Bio Unit 1 Summative

1. Define the following terms:

1. Prokaryotic cell - A simple cell with no nucleus or other organelles

2. Eukaryotic cell - A complex cell with a nucleus and other organelles

3. Unicellular organism - Organisms that is made up of only one cell

4. Multicellular organism - Organism that is made up of many cells

2. Pick one from each group below to match with the correct kingdom.

Group 1: Prokaryotic or Eukaryotic

Group 2: Unicellular or Multicellular

Group 3: Uses Sun, or Eats, or Absorbs materials for energy

• Archeabacteria  Prokaryotic, Unicellular, live in extreme environments

• Eubacteria -  Prokaryotic, Unicellular, live in moderate environments 

• Protist -  Eukaryotic, mostly unicellular, Plant-like use sun for energy, Animal-like eat, Fungi-like absorb dead material

• Fungi-  Eukaryotic, Multicellular, Absorb material

• Plant - Eukaryotic, Multicellular, Use sun (photosynthesis)

• Animal - Eukaryotic, Multicellular, eat

3. Draw and label the parts that ALL cells have in common?

• Cell membrane

• Cytoplasm

• DNA

4. Describe the cell membrane and its function for the cell. 

• Fluid and flexible

• Allows some materials to move into and out of the cell

5. How is the cell membrane involved in…

1. Homeostasis of the cell - Allows needed materials in and waste out of the cell

2. Cell reproduction in unicellular organisms - Splits in half to make two cells

3. Cell growth in multicellular organisms - Splits in half to make more cells 

6. What is the relationship between the outer boundary of organelles (like the nucleus) and the cell membrane?

• They are both made up of the same materials (lipids)

Section 8.2 and Timeline Activity

1. Identify what scientists generally hypothesize about early Earth (atmosphere, hydrosphere and geosphere). 

   1. What are the three layers of the geosphere (Earth) and how do they affect plate tectonics?

      • Crust – made of rocks and minerals which allowed organic molecules to form

      • Mantle – made of rocks, minerals and MOVING magma which allowed for plate tectonics (plate movement)

      • Core – hot dense metal which provided the heat necessary for organic molecules to form

2. What had to happen to early earth before large bodies of water could form?

• the earth had to cool down

3. How is the atmosphere of today different from that of early Earth?

• The early atmosphere was mainly made up of hydrogen sulfide, methane and carbon dioxide – no oxygen

• Today’s atmosphere has oxygen to support life

4. How did the atmosphere of today come to be?  

• Cyanobacteria in the water used the sun to undergo photosynthesis to make oxygen and organic materials

2. Define the following vocabulary:

   1. Organic molecules – those molecules necessary for life (proteins, lipids, carbohydrates, nucleic acids like DNA and RNA)

   2. Protocell – the precursor (came before and led into) to the cell but it is not alive.  It is a lipid membrane containing organic molecules.

   3. Prokaryotic cell – very simple and small basic cell containing organic molecules, like DNA. Prokaryotic cells are considered alive.  Bacteria are prokaryotic cells.  

   4. Eukaryotic cell – Larger and more complex cell containing organic molecules and containing  a nucleus and other specialized structures called organelles.  All cells except bacteria are eukaryotic cells.

USE THE TIMELINE OF LIFE SLIDE PRESENTATION:

• Much later – ozone layer is formed

Be able to place the major events of the formation of earth in a logical order by making connections between events.

1. How are the three layers of the geosphere (Earth) connected to the cycling of material necessary for life?

The core heats up areas of the mantle which allow it to flow.  The flowing of parts of the mantle moves the plates of the crust (plate tectonics).  Plate tectonics (movement of the plates) allowed for recycling of water, carbon dioxide and other materials.  

2. How could first life form if there was no free oxygen?

Prokaryotic cells were the first form of life made up of organic molecules.  They lived in water and did not require oxygen to live.  Instead they used other chemicals to survive.

3. Why were asteroids and comets important for the formation of life?

Comets and asteroids brought water and organic molecules to earth when they struck the earth.  Water and organic molecules are necessary components of life.

4. Why did water have to come before first life?

One of the 3 main components necessary for life is water in addition to organic materials and energy.  Water was the source that brought together the organic molecules that were found separately in it.

5. Why did prokaryotic cells form before eukaryotic cells?

Prokaryotic cells are very simple forms of life.  It is believed that prokaryotic cells evolved into eukaryotic cells.

6. Why did the cyanobacteria have to come before aerobic bacteria?

Cyanobacteria used sunlight to undergo photosynthesis creating oxygen for the aerobic bacteria which need oxygen to live.

7. Aerobic bacteria (use oxygen) did not evolve into eukaryotic cells, but they were necessary to the formation of eukaryotic cells. Why?

When prokaryotic cells went through endosymbiosis (engulfing other bacteria which then became structures inside those cells), they engulfed aerobic bacteria which became a structures  inside of the cell starting to form more complex cells that required oxygen.

8. How did we get from unicellular eukaryotic organisms to multicellular eukaryotic organisms?

Eukaryotic cells formed colonies (individual cells living together) where the individual cells began to specialize.  This led to multicellular organisms evolving.

9. 500 million years ago, there is an explosion of life in the oceans but still no life on land - why not?

There was too much harmful radiation to support life because there is no ozone.

10. Earth was formed 4.6 billion years ago.  First life did not appear until 3.8 billion years ago.  Why do you think it took so long for first life to appear?

There needed to be all the necessary components of life (organic molecules, water and energy) and time for chemical reactions to occur and form the organic molecules.

4. Explain how first life could have formed.

   1. What are the molecules needed and why are they important?

Organic molecules (lipids to form a cell membrane, nucleic acids to form DNA, proteins etc.) 

2. How did these molecules come together?

Water allows organic molecules to mix and become more complex.

Energy was needed for chemical reactions to occur.

3. What kind of energy source might they have used?

Heat and chemical energy from the hydrothermal vents.

5. What are the steps for the evolution of the earth and the earth’s atmosphere? (this does not include any living things - just land, water and atmosphere)

• Earth is formed of molten magma and then cooled

• Volcanoes – first atmosphere is hydrogen sulfide, methane and a lot of carbon dioxide

• Asteroids/Comets bring water

• First oceans

• Movement of plate tectonics to recycle carbon, water and other materials

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6. What are the steps for the evolution of the prokaryotic cell?

• Protocells form in water – not living

• First prokaryotic cell

• First cyanobacteria

• First aerobic (uses oxygen) bacteria

7. What are the steps for the evolution of the eukaryotic cell.

• Prokaryotic cells engulf other types of bacteria to make first eukaryotic cell - unicellular

• Cell specialization – beginning of simple multicellular eukaryotic cells

• Explosion of life (multicellular eukaryotic) in the oceans

• First plants and then first animals evolve