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59 terms

Biology Campbell Reece Ch.5

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macromolecules
Class of biologically import molecule formed by the joining of smaller molecules, usually by a condensation reaction and is very large. Polysaccharides, proteins, and nucleic acids are macromolecules. Also are polymers.
Polymer
long molecule consisting of many similar or identical building blocks linked by covalent bonds
monomer
the repeating units that serve as the building blocks of a polymer
condensation reaction
a chemical reaction in which two or more molecules combine to produce water or another simple molecule
Dehydration reaction
a condensation reaction referring to the molecules that form a covalent bond through the loss of a water molecule
enzymes
specialized macromolecules that speed up chemical reactions in cells
hydrolysis
a process in which polymers are disassembled through the addition a a water molecule, which separates into H+ and OH- to separate the polymer
carbohydrates
Organic compounds made of carbon, hydrogen, and oxygen atoms in the proportion of 1:2:1. Usually sugars and polymers of sugars
monosaccharides
a single carbohydrate molecule
disaccharide
consists of two monosaccharides joined by a glycosidic linkage
glycosidic linkage
a covalent bond formed between two monosaccharides by a dehydration reaction
Polysaccharides
polymers with a few hunderd to a few thoughsand monosaccharides joined by glycosidic linkages
starch
a polysaccharide of glucose monosaccharides. Used to store energy because glucose is a major cellular fuel. Glucose can be separated by means of hydrolysis. Has a helical structure
glycogen
polymer of glucose that is like amylopectin(a type of starch) but more extensively branched. Does not provide as much energy as starches
cellulose
major component of the tough walls that enclose plant cells. Made up of glucose. Forms microfibrils that act like cables. Difference from starch is that the glycosidic linkages are consistantly flipped/alternated. This makes it straight instead of helical
microfibril
A fiber that is made up of cellulose. Weaved together to give cell walls their strength in plants
lipids
class of large biological molecule that is not a true polymer and not generally large enough to be a macromolecules. They are nonpolar.
fat
constructed of two smaller molecules: glycerol and fatty acids. Combines via an ester linkage
glycerol
an alcohol that acts as the organizing part of a fat. Has three carbons, each bearing a hydroxyl group
fatty acid
a long carbon skeleton with a carboxyl group at the end
ester linkage
a bond between a hydroxyl group and a carboxyl group.
triacylglycerol
three fatty acids linked to one glycerol molecule.
triglyceride
synonymous with triacylglycerol
saturated fatty acid
A fatty acid, such as stearic acid, whose carbon chain contains no unsaturated linkages between carbon atoms and hence cannot incorporate any more hydrogen atoms. Observed as multiple straight fatty acid segments
unsaturated fatty acid
A fatty acid, such as oleic acid, whose carbon chain possesses one or more double or triple cis bonds and hence can incorporate additional hydrogen atoms. Observed as having bent fatty acid segments.
phospholipids
two fats and a phosphate group attached to glycerol; fat tail = hydrophobic. phosphate group + 2(CH2) + N(CH3)3 = hydrophilic; examples: membranes, soaps; when added to water, self-assemble into micelles, liposomes, bilayers; major component of all cell membranes
steroids
lipids characterized by a carbon skeleton consisting of four fused rings
cholesterol
a common component of animal cell membranes and is also the precursor from which other steroids are synthesized., helps stabilize the membrane at warm temperatures but also helps keep the membrane fluid at lower temperatures. In a cell, the phospholipid bilayer remains about as fluid as salad oil. Is the precursor for other steroids in the body. Made in the liver.
trans fat
unsaturated fat with a trans double bond, causing the fatty acid to be straight instead of bent.
Adipose cell
fat-containing vacuole that swells and shrinks as fat is deposited and withdrawn from storage. Also cushions vital organs and insulates as a fat layer beneath the skin
Proteins
The tools and building blocks of cells. Made up of one or more polypeptides, each folded and coiled into a specific 3D structure
enzymes
protein that is an biological catalyst
catalyst
chemical agent that selectively speeds up chemical reactions without being consumed by the reaction
Polypeptides
polymers of amino acids
Amino acids
organic molecules possessing both carboxyl and amino groups. The center carbon atom is the alpha carbon, and it bonds to an amino group, a carboxyl group, a hydrogen atom, and an R side group that decides what the protein is.
Peptide bond
the covalent bond formed from the dehydration reaction between the carboxyl group and the amino group of two different amino acids.
Primary Structure
The order of amino acids in a protein
Secondary Structure
The localized, repetitive coiling or folding of the polypeptide backbone of a protein due to hydrogen bond formation between constituents of the backbone.
Tertiary Structure
overall shape of a polypeptide resulting from interactions between the side chains(R groups) of the various amino acids.
alpha helix
a delicate coil held together by hydrogen bonding between every fourth amino acid
Beta pleated sheet
two or more regions of the polypeptide chain lying side by side are connected by hydrogen bonds between parts of the two parallel polypeptide backbones.
hydrophobic interaction
when the side groups of an amino acid are nonpolar, they have a tendency to move towards the core of the protein, away from water, while the more polar side groups move towards the water
disulfide bridges
when two amino acids with sulfhydryl groups are brought close together by the folding of the protein.
Quaternary Structure
The overall protein structure that results from the aggregation of the polypeptide subunits
denaturation
the unraveling of a protein due to alteration of pH, salinity, temperature, or other aspects of the nevironment
chaperonin
a protein molecule that assists in the proper folding of other proteins
X-ray crystallography
technique used to determine 3D protein strucures by analyzing the diffraction pattern of a beam of xrays passed through a crystal of the protein
gene
(genetics) a segment of DNA that is involved in producing a polypeptide chain
nucleic acids
Polymers assembled from individual nucleotides; used to store and transmit hereditary, or genetic, information; the two kinds of nucleic acids are ribonucleic acid (RNA) and deoxyribonucleic acid (DNA)
deoxyribonucleic acid
DNA. the genetic information of an organism(biochemistry) a long linear polymer found in the nucleus of a cell and formed from nucleotides and shaped like a double helix
ribonucleic acid
RNA (biochemistry) a long linear polymer of nucleotides found in the nucleus but mainly in the cytoplasm of a cell where it is associated with microsomes
polynucleotides
A polymer 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
nucleotide
monomer of polynucleotides. Either cytosine, thymine, uracil, adenine, or guanine. In a nucleic-acid chain, a subunit that consists of a five-carbon sugar, a phosphate, and a nitrogenous base
pyrimidine
has a six-membered ring of carbon and nitrogen atoms(the nitrogen atoms tend to take up H+ from the solution, which is why they are call a nitrogenous bases). Can be cytosine(C), thymine(T), or uracil(U)
purines
larger than pyrimidines, they have a six-membered ring fused to a five-membered ring.
deoxyribose
C(HOCH2)HCOC(OH)(H)CH2CH(OH), five-carbon monosaccharide that is a component of DNA nucleotides. Has one less Oxygen than ribose, hence the name
ribose
C(HOCH2)HCOCH(OH)CH(OH)CH(OH), a five-carbon monosaccharide that is a component of RNA nucleotides
double helix
two parallel polynucleotides that spiral around an imaginary axis
antiparallel
the fact that opposing DNA strands run in opposite directions
5'-->3'
3'<--5'