Chapter 3 Flashcards
(84 cards)
1
Q
Organic molecules
A
Organic molecules contain carbon
Organic molecules are abundant in living organisms
All organic molecules contain carbon, but not all carbon containing molecules are organic
2
Q
Macromolecules
A
Macromolecules are large, complex organic molecules
3
Q
Carbon
A
Carbon is a small, relatively light element with 4 valence electrons
Carbon needs 4 more electrons to fill the shell
It can make up to 4 bonds, usually single or double bonds
Carbon can form polar or nonpolar bonds
Carbon atoms attach to each other to form straight and branched chains and ring structures of various sizes and complexity that act as the backbones of biological molecules
4
Q
An organic compound has unique properties that depend upon what?
A
The size and shape of the molecule
The groups of atoms (functional groups) attached to it
5
Q
What are functional groups?
A
Groups of atoms attached to compounds
Affect a biological molecule’s function in a characteristic way
Compounds containing functional groups are hydrophilic, meaning they are soluble in water, which is a necessary prerequisite for their roles in water-based life
6
Q
Functional groups
A
Hydroxyl group Carbonyl group Carboxyl group Amino group Phosphate group Methyl group
7
Q
Hydroxyl group
A
Consists of a hydrogen bonded to an oxygen
—OH
8
Q
Carbonyl group
A
A carbon linked by a double bond to an oxygen atom
\
C=O
/
9
Q
Carboxyl group
A
Consists of a carbon double bonded to both an oxygen and a hydroxyl group
—COOH
10
Q
Amino group
A
Composed of nitrogen bonded to two hydrogen atoms and the carbon skeleton
—NH2
11
Q
Phosphate group
A
Consists of a phosphorus atom bonded to four oxygen atoms
12
Q
Methyl group
A
A carbon which is single-bonded to three hydrogens, and has one free bond to the rest of the molecule
—CH3
13
Q
Isomers
A
Two molecules with an identical molecular formula but different structures and characteristics
14
Q
Structural isomers
A
Contain the same atoms but in different bonding relationships
15
Q
Stereoisomers
A
Identical bonding relationships, but the spatial positioning of the atoms differs in the two isomers
16
Q
Cis-trans isomers
A
Differ in positioning around double bonds
17
Q
Enantiomers
A
Mirror image isomers
18
Q
Polymers
A
Large molecules formed by joining many subunits together
19
Q
Monomers
A
Smaller subunits that make up a polymer
20
Q
Four main types of macromolecules
A
Carbohydrates
Lipids
Proteins
Nucleic acids
21
Q
Monomers of carbohydrates
A
Monosaccharides
22
Q
Monomers of lipids
A
Glycerol and fatty acids
23
Q
Monomers of proteins
A
Amino acids
Proteins are made from 20 different amino acids
24
Q
Monomers of nucleic acids
A
Nucleotides
DNA is built from four kinds of nucleotides
25
Dehydration synthesis
Monomers are joined to form polymers through the removal of water molecules
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Hydrolysis
Polymers are broken down into monomers through the addition of water molecules
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Carbohydrates
Composed of carbon, hydrogen, and oxygen atoms
Cn(H2O)n
n = number
Most of the carbon atoms in a carbohydrate are linked to a hydrogen atom and a hydroxyl group
Include sugars and starches
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Carbohydrate classification
Carbohydrates are classified according to size
Monosaccharides - “single sugar”
Disaccharides - “two sugars” joined by dehydration synthesis
Polysaccharides - “many sugars,” long-branching chains of linked simple sugars
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Monosaccharides
Monosaccharides are the simplest carbohydrates; they are sugars consisting of a single monomer
The carbon skeletons of monosaccharides vary in length
They are the main fuels for cellular work, and are also used as raw materials to manufacture other organic molecules
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Disaccharides
Two monosaccharides/monomers can bond to form a disaccharide in a dehydration reaction
ex. a glucose monomer bonds to a fructose monomer to form sucrose, a disaccharide
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Polysaccharides
Polymers of monosaccharides
They can function in the cell as a storage molecule or as a structural compound
Are hydrophilic
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Starch
Starch is a storage polysaccharide composed of glucose monomers and found in plants
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Glycogen
Glycogen is a storage polysaccharide composed of glucose, which is hydrolyzed by animals when glucose is needed
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Cellulose
Cellulose is a polymer of glucose that forms plant cell walls
