BIOL 3600 – Plant Section – Exam 3 Study Guide

A comprehensive set of flashcards covering key concepts, definitions, and important processes in plant biology as outlined in the lecture notes.

Haplodiplontic life cycle

A life cycle with alternating haploid (gametophyte) and diploid (sporophyte) generations.

Bryophyte

A group of small, non-vascular land plants, such as mosses, liverworts, and hornworts, that lack true roots and conduct water and nutrients directly through their surfaces.

Major characteristics of Bryophyte

lacks true roots, stem and leaves possessing a dominant haploid gametophyte body and a dependent sporophyte requiring water for sexual reproduction

Tracheophyte

A group of vascular plants that have specialized structures for conducting water and nutrients, including lycophytes, ferns, and seed plants.

Major characteristics of Tracheophytes

a specialized vascular system (XYLEM & PHLOEM) for water and nutrient transport

Significance of XYLEM & PHLOEM

Vascular tissues responsible for transporting water, nutrients, and sugars throughout a plant

Xylem

Vascular tissue responsible for transporting water and dissolved minerals upward from roots to leaves.

Phloem

Vascular tissue responsible for transporting organic nutrients, primarily sugars, throughout the plant.

Meristem

A clump of undifferentiated cells capable of division and growth, giving rise to new tissues in plants.

Transpiration

The process of water evaporation from plant leaves, which helps in the movement of water and nutrients from roots to leaves.

Translocation

The movement of dissolved nutrients, primarily sugars, throughout the plant via the phloem.

Aquaporin

Membrane channels that facilitate the rapid movement of water across cell membranes.

Turgid

A state of a plant cell that occurs when it takes in water, causing the cell to swell and become firm due to osmotic pressure.

Photon

The fundamental particle of light and all other forms of electromagnetic radiation.

Calvin Cycle

The light-independent stage of photosynthesis where carbon dioxide is fixed into glucose using ATP and NADPH.

Pressure-Flow Hypothesis

A model explaining the movement of carbohydrates in phloem, where water moves into the phloem by osmosis and creates turgor pressure that drives sugar transport.

Hydroponics

A method of growing plants without soil, using nutrient-rich water solutions instead.

Phytoremediation

The use of plants and associated microbes to clean up contaminated soil, water, or air.

Topsoil

The uppermost layer of soil, containing the highest concentration of organic matter and nutrients, crucial for plant growth.

Macronutrient

Nutrients required by plants in large amounts for energy, growth, and body structure.

Micronutrient

Nutrients required by plants in trace amounts, essential for various biochemical functions.

3 basic plant tissue types & functions

• Ground- function in storage, photosynthesis and secretion

• Dermal- outer protective cover

• Vascular- conducts fluids and dissolved substances

Apical meristem

located at tips of stems and roots, give rise to primary tissues, responsible for length of the plant body

Lateral meristem

found in plants that exhibit secondary growth, give rise to secondary tissues, woody plants have two types (Cork Cambium produces outer bark) (Vascular Cambium produces secondary vascular tissue)

3 primary meristems

• Protoderm - Epidermis

• Procambium - primary vascular tissue

• Ground meristem- ground tissue

Secondary meristems

Lateral meristem -vascular cambium, cork cambium

Parenchyma

function in storage, photosynthesis and secretion ( found in leaves, fruits and flowers)

Collenchyma

provide flexible support and protection ( found in woody plants, stems,and leaves of mature herbaceous plants)

Sclerenchyma

provide rigid support and protection ( found in stems, around vascular bundles in the veins of the leaves and the hard covering of the fruit, seed and nuts)

Basic characteristics of dermal tissue

• forms the epidermis (outer layer)

• one cell layer thick in most plants

• forms the outer protective covering of the plant

• covered with a waxy cutin layer constituting the cuticle

• contains special cells including Guard cells, Trichomes, and Root Hairs

Pigments used in green plants

• Chlorophyll (a and b) and Carotenoids (yellow/orange) to drive photosynthesis

• Carotenoids give an orange color

3 stages of photosynthesis

• Light dependent reactions ( in the thylakoids membrane)

• light independent reactions (Calvin cycle) in the stroma

- carbon fixation, reduction and regeneration

Requirements for photosynthesis to occur

Sunlight, Water( H2O) and carbon dioxide (CO2) along with green pigment chlorophyll to convert light energy to chemical energy

• sunlight: provides the energy necessary to power the entire process, chlorophyll found within chloroplasts acts as the primary receptor for this energy

• water:absorbed by the roots from the soil, water is broken down during the light-dependent reactions to provide electrons and protons

• carbon dioxide: absorbed from the air through the stomata( small pores) in the leaves CO2 is used in the light- dependent reactions (Calvin cycle) to create sugar

• chlorophyll: pigment located in the thylakoid membrane of chloroplasts that absorbs light primarily in the blue and red wavelengths while reflecting green

Two components of photosynthesis

• Antenna complex: light harvesting complex, hundreds of accessory pigment molecules, gather photons and feed the captured light energy to the reaction center

• Reaction center: 1 or more chlorophyll a molecules, passes excited electrons out of the photosystem (uses that energy from antenna complex to initiate electron transfer creating chemical energy)

Photosytem I

reaction center is P700requires electrons from the transport chain & uses light energy to produce NADPH

Photosystem II

reaction center is P680 uses light energy to oxidize water ( the reactant producing oxygen, protons ) energized electrons

Travels in XYLEM

transport water and dissolves minerals upward from roots to leaves/ stems (one direction)

Travels in PHLOEM

transport organic nutrients (sucrose,sugar& amino acids) produced via photosynthesis

• flow is bidirectional the phloem transports nutrients nothing up & down contrary to the indirection flow of xylem

Water potential

measures the potential energy of water per unit volume, moves from HIGHER to LOWER

3 transport routes that exist between cells

• Apoplast route: movement through cell walls and space between cells (avoids membrane transport)

• Symplast route: movement through the cytoplasm continuum between cells connected by plasmodesmata

• Transmembrane route: movement across transport between cells and across the membrane of vacuoles within cells ( permits the greatest control)

Topsoil

the uppermost layer of soil typically 2 to 12 inches deep containing the highest concentration of organic matter,mircoorgansisms and nutrients

• mixture of mineral particles of varying sizes, living organisms and humus

• characterized by their relative amounts of sand,silt and clay

• soil composition determines the degree of water and nutrient binding to soil particles

Lost of topsoil

if topsoil is lost, soil’s water holding capacity and nutrients content are adversely affected

• methods to prevent: planting cover crops, practicing no-till farming, terracing, using windbreaks

3 special nutritional strategies

• Mycorrhizae: symbiotic fungi that attacks to plant roots, vastly extending their surface area to enhance nutrient and water uptakes particularly phosphorus, nitrogen and micronutrients

• Rhizobium: bacterium found in soil that helps in fixing nitrogen in leguminous plants( requires oxygen and carbohydrates to support their energetically expensive lifestyle as nitrogen fixers)

• Carnivorous Plants:often grow in acidic soils that LACK nitrogen, trap and digest small animals such as insects to obtain adequate nitrogen supplies, have modified leaves adapted for luring and trapping prey, prey is digested with enzymes secreted from specialized glands

3 Main types of phytoremediation

• Phytodegradation: contaminant is taken up from soil and broken down

• Phytocolatilization: contaminant is taken up from soil and released through stomata

• Phytoaccumlation: contaminant is taken up from soil and concentrated in shoots ( that are later harvested)