🌎 Cell Origins
What are the four major steps scientists think led to the first cells?
Simple organic molecules → macromolecules → replication → membrane.
What are the three domains of life?
Bacteria, Archaea, and Eukarya.
Which organelle produces ATP through aerobic respiration?
Mitochondria.
What structure surrounds the cell and controls what enters and leaves?
The plasma membrane.
What type of genetic material can a virus contain?
DNA or RNA.
What experiment tested whether organic molecules could form from nonliving materials under early-Earth conditions?
The Miller-Urey experiment.
Where is bacterial DNA located?
In the nucleoid.
Which organelle performs photosynthesis?
Chloroplasts.
What organelle is responsible for protein synthesis?
Ribosomes
What is the protein coat surrounding a virus called?
The capsid.
What two amino acids were found in the Miller-Urey experiment?
Alanine and glycine.
What type of DNA do prokaryotes usually have?
Circular DNA.
Which organelle modifies, packages, and ships proteins?
The Golgi apparatus.
What organelle acts as the cell's digestive and recycling system?
Lysosomes.
Why can't viruses reproduce on their own?
They must infect a host cell and use the host cell's machinery.
What molecule may have been the first molecule capable of storing genetic information and performing chemical reactions?
RNA
What are three reasons that limit how large a cell can become?
Surface area-to-volume ratio, diffusion, and maintaining adequate concentrations.
What is the difference between rough ER and smooth ER?
Rough ER has ribosomes and makes proteins/polypeptides.
Smooth ER has no ribosomes and helps make lipids/steroids and detoxify substances.
What are the three major components of the cytoskeleton?
Microtubules, microfilaments, and intermediate filaments.
What are the basic steps of viral replication?
Make viral components → copy viral genetic material → assemble new viruses → produce new virus particles.
What is a liposome, and why is it important to understanding the origin of cells?
A liposome is a structure surrounded by a lipid membrane. It may have helped trap molecules such as RNA inside a membrane, creating a primitive protocell.
How did scientists discover that Bacteria and Archaea are different groups?
They compared rRNA sequences and discovered that prokaryotes could be divided into Bacteria and Archaea
What evidence supports the endosymbiotic theory?
Mitochondria and chloroplasts have their own DNA, circular DNA, their own ribosomes, double membranes, bacteria-like size, and similarities to bacteria in rRNA.
What is the main material in a plant cell wall?
Cellulose. The cell wall provides support, protection, and rigidity
What three structures or components found in normal cells are viruses lacking?
Cytoplasm, ribosomes, and normal cell organelles.