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Chitin
Chitin is a polysaccharide used by insects and crustaceans to build an exoskeleton
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Lipids
Composed predominantly of hydrogen and carbon atoms
Defining features of lipids is that they are nonpolar and therefore hydrophobic
Compounds important in energy storage and contain twice as much energy as a polysaccharide
Include fats, phospholipids, steroids, and waxes
Lipids comprise about 40% of the organic matter in the average human body
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Fats
Fats are lipids that are mostly energy-storage molecules made from glycerol and fatty acids
Also known as triglycerides or triacylglycerols
Formed by bonding glycerol to 3 fatty acids
Joined by dehydration; broken apart by hydrolysis
Fats are important for energy storage and can also be structural, providing cushioning and insulation
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Saturated fatty acids
All carbons linked by single bonds
Tend to be solid at room temperature
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Unsaturated fatty acids
Contain one or more double bonds
Tend to be liquid at room temperature (known as oils)
Cis forms naturally; trans for artificially
Trans fats are linked to disease
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Phospholipids
Formed by glycerol, two fatty acids, and a phosphate group
Phospholipids are amphipathic molecules
Phosphate head - polar/hydrophilic
Fatty acid tail - nonpolar/hydrophobic
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Steroids
Four interconnected rings of carbon atoms
Usually insoluble in water
ex. cholesterol
Tiny differences in structure can lead to profoundly different, specific biological properties
e.g. estrogen vs testosterone
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Cholesterol
A lipid (steroid) that is biosynthesized by all animal cells because it is an essential structural component of all animal cell membranes that is required to maintain both membrane structural integrity and fluidity.
In addition to its importance for animal cell structure, cholesterol also serves as a precursor for the biosynthesis of steroid hormones and bile acids.
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Two types of cholesterol
LDL (low-density lipoproteins)
HDL (high-density lipoproteins)
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HDL (high-density lipoproteins)
Good cholesterol carries excess cholesterol in your blood to your liver where it is broken down and removed from the body. This means high levels of HDL help to maintain heart health.
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LDL (low-density lipoproteins)
Bad cholesterol carries cholesterol to tissues throughout the body. When you have too much LDL, it can build up in the walls of your arteries, causing narrowing and reduced blood flow. This is bad for heart health.
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Triglycerides
The body converts excess calories, sugar, and alcohol into triglycerides.
People who are overweight, inactive, smokers, heavy drinkers, or eat a high carb diet tend to have high triglycerides.
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Sources of cholesterol
```
Egg yolk
Dairy products
Oils
Red meat
Fast food
```
48
Proteins
Composed of carbon, hydrogen, oxygen, nitrogen, and small amounts of other elements, notably sulfur.
Proteins are essential to the structures and functions of the cell.
Provide for construction material in body tissues
Play a vital role in cell function
Act as enzymes, hormones, antibodies
Built from amino acids
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Antibodies (immunoglobulins)
Highly specialized proteins that recognize, bind with, and inactivate bacteria, toxins, and some viruses; function in the immune response, which helps protect the body from “invading” foreign substances.
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Hormones
Help to regulate growth and development.
e.g.
Growth hormone - an anabolic hormone necessary for optimal growth
Insulin - helps regulate blood sugar levels
Nerve growth factor - guides the growth of neurons in development of the nervous system
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Transport proteins
Hemoglobin transports oxygen in the blood; other transport proteins in the blood carry iron, cholesterol, or other substances.
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Enzymes (catalysts)
Essential to virtually every biochemical reaction in the body; increase the rates of chemical reactions by at least a millionfold; in their absence (or destruction), biochemical reactions cease.
