Biology 101- Chapter 2

Freshman year Biology 101

Atoms

Smallest Unit of Matter

What do Atoms Consist of?

Protons (+), Neutrons (No Charge), Electrons (-)

Shells

Electrons distributed around the nucleus at different energy levels

Valence Shell

The Outermost electron shell of an atom

How much can Each Shell Hold?

1st Shell has a Max of 2 electrons

All other shells have a max of 8 electrons

How does a Valance Electron Fill up it’s shell?

Chemical bonding between atoms

Molecule

2 or more atoms linked by chemical bonding

What are the 4 types of Chemical Bonds?

Nonpolor covalent

Polar covalent

Ionic

Hydrogen

Nonpolor covalent

Equal sharing of e: Their electronegative are equal or almost the same

Polar Covalent

Unequal sharing of e: Due to a difference of electronegative

Ionic Bonding

Donating/ Stealing: Due to a LARGE difference of electronegative

Hydrogen Bonding

No sharing or Donating: When there’s a partial positive Hydrogen interacts with a partial negative atom of a different Molecule

Electronegativity

Tendency to attract electrons. (More = Higher)

What Does Electronegativity influence?

Chemical Bonding

What kind of Molecule is Water?

Polar Molecule

Hydrophillic

Loves Interacting with water

Hydrophobic

Hates interacting with water

What is the result of the H and O bond in water?

Water always has a partial positive Hydrogen and a partial negative Oxygen

Water

required for living organisms and is a universal solvent

PH

Influences the rate of chemical reactions and homeostasis

What is the PH of Water?

7

[H+] = [OH-]

Acidic Solution

[H+] > [OH-]

Basic Solution

[H+] < [OH-]

Cohesion

The attraction of water molecules to one another. A result of Hydrogen bonding.

An Example of Cohesion

When water is Frozen. The water is more stable (bonds) but less dense (why it floats)

What Chemical make up Living Organisms?

Carbon, Oxygen, Hydrogen, Nitrogen

What Molecules do you need to be consider an Organic Molecules?

Carbon and Hydrogen

What Special about Carbon?

Can from 4 covalent bonds and allows for structurally diverse molecules to be made

Structurally diverse molecules allows for?

Functionally diverse organic molecules.

Structure and function?

Go hand in hand!!

4 Types of Organic Molecules

Proteins, Nucleic Acids, Carbohydrates, Lipids

Proteins

-Provides structural support of cells and helps chemical reactions occur (enzymes)

-They are also known as Polypeptides

What are the Polymers and Monomers of Proteins?

They are Polymers that are created by joining amino acids (monomers) by using a covalent bonds called peptide bonds.

• They are also linked by peptides bonds

How do Proteins look like?

Nucleic Acids

Encode and transmit genetic information

• DNA and RNA

What Polymers and Monomers do Nucleic Acids have?

They are polymers created by linking nucleotide monomers together via a covalent bond called a phosphodiester bond.

What are the Nucleotides Bases?

Cytosine, Thymine(DNA), Uracil (RNA), Guannie, Adenine

What are Pyrimidine bases?

Cytosine, Thymine(DNA), Uracil (RNA)

What are Purine bases?

Guannie, Adenine

What are the inches ends of the Polynucleotide strand?

5’ end (1st) and 3’ end (last)

What can DNA structural look like?

Double helix: 2 twisted polynucleotide strands

Base Pair: 2 nitrogenous based on opposing polynucleotides strands held together by hydrogen bonds

Base Pairs are found in Double helix.

Carbohydrates

Provide structural support for many organisms and a source of energy.

Vary in their structures and functions

What are Carbohydrates polymers and monomers?

They polymers created by linking monsaccharide monomers who are linked via covalent bonds called glycosidic bonds.

Monosaccharides

CnH2nOn

Types of Sugar Molecules

Monosaccharides and Polysaccharides (Glycosidic bonds)

Lipids

Make up cell membranes, store energy, and are important in cell communication.

They are all hydrophobic.

What are Lipids polymers and monomers?

They are not polymers therefore no monomers are able to link up with them.

What are the Lipids groups?

Triglycerides (fats), Steroids, Phospholipids

Triglycerides

Are composed of 3 fatty acids and Glycerol

Fatty acids

Long chains of carbons with a carboxyl group at the end

Saturated Fatty acids

• Single-bonded carbons

• Max # hydrogens

• Straight structure

• Solid at room temperature

Unsaturated Fatty acids

• Double-bonded carbons

• Less than Max # of hydrogens

• Bent structure

• Liquid at room temperature

Amino

Carboxyl

Phosphate

Hydroxyl

Methyl