The Molecules of Life Lecture 5 test 2

Carbon is the

fundamental element of life

Four electrons in outer orbital can be shared with other atoms, including

Carbon

Carbon is the ideal

atomic building block to form the backbone of organic molecules

Most of the chemical reactions and structures of living things involve more complex molecules,

termed organic compounds

Organic compounds are

carbon compounds with a basic framework of the element carbon bonded to other atoms (ex: from CH4 to large antibody molecules)

These are the groups of atoms directly involved in chemical reactions in an organic compound

Hydroxyl property

Polar

These are the groups of atoms directly involved in chemical reactions in an organic compound

Methyl property

Nonpolar

These are the groups of atoms directly involved in chemical reactions in an organic compound

Carbonyl property

Polar +

These are the groups of atoms directly involved in chemical reactions in an organic compound

Amino property

Charged, accepts H+ to form NH3+. They are considered basic

These are the groups of atoms directly involved in chemical reactions in an organic compound

Phosphate and Carbonyl properties

Charged, ionizes to release H+. Since phosphate groups can release H+ ions into solution, they are considered acidic

Biological molecules are organic compounds produced by

living things, and they include four main families:

1. carbohydrates

2. lipids *

3. proteins

4. nucleic acids

These very large compounds are termed

macromolecules

All macromolecules except lipids are formed by

polymerization

Polymerization a process in which repeating subunits termed

monomers are bound into chains of various lengths termed polymers

a chain of amino acids (monomers) polymerize to form

proteins (polymers)

Cells link monomers together to form a

polymer through a dehydration reaction

Dehydration reaction chemical reaction involves

removing a molecule of water

The breakdown of polymers occurs by a process called

hydrolysis

Hydrolysis means to

break (lyse) with water (hydro)

Cells break bonds between

monomers by adding water to them, a process that is essentially the reverse of a dehydration reaction

Carbohydrates

A class of molecules that includes sugars and polymers of sugars

Carbohydrates: Monosaccharides are

simple sugars that are the monomers of carbohydrates (glucose: C6H12O6, fructose)

Carbohydrates: Disaccharides or double sugar, is

constructed from two monosaccharides by a dehydration reaction (sucrose, lactose)

Carbohydrates: Polysaccharide is a

polymer of five or more monosaccharides (starch, glycogen)

Carbohydrates Polysaccharides: Starch

long strings of glucose monomers that are stored by plant cells, providing a sugar stockpile that can be tapped when needed

Carbohydrates Polysaccharides: Glycogen

polymer of glucose monomers that is mostly stored in liver and muscle cells, which break down the glycogen to release glucose when you need energy

Carbohydrates Polysaccharides: Cellulose

the most abundant organic compound on Earth, forms cable-like fibrils in the tough walls that enclose plant cells and is a major component of wood and other structural components of plants

Almost all carbohydrates are

hydrophilic (“water-loving”) molecules that dissolve readily in water

lipids are

hydrophobic (“water-fearing”); they do not mix with water

Lipids also differ from carbohydrates, proteins, and nucleic acids in that they are

neither huge macromolecules nor are they necessarily polymers built from repeating monomers

Lipids are a diverse group of

molecules made from different molecular building blocks

Fat consists of a

glycerol molecule joined with three fatty acid molecules by dehydration reactions

A fat molecule is called a

triglyceride

A fatty acid is a

long molecule that stores a lot of energy

We store fat long-term in specialized reservoirs called

adipose cells, which swell and shrink when we deposit and withdraw fat from them

This adipose tissue, or body fat, not only stores energy but also

cushions vital organs and insulates us, helping maintain a constant, warm body temperature

Lipids: Unsaturated fatty acid

has fewer than the maximum number of hydrogens at the double bond

Lipids: Saturated fatty acid

contain the maximum number of hydrogen atoms, giving them a straight shape

Lipids: A polyunsaturated fat

has several double bonds within its fatty acids

Most animal fats, such as lard and butter, have a relatively high

proportion of saturated fatty acids

Diets rich in saturated fats may

contribute to cardiovascular disease by promoting atherosclerosis

is the leading cause of death among people in the United States and other industrialized nations.

