Biology exam 106 chapter 7

Cellular respiration

producers and consumers are able to extract the energy from the bonds in glucose and convert it into a form that all living things can use ATP, this series of metabolic reactions

oxidation reactions

strip an electron from an atom in a compound

reduction reaction

add the electron to another compound

chemiosmosis

when ions move by diffusion across a semi permeable membrane

aerobic

oxygen required

anaerobic

oxygen not required

fermentation

processes that use an organic molecule to regenerate NAD+ from NADH

Redox reaction

Oxidation and reduction reactions occur together

The series of reactions that producers and consumers use to extract energy from the bonds of sugar molecules is called?

Cellular respiration

How does the cell harness/transfer energy through redox reactions?

by using electron carriers to move electrons like oxidative and reduction reactions

What are electron carriers? Name two examples.

some compounds readily accepting and donating electrons (NADH, FAD2)

What is NAD? What is its oxidized/reduced form?

Nicotinamide adenine dinucleotide (NAD+, Reduced NADH)

What is FAD? What is its oxidized/reduced form?

Flavin adenine dinucleotide (FAD+/FADH2)

reducing agent

a compound that reduces another compound

oxidizing agent

a compound that oxidizes another compound

What are the four major steps of cellular respiration?

glycolysis, citric acid cycle, oxidation of pyruvate, electron transport chain

Which of the four steps require oxygen? Which do not?

glycolysis citric acid cycle, oxidation of pyruvate, electron transport chain, dont: glycolysis and fermentation

What is the purpose of the reduction and subsequent oxidation of all the electron

carrier molecules?

facilitate the transfer of electrons and energy

What happens to reduction and subsequent oxidation after they have served their purpose?

they are recycled and used again

What is the energy from the redox reactions in the electron transport chain used to

do?

pump protons across a membrane

Chemiosmosis energy transfer and ions involved

Complexes I, III, IV transport hydrogen ions (H+) across the inner mitochondrial membrane from the matrix, into the inter membrane space

Where does the chemiosmotic gradient occur in eukaryotic cells?

inner mitochondrial membrane

How do the protons move back across the membrane?

ATP synthesis

Oxidative phosphoralation products

38 ATP per glucose, on average 30-32 ATP

 How is the energy transferred to ATP?

synthesizing it from ADP and inorganic products

What is the theoretical energetic yield of cellular respiration?

38 ATP

 What is a more realistic estimate of energy yield?

30-32

Why is there such variation in the amount of energy actually made?

How are carbohydrates other than glucose, proteins, and lipids used as sources of

energy?

Carbohydrates are stored as glycogen and broken down

to glucose to enter glycolysis

What is the limiting factor in performing cellular respiration in the absence of

oxygen?

The inability to complete the electron transport chain and oxidative phosphorylation

How is glycolysis able to work around this limitation?

through fermentation pathways, also doesn’t need oxygen to continue on

Alchol fermentation

Pyruvate is enzymatically converted to a 2-carbon molecule called

acetaldehyde.

Also produces ethanol to help make bread. They release Carbon dioxide

Lactic Acid fermentation

Our muscle cells use lactic acid fermentation when oxygen supply

is depleted. The enzyme lactate dehydrogenase (LDH) converts pyruvate into

lactate, and in doing so, NADH is oxidized back to NAD+

 How is NADH oxidized in each of the two types of fermentation?

Lactic Acid- converts pyruvate into lactate, and in doing so, NADH is oxidized back to NAD+

Alcohol Fermentation-Acetaldehyde serves as an electron acceptor for NADH, forming the NAD+ required.

List two reasons why cellular respiration should be regulated.

to maintain energy balance and to use intermediate molecules for other pathways

Give two specific examples of feedback inhibition on the rate of cellular respiration.

The enzyme phosphofructokinase is the main enzyme controlled in glycolysis. High levels of ATP or product (citrate) decrease this enzymes activity and slow glycolysis.

The rate of electron transport through the ETC pathway is slowed by high levels of ATP, and sped up by high levels of ADP.

Give specific examples of how cellular respiration regulated

By proteins which transport glucose into the cell

By the number and specificity of the glycolysis, oxidation,

fermentation, citric acid cycle, etc. enzymes.

By the presence of coenzymes, cofactors, competitive &

allosteric inhibitors