Bio 10: Intro to BiologyInstructor: Paul Nagami

Laney College October 2, 2013

Photosynthesis

Agenda

• Administrative Stuff• How to Earn Partial Credit for Test

Corrections• Photosynthesis: Using the Sun’s

Energy to Piece Together Carbon• Photosynthesis and Respiration• The Calvin Cycle in brief• Wrap-up

How to Correct a Test• For any test, you can earn back half-credit for

answers you missed.• To do so, you must return your test to me

within one week of getting it back.• Staple a list of corrections to the test. These

corrections must include• Correct answers for the questions you

missed• Clear explanations of why each answer

was incorrect.Example: If you answered B to some multiple-

choice question, and the answer was E, you must not only include “E” in your answers. You must also explain why B was wrong!

What Do You Already Know?

Why is photosynthesis important?

Explain on your index

cards.

Without Photosynthesis… We Can’t Breathe!

Photosynthesis: Not Just for Plants“Protist”

AlgaePlants Cyanobacteria

Eukaryote Eukaryote ProkaryoteCyanobacteria: Cyan = blue-green

Autotroph: Auto = self, troph = feeding

Which of the Following Is Necessary for Photosynthesis in Living Things?

A) A nucleus

B) Chloroplasts

C) Mitochondria

D) A cell membrane

E) None of the above

Photosynthesis in Prokaryotes

This picture depicts a cyanobacterium, a prokaryote. But… what feature of this cell appears to contradict that statement?

ChloroplastsOrganelles that contain “internal sacs.”

Green from chlorophyll.

Photosynthesis in Two Parts

Light reactions: Use sun’s energy to make ATP and convert NADP+

to NADPH.

Dark reactions:Use NADPH to put together sugar from carbon dioxide.How does this

compare to glycolysis and respiration?

The Light ReactionsConsider this scenario:

Maria is growing flowers by the window of a room. The window’s the only light source. Trying to liven up the room with color, a friend of hers puts a green plastic curtain in front of the window. He reasons that since green light can still get through the curtain, the plants will be okay.What do you think would happen to the plants,

and why? Would blue curtains have been better?

Plants Don’t Use Green Light Efficiently!

Light Energy is Used to Move an Electron

Don’t Sweat These Details!

You should know what photosynthesis does and how it is similar to or different from what we’ve studied before. You do not need to know the exact path the electrons take…. just where they begin and end!

Don’t panic! Follow the electrons!Does water get oxidized or reduced?

Does NADP+ get oxidized or reduced?

Chloroplasts vs. Mitochondria

What you know about respiration will help you understand photosynthesis!

Electron Transport, Simplified

The Dark Reactions: Making Sugar

Know what goes in.Know what comes out.

Don’t sweat the fine details of the Calvin cycle! Have a broad sense of how it works.

Don’t memorize this.

Let me show you a simpler version!

The Calvin Cycle, Simplified

The Big Picture

Review!