Energy Flow

1
Energy Flow
2
All cells require energy to do work

• Animal cells get their energy from food
• Plant cells get their energy from light or food
  they already made.

Energy to do work
ATP
ADP
Energy from food (mitochondria) Energy from
sunlight (chloroplasts)
3
Biology uses these terms to describe how
organisms get their energy

• Autotrophs
• Heterotrophs
• Chemoautotrophs
• photoautotrophs

4
Autotrophs can make their own food energy

• Photoautotrophs make their food using sunlight
  energy (plants)
• Chemoautotrophs make their food using chemicals
  like sulfur (ocean vent bacteria)

5
Autotrophs are also known as producers
6
Heterotrophs must consume food for energy

• Herbivores consume plant material for food
• Carnivores consume animal material for food
• Omnivores consume both plants and animals
• Scavengers consume dead material

7
Heterotrophs are also known as consumers
8
The flow of energy through ecosystems is mapped
using food chains and food webs.

• Food webs are built by combining food chains
• The arrows indicate energy flow from the food to
  the consumer
• All food webs start with a producer

9

• Ocean Food Web

10

• Terrestrial food web

11
Most of the energy flowing through a food web is
lost as heat or in body waste.

• Only about 10 of the energy in food makes it
  into the cells of the consumer
• 90 of the energy is lost as heat or remains in
  waste products

12
Decomposers harvest energy from body waste or
dead material as it rots.

• Decomposers convert dead matter into carbon
  dioxide, water, and fertilizer minerals
• Decomposers release carbon, water, nitrogen,
  potassium and phosphorus for recycling by plants

13

• Decomposers make fruit rot

14
Decomposers

• Fungi prefer dead plants
• Molds
• Mildews
• mushrooms
• Bacteria decompose everything
• E. coli
• Soil bacteria

15
Biomass is matter made by living organisms

• Biomass can be living
• Plants, animals, bacteria, fungi
• Biomass can be newly dead
• Carrion- dead animal material
• Detritus- dead plant material
• Biomass can be very old dead
• Fossil fuels like coal and petroleum

16

• Carrion includes all dead animal material that
  feeds scavengers like
• Crows
• Opossums
• Vultures

17

• Detritus is dead plant material that feeds
  scavengers like
• Earthworms
• Termites
• Millipedes

18
Trophic Pyramids track biomass through ecosystems

• Base contains producer biomass
• Next level up contains primary consumer biomass
  herbivores
• Next level contains secondary consumer biomass-
  carnivores and omnivores
• Next level- tertiary consumers, usually
  carnivores
• Apex quaternary or top predators

19
Each level in the trophic pyramid is MUCH smaller
than the level below it.

• Remember 90 of energy/biomass is lost at each
  step up
• Energy/biomass is lost as heat and waste
• Decomposers consume the waste and make it rot
  away into carbon dioxide, water, and mineral
  fertilizers

20
PHOTOSYNTHESIS
21
Photosynthesis is the metabolic pathway plants
use to make biomass

• Reactants water, carbon dioxide
• Energy source light energy
• Products glucose(biomass) and oxygen

Chemical Equation for Photosynthesis 6H2O
6CO2 C6H12O6 6O2 ATP energy
22
Photosynthesis has two parts

• Light Reactions (ATP production)
• Calvin Cycle (Carbon fixation)

23
Light Reactions

• The light reactions accomplish two tasks
• 1. breaks apart water molecules to produce
  electrons, hydrogen ions, and oxygen
• 2. uses light energy to change ADP into ATP.

24
The light reactions can only use certain colors
of light

• Bluish light works
• Reddish light works
• Greenish light does not work

25
Chlorophyll is the pigment plants use to do
photosynthesis.

• Chlorophyll is built into the membranes of
  thylakoids inside chloroplasts.
• Chlorophyll absorbs reddish and bluish light
• Chlorophyll reflects or transmits greenish light.

26

• Chloroplast

27
Calvin Cycle

• The Calvin cycle uses electrons, hydrogens, and
  ATP to build glucose
• 1. 6 carbon dioxides are combined to make one
  glucose
• 2. ATP and electrons from the light reactions are
  used up to build glucose
• Glucoses are polymerized to build polysaccharides
  (biomass)

28
Structure of a plant Leaf
Cuticle
29
Respiration
30
There are two kinds of respiration

• Aerobic aka Cellular Respiration
• Anaerobic respiration aka fermentation

31
Cellular Respiration is the metabolic pathway
cells use to make ATP from food using mitochondria
32
Cellular Respiration

• Also called aerobic respiration
• Requires oxygen and glucose
• Takes place in mitochondria
• Produces ATP and heat energy
• Each glucose is broken down into 6 carbon dioxides

33

• Mitochondrion structure

34
Fermentation is another way of getting energy
from glucose

• Does not require oxygen
• Produces dangerous waste products
• Also known as anaerobic respiration

35
Alcohol Fermentation

• Changes glucose into ethanol and carbon dioxide
• Produces ATP from ADP
• Performed by yeast cells
• Make bread rise
• Change juices into alcoholic beverages

36
Fermentation Industries
Beer-making
Bread-making
37
Lactic acid fermentation

• Changes glucose into lactic acid
• Changes ADP into ATP
• Performed by bacteria and muscle cells
• bacteria milk go sour
• Bacteria change milk into yogurt
• Muscle cells switch to anaerobic lactic acid
  fermentation when they run out of oxygen

38
Glucose is first split into two pyruvate molecules

• Glycolysis means to break sugar
• One glucose ? two pyruvates

39
Aerobic respiration processes pyruvate inside
mitochondria

• Glucose?2 pyruvates
• Pyruvates actively transported into mitochondria
• Pyruvate converted to CO2 and H2O to release
  energy

40
Respiration changes pyruvate in the cytoplasm

• Glucose?2 pyruvates
• Pyruvates processed to release energy
• Aerobic respiration uses mitochondria to burn
  pyruvate into CO2 and H2O
• Alcohol fermentation
• Pyruvates changed to CO2 and ethanol
• Lactic acid fermentation
• Pyruvates changed to lactic acid

41
Efficiency

• Aerobic respiration gets a lot more energy out of
  glucose than anaerobic respiration
• Aerobic respiration produces about 36 ATPs per
  glucose molecule