A - Glycolysis B - Intermediate Step C - Kreb's Cycle D - Electron Transport Chain E - Anaerobic Respiration 1. Produces approximately 34 ATP. 2. Glucose is broken down into 2 pyruvic acid. 3. Without oxygen in the system, occurs. 4. Releases carbon dioxide and generates FADH2. 5. Pyruvate is turned into acetyl CoA. 6. No energy is produced here, only energy carriers. 7. Location where ATP synthases are found. 8. Requires the use of 2 ATP as activation energy. 9. Lactic acid is sometimes generated in an animal cell. 10. Two cycles are possible for each glucose.

1. D

2. A

3. A

4. C

5. B

6. B

7. D

8. A

9. E

10. C

Explanation:

The process of cellular respiration, which generally involves the synthesis of energy from carbohydrate molecule (glucose), occurs in four major steps in eukaryotic cells. These steps are glycolysis, kreb cycle, bridge or intermediate step and oxidative phosphorylation (electron transport chain).

The features of each step is highlighted below:

GLYCOLYSIS: This is the first stage if cellular respiration in which Glucose is broken down into 2 pyruvic acid (pyruvate). It can occur without oxygen in the system and it uses 2 ATP molecules to start the process.

INTERMEDIATE STAGE: This stage is also called bridge or transition reaction. It does not produce any ATP molecule but only prepares the reaction for aerobic respiration in the mitochondria by turning Pyruvate molecule into acetyl CoA.

KREB'S CYCLE: This is the third step in the process. AcetylcoA undergoes series of chemical processes to release 4 carbon dioxide molecules and generates FADH2 and NADH electron carriers. It takes two cycles to process two glucose molecules that is used in the respiration process.

ELECTRON TRANSPORT CHAIN: In this stage, approximately 34 ATP molecules are produced in the mitochondria using enzyme called ATP synthase, which catalyse the conversion of ADP to ATP.

ANAEROBIC RESPIRATION: This type of respiration occurs in the absence of oxygen. In animal cells, lactic acid/lactate is produced and stored in the muscle as an end product

step 1: initiation

initiation is the beginning of transcription. it occurs when the enzyme rna polymerase binds to a region of a gene called the promoter. this signals the dna to unwind so the enzyme can ‘‘read’’ the bases in one of the dna strands. the enzyme is now ready to make a strand of mrna with a complementary sequence of bases.

step 2: elongation

elongation is the addition of nucleotides to the mrna strand. rna polymerase reads the unwound dna strand and builds the mrna molecule, using complementary base pairs. there is a brief time during this process when the newly formed rna is bound to the unwound dna. during this process, an adenine (a) in the dna binds to an uracil (u) in the rna.

step 3: termination

termination is the ending of transcription, and occurs when rna polymerase crosses a stop (termination) sequence in the gene. the mrna strand is complete, and it detaches from dna.