Biology Study Guide Chapter 3

Question 1

Nucleotide

Answer 1

The building blocks of a nucleic acids, including DNA and RNA, phosphate group, a sugar, and a nitrogen-containing base.

Question 2

DNA

Answer 2

Deoxyribonucleic acid, a self-replicating material present in nearly all living organisms as the main constituent of chromosomes. It is the carrier of genetic information- Web

DNA codes fro proteins- Notes

Question 3

RNA

Answer 3

Ribonucleic acid, a nucleic acid present in all living cells. Its principal role is to act as a messenger carrying instructions from DNA for controlling the synthesis of proteins, although in some viruses RNA rather than DNA carries the genetic information.

Question 4

Amino Acid

Answer 4

A simple organic compound containing both a carboxyl (-COOH) and an amino (-NH2) group.

Question 5

Protein

Answer 5

They perform the greatest amount of tasks in living organisms.

a) structural proteins, like hair nails.
b) Storage proteins, like in food.
c) Contractile proteins.
d) Trans protein.

Question 6

Peptide Bond

Answer 6

The primary linkage of all protein structures; the chemical bond between the carboxyl groups and amino groups that unites a peptide

Question 7

Monosaccharide

Answer 7

Any of the class of sugars (e.g., glucose) that cannot be hydrolyzed to give a simpler sugar.

Question 8

Disaccharide

Answer 8

Any of a class of sugars whose molecules contain two monosaccharide residues.

Question 9

Polysaccharide

Answer 9

A carbohydrate (e.g., starch, cellulose, or glycogen) whose molecules consist of a number of sugar molecules bonded together.

Question 10

Condensation Reaction

Answer 10

The conversion of a vapor or gas to a liquid.

Question 11

Hydrolysis

Answer 11

The chemical breakdown of a compound due to reaction with water.

Question 12

1. What are two characteristics of carbon that make it such a valuable element in living organisms?

Answer 12

The two most important characteristics of carbon as a basis for the chemistry of life, are that it has four valence bonds and that the energy required to make or break a bond is just at an appropriate level for building molecules which are not only stable, but also reactive.

Question 13

2. What are the functional groups important in biological systems? Give an example of where these functional groups are found in living organisms.

Answer 13

A functional group is a group of atoms that confers a special property in a carbon molecule.
Functional groups have their atoms bonded in a special orientation and this orientation helps. Functional groups to be directly involved in biological reactions in biological systems.

Question 14

3. Describe condensation and hydrolysis reactions and what are formed as products of these reactions (bigger or smaller compounds).

Answer 14

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Question 15

Carbohydrates and Lipids

1. What is a monosaccharide used for in a living organism? A polysaccharide? Give examples of monosaccharides, disaccharides and polysaccharides. What functional group is found in mono-, di- and polysaccharides?

Answer 15

Monosaccharide is used as an energy source, Disaccharide: starch, glucose, cellulose.

Question 16

2. Draw the basic structure of a glyceride and triglyceride. What is the difference between a saturated and an unsaturated fat? What kind of fats are the best fats to have in your diet? What are the worst? What functional groups are found in glycerides and where?

Answer 16

Triglycerides are formed by combining glycerol with three molecules of fatty acid. Alcohols have a hydroxyl (HO-) group. Organic acids have a carboxyl (-COOH) group.

Saturated fats contain the maximum amount of hydrogen in their fatty acid chains, and are thus more compact. Unsaturated fats naturally bend because they have double bonds. Fat cells cannot store as much unsaturated fat because it is less dense, thus unsaturated fat does not make people as fat.

Question 17

3. What is a steroid? Give examples of steroid molecules. What are the functions of cholesterol? What functional group(s) are found in cholesterol?

Answer 17

It is a class of lipids that have a, central element in their structure, four carbon rings. 
Cholesterol molecules help stabilize cells from temperature changes. It is an important compent in cell membraces. It helps transfer calcium into the bone.
alkane, alkene, aromatic, alcohol

Question 18

4. Describe the structure of a phospholipid. What is biologically significant about this structure? What important cellular structure is made up of phospholipids? What functional groups are found in phospholipids and where?

Answer 18

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Question 19

Proteins

1. Draw the general structure of an amino acid.

Answer 19

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Question 20

2. An amino acid always contains what two functional groups?

Answer 20

Amino group: NH2

Carboxyl group: COOH

Question 21

3. What is the bond between two amino acids called?

Answer 21

Peptide bond.

Question 22

4. What two functional groups come together to form this bond?

Answer 22

The amino group and carboxyl group.

Question 23

5. What is a byproduct of the formation of a peptide bond?

Answer 23

Two hydrogens and an oygen, which form water ????

Question 24

6. A dipeptide consists of two amino acids held together by a peptide bond. A tripeptide consists of three amino acids held together by peptide bonds. A _____________ consists of many amino acids held together by ___________ bonds.

Answer 24

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Question 25

7. Describe the four different levels of protein structure. What level(s) of structure considered to be functional?

Answer 25

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Question 26

8. Why is the structure of proteins, from the primary to the quaternary structure, so important to the function of the protein? Describe an example from class what happens when one amino acid is replaced by another through a mutation in human DNA.

Answer 26

Because thats what determines the rest of the structure. Everything was determined by the amino acids.

Question 27

Nucleic Acids
1. What is the monomer of the nucleic acids DNA and RNA molecule? What three components make up this monomer? What functional groups are found in these components?

Answer 27

The monomer of DNA and RNA is nucleotide
The monomer of DNA is called a nucleotide, and consists of a sugar (deoxyribose), a phosphate and a nitrogenous base (A, T, C or G).
A single nucleotide is composed of three functional groups: a sugar, a triphosphate, and a nitrogenous (nitrogen-containing) base.

Question 28

2. What forms the ‘backbone’ of nucleic acids? IN DNA, what kind of bond exists between the bases of the two strands of DNA?

Answer 28

A chain of sugar and phosphate groups, linked through phosphodiester bonds.
Hydrogen bond

Question 29

3. How are DNA and RNA similar to each other? How are they different from each other?

Answer 29

Regarding structure, DNA and RNA are similar because they are both built of nucleotides, structures consisting of one nucleobase, a sugar (ribose or deoxyribose respectively) and a phosphate group. For both of them, their function is mainly containing information in the form of code.
Differences DNA has 2 strands, thymine and deoxyribose. RNA has single strand, no thymine (instead uracil) and ribose

Question 30

4. A DNA molecule contains 4 nitrogenous bases called ___________,
   ___________, _______________ and ____________.

Answer 30

Adenine
Guanine
Cytosine
Thymine

Question 31

5. An RNA molecule contains 4 nitrogenous bases called ___________,
   ___________, _______________ and ____________.

Answer 31

Adenine
Guanine
Cytosine
Uracil

Question 32

6. Basepairing in a DNA molecule is complementary. Therefore __________ bonds with ____________ and ________ bonds with_____________.

Answer 32

Glyccine- guymine

Adenine-thymine