Photosynthesis

Previously you read about autotrophs and heterotrophs.  The difference being in the way they obtain energy.  Plants are autotrophs, and today I’d like to focus on how plants get the energy they need.

Plants need the following things to get energy to live:

• Water (H2O)
• Carbon Dioxide (CO2)
• Sunlight

The process of converting H2O and CO2 in the presence of sunlight into energy is called photosynthesis.

In order for the water to get to the leaves of a plant where photosynthesis takes place, it is absorbed from the surrounding ground through roots and is brought up through tissue like your blood vessels.

The carbon dioxide is absorbed my the leaf directly through openings (or pores) on the under side of the leaf.

Light-absorbing molecules called pigments capture sunlight for the plant.  The primary pigment in plants is called chlorophyll.  Chlorophyll gives plants their green color because it absorbs reds and blues and reflects green!

Chlorophyll is housed in organelles called chloroplasts.  This is where photosynthesis takes place.

The equation for synthesis looks like this:

6CO2 + 6H2O (in the process of light) -> C6H12O6 + 6O2

carbon dioxide (in) + water (in) -> glucose (used for energy) + oxygen (out)

(That’s the same oxygen we need to breathe!!!)

All that happens in plants which are pretty fascinating, even if they aren’t furry and cuddly!

Cell Specialization

Animal cells and plant cells.  Fungal cells and bacteria cells.  Turns out cell are even more diverse than that.  A unicellular organism, like a typical bacterium, grows and operates alone.  It may hang out with other cells, but they are all on their own.  Some organisms however, are multicellular, and in more complex organisms these cells specialize what they do.

Animal cells specialize in many ways.  Some cells transport oxygen (red blood cells), some help fight foreign invaders (white blood cells), and some signals from your hands to your spine (nerve cells).

Plant cells specialize in different ways also.  The best example is the guard cell which regulates the exchange of oxygen, water vapor, and carbon dioxide.

Another great example, which can be found in both plants and animals is the male and female sex cell.

A group of similar cells that work together is called a tissue.  A group of tissues working together form an organ and a group of organs working together form an organ system.

Muscle cell > Heart muscle tissue > Heart > Circulatory System