The Ins & Outs of Endosymbiosis

What type of organism was likely the first to absorb another, leading to the development of complex cells?

• A photosynthetic bacterium

• A virus

• A blob-like cell that could engulf others

• A eukaryotic predator

What is the term for one organism living inside another, forming a mutual relationship?

• Symbiosynthesis

• Biomimicry

• Endocytosis

• Endosymbiosis

What happened when blob-like cells absorbed both photosynthetic and aerobic bacteria?

• They developed complex cells with mitochondria and chloroplasts

• They became more vulnerable to oxygen

• hey lost the ability to reproduce

• They stopped performing photosynthesis

Which of the following is NOT a piece of evidence supporting the endosymbiotic theory?

• Mitochondria and chloroplasts divide like bacteria

• They have circular DNA and similar ribosomes to bacteria

• They are created from scratch by the eukaryotic cell when needed

• They have double membranes with bacterial-like inner layers

Why do chloroplasts and mitochondria have two membranes?

• Because they evolved from fungi

• Because they were originally protected from the host cell

• Because they fused with another organelle

• Because one membrane came from the host cell and one from the engulfed bacteria

Why do chloroplasts in euglena have three membranes?

• One was lost during evolution

• They are a completely different type of organelle

• They went through two rounds of endosymbiosis

• They formed through random mutations

How did endosymbiosis help organisms adapt to changing environmental conditions?

• By providing camouflage from predators

• By combining useful traits from multiple organisms

• By eliminating all competition

• By increasing the number of chromosomes