CELL BIOLOGY Flashcards
What distinguishes prokaryotic from eukaryotic cells?
Prokaryotes lack a nucleus and membrane-bound organelles. Eukaryotes have both.
Which organisms are prokaryotic?
Bacteria and Archaea.
What is the structure of the cell membrane?
A phospholipid bilayer with embedded proteins, cholesterol, and carbohydrates.
What does “selectively permeable” mean?
Only certain substances can pass through.
What are the three types of passive transport?.
Diffusion, osmosis, and facilitated diffusion.
What is the sodium-potassium pump?
An active transport protein that moves 3 Na⁺ out and 2 K⁺ into the cell using ATP.
Why is water called the universal solvent?
It dissolves many polar substances.
What gives water its cohesive properties?
Hydrogen bonding.
Why is water’s high heat capacity important?
It stabilizes internal temperatures.
Which organelles are in the endomembrane system?
Nuclear envelope, ER, Golgi, lysosomes, vesicles, plasma membrane.
What does the rough ER do?
Synthesizes proteins for secretion.
What is the role of lysosomes
Break down waste and cellular debris.
What are the 4 classes of macromolecules?
Carbohydrates, lipids, proteins, nucleic acids.
What’s the function of carbohydrates?
Provide energy and structure
What are phospholipids made of?
Glycerol, two fatty acids, phosphate group.
What are proteins made of?
Chains of amino acids linked by peptide bonds
What’s the function of DNA?
Store genetic information.
What are the stages of the cell cycle?
Interphase (G1, S, G2) and Mitosis.
What enzyme builds new DNA strands?
DNA polymerase.
What is the central dogma of biology?
DNA → RNA → Protein.
What happens during transcription?
DNA is used to make mRNA in the nucleus.
What is translation?
mRNA is decoded into a protein at the ribosome
What are introns and exons?
Introns are removed; exons are spliced together to form mRNA.
What are the start and stop codons?
Start: AUG;
Stop: UAA, UAG, UGA.
