Biology Exam 1 Prep Notes

  • Atomic Structure & Electrons

  • Atomic Numbers: Number of protons (identifies the element)

  • Mass Numbers: Protons + Neutrons

  • Isotopes: Atoms of the same element with the same number of protons but different numbers of neutrons.

  • Neutral Atoms: Have an equal numbers of protons and electrons (Protons=Electrons)


Atomic Structure

-Smallest unit of matter that stills remains an element

Subatomic particles make up an atom

+=positive charge

o=neutron: negative charge

mass=0

+ atomic number:-number of protons

+mass number-number of protons of protons + neutrons


Isotopes:-are the same element with different numbers of neutrons resulting in different atomic forms

(Protons are the same atomic masses)


Physical and chemical change the same but as Isotopes gets heavy (more neutrons) they become more radioactive


Carbon 12

  • 6 protons

  • 6 neutrons

  • 6 electrons


Carbon 13

  • 6 protons

  • 7 neutrons

  • 6 electrons


Carbon 14

  • 6 protons

  • 8 protons

  • 6 electrons


  • Carbon-14 Isotope of carbon-12

  • used to radioactively date organic material in fossil rocks. They also use radioactively to label molecules tissues or temors.


Uranium-235

-Fuels nuclear reactors and concertes eletricity through fission reactions.


Electrons configuration; orbitals and shells

-The configuration of electrons (e`) determines an atom’s chemical properties and reactivity.

-Electrons are. held in orbits that can on;y hold 2 e- each.



S-only 1 orbital only holds 2e-

P-only 3 orbitals hold 3e-

D-5 orbitals can hold 10e

they only exsists in different shells or energy shells

  • 1st e-shell-capacity-2e

  • 2nd e shell capacity-8e-

  • 3rd shell-capacity 18e-


-Valence electrons and bonding/reactivity

  • Energy is the ability to do work for atoms

  • Energy flows from High unstable energy starter to lower more stable states


e-are form of energy

  • Energy (and instability) increases as you move away from Nucleus

  • Higher Shells have more energy (Higher shells have more energy Nucelus

  • (octect rule for chemical bonding IMPORTANTTTTT)


Covalent Bonding

  • e- are shared in a way that both have full valence shells

  • sharing of electrons pairs between nonmetal atoms


Nonpolar:e- are shared between atoms equallly due to similar electronegativity

-Polar-are not shaews between atoms due to a difference in eletrconegativity creating partial charges


Electronegatively-increases towards the right on the periodic table (towards F)

Electronegatively increases as you go up and valence shells move closer to the nucelus


Van der Waals-occurs when attraction between 2 molecules is weak and trasncient, a molecule can have short lived ‘‘hot spots’’ off positive and/or negative charge due to tempoary asymmetric electron distrubtions


Hydrogen bonding-often bond to more electronegative atoms making them slightly positive charge (covalentr bonded to an electronegative atom like O or N and another.


Ice-is less dense than liquid water so it floats and insualtes water below (VERY IMPORTANT)


Polar solvent: water dissolves many substances essential substances for life processses

(Water is polar (ALSO IMPORTANT)


  • Solvent: The dissolving agent

  • Solute: the substance that is dissolved

  • solution: a completely homogenous, liquid mixture

  • Hydrophilic: water loving

  • Hydrophobic: water fearing


Acidic and Base

  • An acid is something that increases (H+) and lowers [OH] (lowers ph)

  • a base is something that increases [OH]-] and lowers [H+] (rises ph)


(Inorganic carbon transform into organic carbon via photosynthesis

-valence= bond formation

-valence shells have e- required to fill outer shell


Chemicals Structures and Shape

-Structural: different covalent (arrangement) of atoms in space

Geometric: Different arrangements of atoms in space around a double bond


Enantiomers: Non-super impossible mirror images

6 functional groups are

  1. Hydroxyl

  2. Carboxyl

  3. Carbonyl

  4. Amino

  5. Phosphate

  6. Sulfhydryl


Macromolecules:

  • Carbohydrates: Energy storage cells surface makes cells signaling

  • Lipids: Energy storage cell membrane horomones

  • Proteins: catalyze reactions physical; structure calls signaling


Csrbohydrates: simple sugars


PH=10

POH=4

[H+]=10 to the negative 10 m

[OH]= 10 to the negative 4 m

PH=4

POH=10

[H+]= 10 to the negative 4 m

[OH]= 10 to the negative 7 m

PH=2

POH=12

[H+]=10 to the negative -2 m

[OH]= 10 to the negative -12 m)


  1. Lipids:

  • Not true polymers but they’re still macromolecules

  • Three diffrent types are: Triglycerides (fats), Phospholipids, and Steriods (sterols)

1 glycerol=3-c alochol (3-OHS)


Satuarted fats:all carbon satuarted with hydrogens so no c=c doube bonds

Unsatuarted fat:c=c double bonds present along the fatty acid chain.


Phospholipids:main competent of the cell menbrane considered amphillic due to prescene of both polar and non polar regions.


Steriods: (sterols): made of carbon skeleotn of four fused rings.


Chlestrol: is the main steriod in animals cell (important) for animal cell membrane

3 proteins:one or moe polypeptides folded into a functional conformation.


Polypeptides: are polymeners of amino acids (the monomers prtoeins comprise over 50% of the wieight of the cells


Protein: amino acids have amino groups


(IMPORTANTTT)-there are 20 naturally occuring amino0 acids grouped into the categoties based on their chains

  • Non Polar:hydrophillic

  • Polar:Hydrophobic

  • Chersed (acidic/basic)


Nonpolars-are aminos acids caused by sharing of electrons equally and have no oxygen prsent

Polar:amino acids that have unequal sharing of elctrons and thus are typically oxygen prsenet. They can pull towards electronegatively when it is at the end of the molecules


Things to know and remember

  • Acidic (negative charged)

  • Basic (positive charge!)


Enyzmes are typically named for what they do in an functioning organism.They act as as cataylsts without using anything as a product or reactions speeding up.

Structure and Folding

  • Primary- the aa sequence everything else happens depedning on this

  • Folding refers to the protein aquiring it’s 2 and 3 structure


Secondary (2)

-The 10 chain folds to form alpha helices and beta shets H-BONDS between backbone atoms


Tertiary (3)-complex overall shape a polypeptide takes


Overternary (4)

-Interaction of mutiple polypeptides to form one functionary protein.

proteins may denature when exposed to extreme conditions


NuLEIC ACIDS: acidic polymers of nucleotides found in the cells nucleus held together by phospholipids linkage.


DNA (DEXOYRIBONUCLEIC ACID)

-FOR THE REPOSITORY OF GENETIC INFORMATION


RNA(RIBONUCELIC ACID)-FOR THE EXPRESSION OF GENETIC INFORMATION