Ch 3: Aerobic Respiration and the Mitochondria

Question 1

How do mitochondria reproduce?

Answer 1

can fuse with one another or split in two(fission). It arises from preexisting mitrochondria.

Question 2

describe a mitochondrial structure

Answer 2

Mitochondria are seen as elongated, dark bodies. or a highly branched，interconnected tubular network.

The outer boundary contains two membranes(outer mitochondrial m. and inner mitochondrial m.)

The interior of the organelle contains a series of double-layered membranous sheets，called cristae

Compartment interior to mito is called matrix

Question 3

What is the function of mitochondrial cristae?

Answer 3

The cristae contain a large amount of membrane surface which houses the machinery needed for aerobic respiration and ATP formation

Question 4

What are the main difference between mitochondrial outer membrane and inner membrane?

Answer 4

the outer membrane is composed of approximately 50 percent lipid &; mixture of enzyme (cell wall of bacterial cells)
The inner membrane is 100 different polypeptides 3:1 protein lipid ratio rich in unusual phospholipid，cardiolipin. (bacterial plasma membranes.)

Question 5

Which kind of phospholipids is specially located in the membrane of mitochondria?

Answer 5

cardiolipin

Question 6

7. Where do membrane proteins－porins exist in mitochondria? And in which kingdom do porins also exist?

Answer 6

In the Outer Mitochondrial Membrane and they exist in outer bacterial membranes i.e kingdom Bacteria

Question 7

What is the difference of the permeability of mitochondrial outer membrane and inner membrane and what is the meaning of this difference?

Answer 7

The outer mitochondrial membrane and outer bacterial membrane both contains porins, integral proteins that have a relatively large internal channel（e.g. 2-3nm）surrounded by a barrel of β strands. While the inner mitochondrial membrane is highly impermeable, all molecules and ions require special membrane transporters to gain entrance to the matrix

Question 8

How many copy of double stranded ring like DNAs do exist in matrix of mitochondria?

Answer 8

37

Question 9

How many mitochondrial polypeptides does a ring like mitochondrial DNA encode?

Answer 9

13 in human

Question 10

Where does glycolysis happen?

Answer 10

Cytosol

Question 11

What are the final products of glycolysis and which one can be transported across mitochondrial inner membrane?

Answer 11

pyruvate and NADH. Each pyruvate molecule produced by glycolysis is transported across the inner mitochondrial membrane and into the matrix

Question 12

Which product was fed into TCA cycle in the matrix of mitochondria?

Answer 12

Acetyl CoA

Question 13

What is the ultimate product and also the initiate substrate of TCA?

Answer 13

Oxaloacetate

Question 14

What metabolic pathway do all of a cell’s energy-providing macromolecules go into at last?

Answer 14

They are broken down into metabolites of the TCA cycle and mitochondrion becomes the focus for the final energy-conserving steps in metabolism regardless of the nature of the starting material.

Question 15

During the TCA cycle, how many pairs of electrons are transferred from to electron-accepting coenzymes?

Answer 15

4 pairs of electron

Question 16

How do NADH (formed in the cytosol during glycolysis) were fed into the mitochondrial electron transport chain?

Answer 16

①enter the mitochondrion（by a pathway called the malate-aspartate shuttle）and reduce NAD+ to NADH. OR
[2] transfer its electrons to FAD（by a pathway called the glycerol phosphate shuttle）to produce FADH2

Question 17

Where do electron-transport chain locate inside mitochondria?

Answer 17

located in the inner mitochondrial membrane

Question 18

Through which two steps are electron-accepting coenzymes used to produce ATP?

Answer 18

①high-energy electrons are passed from FADH2 or NADH to a series of electron carriers that make up the electron-transport chain，which is located in the inner mitochondrial membrane; electrons pass along the respiratory chain in energy-releasing reactions
②the controlled movement of protons back across the membrane through an ATP-synthesizing enzyme provides the energy required to phosphorylate ADP to ATP

Question 19

How many ATP are released when one molecular NADH goes through electron-transport chain? and how about one molecular FADH2?

Answer 19

3 & 2 ATPs

Question 20

How many ATPs are formed if one molecule of glucose completely catabolized by means of glycolysis and the TCA cycle?

Answer 20

36 ATPs

Question 21

. What is the usage of endogenous uncoupling proteins（UCPs）?

Answer 21

a source of heat production,determining a person’s basal metabolic rate, which may help explain the physiological basis of obesity.

Question 22

What is the resemblance of mitochondria with peroxisomes?

Answer 22

Both mitochondria and peroxisomes form by splitting from preexisting organelles；
Both import preformed proteins from the cytosol
both engage in similar types of oxidative metabolism

Question 23

Which cell organelle is the site of synthesis and degradation of hydrogen peroxide?

Answer 23

Peroxisomes

Question 24

MCQ
Mitochondrial genes ?
the ATP get from TCA cycle is?

Answer 24

22 tRnas, 2 rRnas, 13 polypeptides

the ATP get from TCA cycle is 24 ATP