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Bio181 > Sec 3- Chemistry of Life > Flashcards

Sec 3- Chemistry of Life Flashcards

Unit I- The Basis for Life

1
Q

What are organic molecules?

A

The molecules of life- carbohydrates, proteins, lipids, and nucleic acids- are organic molecules.

  • Type of molecules that contains carbon (and hydrogen!) atoms.
  • CH4 and C6H12O6 are organic.
  • H2O, O2, CO2, and CaCO3 are inorganic.
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2
Q

Why Carbon?

A

Carbon is a versatile atom.

  • It has four electrons in an outer shell that holds eight.
  • Carbon can share its electrons with other atoms to form up to four covalent bonds.
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3
Q

What are hydrocarbons?

A

The simplest organic compounds are hydrocarbons.

  • These are organic molecules containing only carbon and hydrogen atoms.
  • The simplest hydrocarbon is methane.
  • Are the main molecules in the gasoline we burn in our cars
  • The hydrocarbons of fat molecules provide energy for our bodies
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4
Q

What is carbon arrangements?

A

Carbon can use its bonds to;
* Attach to other carbons
* Form single, double, or triple bonds
* Form an endless diversity of carbon skeletons

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5
Q

What are isomers?

A

Compunds with the same molecular formula but different structures.

Three types-
1. Structural:
* different covalent arrangments
2. Geometric (stereoisomers):
* same arrangment of covalent bonds, but different in spatial arrangment (tras and cis)
3. Enantiomers:
* mirror image of each other
* can’t be superimposed, no matter how they are rotated

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6
Q

What are functional groups?

A

A certain combinations of atoms bound to a carbon in an organic molecule are called functional groups.

Functional groups help determine how molecules are going to react chemically or which other molecules they like to be around.

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7
Q

What are monomers?

A
  • Building blocks
  • Molecules that are subunits of polymers
  • Simple sugars, fatty acids, amino acids, nucleotides
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8
Q

What are polymers?

A
  • Molecules that consist of multiple monomers
  • Carbohydrates, lipids, proteins, nucleic acids
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9
Q

What is the metabolism?

A

The chemical reactions by which cells build, break down (and re-arrange) organic molecules.

Two common metabolic reactions:
1. Condensation (dehydration synthesis)
2. Hydrolysis

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10
Q

What is condensation?

A

Also called dehydration synthesis.

  • “Water-forming”
  • Building
  • Larger molecules are built from smaller subunits.
  • One water molecule forms with each reaction.
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11
Q

What is hydrolysis?

A

“Hydro-lysis” means “water-breaking”.

  • Breaking apart
  • Larger molecules are broken into smaller subunits.
  • One water molecule is needed for each reaction.
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12
Q

What are carbohydrates?

A

Also called sugars, having the molecular formula (CH2O)n.

  • They are “hydrated” carbons
  • Carbohydrates usually end on -ose
  • Cells use carbohydrates for energy and structural materials
  • Examples include small sugar molecules in soft drinks and large starch molecules in potatoes and past
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13
Q

What are some characteristics of sugar?

A

Depending on the location of the carbonyl group, sugars can be described as aldose (end) or ketose (internal).

Sugars have different numbers of carbons… 5 carbons (pentose) and 6 carbons (hexose) are common.

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14
Q

What are monosaccharides?

A

These are simple sugars.

  1. Glucose
    * common energy molecule in cells
    * found in sports drinks
  2. Galactose
    * found in milk (as part of lactose)
  3. Fructose
    * found in fruit and honey
    * sweeter than glucose because it’s a ketose!
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15
Q

What are disaccharides?

A

This is a double sugar.

  • It is constructed from two monosaccharides
  • It forms by a condensation reaction
  • The bond between two monosaccharides is called a glycosidic bond
  • Maltose is made of two glucose molecules
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16
Q

The Dissacharide Sucrose

A

The most common disaccharide is sucrose, common table sugar.

  • It consists of a glucose linked to a fructose
  • Sucrose is extracted from sugar cane and the roots of sugar beets
  • The average American consumes about 64 kg of sugar per year
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17
Q

The Disaccharide Lactose

A

Lactose is made from the monosaccharides glucose and galactose.