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Amino acids
Amino acids are the building blocks of proteins
Have an amino group and a carboxyl group; both of these are bonded to a central carbon atom; also bonded to the central carbon is a hydrogen atom and some other chemical group symbolized by R
Amino acids only vary by R groups
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Peptide bond
Covalent linkage between amino acids in proteins accomplished by an enzyme-mediated dehydration reaction
The carboxyl group of one amino acid links to the amino group of the next amino acid
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The 20 amino acids
```
Alanine (Ala)
Arginine (Arg)
Asparagine (Asn)
Aspartic Acid (Asp)
Cysteine (Cys)
Glutamic Acid (Glu)
Glutamine (Gln)
Glycine (Gly)
Histidine (His)
Isoleucine (Ile)
Leucine (Leu)
Lysine (Lys)
Methionine (Met)
Phenylalanine (Phe)
Proline (Pro)
Serine (Ser)
Threonine (Thr)
Tryptophan (Trp)
Tyrosine (Tyr)
Valine (Val)
```
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Structural proteins
Structural proteins provide associations between body parts
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Contractile proteins
Contractile proteins are found within muscle
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Defensive proteins
Defensive proteins include antibodies of the immune system
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Signal proteins
Signal proteins are best exemplified by hormones
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Receptor proteins
Receptor proteins serve as antennae for outside signals
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Levels of structures in proteins
Primary structure
Secondary structure
Tertiary structure
Quaternary structure
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Primary structure of a protein
The primary structure of a protein is its unique amino acid sequence
The correct amino acid sequence is determined by the cell’s genetic information
The slightest change in this sequence affects the proteins ability to function
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Secondary structure of a protein
Protein secondary structure results from the coiling or folding of the polypeptide
Coiling results in a helical structure called an alpha helix
Folding may lead to a structure called a pleated sheet
Coiling and folding result from hydrogen bonding between certain areas of the polypeptide chain.
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Tertiary structure of a protein
The overall three-dimensional shape of a protein is called its tertiary structure
Tertiary structure generally results from interactions between the R groups of the various amino acids
Disulfide bridges are covalent bonds that further strengthen the protein’s shape
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Quaternary structure of a protein
Two or more polypeptide chains (subunits) associate providing quaternary structure.
Collagen is an example of a protein with quaternary structure.
Its triple helix gives great strength to connective tissue, bone, tendons, and ligaments.
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Fibrous proteins
Also known as structural proteins
Appear in body structures
Examples include collagen and keratin
Stable
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Globular proteins
Also known as functional proteins
Function as antibodies or enzymes
Can be denatured
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Enzymes
Act as biological catalysts
Increase the rate of chemical reactions
Bind to substrates at an active site
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Why are proteins important?
Repair body structures
Regulate metabolic processes in body
A very important source of energy
Involved in the regeneration of mass muscle, skin, hair, and nails
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How does excessive protein intake affect health?
1. Put more stress on the organs
Liver and kidneys are responsible for getting rid of excess proteins in our body.
```
2. Increased risk of diseases such as:
Obesity
Cardiovascular diseases
High blood pressure
Type 2 diabetes mellitus
```
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Effects of excess non-natural protein sources
Prevention of natural creatine synthesis
Stomach cramps
High blood acidity
Kidney stones
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Nucleotides
Nucleotides are the monomers that compose DNA and RNA
Nucleotides have three parts:
A pentose (five-carbon) sugar called ribose in RNA and deoxyribose in DNA
A phosphate group
A nitrogenous group
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The five nucleotides
```
Adenine (A)
Guanine (G)
Cytosine (C)
Thymine (T)
Uracil (U)
```
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Nitrogenous bases of DNA
Adenine (A)
Cytosine (C)
Guanine (G)
Thymine (T)
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Nitrogenous bases of RNA
Adenine (A)
Cytosine (C)
Guanine (G)
Uracil (U)
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Differences between RNA and DNA
1. Ribose sugar
RNA: Ribose
DNA: Deoxyribose
2. T and U
RNA: Has nitrogenous base uracil (U) instead of thymine (T)
DNA: Had nitrogenous base thymine (T) instead of uracil (U)
3. Strand
RNA: Single
DNA: Double
4. Forms
RNA: One form
DNA: Several forms
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DNA (deoxyribonucleic acid)
The genetic material found within the cell’s nucleus
Provides instructions for every protein in the body
Organizes by complementary bases to form a double stranded helix
Contains the sugar deoxyribose and the bases adenine, thymine, cytosine, and guanine
Replicates before cell division
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RNA (ribonucleic acid)
Carries out the DNA’s instructions for protein synthesis
Created from a template of DNA
Organized by complementary bases to form a single-stranded helix
Contains the sugar ribose and the bases adenine, uracil, cytosine, and guanine
Varieties include messenger, transfer, and ribosomal RNA
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Monosaccharide examples
```
Glucose
Fructose
Ribose
Deoxyribose
Galactose
```
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Disaccharide examples
Maltose
Sucrose
Lactose
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Polysaccharide examples
Glycogen
Cellulose
Chitin
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Fibrous protein examples
Keratin
Elastin
Collagen
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Globular protein examples
Antibodies
Hormones
Enzymes
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Lipid examples
Triglycerides
Phospholipids
Steroids
Eicosanoids
