Chapter 5: The Structure and Function of Large Biological Molecules Flashcards

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1
Q

What are carbohydrates ? Describe its function and name examples.

A

Carbohydrates serve as fuel and building material. Examples are glucose and fructose which are monosaccharides and lactose and sucrose which are disaccharides.

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2
Q

What are lipids? Describe its function and name example(s).

A

Lipids serve as an important energy source. Some examples are triglycerides, phospholipids and steroids.

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3
Q

What are proteins? Describe its function and name example(s).

A

A protein is a biologically functional molecule made up of one or more polypeptides, each folded and coiled into a specific three- dimensional structure. Proteins have many functions, some of are that include catalyzing chemical reactions, protecting against disease, transport substances, and storing amino acids. Some examples are enzymes, defensive proteins, and hormones

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4
Q

What are nucleic acids? Describe its function and name example(s).

A

Nucleic acids store, transmit, and help express hereditary information. Some examples are DNA (Deoxyribonucleic acid) and RNA (Ribonucleic acid)

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5
Q

What is a a polymer?

A

A polymer is a long molecule consisting of many similar or identical building blocks linked by covalent bonds.

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6
Q

What is a monomer?

A

The repeating units that serve as the building blocks of a polymer are smaller molecules is a monomer.

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7
Q

What is dehydration reaction?

A

A reaction in which two molecules are covalently bonded to each other with the loss of a small molecule. If a water molecule is lost, it is known as a dehydration reaction.

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8
Q

What is hydrolysis?

A

A process that is essentially the reverse of the dehydration reaction. Hydrolysis means water breakage (from the Greek hydro, water, and lysis, break).

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9
Q

What is a monosaccharide? What groups does it contain?

A

Monosaccharides (from the Greek monos, single, and sacchar, sugar) generally have molecular formulas that are some multiple of the unit CH2O. Glucose (C6H12O6), the most common monosaccharide, is of central importance in the chemistry of life.

The molecule has a carbonyl group and multiple hydroxyl groups.

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10
Q

What is the function of monosaccharides?

A

They function as the raw material for the synthesis of other monomers, such as amino acids and fatty acids.

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11
Q

What is a disaccharide?

A

A disaccharide consists of two monosaccharides joined by a glycosidic linkage.

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12
Q

What is a glycosidic linkage?

A

A covalent bond formed between two monosaccharides by a dehydration reaction (glyco
refers to carbohydrate).

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13
Q

What is a polysaccharide? What is its function?

A

Polysaccharides are macromolecules, polymers with a few hundred to a few thousand monosaccharides joined by glyco- sidic linkages. It serves for storage and are hydrolyzed as sugars are needed.

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14
Q

What is starch?

A

A polymer of glucose monomers, as granules within cellular structures known as plastids. The simplest form of starch is amylose which forms an unbranched helix.

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15
Q

What is glycogen?

A

A polymer of glucose that is like amylopectin but more extensively branched. Animals store glucose in glycogen.

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16
Q

What is amylopectin?

A

A more complex starch, is a branched polymer with 1–6 linkages at the branch points.

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17
Q

What is cellulose?

A

A major component of the tough walls that enclose plant cells.

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18
Q

What is chitin?

A

The carbohydrate used by arthropods (insects, spiders, crusta- ceans, and related animals) to build their exoskeletons—hard cases that surround the soft parts of an animal

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19
Q

What are lipids?

A

Lipids are the one class of large biological molecules that does not include true polymers, and they are generally not big enough to be considered macromolecules. The compounds called lipids are grouped with each other because they share one important trait: They are hydrophobic: They mix poorly, if at all, with water. This behavior of lipids is based on their molecular structure.

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20
Q

What is a fat?

A

A fat consists of a glycerol molecule joined to three fatty acids. Glycerol is an alcohol; each of its three carbons bears a hydroxyl group.

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21
Q

What is a fatty acid?

A

A fatty acid has a long carbon skeleton, usually 16 or 18 carbon atoms in length. The carbon at one end of the skeleton is part of a carboxyl group, the functional group that gives these molecules the name fatty acid.

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22
Q

What is a glycerol?

A

A three carbon alcohol with a hydroxyl group attached to each carbon.

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23
Q

What is a saturated fatty acid?i

A

If the fatty acid has no carbon carbon double bonds, then the molecule is a saturated fatty acid.

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24
Q

What is an unsaturated fatty acid?

A

If the fatty acid has one or more carbon carbon double bonds formed by the removal of hydrogen atoms from the carbon skeleton, then the molecule is an unsaturated fatty acid.

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25
Q

What is the major function of fats?

A

The major function of fats is energy storage.

26
Q

What is the function of adipose tissue?

A

It serves to cushion vital organs such as the kidneys.

27
Q

What is a phospholipid?

A

They are the major components of cell membranes. They have two fatty acids attached to glycerol and a phosphate group at the third position. A phospholipid has a hydrophilic (polar) head and two hydrophobic (nonpolar) tails.

28
Q

What is a steroid?

