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Flashcards in Lecture 5 Deck (32):
1

ATP

(adenosine triphosphate) An adenine-containing nucleoside triphosphate that releases free energy when it's phosphate bonds are hydrolyzed. This energy is used to drive endergonic reactions in cells.

2

amino acid

An organic molecule
possessing both a carboxyl and an amino
group. Amino acids serve as the monomers
of polypeptides.

3

carbohydrate

A sugar
(monosaccharide) or one of its dimers (disaccharides)
or polymers (polysaccharides).

4

condensation reaction

Monomers are connected by covalent bonds via a condensation reaction or dehydration reaction.
? One monomer provides a hydroxyl group and the other provides a hydrogen and together these form water.
? This process requires energy and is aided by enzymes.

5

dehydration reaction

Monomers are connected by covalent bonds via a condensation reaction or dehydration reaction.
? One monomer provides a hydroxyl group and the other provides a hydrogen and together these form water.
? This process requires energy and is aided by enzymes.

6

denaturation

In proteins,
a process in which a protein loses its
native shape due to the disruption of weak
chemical bonds and interactions, thereby
becoming biologically inactive; in DNA, the
separation of the two strands of the double
helix. Denaturation occurs under extreme
(noncellular) conditions of pH, salt concentration,
or temperature.

7

deoxyribonucleic acid (DNA)

A nucleic acid molecule,
usually a double-stranded helix, in which
each polynucleotide strand consists of
nucleotide monomers with a deoxyribose
sugar and the nitrogenous bases adenine
(A), cytosine (C), guanine (G), and thymine
(T); capable of being replicated and determining
the inherited structure of a cell?s
proteins.

8

deoxyribose

The sugar
component of DNA nucleotides, having one
fewer hydroxyl group than ribose, the sugar
component of RNA nucleotides.

9

disaccharide

A double sugar,
consisting of two monosaccharides joined
by a glycosidic linkage formed by a dehydration
reaction.

10

double helix

The form of native DNA, referring
to its two adjacent antiparallel polynucleotide
strands wound around an imaginary
axis into a spiral shape.

11

fat

A lipid consisting of three fatty acids linked
to one glycerol molecule; also called a triacylglycerol
or triglyceride.

12

fatty acid

A carboxylic acid with a long carbon
chain. Fatty acids vary in length and in
the number and location of double bonds;
three fatty acids linked to a glycerol molecule
form a fat molecule, also known as a
triacylglycerol or triglyceride.

13

gene

A discrete unit of hereditary information
consisting of a specific nucleotide sequence
in DNA (or RNA, in some viruses).

14

glucose

Monosaccharides generally have molecular formulas that are some multiple of CH2O.
? For example, glucose has the formula C6H12O6.
? Glucose, an aldose, and fructose, a ketose, are structural isomers.
? Glucose and other six carbon sugars are hexoses.

15

hydrolysis

The covalent bonds connecting monomers in a polymer are disassembled by hydrolysis.
? In hydrolysis as the covalent bond is broken a hydrogen atom and hydroxyl group from a split water molecule attaches where the covalent bond used to be.
? Hydrolysis reactions dominate the digestive process, guided by specific enzymes

16

lipid

Any of a group of large biological
molecules, including fats, phospholipids,
and steroids, that mix poorly, if at all, with
water.

17

macromolecule

A giant molecule formed
by the joining of smaller molecules, usually
by a dehydration reaction. Polysaccharides,
proteins, and nucleic acids are
macromolecules

18

monomer

The subunit that
serves as the building block of a polymer.

19

monosaccharide

The simplest carbohydrate, active alone or
serving as a monomer for disaccharides
and polysaccharides. Also known as simple
sugars, monosaccharides have molecular
formulas that are generally some multiple
of CH2O.

20

nucleic acid

A polymer (polynucleotide)
consisting of many nucleotide
monomers; serves as a blueprint for proteins
and, through the actions of proteins, for all
cellular activities. The two types are DNA
and RNA.

