Bio Midterm Study Guide

What are organic molecules?

carbon-based molecules

What is the outermost layer of electrons called?

The valence shell

What are the three subatomic particles of an atom?

protons, neutrons, electrons

What are the atoms that make up 98% of all living things?

CHNOPS: Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus, and Sulfur

What subatomic particle has a neutral charge and a AMU of 1?

Neutrons

What subatomic particle has a positive charge and a AMU of 1?

Protons

Total Protons + Total Neutrons \= ?

Atomic Mass

What is the octet rule?

Atoms tend to gain, lose or share electrons in order to have a full set of valence electrons.

In biology, how many electrons can the 3rd electron layer hold?

8 electrons

What are two types of covalent bonds?

polar and nonpolar bonds

What is electronegativity?

a measure of the tendency of an atom to attract a bonding pair of electrons

Which CHNOPS have similar electronegativity?

Carbon and Hydrogen

Which CHNOPS have very high electronegativity?

Oxygen and Nitrogen

What is a hydrogen bond?

the attraction between a hydrogen atom with a partial positive charge and another atom with a partial negative charge

Why are hydrogen bonds important?

Hydrogen bonds are extremely important in biology because they stabilize and determine the structure of biomolecules like proteins and nucleic acids (DNA & RNA).

Name 4 reasons why carbon is the most versatile atom on Earth.

1. They can form 4 bonds

2. Carbon is able to make long chains of different shapes and sizes

3. Is able to form single, double, triple bonds

4. Functional groups like to attach to carbon which gives a molecules certain properties.

Carboxyl Group

COOH

Amino group

NH2

hydroxyl group

OH

Phosphate Group

PO4

Basic equation for photosynthesis

6CO2 + 6H2O \------\> C6H12O6 + 6O2

How many monomers are there?

40-50

How many polymers are there?

Trillions

How do polymers break down into monomers?

hydrolysis

How do monomers become polymers?

Dehydration synthesis

What is a pentose?

5 carbon sugar

What is a hexose?

6 carbon sugar

What are isomers?

compounds with the same molecular formula but different structures and properties

isomers of glucose

fructose and galactose

What is sucrose made of?

glucose and fructose

What is maltose made of?

2 glucose

What is lactose made of?

glucose and galactose

How do plants transport sugar?

They transport sugar in sap

Function of starch

energy storage in plants

Function of glycogen

energy storage in animals

function of cellulose

provides structure to plant cell walls

What are glycoproteins?

proteins covalently bonded to carbohydrates

Where do glycoproteins attach?

Outer surface of cell membranes

Chemical ratio of carbs

1:2:1 (Carbon : Hydrogen : Oxygen)

Main function of lipids

long term energy storage

Four groups of lipids

fats, phospholipids, waxes, steroids

Structure of fats

Glycerol and three fatty acids.

What is the structure of glycerol?

3 carbons with 3 hydroxyl groups and all open bonds are hydrogen

Chemical ratio of lipids

1:2:

Characteristics of a saturated fatty acid

1. Has no double bonds

2. Every Carbon is connected to a Hydrogen

3. Solid at room temperature

4. Comes from animals (not healthy)

Characteristics of an unsaturated fatty acid

1. Has double bonds

2. Has less than the maximum number of hydrogen

3. Liquid at room temperature

4. Comes from plants (healthy)

5. Can have kinks / bends in it due to double bonds

Monounsaturated vs Polysaturated

Monounsaturated is the carbon-healthiest because it has one double bond. Polyunsaturated is the least carbon-healthy since it has multiple double bonds.

Structure and function of a phospholipid

made of 1 glycerol, 2 fatty acids, and 1 phosphate

phosphate forms a hydrophilic head, fatty acids form hydrophobic tails forms a phospholipid bilayer, basic structure of membranes

Structure of waxes

1 fatty acid attached to OH

Function of waxes

waterproofing and protecting animals (exoskeletons) and plants (top of the leaf).

structure of steroids

4 fused carbon rings. 3 rings that have 6 sides and 1 ring that has 5 sides.

What is the template for a steroid

Cholesterol

What is the function of an amino acid?

To serve as a monomer for a protein

What is a protein?

A polymer of amino acids

What is an alpha carbon?

The central carbon of an amino acid

How many different amino acids are there?

20 different amino acids

What is an R group in an amino acid?

Variable chemical group

-can be any one of 20 different chemical groups

-gives amino acid characteristic chemical properties

-can have different electric charges

-can be hydrophobic or hydrophilic

-can be polar or nonpolar

How do amino acids come together to make a protein?

They come together through dehydration synthesis / a condensation reaction.

What is a peptide bond?

A bond between amino acids

What is a dipeptide? What is a tripeptide?

Dipeptide: 2 amino acids; Tripeptide: 3 amino acids.

What is a polypeptide?

It is a set of amino acids 4+.

What is the 3D structure of a protein actually called?

Conformation

List 7 classes of proteins

1. Structural

2. Contractile

3. Storage

4. Defense

5. Transport

6. Signal

7. Enzymes

What does the shape of a protein determine?

its function

What happens when the shape of a protein is altered?

1. Loss of function

2. Increase of function

3. Decrease of function

4. New function

What is denaturation and what are the causes?

Denaturation is when the protein loses its function and shape. Change in pH, salt concentration, and temperature

What are the four levels of protein structure?

primary, secondary, tertiary, quaternary

What is primary structure

sequence, number, and types of amino acids

What is the secondary structure of a protein?

localized areas of coils, sheets, and loops within a polypeptide

What are the two main types of folding in secondary structure

Alpha Helix and Beta Pleated Sheets

What holds the secondary structure together

hydrogen bonds

What is the tertiary structure of a protein?

The polypeptide folding up into a 3D shape

What is the quaternary structure of a protein?

two or more polypeptide chains joined together

What is the function of an enzyme?

They speed up chemical reactions

How are enzymes named?

They usually end with -ase.