Plant Biology Test 1

Why are plants important?

• Eat them

• Medicines

• Oxygen 

• Building material

• Support ecosystems

• Supporting tourism 

• Decoration 

• Paper 

• Clothing 

• Scientific research

• Scents 

• Wood (fuel)

• Shade

• Animal feed

• Dyes 

• Poisons 

• Protection from natural disasters

• aesthetic/flowers

Heterotrophs

gain energy by consuming other organic material from other organisms/sources

EX. animals, fungi, some single celled organisms

Autotrophs

self-feeding organisms that can make their own food from inorganic substances

EX. plants use sunlight, CO2, and water to produce carbohydrates

Roots

hold the plant in place, absorb water from the soil

Stem

support for above-ground plant parts

Leaves

the main plant organ to gather sunlight for photosynthesis

What is the flow of water?

Soil → Roots → Stem → Leaves → Atmosphere

Cuticle

a waxy material to educe water loss from leaves and impacts gas exchange

Epidermis

outermost covering (layer of cells) on a plant

Stomata

• openings in the epidermis of leaves for gas exchange

• the size of stomata is controlled by a pair of guard cells

Vascular System

• composed of xylem and phloem

• NOT FOUND IN ALL PLANTS!

Xylem

transports water up

Phloem

transports nutrients to the plant body

Meristems

structures that maintain the ability to produce new cells, responsible for a plant’s continual growth

Apical meristem

• found at the tips of roots and shoots

• contains primary growth = increase in length/height

• associated with lateral meristems

Lateral meristems

• composed of cork cambium and vascular cambium

• secondary growth = increase in girth/diameter

Plant categories

ancestor of land plants → green algae

Bryophytes

moss, liverworts, hornworts (non vascular so no X or P)

Ferns and Fern Allies

vascular, reproduce only with spores

Gymnosperms

vascular, produce with seeds (cones)

• naked seeds

• cycads

• conifers

• gnetophytes

• ginkgo - only has one species!

Angiosperms

flowering plants (vascular, reproduce with seeds)

• enclosed seeds (fruits)

Cell Theory

1. All living things are made up of at least one cell.

2. Cells come from pre-existing cells.

3. A cell is the basic unit of structure and function in organisms’

4. Metabolism occurs inside cells.

5. Cells have DNA that can be passed from the parent cell to daughter cells.

Robert Hooke

• 1600s

• coined the term cell

Schleiden

• botanist

• discovered that all plants are made of cells

Schwann

• zoologist

• discovered that all animals are made of cells

Virchow

• pathologist

• discovered that cells come from other cells

Prokaryotes

• lacks a nucleus

• archaea (archaebacteria) and bacteria (eubacteria)

• circular DNA

• lack of membrane-bound organelles

• smaller (1-10 micrometers)

Eukaryotes

• have a nucleus

• plants, animals, fungi, and protists

• linear DNA

• have membrane-bound organelles

• larger (5-100 micrometers

Cell wall

provides strength to the plant cell (mostly cellulose)

Protoplast

plant cell components without the cell wall

Cytoplasm

space outside the nucleus (organelles and cytosol)

Cytosol

fluid/liquid component of the cytoplasm

Plasma membrane

semi-permeable structure surrounding the cytoplasm

Nucleus

the nuclear genome, nucleolus, has a nuclear envelope with pires

Ribosomes

made of rRNA and protein, attached to the rough ER or free-floating in the cytoplasm

Plastids

double-membraned, reproduced by binary fission

Chloroplast

• consists of thylakoid, granum, and stroma

• own DNA and ribosomes

• photosynthesis

bright

In ____ light, chloroplasts line the walls of plant cells.

dim

In ____ light, the chloroplasts line up horizontally to get as much light as they can.

