Module 3

Photoautotrophs

Use light as an energy source to produce organic compounds

Chemoautotrophs

Use environmental inorganic compounds as an energy source to produce organic compounds

Heterotrophs

Must obtain E and carbon by consuming other org or organic matter

Primary producers

Make biomass from environmental CO2

Photo/chemo

Anabolic processes

Build larger molecules from smaller ones

Requires E

Photosynthesis

Process by which sunlight’s energy is captured and used to make CO2 into complex org mol'

6H2O + 6CO2 —? C6H12O6 +6O2

In mesophyll

Chemosynthesis

Uses energy from chemical reactions to build sugars out of smaller mol

Light

E inversely proportional to wavelength

Mesophyll cells

Ground tissue that contains many chloroplasts where photosynthesis occurs

Chloroplasts

Double-mem organelles descended from cyanobacteria found in plants/algae

Stroma

Space inside inner chloroplast membrane

Site of photosynthetic biomass production

Thylakoid membrane

Key components for E production in photosynthesis

Form granum

Photopigments

Molecules that absorb wavelengths in the visible spectrum

Collect solar energy, reflect unabsorbed wavelengths

Chlorophyll a and b

Chlorophyll a

Primary photosynthetic pigment in plants, algae, cyanobacteria

Chlorophyll b

Accessory pigment that broadens light harvesting in plants, green algae, and a few cyanobacteria

Photosystems

Complexes of proteins and photopigments that harvest light E to generate high E electrons that are given up by chlorophyl

I and II

Light reactions

Produce ATP and NADPH in the stroma

PSII —> e —> ETC (PSI) —> H pump —> NADPH + ATP

Biomass

Comes from carbon in CO2

Prochlorococcus

Tiny cyanobacteria that produce oxygen in the ocean

Calvin cycle

CO2 converted into carbohydrates

1. Carbon fixation

2. Reduction

3. Regeneration

Carbon fixation

Carbon from atmosphere into carbohydrates

Via rubisco enzyme

Rubisco

Enzyme in the chloroplast stroma

Combines CO2 and RuBP to make 6 C sugar

Reduction

ATP and NADPH turn low E 3PGA into high energy G3P

2 G3P = 1 glucose

Regeneration

1 of 6 G3P mol forms glucose, the rest are turned into RuBP

C3 photosynthesis

Ancestral/most common form

Pathway driven by Rubisco, slow but plentiful

Cool, humid environments because of H2O loss

C2 Photosynthesis

Rubisco uses O2, less efficient

C4 Photosynthesis

Physically separates carbon fixation from Calvin Cycle

Mesophyll vs bundle sheath

Carbon used by Rubisco

Hot, sunny environments

CAM photosynthesis

Temporally separates carbon fixation from Calvin Cycle

Carbon fixation at night (C4)

Calvin cycle during the day

Arid conditions

Food

Source of energy, organic molecules, and minerals and vitamins needed for survival

Energy

Required for maintenance, activity, growth, reproduction

Feeding factors

Food size/location, mobility, habitat, body size

Predators

Capture and consume other organisms

Solitary/social

Herbivores

Consume plants/algae

Often doesn’t kill the org

Parasites

Obtain nutrients from a living host

Host is harmed

Capture feeding

Pursuing, grasping, trapping, or immobilizing food

Beaks, claws

Scavenging

Consume animals that are already dead

Grazers

Remove food from the surface of another organism/substrate

Feeding structures adapted to bite/scrape food

Radula

Ribbon-like structure covered with hundreds of microscopic chitinous teeth

Grazer

Suspension feeding

Taking food particles out of the water column

Eat plankton, microorg, org particles

Gill rakers

Specialized structures that capture food particles from water

Suspension feeding

Filter feeding

Suspension feeding where food particles are trapped by a filter

Active/passive

Active filter feeder

Create own water currents to strain food with mesh

Passive filter feeder

Allows water to flow in on its own to strain food particles

Tentacles

Capture individual food particles and small org suspended in water, transfers food to mouth

Suspension/deposit feeding

Deposit feeding

Obtaining food from organic material in/on sediments

Micro algae/bacteria/org matter

Metabolism

Chemical reactions that occur in a living org

Catabolic processes

Breaking down larger mol into smaller ones

Releases E

Cell respiration

Basal metabolic rate

Metabolism required for a minimal resting lifestyle with no spontaneous activity/digestion/stress

Measured rate of O2 absorbed

Larger = higher rate

Increases w increased temp

Mass specific metabolic rate

Decreases as size increases

Larger = smaller SA:V

Maximum metabolic rate

Maximal rate at which oxygen can be transported from the environment to tissue mitochondria

Induced by activity/stress

Increases but levels off w increased temp

Aerobic scope

Difference between org maximum and resting rates of O2 consumption

MMR - BMR

Determines excess energy available for movement/growth/reproduction

Glucose

Six carbon sugar that stores energy in chemical bonds

Mitochondria

Double mem organelles where most STP is produced during aerobic cell resp

Cellular respiration

Breaking down glucose to make ATP

Glycolysis, link reaction, citric acid cycle, etc

Glycolysis

Breaking of glucose in the cytosol into 2 pyruvate

Aerobic, anaerobic

Fermentation

Anaerobic, in cytosol

Doesn’t produce additional ATP, produces lactate

Aerobic respiration

O2 present, in MM

ATP produced (TCA cycle, ETC)

Mitochondrial matrix

Site of aerobic respiration

Cristae

Inner mitochondrial membrane folds that increase surface area for energy reactions to occur

Link reaction

Mitochondrial matrix

Pyruvate —> acetyl coA

Citric acid cycle

Makes CO2, 3 NADH, FADH2, ATP

ETC

NADH and FADH2 donate e which power H pump

O2 = final acceptor —> water

Protons power ATP synthase

Most ATP produced