Cellular Respiration

Cellular Respiration

Unit: Cell Energy

Warm Up Question

How do we obtain the energy we need from the sugars made by plants?

Open Ended

Type your answer to the warm up question here

Here is a reminder of what it was:

How do we obtain the energy we need from the sugars made by plants?

Reminder!

Autotrophs are producers. They make their own food via photosynthesis or chemosynthesis.

Heterotrophs are consumers (like us). We must consume things and extract energy from that food.

Cellular Respiration Overview

• Heterotrophs (like us) cannot make their own food, so we have to find and ingest food to get energy. We get energy from our food through a process called cellular respiration.

• Cellular respiration is the process that releases energy by breaking down glucose and other food molecules for use by the cells.

• ALL organisms perform some type of cellular respiration (heterotrophs-to break down food we consume; autotrophs-to break down the glucose they make in photosynthesis)

2 Types of Respiration

• Aerobic Cellular Respiration (with oxygen and mitochondria present)

• Anaerobic Cellular Respiration (without oxygen or mitochondria present)

Multiple Choice

Which type of respiration uses oxygen and takes place in the mitochondria?

• Aerobic Respiration

• Anaerobic Respiration

Aerobic Respiration Overview

• REQUIRES OXYGEN

• Takes place in the MITOCHONDRIA

• Both plants and animals perform aerobic cellular respiration

Aerobic Respiration Steps

• 1. Glycolysis (Glucose converted into 2 Pyruvic Acids)

• 2. Krebs Cycle (aka Citric Acid Cycle) (releases CO₂)

• 3. Electron Transport Chain (most of the ATP made in Chemiosmosis via the enzyme ATP Synthase and H₂O is made from O₂.

• Around 36-38 ATP made in Aerobic Respiration (most made in ETC)

Multiple Choice

Which step of aerobic respiration converts the glucose into 2 pyruvic acids?

• Glycolysis

• Krebs Cycle (aka Citric Acid Cycle)

• Electron Transport Chain

Look again!

Multiple Choice

Which step of aerobic respiration released CO2?

• Glycolysis

• Krebs Cycle (Citric Acid Cycle)

• Electron Transport Chain

Look again! :)

Multiple Choice

Which step of aerobic respiration makes the most ATP and creates H₂O from O₂?

• Glycolysis

• Krebs Cycle (aka Citric Acid Cycle)

• Electron Transport Chain

Where were the reactants used? Where were the products made?

Anaerobic Respiration Overview

• Remember, glycolysis occurs in both aerobic and anaerobic pathways

• If oxygen is not available at the end of glycolysis, then the cell will continue into an anaerobic process called fermentation.

• Occurs in the cytoplasm of the simplest organisms like bacteria and yeast.

• There are two types of fermentation:

• Lactic acid fermentation (makes muscles sore)

• Alcoholic fermentation (yeast, a fungus in bread, uses alcoholic fermentation to flavor the bread and make it rise)

Lactic Acid Fermentation

• After glycolysis, the pyruvic acids are turned into lactic acids and glycolysis starts over (making 2 ATP each time)

• This is a reversible reaction (which is why after your muscles get sore after a workout, they eventually stop hurting when O₂ returns to your cells.

Alcohol Fermentation

• After glycolysis, the pyruvic acids are turned in 2 steps into CO₂ and ethanol alcohol. Then glycolysis starts over (making 2 ATP each time)

• This is an irreversible reaction (because you lost a carbon to the CO2 which you cannot get back).

Multiple Choice

Which step of respiration is a part of both aerobic and anaerobic?

• Krebs Cycle

• Glycolysis

• Electron Transport Chain

Multiple Choice

Fermentation occurs

• with oxygen

• without oxygen

Multiple Select

What are the products of alcohol fermentation?

• CO2

• Ethanol alcohol

• lactic acid

Multiple Select

What are the products of lactic acid fermentation?

• CO2

• Ethanol alcohol

• Lactic acids

What is ATP, anyway?

• Cells need energy to move, grow, reproduce, etc. ATP supplies this needed energy.

• ATP consists of:

• An adenine (adenosine) molecule

• A monosaccharide called ribose 

• Three phosphate groups (the bonds between these phosphates are where most of its energy is stored)

• When a cell "uses" ATP, it is really breaking off a phosphate (ATP -> ADP) and coupling the energy release from the break to power a reaction such as active transport.

Multiple Choice

Which cell organelle is the site for cellular respiration?

• mitochondria

• chloroplast

• vacuole

• nucleus

Multiple Choice

If an animal has a limited supply of O2, which process would be most affected?

• Alcoholic Fermentation

• Lactic Acid Fermentation

• Aerobic Cellular Respiration

• Anaerobic Cellular Respiration

Multiple Choice

In which way are photosynthesis and cellular respiration different?

• Cellular respiration stores ATP, while photosynthesis releases ATP.

• Cellular respiration produces oxygen, while photosynthesis uses oxygen.

• Photosynthesis releases energy, while cellular respiration stores energy.

• Photosynthesis uses carbon dioxide, while cellular respiration produces carbon dioxide.