Homework 7 Due 11/12

What is ATP? What is ADP? Give similarities and differences between the two molecules.

Photosynthesis and Cellular Respiration

ALL CELLS REQUIRE ENERGY

Some chemical reactions release energy (what kind of rxn?) while others absorb energy

All chemical reactions consume activation energy

All cells require energy to perform processes

This is a requirement of life!

Two ways to get food

“troph” = food (nutrition)

Autotrophs– Auto = self– Autotrophs make their own food

Heterotrophs– Hetero = different– Heterotrophs get their food from something else (they

have to eat it)

Two ways to get food

Autotrophs– Producers– Plants, algae, some bacteria

Heterotrophs– Consumers– Animals, fungi, most protists most bacteria– (do you remember the vore terms?)

Cellular Respiration

Cells Breathing

Cellular Respiration

Happens in all cells. Yes both plant and animal cells

Overall Reaction:– C6H12O6 + 6O2 → 6CO2 + 6H2O + 36 ATP

Occurs in Cytoplasm and Mitochondria

Homework 7 Due 11/12

What is ATP? What is ADP? Give similarities and differences between the two molecules.

ATP – when a PO4 is removed, energy is released!

What kind of reaction is this?

Some energy is given off as heat.How would you get back to ATP?

Which comparison between ATP and ADP is correct

A. ATP stores less chemical energy than ADP and phosphate

B. ATP stores more chemical energy than ADP and phosphate

C. Less energy is used to form ATP than is released from ATP and hydrolysis

D. More energy is used to form ATP than is released from ATP and hydrolysis

Which comparison between ATP and ADP is correct

A. ATP stores less chemical energy than ADP and phosphate

B. ATP stores more chemical energy than ADP and phosphate – which is released! This is it!

C. Less energy is used to form ATP than is released from ATP and hydrolysis – NO, it would be the same

D. More energy is used to form ATP than is released from ATP and hydrolysis – see above

A protein in a cell membrane changed its shape to move sodium and potassium ions against their concentration gradients. Which molecule was most likely used by the protein as an energy source?

A. ATP

B. ADP

C. Catalase

D. Amylase

A protein in a cell membrane changed its shape to move sodium and potassium ions against their concentration gradients. Which molecule was most likely used by the protein as an energy source?

A. ATP – Ummm… yeah!

B. ADP – nope, no energy

C. Catalase – nope enzyme (peroxide)

D. Amylase – nope enzyme (digestion)

RESPIRATION

Process of taking ADP and making it ATP again. Involves breaking down

Complicated molecules into simple molecules

Cellular Respiration Overview

Depends on whether or not there is oxygen

Aero = oxygen Aerobic Respiration – makes energy IN O2

Anaerobic Respiration – Fermentation – makes energy WITHOUT O2

3 Stages of aerobic cellular respiration

1. Glycolysis

2. Krebs Cycle

3. Electron Transport System

For each glucose molecule, total ATP = 36

Only 39% efficient, rest is lost as heat.

HOMEWORK 8 – DUE 11/19

Describe the energy changes occurring in each process of photosynthesis.

Describe how energy transformations involved in photosynthesis are related to energy transformations involved in cellular respiration.

Step 1: Glycolysis

Glycolysis makes 2 molecules of ATP (energy) Glycolysis happens in the cytoplasm of the cell Glycolysis is anaerobic Glucose is broken down into smaller molecules

Step 1a: Check for Oxygen

If oxygen is present, two more steps occur in the mitochondria

If no oxygen is present, fermentation occurs Let’s go on as if there IS oxygen

Mitochondria

In ALL eukaryotic cells! (name some. What is NOT?)

Are not original to cells. Most likely a prokaryote of their own Have their own DNA and Ribosomes They take shelter in cells, and in return provide

ATP (cell currency) to their hosts.

Mitochondria Structure

The outer membrane to protect the organelle The intramembrane space (the space between

the inner and outer membranes) The inner membrane is folded into a series

cristae or long folds that greatly increase the surface area of the inner membrane allowing more area for energy production in electron transport.

The matrix – inside the inner membrane

Steps 2 with oxygen:Kreb’s Cycle

Kreb’s Cycle aka citric acid cycle Takes place in matrix Breaks down PRODUCTS from glucose Produces much CO2

Produces 2 ATP

Kreb’s Cycle (Citric Acid Cycle)

Steps 3 with oxygen: Electron Transport Chain

Electron Transport Chain – makes 32-34 ATP H+ ions, FADH2 and NADH are used here. These ions flow across the inner mitochondria

membrane As they flow, they power ATP synthase (sits on

inner membrane) This enzyme attaches PO4 to ADP, making ATP

Energy Tally AEROBIC

36 ATP for aerobic vs. 2 ATP for anaerobic

– Glycolysis 2 ATP

– Kreb’s 2 ATP

– Electron Transport 32 - 34 ATP 36 - 38 ATP

Anaerobic organisms can’t be too energetic but are important for global recycling of carbon

Step 2 without oxygen: Fermentation

The cell must recycle the materials from glycolysis. DOES NOT GIVE AS MUCH ATP.

