Biology 1.5 - Origin of Cells

Question 1

Where do cells come from? (U1)

Answer 1

Division of pre-existing cells.

Question 2

What is the difference between mitosis and meiosis? (U1)

Answer 2

Mitosis creates in genetically identical diploid daughter cells while meiosis makes haploid gametes (sex cells).

Question 3

What are the 2 possibilities where cells came from? (U2)

Answer 3

1. Outer space or extraterrestrial means via asteroid.

2. Life began through interactions amongst non living molecules as early as 3.9 bya.

Question 4

What are the 4 necessary steps for spontaneous origin of life? (U2)

Answer 4

Step 1. Synthesis of simple organic molecules.
Step 2. Assembly into polymers.
Step 3. Origin of self-replicating molecules that make inheritance.
Step 4. Packing of these into membrane with its own internal chemistry.

Question 5

What is the endosymbiotic theory? (U3)

Answer 5

Explains the existence of several organelles of eukaryotes (e.g. mitochondria and chloroplast). Refer to notes for full theory.

Question 6

What do we call mitochondria and chloroplast? (U3)

Answer 6

Endosymbionts.