Botany - Exam 1

Characteristics of plants

1) Multicellular

2) Anchored or free-floating

3) Autotrophic

4) Sexual or asexual reproduction

5) Cellulose within cell walls

How did plants evolve?

Aquatic green algae (not plant) → reached moist soil → bryophytes (primitive plants) → became more and more advanced

*When resources ran low, some evolved back to the water

Are land or aquatic plants more advanced?

Neither, they are the same

Bryophytes

Liverworts, hornworts, mosses

Lycophytes

Fern allies

Pteridophytes

Ferns

Gymnosperms

Non-flowering, open-seeded plants

Angiosperms

Flowering plants

What organisms have a close relationship with plants?

Fungi, bacteria, and algae

*Fungi and bacteria have closer relationship than algae

What kind of relationship do fungi, bacteria and algae have with plants?

Supportive, parasitic or pathogenic

What was important to farming in ancient times?

1) Able to store for long time

2) Easy to harvest

3) Have enough nutrients to live on

What were commonly cultivated crops in ancient agriculture?

Cereals and legumes

Cereals

Wheat, rice, barley, sorghum, corn, millet

Legumes

Beans, peas, soybeans, alfalfa, clover

What are the primary metabolites and are they necessary?

Protiens, carbohydrates, lipids

Essential for growth and function

What are the secondary metabolites and are they necessary?

Terpenes, phenolics, alkaloids

Serve a purpose but not vital

Terpene examples

Frangrance in flowers, carotene, rubber

Phenolic examples

Vanilla, capsacin, tannins, lignins

Alkaloid examples

Narcotics, caffeine, codeine, morphine, quinine, theobromine

Are chloroplasts always found in plant cells?

No → root cells don’t have any

What organelles exist in plant cells but not animal cells?

Chloroplasts and vacuoles

Plasmodesmata

Found in cell walls

Allows for living parts of adjacent cells to communicate

Where are flagellum found in plant and animal cells?

In the gametes of animals and primitive aquatic plants

What organelles are found in animal cells but not in plant cells?

Flagellum (not typical in plants), lysosomes, centrioles

Purpose of vacuoles in plant cells

1) Maintain turgor pressure

2) Store nutrients and waste materials

3) Store toxins to protect plants

4) Stores Ca2+

5) Colored substances in vacuole give colors to plant

Turgor pressure

Pressure exerted by fluid inside cell against plasma membrane and cell wall

Where does the color in plants come from?

Vacuoles or plastids

Plastids

Chloroplasts → photosynthesis

Amyloplasts → starch storage

Chromoplasts → tissue color

Primary cell wall

1) High concentration in young plants → need to divide to grow

2) Rich in cellulose

Secondary cell wall

1) More secondary metabolites → lignin

2) Make things more solid → wood

Meristematic tissue

Sites of cell division by mitosis

*All other tissues arise from meristematic tissues

Three types of meristems

1) Apical

2) Lateral

3) Intercalary

Apical meristems

Increase lenght/height

*Found at growing tips of roots and shoots

Lateral meristems

Increase width/girth

*At mature areas of plant body in dicots

Intercalary meristems

*At nodes or leaf bases in monocots

What kind of plants are the most advanced?

Flowering plants

Monocot

Flowering plants that have seeds with one cotyledon

Dicot

Flowering plants that have seeds with two cotyledons

Cotyledon

Embryonic leaf

Three main tissue groups

1) Dermal (protoderm) → protective layer

2) Vascular (procambium) → conductive tissue

3) Ground tissue → fill up space

Primary meristem

Apical meristem

Secondary meristems

Lateral and intercalary meristems

Where are apical meristems typically found?

Dicots

Where are lateral meristems only found?

Wood dicots

Where are intercalary meristems found?

Only in monocots

What is mitosis used for in plant cells?

1) Growth and development

2) Healing wounds

3) Asexual reproduction

Two types of plant tissues

1) Simple tissues: only one kind of cell

2) Complex tissue: two or more kinds of cells

Simple tissues

Parenchyma, collenchyma, sclerenchyma

Complex tissues

Dermal tissue, vascular tissue, ground tissue

Parenchyma

Composed of relatively unspecialized living cells

Characteristics of parenchyma

1) Thin cell walls

2) Loosely packed cells

3) Varying shape

4) Alive at maturity

Function of parenchyma

1) Food storage

2) Photosynthesis

3) Synthesis and storage of chemicals

4) Healing and filling wounds

Collenchyma

Composed of specialized living cells

Characteristics of collenchyma

1) Irregularly thickened cell walls

2) Tightly packed cells

3) Elongated cell shape

4) Alive at maturity

Function of collenchyma

Provide strength to young/tender parts of plants that need to bend/elongate

Sclerenchyma

Very specialized, dead cells

Characteristics of sclerenchyma

1) Lots of lignin → provides strength

2) Thick cell walls

Two types of sclerenchyma

1) Sclerenchyma fibers

2) Sclereids

Sclerenchyma fibers

Strong, flexible, elongated cells with tapering ends

Sclereids

1) Vary in shape → likely star-shaped

2) Thick cell walls

Function of dermal tissue

Protection and exchange

Function of vascular tissue

Transport of food, water, and other material throughout plant body

What transfers water through the plant cells?

Xylem

Where do the xylem and phloem come from?

Procambrium: keeps dividing → adds xylem on one side and phloem on other

Parts of xylem tissue

1) Xylem fibers (sclerenchyma) → dead

2) Xylem parenchyma → alive

3) Vessel elements and tracheids → dead

Why are the vessel elements and tracheids of xylem tissues dead?

All the organelles of alive cells would get in the way of water transport

What transports food through plant cells?

Phloem

Parts of phloem tissue

1) Phloem sclerenchyma → dead

2) Sieve tubes → alive

3) Companion cells → alive

What organelle do sieve tubes lack, despite being alive?

Nucleus

What to the xylem and phloem make up?

Vascular bundles

Vegetative organs

Leaves, stems, roots, embryos

Reproductive organs

Stamens, pistils

Shoot system

Made of above ground organs

Root system

Made of below ground organs