Thylakoid

disc-shaped sacs

Granum

one stack of thylakoids

Stroma

fluid within the chloroplast

Chromoplast

contain yellow, red, and orange pigments

Leucoplast

lacks pigments and has little structure

EX. amyloplast - store starch

Proplastid

found in meristematic areas, an undifferentiated plastid

Mitochondria

can fuse and divide, have their own DNA and ribosomes, double-membraned, and cristae

Cellular respiration

makes ATP; the number of mitochondria per cell depends on energy needs

Vacuole

surrounded by the tonoplast, the appearance differed based on whether the cell was mature or immature; contains cell sap

Rough ER

• has ribosomes attached

• the purpose is to make proteins

Smooth ER

• no ribosomes

• the purpose is to make lipids

Golgi

synthesizing, processing, and secreting certain polysaccharides and glycoproteins

Cytoskeleton

network of proteins found in the cytosol

Mictrotubules

forming a spindle, cell wall growing

Actin filaments

movement of organelles

Plasmodesmata

openings in the primary cell wall for communication, lined with the plasma membrane

Cell wall

• found in plant cells

• prevents the cell from bursting

• controls the size and shape

• defense

• mostly made of cellulose

Primary cell wall

found in all plant cells

Hemicellulose

connected to cellulose microfibrils to control how much the cell wall can expand

Pectin

a hydrophilic polysaccharide that makes up the primary cell wall and the middle lamella, allows for expansion

Glycoprotein

protein with carbohydrate attached

Lignin

adds strength to the cell wall

Secondary cell wall

• found in some plant cells

• laid down toward the inside of the primary cell wall

Middle lamella

connect nearby plant cells, mostly protein

3

The middle lamella is laid down in ___ layers.

S1, S2, S3

What are the three layers of the middle lamella?

S1

What layer is closest to the primary cell wall?

cellulose

There is a higher percentage of ____ in the secondary cell wall than the primary cell wall.

primary cell wall

The ______ ___ ___ is produced before and while the plant cell is still growing.

thin; plasmodesmata

The primary cell wall has ___ areas in which ________ can be found.

Expansins

cell wall proteins that act to loosen the cell wall

Cellulose synthase

found in the plasma membrane

UDP-glucose

substrate acted by the cellulose synthase

Cellulose microfibril

is produced by cellulose synthase, linking UDP-glucose molecules together

• The cellulose microfibril is extruded on the other surface of the plasma membrane.

Embryogenesis

• process of embryo formation

• establish a body plan → apical-basal and radial

Zygote

in the embryo sac inside the ovule

Division I

• asymmetrical division

• helps set up the apical-basal axis

top cell

The ___ ___ also known as the apical cell is responsible for the mature embryo

bottom cell; suspensor

The ______ ___ also known as the basal cell produces the ______, which hods the embryo at the micropyle (opening in the ovule where the pollen tube entered)

embryo proper

For the other division, the ____ ____ (undifferentiated) is at the top.

basal cell

For the other division, the ___ ___ produces the suspensor

3; apical meristems

There are ___ primary meristems associate with primary growth. These are derived from ______ ______ (shoot,root).

Protoderm

becomes the epidermis

Ground

becomes the ground tissue

Procambium

becomes vascular tissue (xylem and phloem)

Globular stage

sphere-like embryo proper, cotyledons. These have not developed yet

Heart stage

cotyledons (seed leaves) develop in eudicots → 2 seed leaves/cotyledons

Torpedo stage

• cotyledons lengthen along with the axis

• shoot and root apical meristems

• embryonic root (eventually)

eudicots

In ____, the shoot apical meristem is between the two cotyledons.

monocots

In ____, the shoot apical meristem is on one side of the cotyledon and is enclosed by a covering from the base of the cotyledon.

mature embroyo

shoot apical meristem and root apical meristem at opposite ends

Hypocotyl

stem-like structure below cotyledons

Epicotyl

stem-like structure above the cotyledons

1

Monocots have __ cotyledon

cleoptile

Plumule is protected by the ____.

coleorhiza

Radicle is protected by the _____.

coat; integuments

All seeds have a seed ___ developed from the ______ of the ovule.

Hilum

scar left on the seed coat after the seed separates from the ovary wall.

nutrient; dries; hardens; metabolism

What occurs during seed maturation?

• _____ accumulation

• seed ____

• seed coat ____

• little ______.

Seed germination

• the embryo resumes growth

• internal and external factors

• water (imbibition)

embryonic

In seed germination (step 1), ____ root growth occurs.