Download Cellular Energy

Do Now:

Get a textbook and turn to page 221

Read section 9.1: Chemical Pathways

Answer Questions 1-4 on page 225
Cellular Energy
DNA Test Re-takes

Thurs 1/21/16 after school, rm 303

Fri 1/22/16 after school, rm 303
8.1: How Organisms
Obtain Energy
MAIN IDEA: All living
organisms use energy to carry
out all biological processes.
Why do living things need
energy?
Metabolism
 All
of the chemical reactions in a cell
 Metabolic pathway – product of one
reaction is the substrate for the next
reaction; like a chain reaction
2 Types of Metabolic Pathways
– break down large
molecules & release energy
 Anabolic – use energy from catabolic
to build larger molecules from smaller
ones
 Relationship between 2 pathways –
continual energy flow
 Catabolic
Metabolic Pathways in an
Ecosystem
Photosynthesis
Cellular Respiration
 Anabolic
 Catabolic
 Light energy (sun)
 Organic molecules
 chemical energy
broken down to
release chemical
 Stores chemical
energy
energy in glucose
 Can be used by
autotroph or
consumed as food
ATP: Unit of Cellular Energy
 ATP
= Adenosine triphosphate
 Provides chemical energy for cells
 Found in all living things
 Most abundant energy molecule
 Made of adenine base, ribose
(sugar), and 3 phosphate groups
ATP molecule
ATP Function
 ATP
stores energy in bond between
2nd and 3rd phosphate groups
 When this bond is broken:
energy
is released
forms a molecule called adenosine
diphosphate (ADP) and a free
phosphate group
Do Now: Write the answers in
your notebooks

What is the difference between a
heterotroph and an autotroph?

Name an example of a catabolic reaction
and an anabolic reaction

Is a Venus flytrap an autotroph or a
heterotroph?

What would happen if we put an aquatic
plant in the yellow solution that you
exhaled CO2 into?
8.2: Photosynthesis
MAIN IDEA: Light energy is
trapped and converted into
chemical energy during
photosynthesis.
Photosynthesis
Process by which autotrophs like plants
(and some bacteria and green algae)
make their own food
 Takes place if organism has chlorophyll
(green pigment)
 Usually happens in leaves

Photosynthesis cont. (don’t
copy)
 Anabolic
reaction
 Requires energy in form of sunlight
 Uses water, carbon dioxide, and energy
from sunlight to make glucose
What do plants need?
Which are used in
photosynthesis?
Photosynthesis Equation
sunlight
Water + carbon dioxide  oxygen + glucose
sunlight
6H2O + 6CO2 
6O2 + C6H12O6
How do plants get what they
need?
Plant Structure and Photosynthesis
 Plants
get water from roots, transported
to leaves by xylem
 Stomata – “doorways” into leaves for
gases
CO2 in and O2 out
Gases cannot pass through cuticle
 Sunlight captured in chloroplasts in
cells, which produce chlorophyll
Xylem
Stomata
Stomata
Chloroplast
Why do plants need sugar
(glucose)?
Plants use glucose for…
 Sugar
gives plants energy
 Starch (storage) gives consumers
energy
 Cellulose – provides structure
 It can make some larger molecules
plants need (like lipids and proteins)
Photosynthesis Reactions
2
main phases:
Light-dependent reactions
Light-independent reactions
2 Phases
 Phase
1: Light-dependent reactions
Light needed
Occurs in thylakoids
 Phase 2: Light-independent (Calvin
Cycle)
Light not directly needed
Occurs in stroma
Phase 1: Light Reactions
Light energy  chemical
energy in the form of ATP and NADPH
 PURPOSE:
 1.Light
absorbed by pigments (chlorophyll
and accessory pigments)
 2. Water is split by light, oxygen released
Light Reactions
 3.
Electron transport chain: electrons
from water go through chain to make
NADPH
 4. Chemiosmosis: Hydrogen from
water used to store energy in ATP
Phase 2: Light-Independent
Reactions (Calvin Cycle):
 PURPOSE:
Energy from NADPH and
ATP is stored in molecules of glucose
 ATP and NADPH – only short-term
energy storage
 Glucose – stores energy for a long
time
Calvin Cycle
 1.
Carbon dioxide used to start cycle
 2. Enzyme rubisco is used to convert
carbon dioxide to glucose
 3. Glucose = long-term energy
storage
8.3: Cellular
Respiration
MAIN IDEA: Living organisms
obtain energy during cellular
respiration.
What do you remember…?
 How
do our bodies use our food for
energy?
 Is cellular respiration breathing?
Explain.
Cellular Respiration Overview
 catabolic
reaction
 Occurs in mitochondria
 Uses glucose and oxygen to make
energy (ATP)
 ALL organisms go through
respiration- some aerobic (needs
oxygen), some anaerobic (doesn’t
need oxygen)
Cellular Respiration Equation
Glucose + oxygen  carbon + water + energy
dioxide
C6H12O6 + 6O2  6CO2 + 6H2O + energy
REVERSE OF PHOTOSYNTHESIS!!!
Mitochondria: “the powerhouse”
Stages of Respiration
1.
2.
3.
Glycolysis
Krebs cycle
Electron Transport
1st Stage: Glycolysis
 Anaerobic
 Occurs
in cytoplasm
 Breaks down glucose into 2 molecules
of pyruvate
 Makes 2 ATPs
2nd Stage: Krebs Cycle ( A.K.A TCA or citric acid cycle)
still has a lot of energy –
must be broken down to CO2
 Occurs in mitochondrial matrix
 makes 2 ATP
 Pyruvate
Electron Transport
 Final
step of cellular respiration
 Occurs in inner mitochondrial
membrane (cristae)
 The most ATP produced here (about
30-34 ATP)
Review: Put the steps in order at
the top of a chart:
 Krebs
Cycle
 Electron Transport
 Glycolysis
Fill into your chart: (Some are
used more than once!)
 Makes
2 ATP
 Makes 30 ATP
 Aerobic
 Anaerobic
 In cytoplasm
 In
cristae
 Makes carbon
dioxide
 Uses oxygen
 In matrix
Anaerobic Respiration
 Happens
with low oxygen
 Cells still do glycolysis
 CANNOT do Krebs or e- transport
 Instead, cell does fermentation to keep
glycolysis going -ONLY MAKES 2 ATP!!
Fermentation: 2 Types
 Lactic
acid fermentation
Pyruvate  lactic acid
Skeletal muscle produces during
strenuous exercise
Some microorganisms do this –
used to make cheese, yogurt, sour
cream
Fermentation: 2 Types
 Alcohol
fermentation
Occurs in yeast and some bacteria
Pyruvate  alcohol and carbon
dioxide