A&P Lecture Test 1
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What is an ionic bond?
Electrostatic attraction between two oppositely charged ions
What is a covalent bond?
Sharing of a pair of electrons in order to complete unfilled energy orbits
What is a hydrogen bond?
Electrostatic attraction between two polar molecules
What is the driving force for chemical reactions?
The desire of electrons to fill their energy orbits
What is electronegativity?
The ability of an atom to attract additional electrons
Why are sodium, potassium, chloride and calcium called electrolytes?
In the tissues, these atoms exist as ions (they have a charge). When charged particles move they create an electric current.
What is an ion?
An atom that has gained or lost an electron
What is an isomer?
Molecules that have the same formula (same number and type of constituents) but have different structures
What is an isotope?
Forms of the same atom, differing in their number of neutrons
What is a polar molecule?
A covalently bonded molecule with unequal sharing of the pair of electrons, creating small positive and negative charges at opposite end of the molecule
What does it mean to be hydrophilic?
dissolves in water, has charges on the molecule that will react with the polar water molecules (ions or polar molecules)
What does it mean to be hydrophobic?
Does not dissolve in water, no surface charges that can react with the water molecules, cell membranes
What properties of water are the result of hydrogen bonding?
- Heat buffering
- decreasing density when going from liquid to solid
- cohesion or surface tension
- adhesion or coating ability
What is one molar solution?
One molecular weight of a solute in grams dissolved in one liter of water
- Add up molecular weights in a molecule
- 180mg= glucose
- 360mg= surcuse
What are acids and bases and how do they interact?
- Acid are molecules that give up a hydrogen ion in solution
- bases are molecules that give up an ion that will neutralize a hydrogen ion (usually an hydroxide ion)
- acids and bases react to produce neutral solutions
Forms bonds by removing a water molecule from the substrates
Breaks bonds by adding the ions of water to the products
What is the energy of activation?
The energy used to initiate exergnoic reactions, caused by the random collision of molecules
What do all organic molecules have in common?
Why can fats produce more energy than sugars?
More C-H bonds
What are the four types of organic moelcues and what are their building blocks?
- Carbohydrates- monosaccharides
- lipids- fatty acids
- proteins- amino acids
- nucleic acids- nucleotides
What are the characteristics of an enzyme?
- Specific (only does one reaction)
- doesn't change in the reaction
- lowers the energy of activation
How does RNA differ from DNA?
- single strand, sugar is ribose, found all over the cell, uses uracil instead of thymine
- double strand, sugar is deoxyribose, found only in the nucleus, uses thymine instead of uracil
What are the parts of the nucleotide?
sugar, base, phosphate
What make up hand-rails and steps of the DNA ladder?
Handrails- sugar, phosphate, sugar, phosphate
Steps: complementary bases hydrogen bonded together
What are the components of the cell membrane?
- Phospholipid bilayer with cholesterol molecules
- cytoskeletal supports
- transmembrane proteins
- extrinsic and intrinsic proteins
What is a glycoclayx?
A layer of glycoprtoeins secreted by the cell and found covering the external surface of the cell membrane
How does the receptor-second messenger system work?
Binding of chemicals to external receptors causes them to change the shape of their internal portions which cause the release of a molecule that had been bound to them. The released molecule causes changes inside the cell
What is ligand gated protein channel?
channels that open when a chemical (a ligand) binds to them
What is a voltage gated protein channel?
channels that open when the voltage of the cell changes
What is the mechanical gated protein channel?
channels that open when they are directly moved
What do membrane enzymes do?
Break down molecules that come in contact with the external cell membrane
What are pumps?
Transmembrane protein channels that move substance AGAINST their concentration gradient; channels that require energy
Movement of a substance down its concentration gradient
Difference between areas of high and low concentrations
The movement of water across a membrane to decrease the concentration gradient of a solute that cannot pass the membrane
the amount o hydrostatic pressure (created by the increase in water from osmotic flow) that will stop the osmotic flow of water
The difference in osmotically active solute concentrations between two substances
What are the functions of the cytoskeleton?
- Support for the cell membrane
- holds cell organelles in place
- allows movement of cillia and flagella
- creates the mitotic spindle
- moves things around within the cell
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