Endosymbiosis

Question 1

What is the cell theory?

Answer 1

• All living things are composed of cells,
• They are the basic unit for structure and function for living things,
• New cells derive from existing cells

Question 2

What is the Endomembrane system?

Answer 2

• A network of membranes inside and around a eukaryotic cell,
• Connected directly or through membranous vesicles

Question 3

What are the organelles in the Endomembrane system?

Answer 3

• Nucleus
• Vacuoles,
• ER,
• Golgi apparatus
• Vesicles
• Lysosomes

Question 4

What are endosybionts?

Answer 4

• Mutualistic organism/organelle that entered a host cell and serves a function

Question 5

What is Endosymbiosis?

Answer 5

A theorized process in which early eukaryotic cells were formed from simpler prokaryotes

Question 6

What is a Eukaryotic cell?

Answer 6

• Cells that have a nucleus and membranes around other organelles,
• Found in the domain Eukarya

Question 7

What are infoldings?

Answer 7

Sections of the plasma membrane that have grown and folded inwards to create compartments in a cell or increase surface area

Question 8

What is an organelle?

Answer 8

Specialized structures that perform a function in a eukaryotic cell

Question 9

What is a Prokaryotic cell?

Answer 9

• A type of cell lacking a membrane enclose nucleus/ organelles
• Found only in the domains Bacteria and Archaea

Question 10

What is binary fission?

Answer 10

• The form of asexual reproduction in single celled organisms,
• One cell divides into a similar cell the same size and results in identical cells

Question 11

What is circular DNA?

Answer 11

The genetic material of prokaryotic cells

Question 12

What is linear DNA?

Answer 12

The genetic material of eukaryotic cells

Question 13

What is Archaea?

Answer 13

A domain of single celled organisms, lacking a cell nuclei making them prokaryotes

Question 14

How do photosynthetic bacteria get energy?

Answer 14

Photosynthetic pigments embedded in the internal membranes use sun light for energy

Question 15

How are chloroplasts and mitochondria believed to have come about in a cell?

Answer 15

They entered the cell as a prokaryote and evolved along with the cell, it was an endosymbiont/ at a relationship of symbiosis with the cell

Question 16

What evidence supports the flipped endosymbiotic theory?(4)

Answer 16

• Mitochondria and Chloroplasts both have circular DNA, similar to bacteria
• They also both have two membrane layers, one presumed to be the original (the inner), and the other presumed to be constructed by the cell membrane of the host,
• Mitochondria is similar size to a bacteria
• Both are theorized to be related to bacteria (purple bacteria for M and Photosynthetic bacteria for Ch)

Question 17

What is ER?

Answer 17

Endoplasmic reticulum,

- The biggest membrane structure in a cell

Question 18

How is endoplasmic reticulum believed to have developed in a cell?

Answer 18

• Along side the nuclear envelope, it may have evolved from infoldings of the plasma membrane in an ancestral prokaryotic cell,
• Similar infoldings are common in modern prokaryotic cells

Question 19

What are the energy producing organelles believed to have previously been prokaryotes?

Answer 19

• Mitochondria

- Chloroplasts

Question 20

How did organelles come to exist in a cell?

Answer 20

• Most organelles were made from infolding from the membrane of a cell,
• The exception to this is those that are endosymbionts which got their outer membrane after entering the cell and already existed as an independent organism before this

Question 21

Explain if mitochondria and chloroplast included in the endomembrane system?

Answer 21

No

• Because they were independent organisms before they entered the eukaryote, this means that it was not created from infolding from the membrane,
• To be part of the endomembrane system, the organelle must have derived from infolding