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BIOSC 10 ANNOUNCEMENTS 2/9

•  Review Q3 (chapter 3- notes allowed!)

•  Lecture: chapter 4

•  Wed: Quiz covering chapters 3-4

•  Next Wed (2/18)- Exam 1 (chapters 1-4)

•  Extra Credit: answer all study guide Q’s (guide posted Wed) and submit via Angel before exam

CHAPTER 3 REVIEW

•  What are the main differences in organelles between prokaryotic and eukaryotic cells?

•  What are the main differences between plant and animal cells?

•  What are the components and function of the endomembrane system?

CHAPTER 3 REVIEW

•  What is the function and structure of the cell (plasma) membrane?

•  Know the function of all organelles/ components on your chart!

•  Hypotonic vs hypertonic vs isotonic

•  What is the difference between passive and active transport? Examples of each?

REVIEW Q3

Part 1: Which of the following are present in plant cells but not animal cells?

a.  Plasma membrane and mitochondria b.  Cell wall and chloroplasts c.  Mitochondria and chloroplasts

d.  Vesicles and vacuoles Part 2: True or false? During diffusion, a substance moves from an area of low concentration to an area of high concentration until equilibrium is reached.

CONCEPTS OF BIOLOGY

Chapter 4 HOW CELLS OBTAIN ENERGY

SECTION 4.1: ENERGY & METABOLISM

A hummingbird needs energy to maintain prolonged flight. The bird obtains its energy from taking in food and transforming the energy contained in food molecules into forms of energy to power its flight through a series of biochemical reactions. (credit: modification of work by Cory Zanker)

FIGURE 4.1

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FIGURE 4.2

•  Ultimately, where do most life forms get their energy?

•  Plants (autotrophs) use photosynthesis to capture sunlight

•  Herbivores eat the plants to obtain energy

•  Carnivores eat the herbivores

•  Eventual decomposition of plant and animal material contributes to Earth’s nutrient pool

FIGURE 4.3

•  Both anabolic and catabolic pathways are required to maintain the cell’s energy balance

•  What is the term for the sum of all the chemical reactions inside cells?

•  Energy is stored in bonds •  Sugar molecules have a LOT of energy stored in bonds

6CO2 + 6H2O (+ energy) à C6H12O6 + 6O2

C6H12O6 + 6O2 à 6CO2 + 6H2O (+ energy)

•  Each step of metabolic reactions is facilitated (catalyzed) by enzymes (proteins)

FIGURE 4.4

•  What is the first law of thermodynamics?

•  Energy is transferred and transformed from one system (and form) to another

•  Food we consume provides our cells with the energy required to carry out bodily functions

•  Where is chemical energy stored?

•  What is heat energy?

FIGURE 4.5

•  Still water has potential energy •  Moving water has kinetic energy

•  Endergonic processes require energy •  Exergonic processes release energy

http://www.dbriers.com/

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FIGURE 4.7

Enzymes lower the activation energy of the reaction but do not change the free energy of the reaction

FIGURE 4.8

•  The induced-fit model is an adjustment to the lock-and-key model and explains how enzymes and substrates undergo shape changes to increase the affinity of the substrate for the active site

•  What is competitive inhibition? •  Noncompetitive inhibition?

FIGURE 4.9: NONCOMPETITIVE INHIBITION

•  Allosteric inhibition works by indirectly inducing a conformational change to the active site such that the substrate no longer fits

•  In allosteric activation, the activator molecule modifies the shape of the active site to allow a better fit of the substrate. FIGURE 4.10

How are pharmaceutical drugs developed?

Careers in action: pharmaceutical drug developer

FIGURE 4.11

•  Metabolic pathways are a series of reactions catalyzed by multiple enzymes

•  Feedback inhibition, where the end product of the pathway inhibits an upstream process, is an important regulatory mechanism in cells

SECTION 4.2: GLYCOLYSIS (Step 1 of breaking down glucose to free its energy)

How are endergonic reactions powered? Where is energy stored in ATP?

