Transcript What is a plant?

Inside the living plant
The key to life on our planet
Why are plants the key to life on our planet
• Earth needs a constant input of
energy to sustain life
• The sun is this source
• Plants convert solar energy into
sugar so it is usable for all
organism
• This stored sugar is passed
through the food chain and life
is sustained.
What is a plant?
• Plants are multi-cellular
eukaryotes
• They have cells with
walls made of cellulose.
• They carry out
photosynthesis by using
chlorophyll.
Plants need 4 things to live
1. Sunlight: plants
convert solar energy
into chemical energy
in the form of sugar.
2. water and minerals:
also involved in
making sugar
3. gas exchange: CO2 in and O2
out. The Carbon on the CO2 is
used to make an organic
sugar C6H12O6.
4. Transport of water and
nutrients: roots and other
structures that take water
and minerals to leaves and
other cells.
Special plant cells.
• Leaves are the site of the
food making process called
photosynthsis
• Leaves have special cells
called stomata and guard
cells.
• Stomata is a tiny pore,
found on the underside of a
plant leaf and used for gas
exchange.
• Guard cells are cells on
the underside of leaves
for controlling gas
exchange and water
loss.
• Guard cells occur in
pairs and are shaped so
that a pore, or stomata,
exists between them.
• During dry weather,
when a plant is in
danger of losing
water, the guard cells
close, cutting down
evaporation from the
interior of the leaf.
•Cross
section of a
leaf
•Leaf activity
Section 23-4
Guard Cells
Guard cells
Guard cells
Inner cell wall
Inner cell wall
Stoma
Stoma Open
Stoma Closed
When the plant has water, sun, carbon dioxide and
minerals, sugars and be made.
Sugars are a chemical energy (stored) created from
solar energy
Solar energy
chemical energy
This is what photosynthesis is all about
Photosynthesis: Turning light energy from
the sun into chemical energy of sugar
Light intro
Key Ideas of photosynthesis
• Carbon dioxide is converted to
glucose (sugar).
• CO2 is an inorganic form of carbon.
• Its converted to glucose sugar, an
organic form of carbon.
• Inorganic
organic
• Occurs in chloroplast of most plant
cells and some single celled
organisms.
Organisms come in two forms.
1. Heterotrophic organisms: obtain energy from
the food they eat. Cannot use the sun to make
food (energy).
• Name One________________
• 2. Autotrophic organism: Can use the sun’s
energy to make food (energy).
ATP
• ATP is the form of energy that is stored in and
used by cells.
• ATP stands for adenosine triphosphate.
• How many phosphates does it have?____
• Energy is released when ATP is converted to
ADP or adenosine diphosphate.
• Can you guess what happened? Tri to di
• ATP to ADP means that one phosphate is
removed
• As a result, energy is released.
• The cell can use this energy for daily activities.
• ATP is the basic energy source for all cells.
Glucose
• ATP is used by the cell. They have only
enough energy for a few seconds.
• It’s not very good for storage
• Glucose is the stored form of energy. It is a
form of sugar stored by the body.
• When cells need more ATP, they break down
the glucose molecule in the mitochondria.
• This is called cellular respiration.
Photosynthesis
• Photosynthesis is when plants use the energy
of the sun to convert water and carbon
dioxide into oxygen and high energy
carbohydrates (sugars and starches).
• The equations:
• Sunlight reaches earth and hits the plant.
• Plants absorb the sunlight with pigments such
as cholorphyll.
• Notice in the equation above that a plant
converts 6 molecules of carbon dioxide at a
time.
• How many carbons does the sugar product
have? Why?
• Plants use this sugar that they created to
produce complex carbohydrates such as
starches.
What is photosynthesis: review
Why does the plant make it’s own sugar?
1. It uses the energy for growth and
development.
2. The sugar is usually a starch in which other
animal can eat.
• Through the food chain, the animal indirectly
uses the energy of the sun with the plant
being the middle man.
Flowers
• Many plants have flowers
for reproduction
• Flowers not only look and
smell pretty but are
important in the
reproduction process
• The sweet smell and bright
colors attract other
organisms to pollinate.
• Bees and butterflies are
examples of pollinators.
Flowers have some basic parts.
Most have both male and female
organs.
A. Pistil: female organ.
• The pistil usually is located in the
center of the flower and is made
up of three parts:
1. Stigma: sticky stem-like tube that
catches pollen
2. Style: supports the stigma, holds it
up high to catch pollen
3. Ovary: contains the female egg
cells called ovules.
B. Stamen: The male part of
the flower.
• They usually surround the
pistil.
• The stamen is made up of
two parts:
1. anther produces pollen
(male reproductive cells).
2. filament holds the anther
up.
Fertilization: steps
1. pollen lands on the stigma,
2. a tube grows down the
style and enters the ovary.
2. Male reproductive cells
travel down the tube and
join with the ovule (egg),
fertilizing it.
3. The fertilized ovule
becomes the seed, and the
ovary becomes the fruit.
This is how apples are made
• Petals: help attract
pollinators such as bees,
butterflies and bats.
• Sepals: tiny green leaflike parts at the base of
the flower.
• They help to protect
the developing bud.
• Fruit: the ripened ovary of a
plant containing the seeds.
• How does this happen?
• After fertilization, the ovary
swells and becomes fleshy
to protect the developing
seeds.
• fruits help seeds spread
• Animals do not digest the
seed and excrete them in
another area
• The seed will germinate and
grow where it is excreted.
Ovary to fruit
The Seed
• Seeds are made up of a
small embryo, a food
source and a seed coat.
• Seed coat protects the
seed.
• The embryo grows into
the plant.
• The food source feeds the
embryo until it can
undergo photosynthesis.
• Seeds are a plant's way of
getting from one area to
another
• Usually does this with the
help of wind, water or
animals.
• Every seed is a tiny plant
embryo with leaves, stems,
and root parts.
• It’s waiting for the right
conditions to make it
germinate and grow.
• Water gives it this spark and
growth enzymes are
activated.
Review questions
• Most autotrophs store energy in the form of
1. starches
2. carbon dioxide
3. water
4. nucleic acids
• 7 The largest amount of DNA in a plant cell is
contained in
• (1) a nucleus
• (2) a chromosome
• (3) a protein molecule
• (4) an enzyme molecule
• Which part of a molecule provides energy for
life processes?
• (1) carbon atoms (3) chemical bonds
• (2) oxygen atoms (4) inorganic nitrogen
• The dissolved carbon dioxide in a lake is used
directly by
• (1) autotrophs (3) fungi
• (2) parasites (4) decomposers
How was it discovered?