  • Milk is among the healthier foods you can eat
  • Milk is rich in many nutrients, but it makes some people ill
  • This is called lactose intolerance
  • The enzyme lactase breaks down lactose, but it does not function correctly when you are lactose intolerant
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18
Q

What are complex carbohydrates/polysaccharides?

A

Enzymes assemble complex carbohydrates (polysaccharides) from monosaccharides throuhg glycosidic bonds.

Glucose monomers can bond in different patterns to form different complex carbohydrates
* Starch (energy reserve in plants)
* Glycogen (energy reserve in animals)
* Cellulose (a structural component of plants)

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19
Q

What is starch?

A

Is a chain and energy reserve in plants.

One of the three important polysaccharides.

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20
Q

What is glycogen?

A

Is a branched chain, and is the energy reserve in animals. Stored in liver and muscles.

One of the three important polysaccharides.

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21
Q

What is cellulose?

A

The rows of parallel chains joined by hydrogen bonds, and is a structural component of plants.

  • Cell wall of plants
  • Paper and wood
  • Strong!
  • Most abundant biopolymer
  • One of the three important polysaccharides.
22
Q

What is alpha and beta glucose?

A

Starch and glycogen form from joining alpha-glucose monosaccharides. Cellulose forms from joing beta-glucose monosaccharides.

23
Q

Why can’t cows digest cellulose?

A

Most animals cannot derive energy by breaking down cellulose (fiber) because they don’t have the enzyme break beta-glucose glycosidic bonds (cellulase).

  • How do grazing animals survive on a diet of cellulose?
  • They have bacteria in their digestive tracts that can break down cellulose.
  • Termites also have microbes in their abdomen that break down cellulose (wood)
24
Q

What is chitin?

A

Chitin is a polysaccharide made of modified glucose monomers which include nitrogen.

  • It is a structural sugar that composes the exoskeleton of insects and crustaceans.
  • Some exoskeleton (like that of lobster) are further hardened by the addition of inorganic calcium carbonate (CaCO3).
  • Chitin is also located in the cell wall of fungi.
25
Q

What are lipids?

A

Fatty oily, or waxy organic compounds.

  • Mostly hydrocarbons
  • Not defined by common sturcture, but by behavior
  • Are hydrophobic; they do not mix with water
  • Are hydrophobic because they are not nonpolar
  • Ex:
    1. Fat/oils
    2. Phospholipids
    3. Steriods
26
Q

What are fats?

A

Dietary fats, such as triglycerides, are the msot abundant source of enrgy in vertebrates - stored in adipose tissue that insulated the body (like blubber).

Fat- lipid wth fatty acid tails
Triglyceride- lipid with three fatty acid tails attached to a glycerol backbone

27
Q

What are fatty acids?

A
  • Consists of a long chain of carbon atoms surrounded by hydrogen atoms.
  • Are usually 12 to 18 carbons in length.
  • Have a carboxyl group at one end.
  • Are added to a glycerol molecule through a dehydration synthesis reaction.

Triglycerides- Lipid with three fatty acid tails attached to a glycerol backbone.

28
Q

What are saturated fats?

A

Fatty acids have the maximum number of hydrogen atoms bonded to carbons.

Saturated fats pack more tightly than unsaturated fats, and tend to be more solid.

29
Q

What are unsaturated fat?

A

Fatty acids have less than the maximum number of hydrogens bonded to carbons (= have doube bonds).

Unsaturated fatty acids bend.

30
Q

The difference between animal vs. plant fats:

A
  • Most animal fats have a high proportion of saturated fatty acids
  • Ex: butter
  • Most plant oils tend to be low in saturated fatty acids
  • Ex: corn oil
31
Q

What is hydrogenation?

A

Artificial hydrogenation is the adding of hydrogen to unsaturated fats to make them solid at room temperature.

  • Examples are margarine and shortening
  • They should be avoided because hydrogenation created trans fats.
32
Q

What are phospholipids?

A

Main structural component of cell membranes.
A lipid with a phosphate group in its hydrophilic head, and two nonpolar, hydrophobic fatty acid tails.

  • Are amphipathic
  • Phospholipids form bilayer membranes
33
Q

What are steroids?

A

A type of lipid with four carbon rings (three 6-carbon and one 5-carbon) and no fatty acid tails.

