Introduction to Plant Biology

First off: What is a plant?

Domain?

Kingdom?

Categories?

What does a plant need?

Water

Sunlight

Nutrients

How do they get them?

Plant cells are specially designed to help the whole plant get everything it needs

These cells make up the plant structure, which is designed to optimize photosynthesis, hydration, and nutrition

Recall: Eukaryotic Cells

What are some things that all eukaryotic cells have? What do these things do? 2 mins

Eukaryotic cells have: A Nucleus, DNA in Chromosomes, Mitochondria, Golgi Bodies, Cell Membranes, Endoplasmic Reticulum, Ribosomes, Vesicles, and proteins of all kinds doing all sorts of different things

What a plant cell different?

A large, central vacuole

A cell wall composed of cellulose

Chloroplasts, which allow the plant to convert solar energy into sugars

Plasmodesmata, which allow plant cells to communicate

Large Central Vacuole

Filled mostly with water

In standing plants, gives the plant internal support to allow rigidity (called turgor) Demo

Also used as a massive storage space, for wastes, cellular materials, and water

Cell Wall Composed of Cellulose

Cell wall has a similar function in plants to that in bacteria:

Protects the plant cell against physical damage, and gives it external structural support to form its shape

However, made of different material... Cellulose!

Structure of Cellulose

In contrast... Bacterial Cell Wall

Chloroplasts

Chloroplasts use the following formula to convert sunlight into sugars:

Sunlight + CO2 + H2O C6H12O6 + O2

Sugars then link up to form starch, which is how they are stored until they are needed

Aside: Endosymbionts

Endo = Inside/Within, Sym = Together, Biosis = Living

Chloroplasts (and mitochondria) are thought to have evolved as their own little microscopic organisms, with their own genome and their own structure

At some point in cellular history, they were absorbed by a distant eukaryotic ancestor, and now are used to perform metabolic tasks inside our cells

Plasmodesmata

Occur only in plants living as multicellular organisms

They are pores between plant cells, which allow the transport of nutrients, wastes, proteins and RNA

Can also allow viral particles to get through...

Recall: TMV

Can transport itself between targets using the plasmodesmata as a way through

In Summary:

Plants are not bacteria Nucleus, Membrane-Bound Organelles, Cellulose

Plants are not protists Complex, Multicellular, Plasmodesmata, Differentiated

Plants are not animals Cell Wall, Chloroplasts, Photosynthesis, Vacuole

Plants are Plants!