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 + CO 2 + H 2 O  C 6 H 12 O 6 + O 2 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!