  • Cholesterol is the “base” steroid from which your body produces other steroids.
  • Ex: are the sex hormones
34
Q

What are protiens?

A

A protein is a polymer constructed from amino acid monomers.

  • The same twenty different amino acids make up the protiens in all living beings.
  • Poriteins ar emajor structural components of our bodies, and they perform most of the tasks the body needs to function (enzymes).
35
Q

What are amino acids?

A

Small organic compund with a carboxyl group, amine group, and a characteristic side group (R).

  • Amino acids are either:
    1. Non-polar
    2. Polar
    3. Positively charged
    4. Negatively charged
36
Q

What are side groups (R)?

A

There are twnety different amino acids, which only differ by their side group.

  • Two additional amino acids hjave been discovered, but they are modification of existing amino acids after they have been incorporated into a protein.
37
Q

What are peptide bonds?

A

A bond between the amine group of one amino acid and the carboxyl group of another.

  • Amino acids are linked by peptide bonds.
38
Q

What is a polypeptide formation?

A

Chain of amino acids linked by peptide bonds.

  • There are endless combinations!
  • You body has tens of thousands of different kinds of proteins
  • The length and arrangement of amino acids maked each one different.
39
Q

What are the levels of protein structure?

A

There are four levels of protein structure:
1. Primary
2. Secondary
3. Tertiary
4. Quaternary

40
Q

What is the primary structure?

A

A linear sequence of amino acids.

  • Polypeptide formation
  • Average length: ~400 amino acids
  • Smallest: 11 amino acids (TAL protein in flies)
  • Largest: 35,000 amino acids (Titin in muscles)
41
Q

What is the secondary structure?

A

Formed by hydrogen bonds between the carboxyl and amine groups of different amino acids in a polypeptide.

  • Can form either alpha helixes or beta pleated sheets.
42
Q

What are tertiary structure?

A

Formed between the R groups within a polypeptide:
1. Ionic
2. Covalent (disulfide bonds)
3. Hydrogen bonds
4. Hydrophobic interactions

43
Q

What is quaternary structure?

A

Some proteins are composed of more than one polypeptide chain.

These proteins have quaternary structure.

44
Q

What is the importance of protein structure?

A

Changes in a protein’s sturcutre may also alter its function.

  • Even the substitution, addition, or deletion of one amino acid can render the protein non-functional by altering its structure.
45
Q

What is denaturation?

A

Unfavorable temperature and pH changes can cause a protein to unravel and lose its shape (and function!).

46
Q

What are nucleic acids?

A

Are information storage molecules.

  • Provide direction for building proteins.
  • “Nucleic” refers to their location in the nuclei of eukaryotic cells.
  • Polymers are composed of nucelotide monomers.
  • Ex: are DNA and RNA
47
Q

What is DNA and RNA?

A

Deoxyribonucleic acid
* Nucleis acid that carried hereditary material.
* Makes up the genes
* Codes for the amino acid sequence of proteins.
* Two nucelotide chains twisted in a double helix.

Ribonucleic adic (RNA)
* Typically single-stranded nucleic acid
* Middle man: helps to translate DNA language into the language of proteins

  • The DNA double helix is held togehter by hydrogen bonds betwen the bases
  • A hydrogen bonds with T
  • C hydrogen bonds with G
48
Q

What is the nucleotide monomer?

A

A nucleotide consistst of three components:
1. Sugar
2. Phosphate
3. Base

49
Q

What is the nitrogenuous base?

A

Each nucleotide has one of the following bases:
DNA
* Adenine (A)
* Guanine (G)
* Cytosine (C)
* Thymine (T)
RNA
* Uracil (U)

50
Q

What is a nucleic acid polymer?

A

Nucleotide monomers are linked to each other to make a nucleic acid polymer.

  • This creates an alternating sugar-phosphate backbone of one strand of DNA or RNA.
  • Information is stored in the order of bases.
51
Q

What are phosphodiester bonds?

A

Nucleotides are linked to each other by covalent, phosphodiester bonds between the sugar of one nucleotide and the phosphate group of another nucleotide.

52
Q

Sometimes one nuceltide by itself is important!

A

ATP is an important energy molecule of cells.

Bio181 (4 decks)

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