Plants vocab exam 2

stem cell

an unspecialized cell that divides by mitosis to generate many daughter cells that specialize for a particular role. In plants, they are typically found in the meristems.

botany

the study of plants; a branch of the biological sciences

eukaryote

an organism whose cell(s) have a nucleus and organelles. these include plants, algae, fungi, and animals and all share a common ancestor

photosynthesis

a biological reaction that uses energy from light to convert carbon dioxide into organic molecules, like sugar. used by plants, algae, and cyanobacteria to make food and it produces oxygen as a byproduct

cyanobacteria

a group of bacteria (prokaryotes) that were the first oxygen-producing photosynthetic life on earth that increased the oxygen content of the atmosphere

oxygen revolution

the mass-oxygenation of earth’s atmosphere around 2.5 billion years ago caused by the photosynthetic activity of cyanobacteria

embryophyte

the true land plants, united by certain specialized traits. used as a synonym for “plant” in the text

charophytes

a group of green algae that are the closest living lineage to the land plants

green algae

a group of photosynthetic eukaryotic organisms that are distantly related to true land plants. sometimes used as a synonym for charophyte

sporopollenin

a tough polymer employed by both algae and plants to encase reproductive cells to protect them from drying out. forms the walls of spores and pollen

anthocyanins

pigments produced by plants to prevent damage from solar radiation and herbivores

hydrostatic skeleton

the rigid structural support of land plants resulting from internal turgor pressure acting on tough cellulose-based cell walls from the water-filled cell inside

lignin

a very tough polymer used by plants to structurally reinforce certain cell walls. it is an important component in wood that gives it its strength

roots

one of the main organ systems in vascular plants. vascular structures that anchor the plant in a substrate, usually soil, extract water and nutrients from it and transport them to the rest of the plant

holdfast

a structure in algae that secures them to a particular spot

rhizoids

simple root-like structures in nonvascular plants that anchor them to a substrate but do not transfer anything like true roots

gametes

sex cells. usually haploid cells, male and female, that fuse during fertilization to form a zygote

meiosis

a type of cell division that produces four haploid daughter cells from a single diploid cell. used to form gametes in humans and spores in plants as part of the sexual cycle

zygote

a new, diploid organism resulting from the fusion of haploid gametes during fertilization

diploid

an organism whose cells have two complete sets of chromosomes in their nuclei, abbreviated as 2n

haploid

an organism whose cells have one complete set of chromosomes in their nuclei, abbreviated as n

sperm

the male gamete, haploid and smaller than the egg

egg

the female gamete. haploid and larger than the sperm

mitosis

a type of asexual cell division that produces two genetically identical diploid daughter cells from a single diploid cell. used to create more tissue

sporangium

a part of the sporophyte that produces spores by meiosis

spore

a single haploid cell produced by sporophyte through meiosis. it gives rise to the gametophyte through mitosis. in some plants it is the dispersive element, while in others it remains within the tissue of sporophyte

sporophyte

a stage in the lifecycle of plants and certain algae. exists as a multicellular, diploid organism that produces spores by meiosis

gametangium

the part of the gametophyte that produces gametes by mitosis

gametophyte

a stage in the lifecycle of plants and certain algae. exists as a multicellular, haploid organism that produces gametes by mitosis

phylogenetic tree

a branching diagram used to represent evolutionary relationships and relatedness between different organisms based on their common ancestors

bryophytes

a commonly used but scientifically flawed grouping of all the nonvascular land plants that include mosses

seedless vascular plants

a grouping of vascular plants that do not produce pollen or seeds, and instead disperse via spores. includes the ferns, horsetails, clubmosses and others

gymnosperms

cone-bearing plants; the group of vascular seed plants that produce pollen and seeds in cones

angiosperms

flowering plants; the group of vascular seed plants that produce flower and fruit

apical meristem

regions of continuous cell division at the tips of shoots and roots that are responsible from primary growth

waxy cuticle

a waterproof lipid layer coating the surfaces of land plants to minimize water loss to evaporation

stomata

pores in a plants’ epidermis, mostly on the undersides of leaves, that allow for gas movement and transpiration in and out of the plant

vascular tissue/vasculature

one of the three types of plant tissue in vascular plants. made up of systems of tube-like, rigid cells that move water and dissolved solutes

vascular plants

the group that includes all living land plants except the bryophytes. they have specialized tissues, xylem and phloem, for conducting water and dissolved solutes throughout the plant

xylem

type of vascular tissue comprised of the cell walls of dead cells that conduct water and dissolved minerals from the roots up the plant, eventually to be transpired

phloem

type of vascular tissue comprised of living cells that moves sugars dissolved in water across the plant, from where the sugar is made to where it is needed

cone

the reproductive structure of a gymnosperm that produces pollen (male) or ovules (female), and where the seeds are later formed

pollen

a tiny, tough shelled granule produced by the cones or flowers of seed plants that contain the male gametophyte and is carried to a female gametophyte for fertilization

megaspore

the “large” haploid spore of seed plants (gymnosperms and angiosperms) that give rise to the female gametophyte

microspore

the “small” haploid spore of seeds plants (gymnosperms and angiosperms) that give rise to the male gametophyte which is encased in a pollen grain

pollination

the movement of pollen to a receptive part of a plants where it can fertilize an egg cell. wind and animals are common pollinators

seed

dispersive structures produced by gymnosperms and angiosperms from ovules following their fertilization. consists of an embryo and nutrient reserves enclosed in a coat

embryo

the underdeveloped, multicellular sporophyte plant inside of a seed before germination

seed coat

the protective shell of a seed formed from the integument tissue around the ovule

ovary

the female structure at the base of the carpel in a flower that contains the ovules and, following pollination, matures into a fruit

