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Biochemistry Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

Most of the world’s population cannot digest milk-based foods.

A

These people are lactose intolerant, because they lack the enzyme lactase.
This illustrates the importance of biological molecules, such as lactase, in the daily functions of living organisms.

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2
Q

Diverse molecules found in cells

A

are composed of carbon bonded to
other carbons and
atoms of other elements.

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3
Q

Carbon-based molecules

A

are called organic compounds.

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4
Q

By sharing electrons

A

carbon can
bond to four other atoms and
branch in up to four directions.

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5
Q

Methane (CH4)

A

is one of the simplest organic compounds.
Four covalent bonds link four hydrogen atoms to the carbon atom.
Each of the four lines in the formula for methane represents a pair of shared electrons.

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6
Q

hydrocarbons

A

Methane and other compounds composed of only carbon and hydrogen are called hydrocarbons.

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7
Q

A carbon skeleton

A

is a chain of carbon atoms that can be
branched or
unbranched.

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8
Q

isomers

A

Compounds with the same formula but different structural arrangements are call isomers.

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9
Q

An organic compound has unique properties

A

that depend upon the
size and shape of the molecule and
groups of atoms (functional groups) attached to it.

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10
Q

A functional group

A

affects a biological molecule’s function in a characteristic way.

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11
Q

hydrophilic

A

Compounds containing functional groups are hydrophilic (water-loving).

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12
Q

The functional groups are

A 
hydroxyl group
carbonyl group
carboxyl group
amino group
phosphate group
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13
Q

hydroxyl group

A

consists of a hydrogen bonded to an oxygen,

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14
Q

carbonyl group

A

a carbon linked by a double bond to an oxygen atom

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15
Q

carboxyl group

A

consists of a carbon double-bonded to both an oxygen and a hydroxyl group

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16
Q

amino group

A

composed of a nitrogen bonded to two hydrogen atoms and the carbon skeleton

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17
Q

phosphate group

A

consists of a phosphorus atom bonded to four oxygen atoms

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18
Q

There are four classes of molecules important to organisms:

A

carbohydrates,
proteins,
lipids, and
nucleic acids.

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19
Q

macromolecules

A

The four classes of biological molecules contain very large molecules.
They are often called macromolecules because of their large size.

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20
Q

The four classes of biological molecules

A

They are also called polymers because they are made from identical building blocks strung together.

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21
Q

Monomers

A

The building blocks of polymers are called monomers.

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22
Q

dehydration reactions

A

Monomers are linked together to form polymers through dehydration reactions, which remove water.

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23
Q

hydrolysis

A

Polymers are broken apart by hydrolysis, the addition of water.

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24
Q

enzymes

A

All biological reactions of this sort are mediated by enzymes, which speed up chemical reactions in cells.

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25
Q

A cell makes a large number of polymers from a small group of monomers

A

For example,
proteins are made from only 20 different amino acids and
DNA is built from just four kinds of nucleotides.
The monomers used to make polymers are universal.

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26
Q

Carbohydrates

A

range from small sugar molecules (monomers) to large polysaccharides.

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27
Q

monosaccharides

A

Sugar monomers are monosaccharides, such as those found in honey,
glucose, and
fructose.
Monosaccharides can be hooked together to form
more complex sugars and
polysaccharides.
The carbon skeletons of monosaccharides vary in length.
Glucose and fructose are six carbons long.
Others have three to seven carbon atoms.
Monosaccharides are
the main fuels for cellular work and
used as raw materials to manufacture other organic molecules.
Many monosaccharides form rings.

28
Q

disaccharide

A

Two monosaccharides (monomers) can bond to form a disaccharide in a dehydration reaction.
The disaccharide sucrose is formed by combining
a glucose monomer and
a fructose monomer.
The disaccharide maltose is formed from two glucose monomers.

29
Q

Polysaccharides

A

are
macromolecules and
polymers composed of thousands of monosaccharides.
Polysaccharides may function as
storage molecules or
structural compounds.
Polysaccharides are usually hydrophilic (water-loving).

30
Q

Starch

A

is a polysaccharide composed of glucose monomers and used by plants for energy storage

31
Q

glycogen

A

is a polysaccharide composed of glucose monomers used by animal cells for energy storage

32
Q

Cellulose

A

is a polymer of glucose and

forms plant cell walls.

33
Q

Chitin

A

is
a polysaccharide and
used by insects and crustaceans to build an exoskeleton.

34
Q

Proteins are

A

involved in nearly every dynamic function in your body and
very diverse, with tens of thousands of different proteins, each with a specific structure and function, in the human body.
Proteins are composed of differing arrangements of a common set of just 20 amino acids.

35
Q

Amino acid

A

have
an amino group and
a carboxyl group (which makes it an acid).
Also bonded to the central carbon is
a hydrogen atom and
a chemical group symbolized by R, which determines the specific properties of each of the 20 amino acids used to make proteins.

36
Q

peptide bond

A

Amino acid monomers are linked together
in a dehydration reaction,
joining carboxyl group of one amino acid to the amino group of the next amino acid,
creating a peptide bond.
Additional amino acids can be added by the same process to create a chain of amino acids called a polypeptide.

37
Q

enzymes

A

Probably the most important role for proteins is as enzymes, proteins that
serve as metabolic catalysts and
regulate the chemical reactions within cells.

38
Q

Structural proteins

A

provide associations between body parts.

39
Q

Contractile

A

proteins are found within muscle.

40
Q

Defensive

A

proteins include antibodies of the immune system.

41
Q

Signal

A

proteins are best exemplified by hormones and other chemical messengers.

42
Q

Receptor

A

proteins transmit signals into cells.

43
Q

Transport

A

proteins carry oxygen.

44
Q

Storage

A

proteins serve as a source of amino acids for developing embryos.

