Title: The digestive system, thermodynamics, enzymes, and transport across membranes
1The digestive system, thermodynamics, enzymes,
and transport across membranes
- April 28, 2003
- Learning objectives-
- Understand the major organs involved in the
digestive system - Understand the molecular difference between
sugars and lipids - Understand how enzymes break down complex
molecules to derive energy - ATP is the energy currency of the cell
- Understand how complex molecules are built up and
know that this is an energy-requiring process - Workshop-Work in groups to report on some aspect
of digestion - Homework-see last slide
2Grading
- Quizzes (15), Homework (10), Midterm (25),
Writing assignment (15), Final Exam (35) - 6 Quizzes (each 10 points) 60 points
- 1 Midterm 100 points
- 1 paper 60 points
- 1 final 140 points
- 6 homeworks (ea. 6.67) 40 points
- Total 400 points
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9(ATP) (warmth)
First Law of Thermodynamics-Energy cannot be
created or destroyed but it can change
form. Second Law of Thermodynamics-Systems
change in a way that increases disorder of the
system and its surroundings
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12- Enzyme action video 1
- Enzyme action video 2
- Enzyme action video 3
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14Characteristics of enzymes
- Globular proteins that function as biological
catalysts to mediate specific biochemical
chemical reactions - Enzymes are not changed by the reactions they
mediate - Functional units of metabolism - responsible for
all biochemical reactions - May require cofactors/coenzymes for reaction to
occur - metal ions - e.g., Mn2, Zn2, Fe3
- coenzymes (NAD, TPP, THF, etc.)
15Characteristics of enzymes (cont.)
- Apoenzyme - enzyme lacking essential cofactor
- Holoenzyme - intact functional enzyme
containing all cofactors/coenzymes - Substrate (S) - molecules that enzymes react with
- Product (P) - molecules formed by enzyme-mediated
reactions
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18Obesity in America
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20What is a calorie?
- The calorie (symbolized cal) is the unit of heat
Heat is a form of kinetic energy transfer from
one medium or object to another. An energy
transfer of 1 cal will raise the temperature of
one gram (1 g) of pure liquid water by one degree
Celsius (1 oC) - In nutrition, a unit called the diet calorie is
sometimes mentioned this unit is equivalent to
1000 cal, or one kilocalorie (1 kcal). - Calorie content is measured with a bomb
colorimeter
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22H
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24Workshop
- Websites on human digestive system
- Work in assigned groups of two to give a 6 minute
presentation to the class on a molecular aspect
of human digestion prepare a 3 question quiz for
the class - Starch hydrolysis
- Protein digestion
- Fat emulsification
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26Types of transport
- Passive-requires no energy
- Facilitated-requires no energy (put needs a
protein transporter) - Active transport-requires energy
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30Video on transport systems
31Endocytosis vs. exocytosis
Do the following exercises
32Homework Due May 5
- Answer Reviewing Ideas on p. 74, problems 1, 2,
5-9, 11 Using Concepts on p. 75, problems 2, 3,
6, 8, 10 - Answer Check and Challenge questions on p. 85
- Reading for next week 226-229 and familiarize
yourself with the following website
http//www.ncbi.nlm.nih.gov/books/bv.fcgi?callbv.
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