ch1 solutions

Question 1

hydrocarbon –

Answer 1

hydrophobic molecules composed of carbon and hydrogen atoms

Question 2

hydrophilic

Answer 2

capable of hydrogen bonding with water and polar biomolecules

Question 3

hydrophobic

Answer 3

incapable of hydrogen bonding with water and polar biomolecules

Question 4

functional group

Answer 4

group of atoms within an organic molecule with distinct chemical properties

Question 5

R group –

Answer 5

group of atoms that make up a side chain in amino acids

Question 6

carboxyl group

Answer 6

a weakly acidic functional group in which a carbon atom is connected to both an alcohol and a carbonyl group

Question 7

carbonyl group

Answer 7

a polar functional group in which a carbon atom is connected to an oxygen atom by a double bond

Question 8

amino group

Answer 8

weakly basic functional group in which one or two hydrogens are connected to a nitrogen atom

Question 9

.hydroxyl group –

Answer 9

a polar group in which an oxygen atom is directly connected to a hydrogen atom

Question 10

peptide bond –

Answer 10

an amide linkage formed between the amino group of one amino acid and the activated carboxyl group of another

Question 11

. polypeptide

Answer 11

an amino acid polymer with more than 50 amino acid residues

Question 12

peptide

Answer 12

an amino acid polymer with fewer than 50 amino acid residues

Question 13

protein

Answer 13

a macromolecule composed of one or more polypeptides

Question 14

standard amino acids

Answer 14

20 amino acids commonly found in polypeptides: each consists of a specific R group, an amino group, and a carboxyl group attached to the same α-carbon atom

Question 15

neurotransmitter

Answer 15

signal molecules released by nerve cells

Question 16

sugar

Answer 16

a polyhydroxy aldehyde or ketone; the basic unit of carbohydrates

Question 17

glucose

Answer 17

an aldohexose sugar

Question 18

monosaccharide

Answer 18

a carbohydrate that consists of a single sugar molecule

Question 19

polysaccharide

Answer 19

polymer of sugar molecules containing more than 20 monosaccharide units

Question 20

cellulose

Answer 20

a glucose polymer with β (1,4) glycosidic bonds

Question 21

triacylglycerol

Answer 21

esters containing glycerol (three carbon alcohol with three hydroxyl groups) and three fatty acids

Question 22

phosphoglyceride

Answer 22

an ester containing glycerol with two fatty acids and a phosphoric acid

Question 23

fatty acid

Answer 23

monocarboxylic acid, represented by R-COOH, in which R is an alkyl group that contains carbon and hydrogen atoms.

Question 25

What is a **saturated fatty acid**?

Answer 25

Fatty acid that contains no carbon–carbon double bonds ## Footnote Saturated fatty acids are typically solid at room temperature.

Question 26

What is an **unsaturated fatty acid**?

Answer 26

Fatty acid that contains one or more double bonds ## Footnote Unsaturated fatty acids are usually liquid at room temperature.

Question 27

Define **nucleic acid**.

Answer 27

Polymer of nucleotides linked together by phosphodiester bonds ## Footnote Nucleic acids include DNA and RNA.

Question 28

What is a **nucleotide** composed of?

Answer 28

* 5-carbon sugar * A nitrogenous base * One or more phosphate groups ## Footnote Nucleotides are the building blocks of nucleic acids.

Question 29

What is a **purine**?

Answer 29

Bicyclic nitrogenous base ## Footnote Purines include adenine and guanine.

Question 30

What is a **pyrimidine**?

Answer 30

Monocyclic nitrogenous base ## Footnote Pyrimidines include cytosine, thymine, and uracil.

Question 31

What is **deoxyribose**?

Answer 31

5 carbon sugar derived from ribose in which a hydrogen replaces a 2’-hydroxyl group ## Footnote Deoxyribose is a component of DNA.

Question 32

Define **deoxyribonucleic acid (DNA)**.

Answer 32

A polynucleotide that is an organism’s genetic information ## Footnote DNA is double-stranded and contains the genetic blueprint for organisms.

Question 33

What is **ribonucleic acid (RNA)**?

Answer 33

A polynucleotide involved in protein synthesis or in diverse roles such as gene regulation ## Footnote RNA is typically single-stranded.

Question 34

What is a **genome**?

Answer 34

An organism’s entire set of genes or genetic material ## Footnote The genome contains all the information needed for the growth and functioning of an organism.

Question 35

What is **transcription**?

Answer 35

Process where RNA molecules are synthesized from a DNA template ## Footnote Transcription is the first step in gene expression.

Question 36

What is **fructose**?

Answer 36

A ketohexose sugar ## Footnote Fructose is commonly found in fruits and honey.

Question 37

What does **rRNA** stand for?

Answer 37

Ribosomal RNA ## Footnote rRNA is a component of ribosomes.

Question 38

What does **tRNA** stand for?

Answer 38

Transfer RNA ## Footnote tRNA is responsible for bringing amino acids to the ribosome during protein synthesis.

Question 39

What does **mRNA** stand for?

Answer 39

Messenger RNA ## Footnote mRNA carries the genetic information from DNA to the ribosome.

Question 40

What does **siRNA** stand for?

Answer 40

Small interfering RNA ## Footnote siRNA is involved in RNA interference and gene silencing.

Question 41

What does **miRNA** stand for?

Answer 41

Micro RNA ## Footnote miRNA plays a role in regulating gene expression.

Question 42

Define **ribosome**.

Answer 42

Large complex supramolecular structures composed of rRNA and proteins; converts mRNA base sequence to amino acid sequence in a polypeptide ## Footnote Ribosomes are essential for protein synthesis.

Question 43

What is a **transcription factor**?

Answer 43

A protein that regulates the synthesis of specific RNAs by binding to DNA sequences called response elements ## Footnote Transcription factors are crucial for gene expression regulation.

Question 44

What are **signal molecules**?

Answer 44

General term for molecules that provide cells with information from their environments; initiates a signal transduction mechanism when it binds to a specific receptor molecule ## Footnote Signal molecules play a key role in cellular communication.

Question 45

What is a **response element**?

Answer 45

A DNA sequence within the promoter of genes; transcription is triggered when specific hormone receptor complex or transcription factor binds ## Footnote Response elements are critical for gene regulation.

Question 46

Define **RNA interference**.

Answer 46

Process in which RNA molecules inhibit/neutralize mRNA molecules, thereby inhibiting (or silencing) gene expression or translation; antiviral defense mechanism ## Footnote RNA interference is a vital mechanism for regulating gene expression and defending against viruses.

Question 47

In living organisms, energy is usually generated by

Answer 47

REDOX REACTIONS.