Heart Disease

Lipids: Steroids are lipids that are very

different from fats in structure and function

All steroids have a

carbon skeleton with four fused rings

One common steroid is

cholesterol

Cholesterol key component of the membranes that surround your

cells

Cholesterol : Base Steroid

It is also the __ from which your body produces other steroids, such as the hormones estrogen and testosterone, which are responsible for the development of female and male sex characteristics

Cholesterol is a Waxy substance found

in your blood

Your body needs cholesterol to

build healthy cells

With high cholesterol, you can develop

fatty deposits in your blood vessels making it difficult for enough blood to flow through your arteries

Sometimes, those cholesterol deposits can break suddenly and form a clot that causes a

heart attack or stroke

Cholesterol is carried through your blood, attached

to proteins

This combination of proteins and cholesterol is called a

lipoprotein

There are different types of cholesterol, based on what the lipoprotein carries:

Low-density lipoprotein (LDL) or High-density lipoprotein (HDL)

Low-density lipoprotein (LDL):

"bad" cholesterol that transports cholesterol particles throughout your body. Builds up in the walls of your arteries, making them hard and narrow

High-density lipoprotein (HDL)

"good" cholesterol, picks up excess cholesterol and takes it back to your liver

Some amateur and professional athletes take

anabolic steroids to help them build strength (“bulk up”).

A protein is a

polymer of amino acid monomers

Proteins account for more than

50% of the dry weight of most cells, and they are instrumental in all cellular processes

Proteins are the ___ of your body: chances are, if something is getting done, there is a protein doing it

“worker bees”

Your body has tens of thousands of different kinds of proteins, each with

a unique three-dimensional shape corresponding to a specific function

Proteins are the most

structurally sophisticated molecules in your body

All proteins are made by stringing together a common set of

20 kinds of amino acids

Each type of amino acid has a unique

side chain which gives that amino acid its special chemical properties

Some amino acids have very simple side chains

the amino acid glycine, for example, has a single hydrogen as its side chain

Other amino acids have more complex side chains, some with

branches or rings within them

The bond that joins adjacent amino acids is called a

peptide bond

The resulting long chain of amino acids is called a

polypeptide

A functional protein is

one or more polypeptide chains precisely twisted, folded, and coiled into a molecule of unique shape

The amino acid sequence of each polypeptide determines the

three-dimensional structure of the protein

It is a protein’s three-dimensional structure that

enables the molecule to carry out its specific function

Nearly all proteins work by recognizing and binding to

some other molecule

For all proteins, structure and function are

interrelated

A protein’s shape is sensitive to the

environment

An unfavorable change in __, __ or some other factor can cause a protein to unravel

temperature, pH

The protein’s amino acid sequence of each polypeptide chain is specified by a

gene

Nucleic acids are

macromolecules that store information and provide the instructions for building proteins

There are two types of nucleic acids:

– DNA (deoxyribonucleic acid)

– RNA (ribonucleic acid)

The genetic material that humans and all other organisms inherit from their parents consists of giant molecules of

DNA

The DNA resides in the cell as

one or more very long fibers called chromosomes

A gene is a unit of

inheritance encoded in a specific stretch of DNA that programs the amino acid sequence of a polypeptide

Those programmed instructions, however, are written in a chemical code that must be

translated from “nucleic acid language” to “protein language”

A cell’s RNA molecules help make this translation

DNA » (TRANSCRIPTION) mRNA » (TRANSLATION) protein

Nucleic acids are polymers made from monomers called

nucleotides

Each nucleotide contains___ parts

3

Each nucleotide contains three parts:

1. a five-carbon sugar (deoxyribose in DNA; ribose in RNA)

2. a phosphate group

3. a nitrogen-containing base

The sugar and phosphate are the same in all nucleotides; only the __ varies

base

Each DNA nucleotide has one of four possible nitrogenous bases:

adenine (A), guanine (G), cytosine (C), or thymine (T)

Dehydration reactions link nucleotide monomers into long chains called

polynucleotides

In a polynucleotide, nucleotides are joined by

covalent bonds between the sugar of one nucleotide and the phosphate of the next

This bonding results in a sugar-phosphate backbone

a repeating pattern of sugar- phosphate-sugar-phosphate, with the bases (A, T, C, or G) hanging off the backbone like appendages

With different combinations of the four bases, the number of possible polynucleotide sequences is

vast

A molecule of cellular DNA is

double-stranded, with two polynucleotide strands coiled around each other to form a double helix

The base pairing in a DNA double helix is specific:

The base A can pair only with T, Apple Tree

and G can pair only with C Group Chat

There are three important differences between

DNA and RNA: RNA’s sugar is

ribose rather than deoxyribose

There are three important differences between

DNA and RNA: Instead of thymine, RNA has a

similar but distinct base called uracil (U)

There are three important differences between

DNA and RNA: RNA is usually found in living cells in

single-stranded form, whereas DNA usually exists as a double helix

Each year, industrial chemists develop and test thousands of new

organic compounds for use as insecticides, fungicides, and weed killers.

One isomer of methamphetamine is the addictive illegal drug known as “crank.” Another isomer is a medicine for sinus congestion. How can you explain the differing effects of the two isomers?

same molecular construct but different functional group. Backbones are the same

Monomers are joined together to form larger polymers through

_________. Such a reaction releases a molecule of

dehydration, h2o