Cards 11-20 Flashcards
Why don’t lipids dissolve in water?
Lipids have no polar groups that can interact with water.
Describe an anion of Boron (atomic number = 5). The mass number is 11. State number of electrons, protons, and neutrons.
2 electrons in first shell; 4 or more electrons in second shell. All surrounding a nucleus with 5 protons and 6 neutrons.
The mass number = protons + neutrons.
Give three reasons carbon is such an important molecule in biology.
It can bond to itself thus forming long chains
It has 4 valence electrons (the ultimate Lego block)
It can form single bonds (tetrahedral structure), double (linear bonds), or triple bonds (linear).
Explain how saturated fats can lead to heart attack and stroke.
Chains of carbons are saturated with hydrogen and, therefore, form straight chains. These chains can pack on the inside of vessels causing the heart to overwork and oxygen flow to the brain to be restricted.
Why is alanine (an amino acid whose R group is CH3) likely to be found in the middle of a protein.
Alanine must be a hydrophobic amino acid and it is. The r-group of alanine is -CH3.
Why does fluorine (atomic number 9) have a higher electronegativity than oxygen (atomic number 8).
It has a greater number of protons and about the same amount of proton shielding by its electrons.
What gets hotter faster, the pot or the water in the pot? Why?
Water takes longer to get hot because of all the H-bonds that must be broken becore its temperature can increase. The specific heat of water is greater than the specific heat of the pot.
Will nitrogen (atomic number = 7) form an anion or cation when it becomes part of an ionic compound? What will be the charge of the anion or cation? Explain your answer.
Nitrogen has 7 electrons, 5 valence electrons. In ionic bonding nitrogen will try to fill its valence shell with three more electrons. This would give Nitrogen a charge of -3. A negative ion is an a-n-ion.
Why does chlorine (17 protons) become an anion when it forms an ionic compound with another element?
The valence shell of Cl has 7 electrons (atomic number 17) - it is much easier for Cl to gain an electron than it is to lose 7. Therefore the charge on CL will be -1.
What is this a picture of?
The protein secondary structure called an alpha helix