45
Q

A polypeptide

A

A polypeptide contains hundreds or thousands of amino acids linked by peptide bonds.
The amino acid sequence causes the polypeptide to assume a particular shape.
The shape of a protein determines its specific function.
If a protein’s shape is altered, it can no longer function.

46
Q

denaturation

A

In the process of denaturation, a polypeptide chain
unravels,
loses its shape, and
loses its function.
Proteins can be denatured by changes in salt concentration, pH, or by high heat.

47
Q

A protein can have four levels of structure

A

primary structure
secondary structure
tertiary structure
quaternary structure

48
Q

The primary structure of a protein

A

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 may affect the protein’s ability to function.

49
Q

Protein secondary structure

A

results from coiling or folding of the polypeptide.
Coiling results in a helical structure called an alpha helix.
A certain kind of folding leads to a structure called a pleated sheet, which dominates some fibrous proteins such as those used in spider webs.
Coiling and folding are maintained by regularly spaced hydrogen bonds between hydrogen atoms and oxygen atoms along the backbone of the polypeptide chain

50
Q

tertiary structure

A

hydrogen atoms and oxygen atoms along the backbone of the polypeptide chain.
The overall three-dimensional shape of a polypeptide is called its tertiary structure.
Tertiary structure generally results from interactions between the R groups of the various amino acids.
Disulfide bridges may further strengthen the protein’s shape.

51
Q

quaternary structure

A

Two or more polypeptide chains (subunits) associate providing quaternary structure.
Collagen is an example of a protein with quaternary structure.
Collagen’s triple helix gives great strength to connective tissue, bone, tendons, and ligaments.

52
Q

gene

A

The amino acid sequence of a polypeptide is programmed by a discrete unit of inheritance known as a gene.

53
Q

DNA

A

Genes consist of DNA(deoxyribonucleic acid), a type of nucleic acid.
DNA is inherited from an organism’s parents.
DNA provides directions for its own replication.
DNA programs a cell’s activities by directing the synthesis of proteins.
DNA does not build proteins directly.
DNA works through an intermediary, ribonucleic acid (RNA).
DNA is transcribed into RNA.
RNA is translated into proteins.

54
Q

nucleotides

A 
DNA (deoxyribonucleic acid) and RNA (ribonucleic acid) are composed of monomers called nucleotides.
Nucleotides have three parts:
a five-carbon sugar called ribose in RNA and deoxyribose in DNA,
a phosphate group, and
a nitrogenous base.
DNA nitrogenous bases are
adenine (A),
thymine (T),
cytosine (C), and
guanine (G).
RNA
also has A, C, and G,
but instead of T, it has uracil (U).
55
Q

polynucleotide

A

A nucleic acid polymer, a polynucleotide, forms
from the nucleotide monomers,
when the phosphate of one nucleotide bonds to the sugar of the next nucleotide,
by dehydration reactions, and
by producing a repeating sugar-phosphate backbone with protruding nitrogenous bases.

56
Q

double helix

A

Two polynucleotide strands wrap around each other to form a DNA double helix.
The two strands are associated because particular bases always hydrogen bond to one another.
A pairs with T, and C pairs with G, producing base pairs.
RNA is usually a single polynucleotide strand.

57
Q

Lipids

A

are water insoluble (hydrophobic, or water-fearing) compounds,
are important in long-term energy storage,
contain twice as much energy as a polysaccharide, and
consist mainly of carbon and hydrogen atoms linked by nonpolar covalent bonds.
Lipids differ from carbohydrates, proteins, and nucleic acids in that they are
not huge molecules and
not built from monomers.
Lipids vary a great deal in structure and function.

58
Q

three types of lipids

A

simple lipids (fats and oils),
phospholipids, and
steroids.

59
Q

A simple lipid

A

A simple lipid (fat or oil) is a large lipid made from two kinds of smaller molecules,
glycerol and
fatty acids.
A fatty acid can link to glycerol by a dehydration reaction.
A fat contains one glycerol linked to three fatty acids.
Fats are often called triglycerides because of their structure.

60
Q

unsaturated fatty acids

A

Some fatty acids contain one or more double bonds, forming unsaturated fatty acids that
have one fewer hydrogen atom on each carbon of the double bond,
cause kinks or bends in the carbon chain, and
prevent them from packing together tightly and solidifying at room temperature.

61
Q

saturated fatty acids

A

Fats with the maximum number of hydrogens are called saturated fatty acids.
Unsaturated fats include corn and olive oils.
Most animal fats are saturated fats.

62
Q

trans fats

A

Hydrogenated vegetable oils are unsaturated fats that have been converted to saturated fats by adding hydrogen.
This hydrogenation creates trans fats associated with health risks.

63
Q

Phospholipids

A

Phospholipids are
structurally similar to fats and
the major component of all cells.
Phospholipids are structurally similar to fats.
Fats contain three fatty acids attached to glycerol.
Phospholipids contain two fatty acids attached to glycerol.
Phospholipids cluster into a bilayer of phospholipids.
The hydrophilic heads are in contact with
the water of the environment and
the internal part of the cell.
The hydrophobic tails band in the center of the bilayer.

64
Q

Steroids

A

are lipids in which the carbon skeleton contains four fused rings.

65
Q

Cholesterol

A

is a
common component in animal cell membranes and
starting material for making steroids, including sex hormones.

66
Q

Anabolic steroids

A

are synthetic variants of testosterone,
can cause a buildup of muscle and bone mass, and
are often prescribed to treat general anemia and some diseases that destroy body muscle.
Anabolic steroids are abused by some athletes with serious consequences, including
violent mood swings,
depression,
liver damage,
cancer,
high cholesterol, and
high blood pressure.

Human Biology (16 decks)

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