Flashcards in Cell Biology Deck (136)
What is the cell theory?
• Cells are the smallest independent units of life
• All living things are made up of cells
• Cells are formed by the reproduction of existing cells
Life on earth is what?
What is an element?
A chemically pure substance that cannot be broken down
What are covalent bonds?
When electron pairs are shared, very strong
What is a valence shell?
The outer layer of the atom
What is electronegativity?
The attractive force that an atom exerts on electrons
How do ionic bonds form?
By chemical attraction of opposite charges
- The more electronegative atom steals an electron
What kind of bond does solid, water, liquid, and gas have?
Hydrogen bonds (sharing of an H atom)
Polar molecules are:
Non-polar molecules are:
What is hydrophilic interaction?
Attraction, polar to polar
What is hydrophobic interaction?
Attraction, non-polar to non-polar
What ions do acids release?
What ions do bases release and accept?
Accepts H+ and releases OH-
What is carbon?
A “tinkertoy” atom
- Incredibly flexible- used to build many types of complex macro molecules
What is a common theme between living systems?
Many are biological polymers with repeated subunits
What is a polymer?
A repeating unit (more than two)
What are carbohydrates?
A source of energy
- Basic unit: CH2O
- Ex: glucose (disaccharides)
What are polysaccharides?
Form rigid biological structures (ex: cellulose + chitin)
What are the 3 classes of amino acids?
Electrically charged, polar, non-polar
What is the shape of a protein?
A folded polypeptide
What is the structure of a non-polar amino acid?
Amino acids have a hydrocarbon side-chain (ex: CH3)
What is the structure of a polar amino acid?
Amino acids have side chains with partial charge (polar uncharged), or net (+) charge, or net (-) charge
What are lipids?
Fats, steroids, phospholipids
What is fat?
Simple 3-carbon lipid
- Fatty acid tails, hydrophobic
What is a phospholipid?
2 fatty acid tails (hydrophobic) and charged phosphate head (hydrophilic)
What is a steroid?
Composed of carbon rings (5 or 6 carbons per ring)
- Cholesterol, estrogen, testosterone (hormones)
- Cell membranes (animals only)
What are the 4 bases of nucleic acids?
A (adenine), G (guanine) --- Purines
T (thymine), C (cytosine) --- Pyrimidines
What are the subunits of a nucleotide?
1 of 4 bases + a phosphate + a sugar