General Biology

Question 1

Identification

Living things convert chemical energy from biomolecules (glucose) to usable energy (ATP) through reactions from this.

It involves the following events: glycolysis, pyruvate oxidation, Krebs’ cycle, and electron transport chain and chemiosmosis.

Answer 1

Cellular Respiration

Question 2

Fill in the blanks

Cellular Respiration is a (?) Process.

Answer 2

Redox

Cellular Respiration is a Redox Process

During redox reactions in cellular respiration,
* glucose donates electrons and hydrogen, and is oxidized
* oxygen accepts electrons and hydrogen, and is reduced

Question 3

Fill in the blanks

Cellular Respiration is the process that releases (1) _ by breaking down (2) _ and other food molecules in the presence of (3) _

Answer 3

(1) Energy
(2) Glucose
(3) Oxygen

Question 4

Identification

It breaks the chemical bonds in glucose to release energy to do work in a cell.

Answer 4

The Mitochondrion

Question 5

Parts of the Mitochondrion

It contains proteins known as porins, which allow movement of ions into and out of the mitochondrion.
It acts as barrier between the cytosol and the inner compartments of the mitochondrion.

Answer 5

Outer Membrane

Question 6

Parts of the Mitochondrion

It is enclosed by the outer and the inner membrane of the organelle, serving as the reservoir of hydrogen ions during chemiosmosis.

Answer 6

Intermembrane Space

Question 7

Parts of the Mitochondrion

It contains a variety of enzymes, including ATP synthase, which generates ATP in the matrix, and transport proteins that regulate the movement of metabolites into and out of the matrix.

Answer 7

Inner Membrane

Question 8

Parts of the Mitochondrion

Invaginations in the inner membrane that increase the surface area available for energy production (ATP synthesis) via oxidative phosphorylation.

Answer 8

Cristae

Question 9

Parts of the Mitochondrion

It is the liquid (colloidal) area encircled by the inner
membrane, that contains the soluble enzymes of the Krebs cycle.

Answer 9

Matrix

Question 10

Parts of the Mitochondrion

They perform protein synthesis inside mitochondria.

Answer 10

Ribosomes

Question 11

Parts of the Mitochondrion

It encodes genes for normal mitochondrial function and synthesis of enzymes for oxidative phosphorylation.

Answer 11

DNA

Question 12

Parts of the Mitochondrion

It is the enzyme used to synthesize ATP from ADP and inorganic phosphate (Pi) in the F1 sector.

Answer 12

ATP Synthase

Question 13

Parts of the Mitochondrion

It is found to localize either in the mitochondrial intracristal space or between the inner and outer membrane.
It signals morphologic abnormalities of mitochondria.

Answer 13

Inclusion

Question 14

Identify the events in Cellular Respiration

Breakdown of glucose to extract energy

Glucose undergoes a series of transformations and is converted into pyruvate molecules. Additionally, these reactions yield ATP and reduce NAD+ to NADH.

Answer 14

Glycolysis

It does not generate oxygen, and is therefore anaerobic.

Question 15

Identify the events in Cellular Respiration

Conversion of pyruvate to acetyl CoA

Each pyruvate molecule goes into the mitochondrial matrix where it gets converted into acetyl CoA. In the process, carbon dioxide is released and NADH is produced.

Answer 15

Pyruvate Oxidation

Question 16

Identify the events in Cellular Respiration

Citric Acid Cycle or Tricarboxylic Acid Cycle

The acetyl CoA combines with a four-carbon compound and undergoes a series of redox reactions ultimately yielding the four-carbon starting molecule. The reactions produce ATP, NADH and FADH2, and releases carbon dioxide.

Answer 16

Krebs’ Cycle

Initial Product:
- Citric Acid
- 3 Carboxyl Groups

Question 17

Identify the events in Cellular Respiration

The electrons from NADH and FADH2 will be transported by carrier molecules in the cristae. As electrons move down the chain, energy is released and used to pump H+ ions out of the matrix, forming a proton gradient. H+ ions flow back into the matrix via ATP synthase, yielding ATP. At the end of the ETC (electron transport chain), oxygen accepts electrons and takes up H+ ions to form water.

In short:
It is a chemical reaction happening in the mitochondrial cristae. During this reaction, chemiosmosis couples electron transport to ATP synthesis.

Answer 17

Oxidative Phosphorylation

Question 18

Fill in the blanks

Glycolysis converts (1) _ to (2) _.

Answer 18

(1) Glucose
(2) Pyruvate

Question 19

Arrange the Cellular Respiration Process in the correct order

( ) During the Krebs cycle or TCA cycle in the matrix, acetyl CoA undergoes redox reactions that yield more NADH, FADH2, carbon dioxide and ATP.

( ) During the linked reaction, pyruvate is transformed to acetyl CoA and carbon dioxide.

( ) NADH, FADH2 and oxygen are used to create large amount of ATP via electron transport chain. Oxygen is reduced, and yields water molecules.

( ) During glycolysis in the cytoplasm, glucose molecules are broken down to create ATP, pyruvate and NADH molecules.

Answer 19

(3)
(2)
(4)
(1)

Question 20

Fill in the blanks

When oxygen is not present, glycolysis is followed by a pathway that makes it possible to continue to produce ATP without oxygen. The combined process of this pathway and glycolysis is called (?).

Answer 20

Fermentation

Question 21

Fill in the blanks

Out of 36 ATP molecules produced per glucose during aerobic respiration, (1) _ are produced in the cytosol and (2) _ are produced inside the mitochondrion.

Answer 21

(1) 2
(2) 34

Question 22

Fill in the blanks

If oxygen is absent in the mitochondrion of a eukaryotic organism, (?) will stop running.

Answer 22

Electron Transport Chain (ETC)

Question 23

Identify the type of fermentation

Pyruvate and NADH from glycolysis enter the fermentation process. Energy from the NADH molecules is used to convert pyruvate into lactic acid. NADH molecules are converted into NAD+ molecules that are recycled to glycolysis to pick up more electrons.

Pyruvic acid + NADH → Lactic acid + NAD+

Answer 23

Lactic Acid Fermentation

Question 24

Identify the type of fermentation

Pyruvate and NADH from glycolysis enter fermentation. Energy from NADH is used to break down pyruvate into ethyl alcohol and carbon dioxide. NADH molecules are converted into NAD+ molecules that are recycled to glycolysis.

Pyruvic acid + NADH → Alcohol + CO2 + NAD+

Answer 24

Alcoholic Fermentation

Question 25

Identification

It is a type of respiration that does not use oxygen.
In the absence of oxygen;
* Oxidative phosphorylation cannot take place.
* Hydrogen cannot be used by combining it with oxygen to give water, so NADH cannot be recycled.
* Mitochondrion runs out of NAD or FAD that accept H+.
* Glycolysis can still continue, so long as pyruvate can be removed and NADH can be recycled to NAD.

Answer 25

Anaerobic Respiration

Question 26

Identification

Two pathways allow the recycling of NADH formed during glycolysis.

Answer 26

Anaerobic Pathways