanin)

Cytochrome b6f function

Pumps protons from stroma into thylakoid lumen using energy from ETC electrons

PSI mechanism

Excites electron and passes it to NADP+ reductase to form NADPH

ATP Synthase mechanism in photosynthesis

Synthesizes ATP via phosphorylation powered by proton concentration gradient (chemiosmosis)

Dark reaction process summary

Uses NADPH and ATP to convert CO2 into glucose via carbon fixation with RuBP

Carbon fixation discoverer

Melvin Calvin

RuBP full name

Ribulose bisphosphate (prefabricated 5-carbon sugar phosphate)

C3 Cycle step 1

CO2 combines with RuBP and breaks down into two molecules of Phosphoglyceric Acid (PGA)

C3 Cycle step 2

PGA is converted into Biphosphoglyceric acid (BPGA) using ATP

C3 Cycle step 3

BPGA is converted into PGAL (phosphoglyceraldehyde) using NADPH

PGAL to glucose ratio

2 molecules of PGAL = 1 glucose molecule

Carbon fixation requirement for 1 glucose

Must occur 6 times (produces 12 PGAL: 2 for glucose, 10 to replace 6 RuBP)

C3 photosynthesis first stable product

3-phosphoglycerate (3-PGA), a 3-carbon compound

C4 photosynthesis first stable product

Oxaloacetate (OAA), a 4-carbon compound

CAM photosynthesis first stable product

Organic acids (e.g., malic acid), a 4-carbon compound

C3 primary enzyme for CO2 fixation

RuBisCO

C4 primary enzyme for CO2 fixation

PEP carboxylase initially, then RuBisCO

CAM primary enzyme for CO2 fixation

PEP carboxylase at night, then RuBisCO during day

C3 site of carbon fixation

Mesophyll cells

C4 site of carbon fixation

CO2 fixed initially in mesophyll cells; Calvin cycle in bundle-sheath cells

CAM site of carbon fixation

CO2 fixed at night in mesophyll cells; Calvin cycle during day in same cells

C3 time of CO2 fixation

Day

C4 time of CO2 fixation

Day

CAM time of CO2 fixation

Night (CO2 fixation), Day (Calvin cycle)

C3 environment

Cool, wet, moderate

C4 environment

High light intensity, high temperatures, low CO2

CAM environment

Arid, dry, water-scarce

C3 water use efficiency

Low

C4 water use efficiency

High

CAM water use efficiency

Very high

C3 photorespiration level

High

C4 photorespiration level

Minimal

CAM photorespiration level

Minimal

C3 plant examples

Rice, wheat, soybeans

C4 plant examples

Sugarcane, maize, crabgrass

CAM plant examples

Cactus, pineapple, agave

C3 other name

Calvin-Benson Cycle

C4 other name

Hatch-Slack Pathway

CAM other name

Crassulacean Acid Metabolism

C3 stomatal behavior

Open during day

C4 stomatal behavior

Open during day

CAM stomatal behavior

Open at night, closed during day

C3 CO2 fixation reaction

CO2 + H2O + RuBP -> 2 x 3-PGA

C4 CO2 fixation reaction

CO2 + PEP -> OAA -> Malate -> Calvin Cycle

CAM CO2 fixation reaction

CO2 + PEP -> Organic acid (night); Organic acid -> CO2 -> Calvin Cycle (day)

Plant transpiration definition

Loss of water vapor from aerial parts of the plant, mainly through leaf stomata

Factors increasing transpiration rate

High temperature, low humidity, increased wind speed, higher light intensity