Plants

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Plants

• How do plants obtain nutrients?

Through photosynthesis (process that converts
energy from sunlight into sugars
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• Plants are autotrophs which means they make their
  own food by photosynthesis.
• During photosynthesis, plants use carbon dioxide
  gas and water to make food and oxygen.

http//grapevine.net.au/grunwald/une/KLAs/science
/irrigation-photosynthesis.gif
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6CO2 6H2O C6H12O6 6O2

• How do you read this equation in words?
• What are the reactants?
• What are the products?

Six carbon dioxide molecules plus 6 water
molecules yields 1 molecule of glucose and 6
water molecules
6CO2 and 6H2O (carbon dioxide and water)
C6H12O6 and 6O2 (glucose and oxygen)
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Plant Cells and Photosynthesis

• In what organelle does photosynthesis occur?
• What are other organelles that plants have that
  are not found in animal cells?

Chloroplast
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• The cell wall is a boundary that surrounds the
  cell membrane and separates the cell from its
  environment.
• The cell wall is made mostly of cellulose
• Chloroplasts are the structures where
  photosynthesis takes place.

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• A vacuole is a large storage area that contains
  water, wastes and food.
• The vacuole expands when water enters and shrinks
  when water leaves.

http//www.biology4kids.com/files/art/cell_vacuole
1.jpg
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Plant Structures

• Plants need adaptations to reduce water loss to
  the air.
• One adaptation is a waxy, waterproof layer called
  the cuticle that covers the leaves of most plants
• Tiny openings or pores found mostly on the
  underside of a plant leaf used for gas exchange
  are called stomata.

Stomata
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• Epidermis is the single cell layer covering a
  plant (especially the leaf).
• Veins are used to transport food and water
  throughout the leaf.

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Plant Life Cycles

• Plants have complex life cycles that are made up
  of 2 different stages or generations.
• In one stage, called sporophyte, the plant
  produces spores (tiny cells that can grow into
  new organisms)
• A spore develops into the next stage called a
  gametophyte.
• In this stage, the plant produces gametes (egg
  and sperm cells)
• The egg and sperm cell join to form a zygote.

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Which components of this plant life cycle are
sexual? Asexual?
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Mosses

• Nonvascular Plants are low growing plants that
  lack vascular tissue.
• Other nonvacular plants are liverworts and
  hornworts.

Liverwort
Moss
Hornwort
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Moss Life Cycle
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Ferns

• Vascular plants are those that have vascular
  tissue which transports water throughout the
  plant.

Spores on underside of fern leaf.
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Fern Life Cycle
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Compare the moss and fern life cycles.
Moss Life Cycle
Fern Life Cycle
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Gymnosperms

• Gymnosperms are plants that produce naked
  seeds.
• Seeds are not enclosed in a protective covering.
• Many gymnosperms also have needle-like or
  scale-like leaves and deep growing root systems.

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Gymnosperm Reproduction

• Most gymnosperms have reproductive structures
  called cones.
• Many plants produce both male and female cones
• Male cones produce tiny grains of pollen.
• Pollen contains the microscopic cells that will
  later become sperm cells.
• Female cones contain one ovule at the base.
• The ovule is the structure that contains an egg
  cell.

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Life Cycle of Gymnosperms

1. Pollen falls from male cone onto a female cone.
2. In time, a sperm cell and egg cell join together
   in an ovule on the female cone.
3. After fertilization occurs, the zygote develops
   into the embryo part of the seed.

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Angiosperms

• Angiosperms are plants that produce seeds
  enclosed in a fruit.
• 2 characteristics of angiosperms
• Produce flowers
• Produce fruits
• The seeds develop in the ovary and the ovary is
  located in the flower.

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Structure of Flowers

• All flowers are used for reproduction.
• Petals- the colorful structures you see when the
  flower opens.
• When the flower is still a bud, it is enclosed by
  leaf-like structures called sepals.

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• Within the petals are the flowers male and
  female reproductive parts.
• Thin stalks topped by small knobs are called
  stamens (male reproductive parts)
• Pistils (female reproductive parts) are usually
  found in the center of the flower.

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Reproduction of Angiosperms

1. Pollen falls on stigma.
2. In time, sperm cell and egg cell join together in
   the flowers ovule.
3. The zygote develops into the embryo part of the
   seed.

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Some key terminology

• Pollination transfer of pollen from male
  reproductive structures to female reproductive
  structures.
• Fertilization joining of egg and sperm cells.
• Germination the early growth stage of the
  embryo plant in a seed.

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Where do you see pollination, fertilization and
germination?
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Think back

• What is the difference between sexual and asexual
  reproduction?

Sexual reproduction involves the joining of egg
and sperm cells Asexual reproduction involves
only one parent no joining of egg and sperm cells
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Asexual Sexual Reproduction in Plants

• Asexual growing new plants by using cuttings
• Sexual pollination
• What are some common types of pollination?

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Seeds

• Seeds are the result of sexual reproduction.
• Seeds are structures that contain a young plant
  inside of a protective covering.

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Spores

• Spores are tiny cells that are capable of growing
  into a new organism.
• Ferns release spores into their surroundings
  where they grow into gametophytes.

http//upload.wikimedia.org/wikipedia/commons/8/8a
/Fern_spores_P1180804.jpg