Photosynthesis! Feed me Seymour!

The first half of…the circle of life!

The autotrophic lifestyle Remember suffix/prefix?: autotrophs make their own food – this allows them to fill the role of producers in our global food web. So what would a different type of organism that consume different things? Hint: Same vs different?

Here, there, and everywhere… Lets take a look Photosynthesis happens in many different organisms: Eukaryotic Plants Protists: algae, euglena Some prokaryotes: cyanobacteria Q: what would be some key differences between photosynthetic eukaryotes and photosynthetic prokaryotes?

Some of the different types of leaves

Basics: Light Where does it come from? Light is the fuel that drives PS. Remember – PHOTOsynthesis – making things with light. The key: as photons are absorbed by the organism, they are able to excite electrons. Hrm… what is the suffix here?

Don’t Look Directly at Me!

Pigments Pigments are compounds that allow plants to absorb light. Examples: Chlorophyll a and b (green) Carotenoids (yellow, red, purple)(don’t’ need to know) Beta-carotene, xanthophyll Phycoerythrin (reddish) (don’t’ need to know) Phycocyanin (blueish) (don’t’ need to know) Q: What do you think are examples of organisms where each is found?

So how do colors work then? Spring Vs. Fall fashion…Why?

Colors? Yea I see’s em Gamma rays X-rays UV Infrared Micro- waves Radio 10–5 nm 10–3 nm 1 nm 103 nm 106 nm 1 m 103 m 380 450 500 550 600 650 700 750 nm Visible light Shorter wavelength Higher energy Longer wavelength Lower energy

Absorption Spectra

Lets look now at some folks who helped discover Jan van Helmont

Joseph Priestley

Jan Ingenhousz Light needed by plant in order to refresh air in jar.

Photosynthesis: Reactants and Products Section 8-2 Light Energy Chloroplast CO2 + H2O Sugars + O2

Making Oxygen for us all As the ‘opposite’ of respiration (we will learn later), photosynthesis consumes carbon dioxide and produces oxygen.

Chloroplast has a structure? YES! Know the basic parts of the chloroplast – it is the source of all eukaryotic photosynthesis. Also Long term Thought: Be able to compare/contrast the chloroplast and mitochondrion – where are similar processes taking place? Q: what are some similarities between a chloroplast and a mitochondrion?

The Goal of Photosynthesis The goal of PS is to FIX carbon dioxide into organic compounds – AKA: Make sugars. This means that in all the flowers, trees, and bushes around you, all the MASS you see was built from carbon dioxide GAS. Q: what else do plants need besides carbon dioxide and why?

So of course…we need to figure out some basics of energy. So…what is ADP then?

A tale of two phases… PS proceeds in two main phases: H2O CO2 Light LIGHT REACTIONS CALVIN CYCLE Chloroplast [CH2O] (sugar) NADPH NADP  ADP + P O2 ATP PS proceeds in two main phases: The ‘Light Reactions’ The Calvin Cycle (‘Dark Reactions’)

The Light Reactions Phase 1! A.K.A. Light Dependent Reactions

Pigments! First a reminder: Q: What is the ‘work’ that is done? Pigments are molecules that absorb light. In photosynthesis, this absorption of energy is translated into excited electrons which then can do work. Chlorophyll is the primary pigment in plants Q: What is the ‘work’ that is done?

What’s up with colors? Light Reflected Chloroplast Absorbed Granum Transmitted

We all know that plants need water! Q: what is given off as a waste product from the splitting of water?

Fast review… What is water again? So what is released?

Inside the thylakoid membrane

How do we move stuff (electrons) around? Well, there is no real containers for energy, so lets just imagine we could put into a container… Mill makes ATP e– Photon Photosystem II Photosystem I NADPH  

These containers have a name... NADP+ and NADPH Ok sounds the same what’s the difference? Well, what do you remember about Electrons? Now if we are carrying electrons… NADP+ NADPH

OMG PICTURES!

Electron Transport Chain Just like in cellular respiration! (After this section) Electrons are passed from higher to lower energy levels – as they are passed down, they can do work – this work is pumping protons across the thylakoid membrane. The gradient (where have you seen this before?)generated causes protons to flow through ATP synthase, and….BAM! ATP is formed.

ATP synthase (You don’t have to mention to your class) An enzyme that catalyzes the reaction in which ATP is made from ADP and inorganic phosphate Consists of many subunits – altogether looks like a windmill – has an axle and subunits that spin around Has a membrane region and a matrix region

Like a windmill

Protons are the wind! The enzyme is powered by the flow of protons through the enzyme across the Inner Mitochondrial Membrane. This has to do with POTENTIAL ENERGY and the ELECTROCHEMICAL GRADIENT

Making the Grade-ient The proton gradient is created by the chain itself – as electrons flow through the chain the protein complexes pump protons across the membrane from the matrix to the Intermembrane space. This creates an electrochemical gradient…

BAM!!! ATP is formed.

To be continued… For your interest: recently in the depths of the South American rainforest, a ‘sinkhole’ was discovered. This is essentially a microenvironment where there has been no gene flow for millions of years and the species inside have been allowed to take their own, unique path of evolution. Here are just some of the never-before seen species from this newly discovered location.

Nah just joking!! PHOTOSHOP BABY!!!! Muhahaha

The end? As a group, your task is to conduct an in-depth top 10 list of YOU think are important topics of photosynthesis Try to make sure you don’t confuse small sections vs. overall topics. NOTE: this will be of great benefit to you…in case you were wondering…