Mitochondria & Chloroplasts (CH 4.5)

Question 1

How are Mitochondria & Chloroplasts similar?

Answer 1

• Structually= both surrounded by a double membrane, contain their own DNA & protein synthesis machinery
• Functionally= involved in energy metabolism

Question 2

What is the structure of a Mitochondria?

Answer 2

-Bounded by smooth outer membrane & folded inner membrane w/ hella layers= Cristae

Question 3

What is the purpose of the mitochondrial Cristae?

Answer 3

• Parts it into 2 compartments
• Matrix= Inside inner membrane, on surface & imbedded are proteins that carry out oxidative metabolism
• Intermembrane space= Outer compartment lying between 2 mitochondrial membranes

Question 4

What does a Mitochondria do?

Answer 4

• Metabolize sugar to generate ATP
• Has own DNA= contains several genes that produce proteins essential to mitochondria’s role in oxidative metabolism
• NOT full autonomous bc most genes that encode enzymes used in oxidative metabolism are in the cell nucleus
• Divide themselves in 2 each time a eukaryotic cell divides

Question 5

What do a Mitochondria need for its division?

Answer 5

-Most components of mitochondrial division are encoded by genes in nucleus & are translated into proteins by cytoplasmic ribosomes

Question 6

What are Chloroplasts?

Answer 6

• Use light to generate ATP & sugars

- Contain chlorophyll that gives plants their green color

Question 7

What is the structure of a Chloroplast?

Answer 7

• Surrounded by 2 membranes
• Bigger & more complex than mitochondria
• Have closed compartments of stacked membranes= Grana/ Granum for singular (lie inside inner membrane)

Question 8

What Thylakoid Disks & what surrounds them?

Answer 8

• Stacked on top of each other in columns called Grana inside inner membrane
• On the surface= light capturing photosynthetic pigments
• Surrounding them= fluid matrix called Stroma which contains enzymes used to synthesize glucose during photosynthesis

Question 9

What is synthesized within the Chloroplast?

Answer 9

-Some elements used in photosynthesis including specific protein components necessary to accomplish the reaction

Question 10

What are Leucoplasts?

Answer 10

• Other DNA-containing organelles in plants
• Lack pigment & complex internal structure
• May serve as starch (amylose) storage sites in root cells &; other plant cells= Amyplasts

Question 11

What are Plastids?

Answer 11

• Produced by division of exisiting plastids

- Includes organelles called Chloroplasts, Leucoplasts, & Amyplasts

Question 12

What is Symbiosis?

Answer 12

-Close relationship between organisms of different species that live together

Question 13

What does the theory of Endosymbiosis propose?

Answer 13

• Some of today’s eukaryotic organelles evolved by symbiosis arising between 2 cells that were each free-living
• Prokaryotes were engulfed by & became part of another cell= precursor of eukaryotes

Question 14

What are the key Eukaryotic organelles that are decendants of Endosymbiotic prokaryotes?

Answer 14

• Mitochondria (orginated as bacteria capable of carrying out oxidative metabolism)
• Chloroplasts (arose from photostynthetic bateria)