Plants

What distinguishes eukaryotes?

Eukaryotic cells have a membrane-bound nucleus and organelles

Which domain is most closely related to Eukaryia?

Archaea

When was the first eukaryote?

2 billion years ago

What are protists?

A collection of diverse eukaryotes that do not fit neatly into the traditional plant, animal or fungi

What are algae?

Photosynthetic organisms that lack true roots, stems or leaves and are mostly found in aquatic environments. They are not considered plants as the lack a dependent embryo

What is a stromatolite?

A layered rocky formation created by microorganisms such as cyanobacteria

What is the technical name for land plants?

Embryophytes

What group did land plants evolve from?

Green algae, specifically charophytes

What evidence links charophytes and land plants?

Their cell wall construction, cell-plate formation involving a phragmoplast and sperm all share similarities

What is a phragmoplast?

A structure involved in forming a new cell=plate and therefore a new cell wall during cell division in plants

What is an embryo in land plants?

A young developing plant that is supported by the parent gametophyte

What is the gametophyte stage?

The haploid stage (n)

What is the sporophyte stage?

the diploid stage (2n)

What is a spore?

A reproductive cell that does not need to fuse to another cell to develop into a new individual

What is an apical meristem?

A region of actively dividing cells at the root or shoot tip that adds length

What is the xylem?

Vascular tissue which aids in the transport of water

What is the phloem?

vascular tissue which aids in the transport of sugars

What is poikilohydric vs homeohydric?

Poikilohydric means the plants internal water content tends to fluctuate with the environment while homeohydric means the plants internal water content remains stable despite fluctuating environments.

What is a seed?

An embryo plus its food supply, and an outer protective layer

Why are seed plants well adapted to life on land?

Seeds/pollen allow reproduction away from aquatic environments, the seed coats protect and nourish the embryo until ready to develop,

Four features that distinguish seed plants?

Reduced gametophytes, heterospory, ovules/eggs and pollen

what is heterospory?

Producing two spore types; mega and microspores

What are mega and microspores?

megaspores are larger and are associated with female gametophytes while microspores are smaller and are associated with male gametophytes

What does it mean that plants are nodular structures?

They grow by repeating similar structures

What is indeterminate growth?

Growth that can continue throughout the plants life rather than stopping at maturity

What are the three plant tissue types?

Dermal, ground and vascular tissue

What is dermal tissue?

The outer protective covering

What is ground tissue?

Tissue that performs a specific function such as photosynthesis, storage, and support

What three cell types create the ground tissue?

Parenchyma, collenchyma and the Sclerenchyma

What are parenchyma cells?

Responsible for photosynthesis, storage and gas exchange and is composed of thin flexible walls

What are collenchyma cells?

unevenly thickened cells used for flexible support

What are Sclerenchyma cells?

unevenly thickened cells responsible for support that are dead at maturity

How do primary and secondary walls differ?

Primary walls form during cell growth and secondary walls are deposited once maturity is reached

What are tracheids?

Long, elongated water-conducting xylem cells

What are vessels?

Broader, hollow water-conducting xylem structures

What are seive tubes?

sugar-conducting phloem structures

What distinguishes monocots?

Long narrow leaves, fibrous roots and little to no secondary growth

What distinguishes eudicots?

Taproot systems and secondary growth

What is primary growth?

Growth in length produced by apical meristems

What is secondary growth?

Growth in width produced by lateral meristems

What is heartwood vs sapwood?

Heartwood is the older inner xylem that no longer conducts water while sapwood is the outer xylem which still does

What is morphogenisis?

The development of an orgnanisms shape and form

What is leaf area index?

A measure comparing leaf area to ground area in a canopy helping to describe density

What are mycorrhizae?

Symbiotic relations between plant roots and fungi typically useful in phosphorus absorption

What is short distance trasnport in plants?

cell to cell transport

What is long distance transport in plants

transport between tissues or organs

What is the apoplast?

The connected pathway outside the cell membrane including the cell walls and extracellular spaces

What is the symplast?

The connected pathway inside the cytoplasm through plasmodesmata

What affects water potential?

Pressure and solute concentration

What is bulk flow?

Movement of fluid from regions of higher to lower pressure

What stimuli effect stomatal opening and closing?

Light, Carbon dioxide, circadian rythms, water potential and abscisic acid

What is a xerophyte?

A plant adapted to dry conditions

What makes a chemical element essential to a plant?

The plant cannot complete its life cycle without it

How do micro and macronutrients differ?

Micronutrients are needed in small quantities while macronutrients are needed in larger quantities

Name some essential elements?

Carbon, Oxygen, Phosphurus, Nitrogen, Hydrogen, Calcium

What is the difference between mobile and immobile nutrients?

Mobile nutrients can move from older tissues to younger growth while immobile nutrients are not readily redistributed

What is the rhizosphere?

The soil area around plants which is influenced by root activity

What is a plant hormone?

An organic compound active at low levels which controls plants physiological proccesses

Name 5 major plant hormones?

Auxin, Cytokinins, Gibberellins, abscisic acid and ethylene

What are tropisms?

Directional growth in response to a stimulus

What is the acid-growth hypothesis?

A model where auxin signalling causes protons to move through the apoplast and cause cell loosening and elongation

Differences between plant and animal hormone?

Plant hormones can be produced anywhere while animal hormones are produced in glands, plant hormones also tend to be very simple while animal hormones are much more complicated

What does auxin do/promote?

Cell elongation, phototropism responses, root initiation

What does Ghibberellins do/promote?

Stem elongation, seed germination, flower + fruit development

What does cytokinen do/promote?

Cell divisions, new shoot formation, delay leaf ageing

What does ascisic acid do/promote?

Seed dormancy, closing of the stomata

What does ethylene do/promote?

Fruit ripening, abcsision/leaf dropping

What does the vascular cambium do?

secondary xylem forms on the inside while secondary phloem forms on the outside of the vascular cambium

What does the cork cambium do?

Produces cells to add to the bark as it grows in width

What is guttation?

When the water pressure is high in roots, and therefore the xylem continues to pull water towards the leaf

What is pattern formation?

When unorganized cells become organized into structures, organs or body plans

trends in flower evolution?

increased bilateral symmetry, reduced number of parts, fusion of parts, lowering of ovary

epigeal germination?

Cotyledons are lifted above soil

Hypogeal germination?

Cotyledons remain below the soil