T1.5 Origin of Cells

Question 1

What was Louis Pasteur’s Experiment?

Answer 1

1) Boiled broth in three swan-neck flasks to kill pre-existing bacteria
A) Broke the neck of one flask to allow air to enter
B) Tilted the neck of one flask to expose broth to microbes in the neck
C) Kept the last one sealed
2) Flask A became cloudy (grew microbes). Flask B also grew microbes. Flask C did not grow any microbes

Question 2

What did Louis Pasteur’s Experiment prove?

Answer 2

Spontaneous generation of cells and organisms does/can not occur on Earth. Proves cell theory point: Cells arise from pre-existing cells.

Question 3

What was Miller-Urey’s experiment?

Answer 3

Designed an apparatus to simulate the ancient water cycle and let it run. Discovered some simple amino acids and complex oily hydrocarbons were in the mixture after a week

Question 4

Conditions for emergence of life

Answer 4

• Simple organic molecules (amino acids, fatty acids, and carbohydrates) must be able to form
• larger organic molecules (phospholipids, RNA, DNA) must be assembled from simpler molecules
• Development of self-contained structures (membranes) to allow set conditions for biochemical reactions
• Replication of nucleic acids must be possible

Question 5

What is the relevance of deep-sea vents in the assembly of carbon compounds?

dunno if you need to know this

Answer 5

• Could be what caused the synthesis of simple carbon based molecules
• Hydrothermal vents are rich in hydrogen fluids, creates a chemical gradiedient and pH that is like a battery. This powered the chemical transformation of CO2 and H into these molecules

Question 6

Describe the formation of membranes

Answer 6

• Simple membranes can form spontaneously with amphipathic compounds found on early Earth.
• Fatty acids in watery solutions are attracted to each other and form spherical structures called micelles
• tucks tails together, away from water

whats a footnote

Question 7

Why was RNA considered the initial genetic material?

Answer 7

• Can self replicate
• short sequences are able to accuratly duplicated
• Can act as a catalyst
• modern cells use RNA catalysts (ribozymes) to remove introns from mRNA and help synthesize new RNA molcules

Question 8

Endosymbiotic theory

Answer 8

Erukaryotic cells come from prokaryotes absorbing other prokaryotes

Making mitochondria and chloroplasts

Question 9

What could the cells have gained from the endosymbiotic theory?

Answer 9

Cells that could carry out aerobic respiration provides energy to the host cell

Question 10

What characteristics do mitochondria and chlorplast have in common with independent prokaryotes?

Or: evidence of endosymbiotic theory

Answer 10

1. Double Membranes
2. Circular, naked DNA, formed as single chromosomes
3. Have 70s ribosomes
4. Divide by binary fisson