Lecture7_MCDB_20.pdf

Lecture7_MCDB_20.pdf - Lecture 7 Cellular Respiration...

Info iconThis preview shows pages 1–6. Sign up to view the full content.

View Full Document Right Arrow Icon
Lecture 7 • Cellular Respiration • rEvolutionary ideas – What is evolution? – How does evolution work? • Evidence for evolution 1 3 Joseph Priestley and the Bell Jar experiment Fires and Mice both consume the same thing: Oxygen 4 Respiration, like fire, is Oxidation Cells oxidize fuel in small steps Cellular Respiration ! Requires (1) fuel and (2) oxygen. ! Potential energy stored in chemical bonds of sugar, protein, and fat molecules. ! Breaks bonds to release the high-energy electrons captured in ATP. ! Oxygen is electron magnet. The first step of cellular respiration: Glycolysis is a universal energy-releasing pathway.
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Glycolysis Three of the ten steps yield energy quickly harnessed to make ATP . High-energy electrons are transferred to NADH . Net result: ! each glucose molecule broken down into two molecules of pyruvate ! ATP molecules produced ! NADH molecules store high-energy electrons The second step of cellular respiration: the Krebs cycle (or TCA cycle) extracts energy from sugar. The Preparatory Phase to the Krebs Cycle Payoff from the Krebs cycle: ! ATP ! NADH ! FADH 2
Background image of page 2
The third step in cellular respiration: ATP is made by ATP Synthase using the electron transport chain . Cellular Respiration is a Three-Step Process #2) This proton concentration gradient represents a significant source of potential energy!
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
What happens if a cell runs out of Oxygen? e.g. muscle cells during intense excercise Alternative Pathways Eating a complete diet: cells can run on protein and fat as well as on glucose. Evolution and Natural Selection Darwin’s dangerous idea: evolution by natural selection Learning Objectives ! Be able to explain evolution in action. ! Be able to explain Darwin’s journey to an idea. ! Be able to describe and explain the four mechanisms that can give rise to evolution. ! Be able to explain how populations of organisms can adapt to their environment through natural selection. ! Be able to explain how the evidence for the occurrence of evolution is overwhelming. 24 What is Evolution? Genetic change in a population over time Measured as changing allele frequencies Evolution is an ongoing process Populations Evolve Invidividual Organisms DO NOT
Background image of page 4
Why do biologists believe in evolution? • Evidence for evolution is overwhelming • We can watch it happen anytime we want in the laboratory 25 What if you breed fruit flies who could live longer than 20 hours on average? What happened? ! Evolution • a genetic change in the population ! Natural selection • the consequence of certain individual organisms in a population being born with characteristics that enable them to survive better and reproduce more than the offspring of other individuals in the population Does evolution occur? ! The answer is an unambiguous:
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 6
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 09/14/2009 for the course MCDB 20 taught by Professor Cooper during the Summer '08 term at UCSB.

Page1 / 18

Lecture7_MCDB_20.pdf - Lecture 7 Cellular Respiration...

This preview shows document pages 1 - 6. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online