This recycling process is called fermentation. The product of fermentation is alcohol (ethanol)

and carbon dioxide (prokaryotes) OR lactic acid (for us).

Which types of respiration are useful in increasing the amount of gas in a food product?

A. Fermentation producing lactic acid only

B. Fermentation producing carbon dioxide and ethanol only

C. Aerobic respiration and fermentation producing lactic acid

D. Aerobic respiration and fermentation producing carbon dioxide and ethanol

Which types of respiration are useful in increasing the amount of gas in a food product?

A. Fermentation producing lactic acid only – need CO2

B. Fermentation producing carbon dioxide and ethanol only YES THIS IS IT

C. Aerobic respiration and fermentation producing lactic acid

D. Aerobic respiration and fermentation producing carbon dioxide and ethanol

All of the following are correct about respiration except

A. All plants and animals carry out respiration all the time

B. It consists of glycolysis, Krebs cycle, and the electron transport chain

C. Oxygen molecules are pumped across the inner membrane of the mitochondria

D. Most ATP is produced in the electron transport chain

All of the following are correct about respiration except

A. All plants and animals carry out respiration all the time

B. It consists of glycolysis, Krebs cycle, and the electron transport chain

C. Oxygen molecules are pumped across the inner membrane of the mitochondria – nope, it’s H+

D. Most ATP is produced in the electron transport chain

Glycolysis

A. Produces water

B. Produces oxygen

C. Involves an electron transport chain

D. Is the breakdown of glucose to produce smaller organic compounds

E. Produces carbon dioxide

Glycolysis

A. Produces water

B. Produces oxygen

C. Involves an electron transport chain

D. Is the breakdown of glucose to produce smaller organic compounds

E. Produces carbon dioxide

Photosynthesis

HOMEWORK 8

Describe the energy changes occurring in each process f\of photosynthesis.

Describe how energy transformations involved in photosynthesis are related to energy transformations involved in cellular respiration.

Used by producers to create glucose

Reactants are 6 carbon dioxide and 6 waterCreates 1 glucose moleculeGlucose can be stored (?), used as

structure (?), or directly in respirationSome ATP is also directly produced

Though respiration occurs, more O2 is generated than used

Which of the following best explains the relationship between photosynthesis and cellular respiration?

A. Both produce CO2 and O2

B. Both require energy from sunlight to occur

C. The products of one are the reactants of the other

D. A plant can carry out one or the other process

Photosynthesis

Takes place in specialized structures inside plant cells called chloroplasts

Chloroplasts surround the central vacuole (water storage) of the plant cell. Why?

Photosynthesis

Chloroplasts are one of the special structures in plants.

Chloroplasts are almost certainly cyanobacteria that have hopped into plant cells for a symbiotic ride.

They get a home, the plant gets sugar. What relationship is this?

Chloroplast –vs- Mitochondria

• Both are surrounded by a double membrane with an intermembrane space.

• Both have their own DNA . • Both are involved in energy metabolism. • Both have membrane reticulations filling

their inner space to increase the surface area on which reactions with membrane-bound proteins can take place.

Structures of chloroplasts

Double membrane surrounds stroma – inner fluid Stacks of disks called thylakoids Thylakoids contain chlorophyll – a pigment that

absorbs light energy.

Light is absorbed by pigments

The primary pigment for photosynthesis is chlorophyll a

It absorbs blue and red light, not green (green light is reflected back!)

Absorption spectrumof chlorophyll a

Chlorophyll a is the primary photosynthetic pigment that drives photosynthesis.

Accessory pigments absorb at different wavelengths, extending the range of light useful for photosynthesis.

Leaves are where most photosynthesis occurs

Leaves need direct access to CO2 and H2O They take these in from atmosphere through

stomata Plants can open stomata to take in CO2 and

release O2 (plural is stoma) Plants also take in water through roots which

travels to leaves through vascular tissue called xylem.

Chloroplast Structure & Function

The chloroplast has different spaces: stroma and thylakoid

These compartments and the membranes that separate them serve to isolate different aspects of photosynthesis. Light reactions take place on the thylakoid

membranes. “Dark” reactions take place in the stroma.

Inside a Chloroplast

• Remember: Structure correlates to function!

Homework 9 Due 11/25

• When temperature becomes too warm, leaves close their stoma to conserve water. How will high temperature most likely affect rate of photosynthesis?

• In the autumn, the amount of daily sunlight decreases in time and strength. Additionally, the amount of water in the air decreases with temperature. Explain how deciduous trees cope with the winter season.

