(3) Chapter 12: Mitochondria, chloroplasts, and peroxisomes

Question 1

How do mitochondria generate energy?

Answer 1

from breakdown of lipids and carbohydrates

Question 2

How do chlorplasts generate energy?

Answer 2

use sunlight energy to generate ATP and reducing power to synthesize carbohydrates from CO2and H2O.

Question 3

What are Peroxisomes?

Answer 3

contain enzymes involved in a variety of metabolic pathways.

Question 4

Discuss genome within powerhouse organelles

Answer 4

-Mitochondria and chloroplasts have their own genomes and include some genes that are transcribed and translated within the organelle

Question 5

Describe the structure of Mitochondria

Answer 5

a) surrounded by double membrane system
b) inner and outer membranes are seperated by an intermembrane space
c) inner membrane has cristae folds that extend into the interior matrix

Question 6

What is found in the matrix of mitochondria?

Answer 6

a) genetic system
b) pyruvate
c) enzymes for oxidative metabolism

Question 7

What is Pyruvate?

Answer 7

• from glycolysis process
• transported to mitochondria
• completely oxidizes to CO2 which
• yields bulk of energy (ATP) of glucose metabolism

Question 8

Where does Glycolysis occur?

Answer 8

-occurs in the cytosol of mitochondria

Question 9

What happens as pyruvate interacts with coenzyme A?

Answer 9

a) Pyruvate undergoes oxidative decarboxylation

b) Pyruvate + CoA-SH –>acetyl CoA; generates 2NADH

Question 10

What happens to Acetyl CoA once it is generated?

Answer 10

a) Acetyl CoA enters the citric acid cycle
b) The two carbon acetyl group combines with oxaloacetate (4C) to yield citrate (6C)
c) remaining 2C’s of citrate are completley oxidized to CO2 and oxaloacetate is regenerated

Question 11

What results from the breakdown of 2 citrate carbons

Answer 11

a) 2 CO2
b) 1 oxaloacetate
c) GTP
d) 3 NADH
e) 1 FADH2

Question 12

What results from the oxidation of glucose at the end of the citric acid cycle (include products from previous processes)?

Answer 12

• 6 molecules of CO2
• 4ATP
• 10 NADH
• 2FADH2

Question 13

What is the total energy yield from oxidation of glucose?What stages are they from?

Answer 13

A) 36-38 ATP
a)glycolysis: 2ATP, 2NADH
b) Kreb’s: 2 ATP, 8 NADH, 2 FADH2
c) oxidative phosphorylation: each NADH yields 3 ATP, each FADH2 yields 2 ATP
B) Total: 2 ATP + 2ATP + 103(NADH) + 22(FADH2) = 38

Question 14

Describe process of transport for electrons from FADH2?

Answer 14

a) complex 2 receives electrons from the citric acid cycle intermediate succinate
b) electrons are transferred to FADH2 and then to coenzyme Q

Question 15

What is the energy level of electrons in NADH and FADH2?

Answer 15

high energy

Question 16

Energy derived from NADH and FADH is transported through the ____ by ___during ETC

Answer 16

the membrane by molecular oxygen

Question 17

What happens to energy derived from ETC process?

Answer 17

energy derived is converted to potential energy and is stored in a proton gradient which drives ATP synthesis

Question 18

Give summary of characteristics of inner membrane of mitochondria

Answer 18

a) principal site of ATP generation
b) surface area is increased by cristae folds
c) contains a high percentage of proteins involved in oxidative metabolism & transport
d) impermeable to most ions and small molecules

Question 19

Give summary of characteristics of the outer mitochondrial membrane

Answer 19

a) highly permeable to small molecules
b) contains porins, which form channels that allow the free diffusion of small molecules
c) composition of the intermembrane space is similar to the cytosol

Question 20

Where is the mitochondria usually found within eukaryotic cells?

Answer 20

position is often near locations of high-energy use, such as synapses in nerve cells

Question 21

Describe a mitochondrial network

Answer 21

-in most cells mitochondria from an interconneted network and are constatntly fusing and dividing to remodel this network which in turn modifies mitochondrial morphology and function