Study Questions #3 Flashcards
September 10-14
What is a lipid, and what function do lipids perform?
Lipids are hydrophobic organic macromolecules. Functions:
- energy storage
- membrane
- signaling
- light absorption
What are glycerolipids?
fatty acids bonded to glycerol
Why do fats store more energy than carbohydrates?
fats have more C-H bonds and are very reduced
Why should you avoid eating fats with trans double bonds?
they fool cells into thinking they’re unsaturated but act like they’re saturated making them hard to digest
Why do unsaturated fatty acids melt at lower temperatures than saturated fatty acids?
The intermolecular interactions are much weaker than saturated molecules. As a result, the melting points are much lower for unsaturated fatty acids.
Why does soap clean up grease?
Hydrophobic ends of soap molecule all attach to the oil. Hydrophilic ends stick out into the water. This causes a drop of oil to form:These drops of oil are suspended in the water. This is how soap cleans your hands - it causes drops of grease and dirt to be pulled off your hands and suspended in water. These drops are washed away when you rinse your hands.
Why do membrane such as phosphatidylcholine form bilayers?
They have two charges so the hydrophilic sides point out and the hydrophobic sides point in
What do triacylglycerols and phospholipids have in common and how do they differ?
Triacylglycerols have fatty acids on all three C’s whereas phospholipids have fatty acids on two and a phosphate on the other. Tricylgylycerols store energy and phospholipids form bilayers.
What are steroids, and what function do they perform?
4C rings
Functions:
-cholestrol in membranes determine structure
-hormones
What are prostaglandins, and what functions do they perform?
They’re altered fatty acid signals
Functions:
-protect stomach lining
-trigger uterine contractions
What are isoprenoids, and what functions do they perform?
two or more units of hydrocarbons, with each unit consisting of five carbon atoms arranged in a specific pattern. range in function from pigments and fragrances to vitamins and precursors of sex hormones
What is the cell theory?
- life is made of multiple cells
- cell is smallest unit of life
- cells come from cells
Why did it take so long for biologists to recognize the importance of cell life?
.
Why are microscopes such important tools for biologists?
they can observe things that are not visible to the eye
How do microscopes work?
light up a specimen, which absorbs certain wavelengths, which is how you can see them
What is the difference between resolution and magnification?
magnification is bending image through lenses and resolution is telling two objects apart
What is the most important property of a microscope?
resolution
Why can we see nuclei with a light microscope, but need an electron microscope to see objects like ribosomes?
light microscopes can’t resolve two objects less than 200 nm apart because the photons overlap
Why are cells so small?
- many things get in and out of cells by diffusion, and if it was too big it would take too long
- if surface area to volume ratio is too small, things can’t be exchanged
What are prokaryotic cells?
Cells without a nucleus
What are the key differences between archeabacteria and eubacteria?
- archaebacteria has no peptidoglycan and eubacteria do.
- archaebacteria have ethers and eubacteria have esters.
- archaebacteria have complex genes and eubacteria have simple genes
What are eukaryotic cells and what is the difference between eukaryotic and prokaryotic?
eukaryotes have organelles
Why can eukaryotic cells grow larger than prokaryotic cells?
they divide the work which reduces diffusion problems, so they have room to grow more