Photosynthesis

• 2 different reactions– Light Reactions

• Capture light energy for photosynthesis

– Calvin Cycle• Produces glucose

sugar

The first stage – Light Dependent

1. Occur in Thylakoid – why?

2. Uses chlorophyll to split H2O

3. Captures sun energy

4. Produces ATP and other energy rich molecules

5. Splits water (H needed for next stage and O2)

6. Release O2 from leaf

Using a microscope, a student observes a small, green organelle in a plant cell. Which energy transformation most likely occurs first within the organelle

A. ATP to light

B. Light to Chemical

C. Heat to electrical

D. Chemical to chemical

Using a microscope, a student observes a small, green organelle in a plant cell. Which energy transformation most likely occurs first within the organelle

A. ATP to light

B. Light to Chemical of course. Come on.

C. Heat to electrical

D. Chemical to chemical

The second stage – Light Independent

1. The “Dark” or Carbon Reactions

2. Also called Calvin Cycle

3. Light independent (can occur in light or dark; some enzymes require activation by light)

4. Occurs in stroma

5. Uses the energy from stage 1 (ATP; NADPH) to “fix” carbon in sugar

Photosynthesis and cellular respiration are two major processes of carbon cycling in living organisms. Which statement correctly describes one similarity between photosynthesis and cellular respiration?

A. Both occur in animal and plant cells

B. Both include reactions that transform energy

C. Both convert light energy into chemical energy

D. Both synthesize organic molecules as end products

Efficiency & Photosynthesis

Photosynthesis is not perfect. Depending upon the plant type, it ranges

from being only 1 - 4 % efficient to having 7% efficiency

Without photosynthesis, virtually all plants and animals would become extinct.

Photosynthesis Respiration

• Reaction: CO2+H2O+sunC6H12O6+O2+H2O C6H12O6+O2CO2+H2O+36ATP

• Reactants: Carbon dioxide, water, sun Glucose, oxygen

• Products: Glucose Energy• By-products: Oxygen Carbon dioxide,

water• Cellular location: Chloroplasts Cytoplasm, mitochondria

• Energetics: Requires energy Releases energy

• Chemical paths: Light reactions & Glycolysis, Krebs cycle Calvin cycle & Electron Transport

Syst.

• Summary: Sugar synthesized using Energy released from energy from the sun sugar breakdown

The oxygen that plants give off

A. Comes from the light dependent reactions

B. Comes from the dark reactions

C. Is a by-product of respiration

D. Comes from CO2 that plants absorb

E. Is carried from the Calvin cycle to the light reactions.

The oxygen that plants give off

A. Comes from the light dependent reactions

B. Comes from the dark reactions

C. Is a by-product of respiration

D. Comes from CO2 that plants absorb

E. Is carried from the Calvin cycle to the light reactions.

Name as Light Dependent or Independent

A. Oxygen released - DEPENDENT

B. Carbon fixation occurs - INDEPENDENT

C. Calvin Cycle occurs - INDEPENDENT

D. ATP produced - DEPENDENT

Which is produced by both respiration and photosynthesis?A. Glucose

B. ATP

C. CO2

D. O2

Which is produced by both respiration and photosynthesis?A. Glucose

B. ATP

C. CO2

D. O2

Respiration, Energy & Carbon Cycle

• Energy• Virtually all organisms require energy of

food for:• Making chemicals

(proteins, carbs, etc.)• Movement• Cell division• Heat, electricity and light production

• The way living organisms obtain energy is throughCell respiration

ENERGY: ability to do workNewton’s First Law of Thermodynamics:

“Energy cannot be created or destroyed, it can only be transformed

from one form to another”

• Once a cell has used energy to do work, it cannot be used again by any organism.

(1701)

ENERGYENERGY FLOW IS LINEARSun Earth Producers 1o consumers 2o consum

heat resp, heat resp, heat resp, heat

Energy flows into ecosystem from the sun

Energy travels in a straight line by way of

food chains.

ENERGYHowever, much energy is lost as heat along

the way – as a result of respiration.

Approximately 90% energy is lost on each step!

• Newton’s Second Law of

Thermodynamics:

“In any transfer of energy there is always a loss of useful energy to the system,

usually in the form of heat”

Food ChainsFood chains demonstrate linear nature of

energy• Producers are the base of the food chain,

they include photosynthetic organisms like:• Plants• Algae• Certain bacteria

Food chains• Primary

consumers – all plant eaters (herbivores).

Secondary consumers – Eat primary consumers, (carnivores)

Food chains

• Decomposers – aka detritivores - obtain energy by breaking down remaining organic material of the other members of the food chain.

• Fungi and bacteria.

Matter• All important elements move in cycles;

Environment Organisms

Cycles called biogeochemical cycles:

Water cycle

Carbon cycle

Nitrogen cycle

The Carbon Cycle• Carbon from the atmosphere (CO2) enters the

biosphere by way of plants!– CO2 used in photosynthesis

– Carbon moves into food chain • Carbon is released to the physical

environment by respiration – Release CO2 during respiration

– Amount CO2 fixed in photosynthesis = the amount released by respiration

Carbon Cycle• Carbon moves from atmosphere to

plants to animals and back to atmosphere.

Venus doesn’t have a carbon cycle. It’s hell.

“Look deep into nature, and then you will understand everything better.” Albert Einstein