Metabolic Reactions

Question 1

Aerobic Respiration

Answer 1

• Cellular respiration with oxygen
• Cells use oxygen to make ATP

Question 2

What is the equation for cellular respiration? What type of reaction is it?

Answer 2

• C₆H₁₂O_{6 ——->} 6CO₂ + 6H₂O + ATP + Heat
• its a redox reaction

Question 3

What are the 3 major steps in Cellular respiration?

Answer 3

1. Glycolysis
2. Citric Acid cycle (Krebs cycle)
3. Electron Transport chain

Question 4

What holds Carbon together? What happens when you break apart glucose?

Answer 4

• Electrons (e-) hold carbon togther , electrons have high energy
• When glucose is broken apart it releases high energy e-

Question 5

Whats the point of cellular respiration?

Answer 5

• To turn glucose into ATP
• To trap chemical energy in ATP

Question 6

What must be present in Cellular respiration to oxidize?

Answer 6

• Oxygen

Question 7

What enzymes are involved in cellular respiration?

Answer 7

1. Dehydrogenase:an enzyme that accelerates the removal of hydrogen from metabolites and its transfer to other substances
2. Oxidases: Transfer oxygen
3. Coenzymes: accept hydrogens (or electrons) ex. NAD and FAD

Question 8

Metabolite

Answer 8

a substance formed in or necessary for metabolism.

Question 9

Step 1 of cellular respiration

Answer 9

• Step one of cellular respiration is called Glycolysis
• Glycolysis happens in the cytosol
• During Glycolysis Glucose gets split into pyruvate and small amounts of ATP are made as well as NADH (an electron carrying enzyme) is made.
• 11-12 enzymes involved in turnng glucose into pyruvate

Question 10

Step 2 of cellular respiration

Answer 10

• Pyruvate is modified into Acetyl CoA
• This happens in the mitochondria
• During the Krebs cycle Acetyl CoA is turned into Carbon dioxide, a small amount of ATP, and NADH (enzyme that carries electrons; think of little cars carrying electrons to their final destination)

Question 11

Phosphorylation

Answer 11

• the process of introducing a phosphate group into an organic molecule.
• oxidative phosphorylation the final common pathway of aerobic energy metabolismin which high-energy phosphate bonds are formed by phosphorylation of ADP to ATPcoupled with the transfer of electrons along a chain of carrier proteins with molecularoxygen as the final acceptor. It occurs in mitochondria.

Question 12

Step 3 of cellular respiration

Answer 12

• This step is called the Electron Transport Chain
• This occurs in the mitochondria in the presence of oxygen
• Electrons are sent through a series of reactions and you get Alot of ATP
• Oxygen is the final electron acceptor (it gets reduced); water is then made

Question 13

Substrate phosphorylation

Answer 13

• When ATP is created during glycolysis and the krebs cycle.

Question 14

Oxidative Phosphorylation

Answer 14

• When ATP is created by chemiosmosis in the electron transport chain.

Question 15

Chemiosmosis

Answer 15

Chemiosmosis is the movement of ions across a selectively permeable membrane, down their electrochemical gradient. More specifically, it relates to the generation of ATP by the movement of hydrogen ions across a membrane during cellular respiration or photosynthesis.

Question 16

What enzymes carriy electrons in cellular respiration?

Answer 16

• NADH
• FADH₂

Question 17

Can cellular respiration occur without oxygen?

Answer 17

• Yes, but very little ATP will be made; this is Anerobic respiration
• This happens during exercise and lactic acid is made because the muscles are not getting enough oxygen

Question 18

When does oxygen come into play in cellular respiration?

Answer 18

• During the Electron transport chain

Question 19

How much ATP can one molecule of glucose yeild?

Answer 19

• 32 ATP molecules

Question 20

1 mole of glucose= 686kcal; 282 kcal captured in an ATP molecule, what happened to the other 404 kcal?

Answer 20

• 404 kcal is lost as heat during the reaction
• Cells are very efficient though; man made machiens are only 10-30% energy efficient.

Question 21

What is this process?

Answer 21

• Protein synthesis

Question 22

What is a ribosome made out of?

Answer 22

• RNA called rRNA

Question 23

What is are the main steps in Protein synthesis?

Answer 23

1. DNA
2. RNA
3. Protein

Question 24

Gene

Answer 24

•segment of DNA molecule containing information to make one polypeptide chain

Question 25

Some genes code for\_\_\_\_\_.

Answer 25

* Different types of RNA

Question 26

mRNA

Answer 26

* Messenger RNA

Question 27

rRNA

Answer 27

* Ribosomal RNA

Question 28

tRNA

Answer 28

* Transfer RNA

Question 29

tRNA

Answer 29

* **Transfer ribonucleic acid** (tRNA) is a type of **RNA molecule that helps decode a messenger RNA (mRNA) sequence into a protein**. tRNAs **function at specific sites in the ribosome during translation**, which is a process that synthesizes a protein from an mRNA molecule. * A transfer RNA (abbreviated tRNA and archaically referred to as sRNA, for soluble RNA) is an adaptor molecule composed of RNA, typically 76 to 90 nucleotides in length, that **serves as the physical link between the mRNA and the amino acid sequence of proteins. Helps in decoding the mRNA to make a polypeptide chain**

Question 30

Steps to protein synthesis

Answer 30

1. Transcription 2. Translation

Question 31

First step of transcription

Answer 31

1. **Initiation**: RNA polymerase binds to the promoter, pries apart the 2 DNA strands and initiates RNA synthesis at the start point on the template strand.

Question 32

Second step of transcription

Answer 32

1. Elongation: RNA polymerase moves across the template strand, elongating the mRNA strand by copying one base at a time, it unwinds and rewinds the DNA double helix behind it as it goes. happens in three steps * **Codon Recognition** * **Peptide Bond formation** * **Translocation**

Question 33

Step 3 of Transcription

Answer 33

3. **Termination**: mRNA synthesis ends when the termination signal is reached. The RNA polymerase and the completed mRNA strand is released when **release factor** binds in the A site of the ribosome.

Question 34

what are the stop codons?

Answer 34

* UGA * UAA * UAG

Question 35

What happens during **Codon recognition**?

Answer 35

* Anticodon of an incomming tRNA binds with the complementary mRNA codon in the A site of the ribosome.

Question 36

What happens during the **Peptide bond formation** step of elongation?

Answer 36

* the growing polypeptide chain in the P site binds to the amino acid attached to the tRNA in the A site and is then transferred over to the A site.

Question 37

What happens during the **Translocation** stage of Elongation?

Answer 37

* The entire ribosome translocates and shifts by one codon along the mRNA * the unloaded tRNA in the P site shifts over to the E site; and is then released * tRNA w/ polypeptide chain in A site moves to P site * A site is now empty; codon (mRNA) is ready to be translated and accept tRNA

Question 38

What 4 things must come togther during the Intiation stage of Translation?

Answer 38

1. Small ribosomal unit 2. Intiator tRNA with amino acid: **Methionine**= start codon 3. mRNA 4. Large ribosomal subunit * once all these things come togther then elongation can occur

Question 39

What is the start codon which codes for methionine?

Answer 39

* AUG