Save
Upgrade to remove ads
Busy. Please wait.
Log in with Clever
or
show password
Forgot Password?
Don't have an account?  Sign up 
Sign up using Clever
or
Username is available taken
show password


Make sure to remember your password. If you forget it there is no way for StudyStack to send you a reset link. You would need to create a new account. Your email address is only used to allow you to reset your password. See our Privacy Policy and Terms of Service.

Already a StudyStack user? Log In

Reset Password
Enter the associated with your account, and we'll email you a link to reset your password.
focusNode
Didn't know it?
click below
 
Knew it?
click below
Don't Know
Remaining cards (0)
Know
0:00
edit
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.

  Normal Size     Small Size show me how

origins of cells

TermDefinition
State the three parts of cell theory. All living things are composed of cells; cells are the smallest units of life; all cells come from pre-existing cells.
Explain why cells cannot arise from non-living material today. Conditions on modern Earth no longer support spontaneous formation of complex molecules; experiments show cells only arise from other cells.
Define spontaneous generation. The outdated idea that living organisms could arise from non-living matter.
State Louis Pasteur’s contribution to cell theory. Pasteur demonstrated that microorganisms do not arise spontaneously; life comes from pre-existing life.
Describe Pasteur’s experiment. Broth in swan-neck flasks remained sterile until the neck was broken, proving microbes come from the air, not spontaneous generation.
Explain the endosymbiotic theory. Eukaryotic cells originated when prokaryotic cells were engulfed and lived inside larger host cells in a mutualistic relationship.
List evidence supporting endosymbiosis. Mitochondria/chloroplasts have circular DNA, 70S ribosomes, double membranes, and replicate independently by binary fission.
Explain why mitochondria and chloroplasts have double membranes. Result of being engulfed by a host cell during endosymbiosis.
State why mitochondria and chloroplasts have 70S ribosomes. They originated from prokaryotes, which have 70S ribosomes.
Explain what binary fission of mitochondria/chloroplasts indicates. They replicate independently, similar to bacteria, supporting prokaryotic origin.
Describe the role of endosymbiosis in evolution. Allowed cells to gain efficient ATP production (mitochondria) and photosynthesis (chloroplasts), enabling complex life.
State one example of a modern endosymbiotic relationship. Coral and photosynthetic algae; gut bacteria in humans; termite gut protists.
Define prokaryote. A cell lacking a nucleus with 70S ribosomes and circular DNA.
Define eukaryote. A cell with a nucleus, membrane-bound organelles, and 80S ribosomes.
Explain how gene transfer supports endosymbiosis. Many mitochondrial and chloroplast genes have moved to the host cell’s nucleus, showing integration over time.
State why early Earth conditions allowed cell formation. High energy (lightning/UV), reducing atmosphere, and warm oceans allowed organic molecules to form.
Define abiogenesis. The theory that life originated from non-living matter under early Earth conditions.
Explain why early cell membranes formed spontaneously. Phospholipids self-assemble into bilayers in water due to hydrophobic/hydrophilic interactions.
State the importance of RNA in early cells. RNA can store genetic information and act as an enzyme (ribozymes), supporting the RNA world hypothesis.
Define the RNA world hypothesis. Early life was based on RNA molecules capable of self-replication and catalysis before DNA and proteins evolved.
Created by: user-1970252
 

 



Voices

Use these flashcards to help memorize information. Look at the large card and try to recall what is on the other side. Then click the card to flip it. If you knew the answer, click the green Know box. Otherwise, click the red Don't know box.

When you've placed seven or more cards in the Don't know box, click "retry" to try those cards again.

If you've accidentally put the card in the wrong box, just click on the card to take it out of the box.

You can also use your keyboard to move the cards as follows:

If you are logged in to your account, this website will remember which cards you know and don't know so that they are in the same box the next time you log in.

When you need a break, try one of the other activities listed below the flashcards like Matching, Snowman, or Hungry Bug. Although it may feel like you're playing a game, your brain is still making more connections with the information to help you out.

To see how well you know the information, try the Quiz or Test activity.

Pass complete!
"Know" box contains:
Time elapsed:
Retries:
restart all cards