Plant Science Exam 3

One Chromosome = 

1 DNA Molecule

Chromosomes of Complex Organisms

Paired

How many chromosome pairs might a plant have?

4-630

Cells with 1 of each chromosome

Haploid (1n or n)

Cells with 2 of each chromosome

Diploid (2n)

Which type of cells undergo meiosis?

Diploid

Mitosis

• Exact copy of original cell

• Common way of cell division

Meosis

• Produces 4 haploid cells from 1 diploid cell

• Usually for reproduction

  • Creating genetic variation in offspring

3 Types of Life Cycles

• Simple Organisms

• Complex Animals

• Land Plants

Life Cycle of Simple Organisms

Life Cycle of Most Animals

Life Cycle of Land Plants

Which is the most complicated life cycle?

Life Cycle of Flowering Plants

Which life cycle is called ‘alternation of generations?’

Life Cycle of Flowering Plants

Flowering Plants

• Most structures reduced in size

• 1 generation kept on previous generation in seed plants

• Hold the haploid generation

Flower

• Modified leaves

• 2 vegetable parts

  • Don’t contribute cells to future generations

• 2 reproductive parts

  • Contribute cells to future generations

4 Main Parts of Flowers

• Sepals

• Petals

• Stamens

• Carpels

Sepals

• Vegetative

• Most leaf-like part

• Usually green

• Usually with functional stomata

Petals

• Vegetative

• Pigmented

  • Attract pollinators

• Usually no functional stomata

• Can be associated with nectar glands

• Can be fused into a tube, partially fused, or separate

Stamens

• Reproductive

  • Produce pollen grains

• Consists of filament & anther

  • Anther - 4 pollen chambers

Pollination Methods

• Insects

• Birds

• Wind

• Water

• Mammals

Carpels

• Reproductive

• 3 Parts

  • Stigma

  • Style

  • Ovary

Seed Production

• Zygote divides many times

• Basal cell & embryonic ball produced

• Then suspensor

• Embryo establishes polarity

• Integuments harden into seed coat

• Endosperm nucleus divides thousands of times

Top Agricultural Crop Families

• Grass (most common)

  • 70% of farmland

• Tomato

• Bean

• Cabbage

• Melon

• Carrot

Plants in the Solanaceae (Nightshades)

• Food plants

• Psychoactive plants

• Ornamentals

Spice Families

• Mint

• Myrtle

• Saffron

  • Most expensive

• Ginger

• Cinnamon

• Licorice

Perfumes

• Basic ingredients are odorants that are extracted

  • Volatile oils

Medicinal Plants

• Used to treat/cure illness

• Usually accidental discovery

• ¼ to ½ modern medicines derived from plants

• Herbalists = strong plant solutions

• Homeopaths = dilute solutions

Types of Medicinal Plants

• Yams

  • Birth control

• Foxglobes

  • Stabilizes arrythmia

• Poppies

  • Opioids

• Cinchona Tree

  • Malaria

• Willows

  • Salicylic acid

• Periwinkles

  • Tumors

Psychoactive Plants

• Affect mainly the central nervous system

• Cause hallucinations, delusions, etc.

• Can be fatal

Types of Psychoactive Plants

• Coca

  • Cocaine

• Peyote

• Marijuana

  • THC

• Opium/Heroin

• Nicotine

• LSD

Nicotine is a part of what family?

Tomato

Stimulating Beverages

• Have caffeine or other stimulant

• E.g. tea, chocolate, coffee

What country is the #1 grower of coffee?

Brazil

Alcoholic Beverages

• Contain ethanol

• Fermented

  • Uses fungus to convert glucose into ethanol

  • Beer, wine

• Distilled

  • Concentrates ethanol

Textiles

Derived from…

• Seed Hairs

  • Cotton

• Stems

  • Linens

• Lignified Leaf Fibers

  • Agave

Flax

• Linen

• Stem tissues provide strong fabric

• Superior to cotton

  • More expensive

Hemp

• Marijuana family

• Stem tissues provide tough, durable fabric

Genetically Modified Crops (GMO)

• Non-plant genes incorporated

• Can be unknown / unpredictable

• E.g. golden rice, Morningstar corn

Vegetative Parts of Flower

• Sepals 

• Petals

Reproductive Parts of Flower

• Stamen

• Carpels

Cell Division vs Sex Cell Division

Mitosis - Cell division

Meiosis - Sex cell division

Parts of a Flower

Alternation of Generations

Life cycle that involves a switch between two multicellular stages: haploid gametophyte (sexual) and diploid sporophyte (asexual)

Pollen Tube & Pollen Grain

After landing on the stigma, the pollen grain germinates and forms a pollen tube, which is a narrow tube that grows down through the style and the ovule, carrying the sperm cells for fertilization

How is reproduction in flowering plants better than conifers

Flowering plants have double fertilization, where one sperm fertilizes the egg and the second fertilizes the central cell to form the endosperm. The second sperm in conifers does not fuse with anything.

Parts of a Seed

Fruit Types

• 1 flower

  • Aggregate (multiple ovaries)

    • e.g. strawberry

  • Simple (1 ovary)

    • Fleshy

      • e.g. berry

    • Dry

      • e.g. nut, legume

• 1 flower + other tissues (accessory)

  • e.g. apple, pear

• > 1 flower (multiple)

  • e.g. corn, pineapple

Tillers

Clones that grow from grass plants

Tomato Family Paradox

Highly toxic