FIGURE 4.12

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FIGURE 4.13

•  In glycolysis, a glucose molecule is converted into two pyruvate molecules

•  Glycolysis occurs in the cytoplasm

•  No oxygen is required for glycolysis!

GLYCOLYSIS is step 1 of breaking down glucose to free its energy

FIGURE 4.14

When oxygen is present, pyruvate is converted into acetyl-CoA before entering the citric acid (Kreb’s) cycle in the mitochondria

SECTION 4.3: CITRIC ACID CYCLE (Step 2) AND OXIDATIVE PHOSPHORYLATION (Step 3)

FIGURE 4.15

(a) The electron transport chain is a set of molecules that supports a series of oxidation-reduction reactions

(b)   ATP synthase is a complex molecular machine that uses an H+ gradient to regenerate ATP from ADP.

(c)  Chemiosmosis relies on the potential energy provided by the H+ gradient across the membrane.

Oxidative phosphorylation (Step 3)

SUMMARY OF AEROBIC RESPIRATION

•  Step 1: Glycolysis •  Step 2: Citric acid (Kreb’s)

cycle

•  Step 3: Oxidative phosphorylation (ETC)

•  Where does each occur? •  Reactants? •  Products?

1 glucose

Krebs cycle

CO2

(matrix)

NADH

FADH2

ATP

(cytosol)

2 2 glycolysis

2 pyruvate

NADH 2

ATP 2

ATP 32

2

2 acetyl CoA

NADH 6

CO2 4

mitochondrion

O2 H2O

electron transport chain

Total: 36 ATP

CoA

2

SECTION 4.4: FERMENTATION

•  Fermentation occurs after glycolysis when no oxygen is present for aerobic respiration

•  Fermentation is a type of anaerobic respiration that does NOT produce ATP

•  Fermentation is required to recycle the energy carrier NAD+ for use during glycolysis (which produces small amounts of ATP)

(cytosol)

glycolysis

2 CO2

cellular respiration

ATP

ATP

1 glucose

2 pyruvate

2 lactate

fermentation

2 ethanol If no O2 is available + If O2 is available

CO2 6 H2O 6

O2

mitochondrion

6

FIGURE 4.16

•  Lactic acid fermentation is common in muscles that have used all available oxygen

•  Other examples of lactic acid fermentation?

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FIGURE 4.17

•  Alcohol fermentation is another type of anaerobic respiration that can occur after glycolysis

•  Reactants? •  Products?

FIGURE 4.18

•  Fermentation of grape juice to make wine produces CO2 as a byproduct

•  Fermentation tanks have valves so that pressure (CO2) inside the tanks can be released

•  Other examples of alcohol fermentation?

FIGURE 4.20

Biomolecules enter the pathway of aerobic respiration at different points

Crash course biology video: https://www.youtube.com/watch?v=00jbG_cfGuQ&index=7&list=PL3EED4C1D684D3ADF

CHAPTER 4 REVIEW

•  Endergonic vs exergonic reactions •  Anabolic vs catabolic reactions •  What is metabolism?

•  Where is chemical energy stored? •  What are enzymes? How is their activity regulated? •  What energy currency is used by cells?

•  What are the three major steps of cellular respiration? Where does each occur? Overall products & reactants?

•  Where and when does fermentation occur? Products & reactants?

HOMEWORK FOR WEDNESDAY

•  Study chapters 3-4 for quiz Wed!

•  Rewriting/typing/consolidating notes is helpful

•  Blank organelle charts posted on Angel

•  Short videos on chapter 3 & 4 topics posted on Angel

•  Review questions in text (end of each chapter)

•  Wed will be review for exam 1 (chapters 1-4)

•  Bring all study materials!

•  Study guide will be posted and handed out

•  Extra Credit: answer all study guide Q’s and submit via Angel before exam