Chapter 2

What is biology in many ways the study of?

How chemistry works in the living

Life is described as what?

Living Chemistry

Biology and Chemistry relate how

Bio is the chemistry occuring in living things

Cells are organized in what?

Chemical systems where thousands of reactions happen

What is organic

Most molecules in living things are organic, meaning they have carbon

Cells work where?

In water based enviorments because cells contain alot of water

What are chemical bonds

how atoms stick together

polymers are

many small molecules that join together to make a large molecule

pH is what?

how acidic or basic something is and how it can affect the cells function

What are Biological Macromolecules?

Proteins, nucleic acid, carbohydrate and lipids

Atoms to Life what is the order

Atoms to Molecules to Macromolecules to Cell Structure to Cell to Life

What is the smallest peice of an element

Atoms are the smallest piece.

What is an element

A substance made of only one type of atom

What is a molecule

2 or more atoms chemically joined. The atoms can be the same or different

What does the atom have

Atom consist of nucleus surrounded by electron cloud

What chare is the nulceus

Nucleus is positively charged, dense and has protons and neutrons

What are electron charge

Electrons are negatively charged and organzied into electron shells.

What does the number of protos in a atom determine

The atomic number

What do different isotopes of a single atom/element do

change the number of neutrons

gain or loss of electrons create

ions

what are cations

positive charge

anions?

negative charge

What are electon shells

Electrons move around the nucleus in different areas

Each shell can hold how many electrons

1st shell- 1; 2nd shell- 8 ; 3rd shell-8 ; 4th shell- 18; 5th shell-18

How do electrons fill shell

From inside out. they start closest to the nucleus

What is important about the outermost shell

Determines how reactive an atom is

Nonreactice and stable atom?

when outer shell is completely full

Covalent bonds are formed by?

Sharing of unpaired electrons in the outermost valence shells to make molecules. Theyre also the strongest bond.

Noncovalent bonds are?

Anytime their not sharing the electrons

Ionic bonds can be desribed as?

from when 1 atom donates an electron to another, resulting in one cation and one anion

More noncovalent bonds are

hydrogen bonds, electrostatic attraction,vander waals, hydrophobic forces.

Double bonds vs Single Bonds

Double bonds are shorter, but stronger than single bonds.

Double bonds are

are a total of 4 shared electrons.

Partial double bonds happen..

when electrons are shared between more than one pair of atoms instead of staying in one specifc bond

What is electronegativtiy?

How strongly an atom pulls electrons towards itself. When its high elctrongativity the high atom pulls the shared elctrons towards itself

Nonpolar covalent

electrons are equally shared. neither atom pulls the electrons much stronger than the other.

van der waals

weak attraction between atoms, happens bc electronms are constantly moving around an atom. electrosn dont spread out evenly

uneven charge is called

Temporary (transient) polarity. Temporary cjhange can cause nearby atoms or molecules to become temporarily polarized too.

What is electrostatic attraction?

Attraction between positive (+) and negative (−) areas of molecules.

Why can large molecules have positive and negative areas on their surfaces?

Because of polar covalent bonds.

What happens when molecules with matching surfaces come together?

They can form many weak noncovalent interactions at once.;

How can many weak noncovalent interactions affect binding?

Together they can create strong and specific binding.;

What is specificity?;

Molecules interact because their surfaces match and fit together.

What is a polar covalent bond?

A covalent bond where electrons are shared unequally.

What happens to electrons in a polar covalent bond?

One atom pulls the shared electrons closer to itself.

What charge does the atom pulling the electrons closer get?

A partial negative charge (δ−).

What charge does the other atom get in a polar covalent bond?

A partial positive charge (δ+).

What is a hydrogen bond?

A weak attraction between polar molecules.

Why do hydrogen bonds happen?

Because of polar bonds.

What bonds commonly allow hydrogen bonding?

O−H and N−H bonds.

What do hydrogen bonds help hold together in water?

Water molecules.

What do hydrogen bonds help hold together in DNA?

The two strands of DNA.

How do hydrogen bonds help proteins?

They help maintain the shape of proteins.

Hydrogen bonds are?

The most important noncovalent bond in biology

What are hydrophobic forces?

Interactions that cause nonpolar molecules to group together in water.

Why do hydrophobic molecules not mix well with water?

They have poor interactions with water.

What does water do to nonpolar molecules?

Water pushes the nonpolar molecules together to reduce contact with them.

What happens when hydrophobic molecules are pushed together?

They clump together.

How does hydrophobic clumping affect water?

It gives water more room and less organization, increasing entropy.

How do hydrophobic forces help form cell membranes?

Hydrophobic regions of lipids group together to help form the lipid bilayer.

What part of lipids is hydrophobic?

The hydrocarbon region

How can polar molecules create acids and bases in water?

By transferring protons (H+) between molecules.

What is an acid?

A molecule that donates H+.

Since water is polar there is

a good balance of hydronium hydroxyl ions

What does an acid do to hydronium concentration?

Increases hydronium ions.

What is a base?

A molecule that accepts H+.

What does a base do to hydronium concentration?

Decreases hydronium ions.

What type of molecules make up most cell components?

Carbon based organic molecules.

What are the 4 major small organic molecules in cells?

Sugars, fatty acids, amino acids, and nucleotides.

What are sugars used for?

They provide energy and are building blocks for larger carbohydrates.

What are fatty acids used for?

They are components of cell membranes and fats.

What are amino acids the building blocks of?

Proteins.

What are nucleotides the building blocks of?

DNA and RNA.

What is a carbohydrate?

A molecule made from sugars, sometimes described as hydrated carbon.

What is a monosaccharide?

One sugar molecule.

What is glucose?

A monosaccharide that can be broken down to provide energy for the cell.

What process breaks down glucose to release energy?

Glycolysis.

What are isomers?

Molecules with the same chemical formula but different 3D shapes.

What are examples of sugar isomers?

Glucose, galactose, and fructose.

What is a disaccharide?

2 sugar monomers linked together.

What is a trisaccharide?

3 sugar monomers linked together.

What is an oligosaccharide?

About 3 to 10 sugar monomers linked together.

What is a polysaccharide?

More than 10 sugar monomers linked together.

What carbohydrate stores energy in animals?

Glycogen.

What carbohydrate stores energy in plants?

Starch.

What carbohydrate provides mechanical support in plant cell walls?

Cellulose.

What carbohydrate provides mechanical support in arthropod exoskeletons? .

Chitin.

What forms when an oligosaccharide attaches to a protein?

A glycoprotein.

What forms when an oligosaccharide attaches to a lipid?

A glycolipid

oligosaccharides attacthed to protein or lipids do what?

found in plasma membrane, protect the cell surface, help cells stick togehter, determine human blood type and help w cell recognition

What is a condensation reaction?

A reaction that joins molecules together while releasing water.

What bond connects sugars together?

A glycosidic bond.;

What is hydrolysis?

A reaction that uses water to break molecules apart.;

What is the easy way to remember condensation vs hydrolysis?

Condensation builds; hydrolysis breaks.;

What is anabolism?

Building small molecules into larger molecules.;

What is catabolism?

Breaking larger molecules into smaller molecules.

What do sugars build?

Oligosaccharides and polysaccharides.

What happens during a condensation reaction between two sugars?

An OH leaves one sugar, an H leaves the other, and the remaining oxygen links the sugars together.

What is removed during a condensation reaction?

A molecule of water (H2O).

How are polysaccharides broken apart?

Through hydrolysis.