Unit 3 Photosynthesis & Carbon Cycle

Photosynthesis and the Carbon Cycle

Where do trees get their mass? How do they get the atoms necessary to grow from a small seed into a giant living structure? To answer that question you have to think about what a tree is mostly made of. The majority of a tree's structure is cellulose - made from individual glucose molecules. Essentially, most of a tree is made of carbohydrates. We know that carbohydrates are made of C, H and O atoms. So where do those atoms come from?

Note the names of each molecule in the chemical equation!

In photosynthesis:

carbon dioxide + water --> glucose + oxygen

In cellular respiration:

glucose + oxygen --> carbon dioxide + water

I don't recommend you simply memorize these equations - you are capable of understanding them! You know that we breath in oxygen gas and you know we exhale more carbon dioxide. You may ask why do all our cells need oxygen? Why will our brain die without it? We need oxygen to make energy! The oxygen is needed to completely break down glucose into carbon dioxide and water. Without oxygen our cells would make very little ATP -surely not enough to keep our busy brain cells going. This is what cellular respiration is all about! Our cells don't exchange gases just for the fun of it. They do it for a good reason!

As for photosynthesis... you may ask how a tree grows so large from a tiny seed. Well, it first starts by making glucose. Then it can turn that glucose into cellulose and build new cell walls. Or it can turn glucose into starch and store away some energy for the long winter when there isn't enough sunlight to do much photosynthesis.

TOPIC 2 - Carbon cycle

Intro to the carbon cycle video: https://www.youtube.com/watch?v=r75NL3gN5yU

https://www.youtube.com/watch?v=r75NL3gN5yU

Looking at carbon dioxide levels over time: https://www.youtube.com/watch?v=H2mZyCblxS4

Use this link for the remaining questions: https://www.youtube.com/watch?v=UatUDnFmNTY

Want to better understand climate change? This guy talks quickly but makes 24 great points.

https://www.youtube.com/watch?v=ffjIyms1BX4

CARBON CYCLE Note: The two main biological processes in the carbon cycle are photosynthesis and cellular respiration. There are, however, very important processes occurring between the biotic (living) and abiotic (nonliving) worlds that are essential for understanding not only the carbon cycle but how the burning of fossil fuels is affecting our carbon cycle at a rate faster than living organisms can adapt to the affects of climate change.

Carbon cycle diagram -See word document below. Use the internet and this video clip below as resources to get started.

Great short video on the carbon cycle to get you started!

Carbon Cycle -- this was a pretty good one I found on the internet!

How have rising carbon dioxide levels impacted our oceans?

Video shown in class about ocean acidification: https://youtu.be/5cqCvcX7buo

How will climate change affect the NW?

https://archive.epa.gov/climatechange/kids/impacts/signs/index.html

Use this resource to take notes on 3 things that you think will impact your life most living here in the NW. You must explain ocean acidification and less snowpack. The other one you can choose. Take notes and be prepared to demonstrate your understanding.

Possible Extra Credit: What is ethanol and is it a solution for climate change?

A video produced by an ethanol plant about what they do. Listen for connections to molecules and processes we talked about. https://youtu.be/npJ1N-1K84E

A video produced by the History Channel that challenges the efficiency of ethanol: https://youtu.be/PYU-DzpweGc (START AT 30:50 and watch until 40:00)

Watch the two videos and take notes on content that relates to what we have learned about organic molecules, photosythesis, cellular respiration, and the carbon cycle. Write two paragraphs describing the pros and cons of using ethanol for fuel. Turn in both your notes and the two paragraphs with your name and class period. Any extra credit missing these requirements will not be considered.