Module 8 Lec 5

Question 1

How many chloroplasts do cells typically have?

Answer 1

Cells have several chloroplasts.

Question 2

How does the genome size of chloroplasts (Cp) compare to mitochondria (Mt)?

Answer 2

Cp genome size is less variable than Mt genome.

Question 3

How do the gene numbers in chloroplasts compare to those in mitochondria

Answer 3

Chloroplasts have more genes than mitochondria, and the genes are closely packed.

Question 4

What do chloroplast genes code for?

Answer 4

Chloroplast genes code for proteins involved in photosynthesis, translation, and other processes.

Question 5

What organism is being discussed for its chloroplast genome?

Answer 5

Marchantia polymorpha, a liverwort.

Question 6

What is significant about the chloroplast genome of Marchantia polymorpha?

Answer 6

It has a compact chloroplast genome, similar to other plants but with some unique features in gene organization.

Question 7

How does the size of Marchantia polymorpha’s chloroplast genome compare to other plants?

Answer 7

The chloroplast genome of Marchantia polymorpha is relatively small compared to other higher plants.

Question 8

What is encoded in the chloroplast genome of Marchantia polymorpha?

Answer 8

The genome encodes proteins involved in photosynthesis, as well as components of the translation machinery.

Question 9

What does semiautonomy mean in the context of mitochondria and chloroplasts?

Answer 9

It means that while mitochondria and chloroplasts have their own DNA, they still rely on the nuclear genome for many proteins and tRNAs.

Question 10

What do mitochondria and chloroplasts need from the nuclear genome?

Answer 10

They need proteins and tRNAs that are coded in the nuclear genome for proper function.

Question 11

How does semiautonomy affect mitochondria and chloroplasts?

Answer 11

They rely on the nuclear genome for many functions

Question 12

How can genomic information “travel” between organelles and the nucleus?

Answer 12

mtDNA sequences are found in the nuclear genome, and some cpDNA can end up in plant mtDNA.

Question 13

How does genomic information move between organelles?

Answer 13

Likely via RNA intermediates or DNA fragments.

Question 14

How does genomic information travel between organelles and the nucleus?

Answer 14

Sequences of mtDNA are present in the nuclear genome, and some cpDNA can be found in plant mtDNA. This transfer likely occurs through RNA intermediates or pieces of DNA.

Question 15

What is the evidence that genomic information travels between organelles?

Answer 15

mtDNA sequences are integrated into the nuclear genome, and some chloroplast DNA (cpDNA) is found in plant mitochondria (mtDNA).

Question 16

How does DNA travel from organelles to the nucleus

Answer 16

The transfer is believed to occur via RNA intermediates or DNA fragments.

Question 17

What supports the Endosymbiont Theory for mitochondria and chloroplasts?

Answer 17

Evidence includes their own genomes, lack of histones, similarity in transcription and translation machinery to prokaryotes, use of N-formyl methionine, and sensitivity to antibiotics

Question 18

How are mitochondria and chloroplasts similar to prokaryotes?

Answer 18

Their transcription and translation machinery is similar to prokaryotes, and mitochondria use N-formyl methionine like bacteria.

Question 19

What antibiotics affect mitochondria and chloroplasts?

Answer 19

Antibiotics that inhibit prokaryotic translation also inhibit translation in mitochondria and chloroplasts.

Question 20

What do genomic comparisons suggest about the origin of mitochondria and chloroplasts?

Answer 20

Mitochondria evolved from nonsulfur purple bacteria, while chloroplasts evolved from cyanobacteria.

Question 21

What is one piece of evidence for mitochondria and chloroplasts being prokaryotic in origin?

Answer 21

Both organelles have their own genomes, which are independent of the nuclear genome.