21

nucleotide

The building
block of a nucleic acid, consisting of a fivecarbon
sugar covalently bonded to a nitrogenous
base and one or more phosphate
groups.

22

phospholipids

A lipid made
up of glycerol joined to two fatty acids and
a phosphate group. The hydrocarbon chains
of the fatty acids act as nonpolar, hydrophobic
tails, while the rest of the molecule acts
as a polar, hydrophilic head. Phospholipids
form bilayers that function as biological
membranes.

23

polymer

A long molecule consisting
of many similar or identical monomers
linked together by covalent bonds.

24

polypeptide

A polymer of
many amino acids linked together by peptide
bonds.

25

polysaccharide

A polymer
of many monosaccharides, formed by
dehydration reactions.

26

protein

A biologically functional
molecule consisting of one or more polypeptides
folded and coiled into a specific
three-dimensional structure

27

protein structure (primary, secondary, tertiary, quartenary)

? The primary structure of a protein is its unique sequence of amino acids.
? Lysozyme, an enzyme that attacks bacteria, consists on a polypeptide chain of 129 amino acids.
? The precise primary structure of a protein is determined by inherited genetic information.

? Even a slight change in primary structure can affect a protein?s conformation and ability to function.
? In individuals with sickle cell disease, abnormal hemoglobins , oxygen-carrying proteins, develop because of a single amino acid substitution.
? These abnormal hemoglobins crystallize, deforming the red blood cells and leading to clogs in tiny blood vessels.
? The secondary structure of a protein results from hydrogen bonds at regular intervals along the polypeptide backbone.
? Typical shapes that develop from secondary structure are coils (an alpha helix) or folds
(beta pleated sheets).
? The structural properties of silk are due to beta pleated sheets.
? The presence of so many hydrogen bonds makes each silk fiber stronger than steel.

? Tertiary structure
? the polypeptide continues to twist, fold and orient itself, until it reaches the final shape:
? a polypeptide subunit
? is determined by a variety of interactions among R groups and between R groups and the polypeptide backbone.
? These interactions include hydrogen bonds among polar and/or charged areas, ionic bonds between charged R groups, and hydrophobic interactions and van derWaals
interactions among hydrophobic R groups.

? While these three interactions are relatively weak, disulfide bridges, strong covalent bonds that form between the sulfhydryl groups (SH) of cysteine monomers, stabilize the structure.

? Quarternary structure results from the aggregation of two or more polypeptide subunits.
? Collagen is a fibrous protein of three polypeptides that are supercoiled like a rope.
? This provides the structural strength for their role in connective tissue.
? Hemoglobin is a globular protein with two copies of two kinds of polypeptides.
? A protein?s conformation can change in response to the physical and chemical conditions.
? Alterations in pH, salt concentration, temperature, or other factors can unravel or denature a protein.
? These forces disrupt the hydrogen bonds, ionic bonds, and disulfide bridges that maintain the protein?s shape.
? Some proteins can return to their functional shape after denaturation, but others cannot, especially in the crowded environment of the cell.

28

purine

One of two types of nitrogenous
bases found in nucleotides, characterized
by a six-membered ring fused to a
five-membered ring. Adenine (A) and guanine
(G) are purines.

29

pyrimidine

One of two
types of nitrogenous bases found in nucleotides,
characterized by a six-membered ring.
Cytosine (C), thymine (T), and uracil (U) are
pyrimidines.

30

ribonucleic acid (RNA)

A type of nucleic acid consisting
of a polynucleotide made up of nucleotide
monomers with a ribose sugar and the nitrogenous
bases adenine (A), cytosine (C),
guanine (G), and uracil (U); usually singlestranded;
functions in protein synthesis,
gene regulation, and as the genome of some
viruses.

31

ribose

The sugar component of RNA
nucleotides.

32

steroids

A type of lipid characterized by a carbon
skeleton consisting of four fused rings
with various chemical groups attached.