Plant and Animal Feeding Strategies & Transport in Biology

Autotroph

Organism that produces its own organic molecules from inorganic sources (ex: plants, chemoautotrophs).

Heterotroph

Organism that obtains energy by consuming organic molecules.

Suspension Feeder (Filter Feeder)

Animal that filters small food particles from water (ex: clams, oysters, baleen whales).

Baleen

Comb-like filtering structure in some whales that traps krill and plankton.

Substrate Feeder

Animal that lives in or on its food source and eats as it burrows (ex: maggots, leaf miners).

Leaf Miner

Insect larva that feeds inside leaf tissue, leaving visible tunnels.

Deposit Feeder

Substrate feeder that ingests soil and extracts organic nutrients (ex: earthworms).

Fluid Feeder

Animal that feeds on nutrient-rich fluids instead of solid food.

Parasite (Fluid Feeder)

Organism that feeds on fluids from a host (ex: mosquitoes, ticks, vampire bats).

Pollinator (Fluid Feeder)

Animal that consumes nectar from flowers and aids in pollination (ex: bees, hummingbirds).

Bulk Feeder

Animal that eats large chunks of food using claws, teeth, or fangs.

Mycorrhizae

Mutualistic association between fungi and plant roots that increases water and mineral absorption.

Nitrogen Fixation

Conversion of atmospheric nitrogen (N₂) into ammonia by bacteria.

Rhizobium

Nitrogen-fixing bacteria found in legume root nodules.

Cell-to-Cell Transport

Movement of substances between adjacent plant cells.

Tissue-Level Transport

Movement within plant organs.

Long-Distance Transport

Transport through xylem and phloem.

Apoplastic Route

Transport through cell walls.

Symplastic Route

Transport through cytoplasm via plasmodesmata.

Transmembrane Route

Transport across cell membranes multiple times.

Transpiration

Loss of water vapor from plant leaves through stomata that drives upward water movement.

Guttation

Occurs when root pressure forces liquid water out of leaf margins, usually at night.

Cohesion-Tension Theory

Plants use NO energy for bulk water flow; Sun's energy drives transpiration.

Stomata

Small openings on plant leaves controlled by guard cells.

Guard Cells

Cells that control the opening and closing of stomata.

Potassium Pump

Mechanism that regulates potassium ions in guard cells.

Root Pressure

Pressure generated in roots that can push water upward.

Pressure-Flow Hypothesis

Model explaining the movement of sugars in phloem from source to sink.

CAM Pathway

Photosynthetic pathway where stomata open at night and CO₂ is stored as organic acids.

Cohesion

Attraction between water molecules via hydrogen bonds.

Tension

Pulling force created by evaporation at leaf surfaces.

Adhesion

Attraction between water and xylem walls.

Evaporative Cooling

Cooling of plants due to water evaporation during transpiration.

Potassium Pump (Guard Cells)

K⁺ enters guard cells causing water to follow by osmosis and the stoma to open.

Photosynthesis-Transpiration Compromise

Plants must open stomata for CO₂ but risk water loss.

Conditions of Highest Transpiration

Hot, dry, windy, and bright conditions.

Xerophyte

Plant adapted to dry environments.

Trichomes

Leaf hairs that trap moisture near stomata.

Stomatal Crypts

Depressions in leaves that protect stomata from dry wind.

Translocation

Movement of sugars through phloem from source to sink.

Phloem

Vascular tissue that transports sugars.

Sugar Source

Plant organ producing sugars (usually mature leaves).

Sugar Sink

Plant organ that consumes or stores sugars (roots, fruits, seeds).

Pressure-Flow Hypothesis

Sugars move by pressure differences between source and sink in phloem.

Transpiration vs. Guttation

Transpiration is vapor loss; guttation is liquid water loss.

Xylem vs. Phloem

Xylem moves water/minerals upward; phloem moves sugar in all directions.

CAM vs C₃ Plants

CAM plants separate gas exchange and photosynthesis by time to conserve water.

Mechanical Digestion

Physical breakdown of food without changing chemical structure.

Chemical Digestion

Enzymatic breakdown of macromolecules into absorbable units.

Mastication

Chewing in the mouth for mechanical digestion.

Peristalsis

Wave-like muscular contractions that move food through the digestive tract.

Churning

Muscular mixing of food in the stomach to form chyme.

Segmentation

Back-and-forth mixing contractions in the small intestine.

Bolus

Chewed mass of food ready to be swallowed.

Chyme

Semi-liquid mixture of partially digested food and gastric juices.

Salivary Amylase

Enzyme that begins starch (carbohydrate) digestion in the mouth.

Mucin

Slippery protein that lubricates food for swallowing.

Parotid Gland

Produces salivary amylase.

Sublingual Gland

Produces mucin for lubrication.

Submandibular Gland

Produces both amylase and mucin.

Epiglottis

Flap that closes the trachea during swallowing.

Esophageal Sphincter

Ring of muscle regulating movement into the stomach.

Mucous Cells

Secrete mucus to protect the stomach lining.

Chief Cells

Secrete pepsinogen.

Parietal Cells

Secrete hydrochloric acid (HCl).

Pepsinogen

Inactive enzyme that becomes pepsin.

Pepsin

Active protease that digests proteins.

Hydrochloric Acid (HCl)

Activates pepsin and kills bacteria.

Small Intestine

Primary site of digestion and absorption (≈90%).

Duodenum

First section; digestion occurs here.

Jejunum

Main site of nutrient absorption.

Ileum

Final absorption section of the small intestine.

Liver

Produces bile.

Gallbladder

Stores and concentrates bile.

Pancreas (exocrine)

Releases digestive enzymes and bicarbonate.

Pancreas (endocrine)

Releases insulin and glucagon for blood sugar control.

Bicarbonate (HCO₃⁻)

Neutralizes acidic chyme from the stomach.

Pancreatic amylase

Continues carbohydrate digestion.

Trypsinogen

Inactive protein-digesting enzyme.

Trypsin

Active enzyme that digests proteins.

Chymotrypsinogen

Inactive protein enzyme.

Chymotrypsin

Active protease.

Lipase

Enzyme that digests fats.

Bile

Substance that emulsifies fats (not an enzyme).

Emulsification

Physical break-up of fats into smaller droplets.

Villi

Finger-like projections that increase intestinal surface area.

Microvilli

Tiny hair-like projections on villi for maximum absorption.

Capillary bed

Absorbs glucose and amino acids.

Lacteal

Lymph vessel inside villus that absorbs fats.

Micelle

Small fat droplet surrounded by bile salts.

Chylomicron

Lipid transport particle formed inside intestinal cells.

Lymphatic system

First transport system for absorbed fats.

Large intestine (colon)

Absorbs water and compacts waste.

Gut bacteria

Produce vitamins (K and B).

Insulin

Hormone that lowers blood glucose.

Glucagon

Hormone that raises blood glucose.

Pulmonary circulation

Blood flow between heart and lungs.

Systemic circulation

Blood flow between heart and body tissues.

Cardiac cycle

One complete heartbeat (~0.8 seconds).

Systole

Phase of contraction.