Topic 2 Part 2

Question 1

How have mitochondria evolved and what is their origins?

Answer 1

Billions of years ago mitochondria was a primitive prokaryotic microbe engulfed by eukaryotic cells, and could perform aerobic respiration, the most effective form of producing AtP. With a prokaryote inside it, the primitive eukaryote would have benefit as the mitochondria lived inside it. Over time these two cells lost the ability to live separately.

Question 2

How have chloroplasts evolved

Answer 2

Some time after eukaryotes acquired mitochondria, again a eukaryote engulfed but did not digest a prokaryote which had the ability to carry out photosynthesis (Cyanobacteria). The eukaryote and prokaryote evolved to become modern day plants.

Question 3

What features do mitochondria and chloroplasts have in common with a whole prokaryotic cell?

Answer 3

• they have their own dna which is arranged as singular circular molecule of Dna, as occurs in bacteria.
• they contain free ribosomes which are slightly smaller than the ribosomes found in he cytosol of eukaryotic cells
• they are made up of a double membrane
• both reproduce by a process of binary fission as occurs in bacteria
• both have sizes which fall within the range of bacterial cells

Question 4

What are the four organic molecules that all organisms are composed of?

Answer 4

Carbohydrates, proteins, lipids, and nucleic acids

Question 5

What is the distinctive feature of organic molecules

Answer 5

They are composed of carbon atoms, arranged as rings or chains, and bonded to other atoms mainly hydrogen and oxygen

Question 6

What are the building blocks of the four organic molecules

Answer 6

Carbohydrates. Monosaccharides
Proteins. Amino acids
Lipids. Fatty acids
Nucleic acids. Sugar phosphate nitrogenous bases

Question 7

What are the differences between organic and inorganic molecules

Answer 7

• living organisms are almost exclusively built of organic molecules, while non living things are made up of inorganic molecules.
• organic molecules are composed of carbon bonded with hydrogen and oxygen, whereas organic molecules do not contain them all.

Question 8

What are some types of organic molecules

Answer 8

Mineral ions
Carbon dioxide
Oxygen
Water
Salts