Biology Test 1

Matter

Anything that has mass and takes up space

Element

a substance that cannot be broken down into other substances

Compound

a substance consisting of two or more different elements combined in a fixed ratio

What makes up 92% of living matter?

CHOPN

What does CHOPN stand for?

carbon, hydrogen, oxygen, phosphorus, nitrogen

AMU mass

protons + neutrons / isotopes

Bohr Model

shows electrons orbiting the nucleus of an atom

Where are electrons placed on shells?

Around the nucleus

Lewis Dot Model

Simplified Bohr diagrams

Where are electrons placed in the Lewis Dot Model?

Around the element symbol

What do elements want to be?

Stable

How do elements become stable?

forming chemical bonds with other elements

Octet rule

Elements will gain, lose, or share electrons to complete their valence shell and become stable

Chemical bonds

An attraction between two atoms resulting from the sharing or transferring of valence electrons

Electronegativity

the measure of an atom's ability to attract electrons to itself

Covalent bonds

when two or more atoms share electrons

What is a single covalent bond?

two atoms held together by sharing one pair of electrons

What is a double covalent bond?

when 4 electrons are shared in one bond

What is a triple covalent bond?

a bond formed by sharing three pairs of electrons

nonpolar covalent bond

electrons are shared equally between atoms

polar covalent bond

electrons are not shared equally between atoms

Ionic bonds

the attraction between oppositely charged ions

What are ionic bonds usually between?

metal and non metal

Cation

A positively charged ion

Anion

A negatively charged ion

Hydrogen bonds

the partially positive hydrogen atom in one polar covalent molecule will be attracted to an electronegative atom in another polar covalent molecule

intermolecular bonds

bond that forms between molecules

Polarity

unequal sharing of the electrons make water a polar molecule

Cohesion

the attraction of molecules for other molecules of the same kind

Hydrogen bonds between H2O molecules hold them together and increase what?

Cohesive forces

What is responsible for surface tension?

cohesion

Cohesion allows for the transport of water and nutrients \______ \_______ in plants

against gravity

Adhesion

The clinging of one molecule to a different molecule

In plants, what allows the water to cling to the cell walls to resist the downward pull of gravity?

Adhesion

Capillary action

the upward movement of water due to the forces of cohesion, adhesion, and surface tension

When does capillary action occur?

when adhesion is greater than cohesion

high specific heat

H2O resists changes in temperature

Evaporative cooling

water has a high heat of vaporization, the molecules with the highest kinetic energy leave as gas

What does evaporative cooling moderate?

Earth's climate

What does evaporative cooling stabilize?

Temps in lakes and ponds

What does evaporative cooling prevent?

Terrestrial organisms from overheating and leaves from becoming too warm in the sun

Density

As water solidifies it expands and becomes less dense

What allows marine life to survive under floating ice sheets?

Hydrogen bonds

Solevent

the dissolving agent of a solution

Water is what type of solevent?

Versatile solevent

What does it mean to be a versatile solevent?

Its polar molecules are attracted to ions and other polar molecules it can form from hydrogen bonds with

Solution

Homogenous mix of 2+ substances

Solute

Substance that is dissolved

What does "like dissolves like" mean?

polar dissolves polar, nonpolar dissolves nonpolar

ionic compounds

The partially negative oxygen in water will interact with a positive atom

Carbon

Organic chemistry

organic chemistry

the study of compounds with covalently bonded carbon

Organic compounds

compounds that contain carbon and hydrogen

How many valence electrons does carbon have?

four

What type of covalent bonds can carbon form?

single, double, or triple

What does the type and number of covalent bonds carbon forms with other atoms affect?

The length of the carbon chain and the shape of the molecule

What can carbon use to form covalent bonds to other carbons?

Its valence electrons

Hydrocarbons

organic molecules consisting of only carbon and hydrogen

What do carbon chains form?

skeletons of most organic molecules

Many regions of a cell's organic molecules contain what?

Hydrocarbons

Functional groups

chemical groups attached to carbon skeletons that participate in chemical reactions

What do variations in carbon skeletons allow for?

molecular diversity

Carbon can form large molecules known as?

macromolecules

What are the four classes of macromolecules?

carbohydrates, lipids, proteins, nucleic acids

What is another name for DNA?

nucleic acid

Polymers

chain like macromolecules of similar or identical repeating units that are covalently bonded together

Monomers

the repeating units that make up polymers

dehydration reaction

bonds two monomers with the loss of H2O

Hydrolysis

breaks the bonds in a polymer by adding H2O

Carbohydrates

include sugars and the polymers of sugars

carbohydrates contain what groups?

A carbonyl group and many hydroxyl groups

Monosaccharides

simple sugars

What is the sugar ratio?

1:2:1

What is the most common monosaccharide?

glucose

What is glucose used in?

cellular respiration

What can monosaccharides serve as?

building blocks for amino acids or as monomers for di- and polysaccharides

Disaccharide

Two monosaccharides joined together by covalent bonds

What is the most common disaccharide?

sucrose

What are the monomers of sucrose?

glucose and fructose

How do plants use carbohydrates?

Transfer them from roots to leaves in the form or sucrose

Polysaccharides

polymers with many sugars joined via dehydration reactions

storage polysaccharides

starch (plants) and glycogen (animals)

structural polysaccharides

cellulose and chitin

Cellulose

tough substance that forms in plant cell walls

chitin

forms exoskeleton of arthropods

Protein

Molecule consisting of polypeptides folded into a 3D shape

Polypepetide

Polymers of amino acids

What are proteins compromised of?

C, H, O, N, and S

What determines the function of a protein?

shape

Amino acids

Molecules that have an amino group and a carboxyl group

How many different amino acids are there?

20

What are the unique aspects of each amino acid based on?

the side chain's physical and chemical properties

How can side chains be grouped?

Nonpolar (hydrophobic), Polar (hydrophilic), Charged/ionic (hydrophilic)

When side chains interact, what do they determine?

The shape and function of the protein

To form a peptide bond, the carboxyl group of one AA must be positioned next to the what of another AA?

Amino group

Polypeptide

many amino acids linked by peptide bonds

Each polypeptide has a unique sequence of what?

Amino acids and directionality

Each end is chemically unique because....

One end is a free amino group and one end is a free carboxyl group

What is an N-terminus?

An amino end

What is the C-terminus?

carboxyl end