flower

the reproductive structure of an angiosperm sporophyte in which the male and/or female gametophytes are produced, and fertilization occurs

fruit

an angiosperm structure formed from the flower’s ovary following the fertilization of the ovules. the mature fruit encloses the seeds and usually aids in their dispersal

receptacle

a swelling of the shoot at the base of a flower to which the flower parts are attached

sepal

a part of a flower derived from highly modified leaves that is external to the petals. for the protective outer layer of the flower bud, but usually do not serve much of a purpose in the opened flower

petal

a part of a flower derived from highly modified leaves that usually serve to attract animal pollinators by displaying color

stamens

the male reproductive structures of a flower. consist of an anther where pollen is made, and a stalk called the filament

anther

the meiotically-active part of the angiosperm stamen (male organ) that houses the microspores and eventually splits to release mature pollen

filament

a part of the angiosperm stamen (male organ) that is the stalk supporting the anther

carpel

the entire female reproductive structure of a flower

ovules

sac-like structures inside a flower’s ovary that hold the female gametophyte. following fertilization, they mature into seeds

style

part of the carpel (female organ) of a flower; a stalk extending up from the ovary and ending in a stigma. it is the organ that the pollen tube grows through to reach the ovules

stigma

part of the carpel (female organ) of a flower; the wide tip at the end of the style which receives pollen and is the target site for pollination

pollen tube

the elongating tube cell of a pollen grain that contains the generative cell and grows down a flower’s style towards the ovules. it delivers the sperm to the egg cell

embryo sac

the female gametophyte of an angiosperm located inside an ovule consisting of eight haploid cells

integument

the layered sporophyte tissue forming the outside of the ovule. within it is the megaspore and then the embryo sac

micropyle

an opening in the integument of an ovule through which a pollen tube can enter to fertilize the embryo sac inside

synergid cell

two haploid, single-nucleated cells present in an angiosperm’s female gametophyte (the embryo sac) at the micropylar end alongside the egg cell. they serve accessory functions

antipodal cell

three haploid, single-nucleated cells present in an angiosperm’s female gametophyte (the embryo sac) opposite the micropylar end that serve accessory functions

polar nuclei

the two haploid nuclei of the central cell of the embryo sac. they both fuse with a single sperm to generate a triploid endosperm

tube cell

one of two cells of the male gametophyte in seed plants, found inside the pollen. it grows out of the pollen grain and elongates rapidly forming a pollen tube that carries the generative cell

generative cell

one of two cells in a pollen grain, found inside the tube cell. it divides my mitosis to generate two sperm cells

double fertilization

the fertilization process in angiosperms where two sperm cells are formed, one fertilizing the egg cell to form the zygote and the other fertilizing the polar nuclei to form the endosperm

endosperm

a triploid tissue within an angiosperm seed that stores nutrients for the developing plant embryo

cotyledon

seed leaves; embryonic structures in a seed that may be the first leaf-like structures to emerge. often play a role in nutrient storage or transport for the developing embryo

monocots

a classification of flowering plants (angiosperms) characterized by having a single cotyledon, coleoptile, and other traits. includes grasses and other relatives

dicots

a no-longer valid classification of flowering plants (angiosperms) characterized by two cotyledons and other traits. used as a synonym for the valid group eudicots

shoots

one of the main organ systems in vascular plants. vascular structures; usually above-ground, that consists of stems and leaves. responsible for photosynthesis and reproduction

radicle

the embryonic root that germinates from a seed and gives rise to the plant’s rot system

hypocotyl

the embryonic shoot that emerges from a seed. it supports the cotyledons

coleoptile

a hollow sheath-like structure found in monocots that emerges from the seed as the beginning of a shoot system, giving rise to the stem and first leaves

primary growth

the development of new tissues in a plant through cell division that cause plant structures like roots and shoots to get longer and more branched

secondary growth

the development of new tissues in certain plants through cell division that cause roots and shoots to grow wider and develop wood and bark

determinate growth

growth of an organism that has genetically predetermined limits in terms of size or number of structures after which growth will stop. seen in humans and certain plant structures like flowers and fruit

indeterminate growth

growth of an organism that lacks genetically predetermined limits in terms of size or number of structures after which growth will stop. often means that growth is continuous with repeating, predictable structures. seen in plant shoots and roots

primary root

the original, often main, mature roots of a plant that develops from the radicle and may produce lateral roots

lateral root

a root that branches from the primary root produced by its primary growth

fibrous root system

a root system with many finely divided roots and no main central taproot. it is usually the root system found in monocots (see taproot)

taproot

a root system with a large, usually thick primary root and many much smaller later roots branching from it. it is usually the root system found in dicots (see fibrous root system)

root hair

cellular extensions of active parts of the root that increase the surface area of the root and absorb water and nutrients from the soil

stem

a stalk-like vascular part of the shoot system that supports leaves and flowers and can be modified for other functions

leaf

part of the shoot system that is usually responsible for most of a plant’s photosynthesis. typically, flat and broad structures attached to the stem

petiole

the leaf stalk by which the leaf connects to the stem

lead blade

the “main body” of a leaf usually consisting of a flat, broad surface

reproductive shoots

in angiosperms, the fertile flower-bearing shoots

vegetative shoot

the sterile shoots that do not produce structures for sexual reproduction

axillary meristem

the buds located within the axil that are usually inactive but have the potential to produce a lateral shoot through primary growth

nodes

the places along the shoot from which leaves branch off

internodes

segments of the shoot in between nodes. once formed, they grow a certain amount by cellular elongation, spacing the nodes farther apart

rhizome

an underground shoot that grows and branches horizontally, often helping a plant colonize an area

tuber

an underground shoot that swells to form a storage organ. it can also produce new plants through asexual reproduction