A

They are lipids characterized by a carbon skeleton consisting of four fused rings. Different steroids are distinguished by the particular chemical groups attached to this ensemble of rings.

29
Q

What is cholesterol?

A

Cholesterol, a type of steroid, is a crucial molecule in animals. It is a common component of ani- mal cell membranes and is also the precursor from which other steroids, such as the vertebrate sex hormones, are synthesized. In vertebrates, cholesterol is synthesized in the liver and is also obtained from the diet. A high level of cholesterol in the blood may contribute to atherosclerosis, although some researchers are questioning the roles of cholesterol and saturated fats in the development of this condition.

30
Q

What is a peptide bond?

A

The bond between amino acids.

31
Q

What are catalysts?

A

Chemical agents that selectively speed up chemical reactions without being consumed in the reac- tion.

32
Q

What is an amino acid?

A

An amino acid is an
organic molecule with both an amino
group and a carboxyl group.

33
Q

What is at the center of an amino acid?

A

At the center of an amino acid is an asymmetric carbon atom called the alpha carbon.

34
Q

What is attached to the alpha carbon?

A

Four components are attached to the alpha carbon; a hydrogen atom, a carbonyl group, an amino group, and a variable R group.

35
Q

What are the four levels of protein structure?

A

Primary structure, secondary structure, tertiary structure, and quaternary structure.

36
Q

What is a primary structure?

A

The primary structure of a protein is its sequence of amino acids.

37
Q

What is a secondary structure?

A

These coils and folds, collectively referred to as secondary structure, are the result of hydrogen bonds between the repeating constituents of the polypeptide backbone (not the amino acid side chains).

38
Q

What is a helix?

A

A delicate coil held together by hydrogen bonding between every fourth amino acid

39
Q

What is a pleated sheet?

A

two or more segments of the polypeptide chain lying side by side (called d strands) are connected by hydrogen bonds between parts of the two parallel segments. d pleated sheets make up the core of many globular proteins, as is the case for transthyretin (see Tertiary Structure), and dominate some fibrous proteins, including the silk protein of a spider’s web.

40
Q

What is a tertiary structure?

A

the overall shape of
a polypeptide resulting from interactions between the side chains
(R groups) of the various amino acids.

41
Q

What are disulfide bridges?

A

Strong covalent bonds that form between the sulfhydryl groups of two cysteine monomers.

42
Q

What causes a hydrophobic interaction?

A

It is caused by the exclusion of nonpolar substances by water molecules.

43
Q

What is a quaternary structure?

A

The overall protein structure that results from the aggregation of these polypeptide subunits.

44
Q

What is hemoglobin?

A

The oxygen-binding protein of red blood cells, is another example of a globular protein with quaternary structure

45
Q

What is collagen?

A

Collagen is a fibrous protein of three polypeptides that are super coiled like a rope.

46
Q

What is sickle cell disease?

A

An inherited blood disorder, is caused by the sub- stitution of one amino acid (valine) for the normal one (glutamic acid) at the position of the sixth amino acid in the primary structure of hemoglobin, the protein that carries oxy- gen in red blood cells. Normal red blood cells are disk-shaped, but in sickle-cell disease, the abnormal hemoglobin molecules tend to aggregate into chains, deforming some of the cells into a sickle shape

47
Q

What is denaturation?

A

Disruption of hydrogen bonds, ionic bonds, and disulfide bridges that maintain the protein’s shape.

48
Q

What is X-ray crystallography?

A

A technique that determines protein conformation.

49
Q

What is a gene?

A

Gene consist of DNA and are a discrete unit of inheritance.

50
Q

What is DNA?

A

DNA or Deoxyribonucleic acid, is a type of amino acid that stores genetic information. It also directs RNA synthesis and through that controls protein synthesis.

51
Q

What is RNA?

A

RNA or Ribonucleic acid, is considered the messenger and interacts with the cells protein synthesizing machinery to direct the ordering of amino acids in a polypeptide.

52
Q

Where does protein synthesis occur?

A

Protein synthesis occurs on cellular structure called ribosomes.

53
Q

What is a polynucleotide?

A

Nucleic acids that exist as polymers are called polynucleotides

54
Q

What is a nucleotide composed of?

A

It is composed of three parts: a five-carbon sugar (a pentose), a nitrogen-containing (nitrogenous) base, and one to three phosphate groups.

55
Q

What are purines?

A

There are two types of purines; Adenine (A) and Guanine (G). Purines have a six membered ring joined to a five membered ring.

56
Q

What are pyrimidines?

A

There are three different pyrimidines; cytosine (C), thymine (T), and uracil (U). They have a six membered ring.

57
Q

What is the sugar in DNA called?

A

It is called deoxyribose.

58
Q

What is the sugar in RNA called?

A

The sugar is called ribose.

59
Q

What is a double helix?

A

A DNA molecule has two polynucleotides, or “strands,” that wind around an imaginary axis, forming a double helix

60
Q

What is a antiparallel?

A

The two sugar backbones that run from 5 to 3 directions from each other.