SBI3U plants unit review

diffusion

• molecules move from an area of high concentration to an area of lower concentration

• moves down a concentration gradient

is diffusion passive or active

passive

rate of diffusion can by influenced by

• temperature

• concentration gradient

diffusion is mainly used for

gases and liquids

osmosis

movement of water molecules across a selectively permeable memberone

is osmosis passive or active

passive

Osmosis is mainly used for

water and solutes

solute

a substance that's dissolved in a solvent

solvent

the substance that is doing the dissolving

hypertonic

• solute concentration is higher than that inside the cell

• there's a net flow of water out of the cell

hypotonic

• solute concentration outside the cell is lower than inside the cell

• there will be a net flow of water into the cell

isotonic

• solute concentration outside the cell is the same as the inside

• there is no net flow of water in or out of the cell

cohesion

force of attraction between water molecules, that causes them to come together

adhesion

force of attraction between water molecules and a surface

water moves from the roots to the leaves in a tall tree due to:

1. transpiration

2. cohesion/adhesion of water

3. root pressure (osmosis)

whatever can dissolve in water is

polar

whatever CANNOT dissolve in water is

non-polar

active transport

the movement of molecules across a cell membrane from an area of lower concentration to an area of higher concentration, which requires energy

tropism

a biological phenomenon indicating growth or turning movement of a plant in response to a environmental stimulus

phototropism

• movement of plants in response to light

• stems → positive tropism

• roots → negative tropism

gravitropism/geotropism

• movement of plants in response to gravity

• stems → negatively gravitropic (they grow up)

• roots → positively gravitropic (they grow down)

thigmotropism

• plants moving in response to touch

hydrophilic

water-loving

hydrophobic

fearful of water

nastic movement

a growth response unrelated to direction of stimulus

types of plant hormones

• auxin

• cytokinins

• gibberellins

• ethylene

• abscisic acid

where is auxin made?

in stem and root tips

how is auxin transported?

by diffusion

purpose of auxin

• causes cell enlargement/elongation in shoots

• causes upward growth over outward growth in shoots (apical dominance)

• promotes formation of lateral and adventitious roots

• restricts cell elongation in roots

• prevents abscission (detachment) in fruits and leaves

• causes fruit growth and development

• results in differmentation and regeneration in vascular tissue

where is cytokinins made?

in root tips

how is cytokinins transported?

from roots to shoots via xylem

purpose of cytokinins

• promotes cell division

• delays leaf senescence (death)

• promotes growth of lateral buds

where is gibberellin made?

in roots, shoot tips, and developing seeds

how is gibberellin transported?

by xylem and phloem

purpose of gibberellin

• affects fruit development

• can cause bolting (premature production of a flowering stem)

• causes hyperelongation of shoots by stimulating cell division and elongation

• breaks seed dormancy

where is ethylene made?

in most tissues in response to stress

how is ethylene transported?

by diffusion from site of synthesis

purpose of ethylene

• Causes flowers to open

• causes fruit to ripen

• discourages cell expansion

• causes leaf abcission (detachment of the leaf)

where is abscisic acid made?

in mature leaves, roots and seeds

how is abscisic acid transported?

from leaves in phloem and from the roots in xylem

purpose of abscisic acid

• prevents seed germination

• leaf abcission

• causes seeds to fall

• causes somata to close to prevent water loss

what was Darwin's experiments

Darwin conducted experiments on plants to study their responses to environmental stimuli, specifically investigating phototropism (response to light) and geotropism (response to gravity), and the role of plant hormones in growth and development.

statoliths

starch-filled organelles that help plants sense gravity

which hormone is a gas?

ethylene

cotyledon

is the first leaf that appears from a seed when it sprouts

plants with one cotyledon are

monocots

plants with two cotyledon are

dicots

types of vascular plants

• angiosperms (flowering plants)

• gymnosperms (confers, ferns)

xylem

carries water throughout the plant

direction of xylem movement

up the plant

direction of phloem movement

up and down the plant

phloem is composed of

• sieve tube elements

• companion cells

phloem

carries mainly sugars and water

meristematic tissue

divides (by mitosis) to produce new cells

Apical Meristem Region and Intercalary Meristem

• found of end of shoot and root tips

• youngest cells found of the tip of the apical meristem

• responsible for primary growth

vascular cambium

• ring of dividing cells found between the xylem and phloem of ONLY DICOT PLANTS

• causes secondary growth and produces secondary xylem and phloem

dicot stem

monocot stem

monocot root

dicot root

cross-pollinating

pollination that includes 2 different plants

self-pollinating

pollination that only occurs in one plant

What is translocation?

is the process by which sugars and other organic nutrients are transported within the plant, primarily through the phloem.

What is transpiration?

the process through which moisture is carried from the roots of a plant to the leaves and released as water vapor into the atmosphere.

megasporangium

ovule

megasporocyte

megaspore mother cell

microsporocyte

microspore mother cell

microsporangium

pollen sac