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Biology 101 Exam 1 Unc Questions And Answers With Verified Solutions 100% Correct!!!
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Biology 101 Exam 1 Unc Questions And Answers With Verified Solutions 100% Correct!!!
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Biology 101 Exam 1 Unc Questions AndAnswers With Verified Solutions 100%
Correct!!!
Molecules - ANSWER✔✔ A molecule is a group of atoms held together by
chemical bonds that store potential energy.
A molecule is formed by 2 to several dozens of atoms
Some molecules have large amounts of potential energy (PF) in their chemical
bonds, they serve as "Energy Molecules" that provide kinetic energy for all cell
activities when their chemical bonds are broken.
Adenosine Triphosphate (ATP) - ANSWER✔✔ Is a universal energy molecule
found in almost all living organisms
Macromolecule - ANSWER✔✔ A macromolecule is formed by hundreds or
thousands of atoms
Chemical bonding's: Ionic Bonds - ANSWER✔✔ Formed by atoms being attracted
to each other due to opposite electrical charges.
• A cation (positive charge) and an anion (negative charge) are usually involved in
ionic bonds.
(e.g. Na++ Cl-→ NaCl).
Chemical Bonding's: Covalent bonds - ANSWER✔✔ Formed by the sharing of
electrons between 2 atoms (e.g. H2O).
• Atoms that form covalent bonds not only gain extra potential energy, they
become more stable because of more electrons on outer orbits.
,• Strongest type of chemical bonding in biological molecules
• Allowing cells to build larger molecules and macromolecules.
*Very strong bond; very difficult to break but once broken it releases lots of
energy.
Electronegativity - ANSWER✔✔ The attraction of an atom for shared
electrons.
If the atoms in a molecule have SIMILAR electronegativity, the electrons remain
equally stored between 2 nuclei and the covalent bond is said to be NON-POLAR.
If one element is more electronegative, it pulls the shared electrons closer to itself,
creating POLAR covalent bond.
Chemical Bonding's: Hydrogen Bonds - ANSWER✔✔ Weakest chemical bond;
but very important bc it plays a key role in forming internal shaping and folding of
larger molecules.; can break and be remade again.
• Hydrogen atoms contain only 1 proton and 1 electron, as a result when it is
sharing its electron with another atom, it has a partial
positive charge (i.e. H+).
• H+ tends to be attracted to the partial negative charge of oxygen (O-) and
nitrogen (N-), forming hydrogen bonds.
Important properties of water (H2O): High polarity - ANSWER✔✔ Partial
electrical charges of oxygen and
hydrogen atoms in water molecules cause polarity, allowing water to interact with
ions and other polar molecules.
Important properties of water (H2O): Heat Storage - ANSWER✔✔ Hydrogen
bonds formed between water
, molecules can absorb heat when they break (release heat when they are formed),
minimizing temperature changes in
living organisms.
Important properties of water (H2O): High Heat of Vaporization - ANSWER✔✔ It
takes a lot of energy to break many hydrogen bonds in water before evaporation is
possible.
Important properties of water (H2O): Low density of Ice - ANSWER✔✔ In cold
temperature, hydrogen bonds
in water spread farther apart, forming ice crystal which is less dense than liquid
water, and as a result ice can float on water.
This prevents freezing of lakes.
Important properties of water (H2O): Cohesion - ANSWER✔✔ Hydrogen bonds
hold water molecules together, which allows water to be transported upward in the
vascular system of plants.
Water as a Powerful Solvent - ANSWER✔✔ Ions and polar molecules are
attracted to the partial charges of water molecules, allowing these molecules to be
dissolved in water and from new chemical
behavior.
Water Organizes Nonpolar Molecules - ANSWER✔✔ Molecules that are nonpolar
(i.e. fat or oil) "does not dissolve) are not water-soluble, as a result will be crowded
together and from their own interaction.
Water ionizes - ANSWER✔✔ When covalent bonds of a water molecule break
Spontaneously, it dissociates into H+ and OH- a process called ionization.
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