Post on 28-Dec-2015
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ATP, Photosynthesis, and Cellular Respiration:
Energy in a Cell
I. Background information
A. What is energy? --the ability to do work
B. Why is it needed?--Cells need energy to maintain homeostasis
and carry out life functions.
C. Heterotrophs get energy from _______ .
Ex: animals, fungi, some protists, some bacteria
D. Autotrophs get energy by __________.
Ex: plants, some protists, some bacteria
E. The chemical bonds in food are broken down to release the chemical energy stored in them.
F. However, NOT all of the energy is used at once. Some of it has to be stored.
II. ATP—adenosine triphosphate—an energy-storing molecule
phosphate bondsATP is made of:3 phosphates1 sugar1 adenine
A. Energy is stored in the phosphate bonds.
B. Energy is released when the phosphate bonds are broken.
C. When energy is released from ATP, a phosphate is released and ADP is left.
D. ADP—adenosine diphosphateADP is made of: 2 phosphates
1 sugar 1 adenine
Let’s look at this reversible reaction
in
3 different ways…
ATP ADP + phosphate + energy
ATPenergy
energy
ADP + phosphate
+ + energy
ADP + phosphate + energy ATP
III. Photosynthesis
photo—means lightsynthesis—means to make
*Photosynthesis is the process in which autotrophs use light energy to make food.
*Chemosynthesis is a similar process in which some bacteria use inorganic compounds to make food.
chemo—means chemical
*Equation for Photosynthesis:
CO2 + H2O light energy C6H12O6 + O2
carbon dioxide + water light energy glucose + oxygen
Note:Chemical equation at topWord equation on bottom
A. Where does photosynthesis take place?
1. in the chloroplasts, which contain the green pigment chlorophyll
2. In plants it mainly occurs in the leaves.
B. Requirements for Photosynthesis:
1. water (H2O)2. carbon dioxide (CO2)
3. sunlight (or light energy)4. chlorophyll (which is
already present in the plant)
Stoma (stomata-plural) of a leaf
C. Products:
1. Main Product—glucose (C6H12O6)
2. Waste Product or by-product—oxygen (O2)
D. Two Stages:1. Light reactions (light-dependent)-
--involves Photosystem I and II
a. Chlorophyll absorbs light energy and uses it to split water.
b. photolysis—splitting of water
c. Take place in the grana or thylakoids
Chloroplast Structure
2. Dark reactions or Calvin Cycle
(light-independent; Calvin-Benson Cycle)
a. Do NOT require light!
b. Glucose is produced.
c. Take place in the stroma
Overview of Photosynthesis
IV. Cellular Respiration *a process in which
organisms (heterotrophs AND autotrophs) break down food to release energy
*There are 2 types of respiration:aerobic – using Oxygenanaerobic – Not using Oxygen
*Equation for Aerobic Respiration:
C6H12O6 + O2 CO2 + H2O + ATP
glucose + oxygen carbon dioxide + water + energy
Mitochondrion Structure
Mitochondrion
1. Aerobic respiration involves 3 processes:
a. glycolysis—splitting of glucose
- doesn’t require oxygen
- occurs in the cytoplasm
- 2 ATPs to start, produces 4 ATP = Net’s 2ATP
- produces 2 Pyruvate molecules
b. citric acid cycle (Krebs cycle)
- 2 pyruvate enter
- in Matrix of Mitochondria
- CO2 waste product
- small amounts of ATP, FADH, NADH produced
c. electron transport chain
- inner membrane of Mitochondria
- Go In: O2and Energy Carrying molecules
- Water, Heat, and 34 – 36 ATP produced
• TOTAL ATP: Glycolysis (2) + ETC (34) = 36 ATP!
2. Anaerobic Respiration
1. Does NOT require oxygen
2. Produces only 2 ATP’s total
3. Takes place in the cytoplasm
4. Also called fermentation
5. Begins with glycolysis
C. Types of Fermentation (Anaerobic Respiration):
1. Lactic acid fermentation—
a. takes place in animals
b. Lactic acid is the waste product.
c. Lactic acid builds up in muscles, causing muscle fatigue.
2. Alcoholic fermentation—
a. takes place in some microorganisms such as yeast
b. Ethyl alcohol and carbon dioxide are the waste products.
c. Process used in making alcoholic beverages
D. Both types of Respiration:
Main product=energy (ATP)
E. For Aerobic:
Waste products=carbon dioxide and water
F. Contrasting TableCategory Photosynthesi
sRespiration
Organelle Chloroplast Mitochondrion
Energy Required Produced
Glucose (food) Produced Required
Oxygen Produced Required
Carbon dioxide Required Produced