Biological Molecules

Question 1

What are the elements that carbohydrates contain?

Answer 1

• Carbon
• Hydrogen
• Oxygen

Carbohydrates can be small molecules or large macromolecules with thousands of repeating units.

Question 2

A single unit in a carbohydrate is called a _______.

Answer 2

monosaccharide

Examples include glucose, fructose, and galactose.

Question 3

What are the two variants of glucose?

Answer 3

• Alpha glucose
• Beta glucose

Alpha glucose is used as an energy source, while beta glucose is found in cellulose.

Question 4

Fructose is a hexose found naturally in _______.

Answer 4

fruit

It is sweeter than glucose and commonly bonds with alpha glucose to form sucrose.

Question 5

What are disaccharides formed by?

Answer 5

• Pairs of monosaccharides

Examples include sucrose, lactose, and maltose.

Question 6

When two monosaccharides join together, what type of reaction occurs?

Answer 6

Condensation reaction

A molecule of water is removed, forming a glycosidic bond.

Question 7

What is the main storage carbohydrate found in most plant cells?

Answer 7

Starch (amylose)

It is formed by a long chain of alpha glucose molecules.

Question 8

What is the storage molecule found in animals and fungi?

Answer 8

Glycogen

It is similar to starch but has branching chains for easier glucose release.

Question 9

What is cellulose primarily used for in plants?

Answer 9

Structural support

It forms plant cell walls and is made of long chains of beta glucose.

Question 10

Lipids contain the elements carbon, hydrogen, and oxygen, but with proportionally _______ oxygen than carbohydrates.

Answer 10

less

They are insoluble in water and commonly known as fats and oils.

Question 11

Fat molecules generally consist of _______ and fatty acids.

Answer 11

glycerol

Fatty acids are long chain hydrocarbons with a carboxyl group.

Question 12

What is formed when one fatty acid binds to glycerol?

Answer 12

Monoglyceride

Two fatty acids form a diglyceride, and three form a triglyceride.

Question 13

What are triglycerides primarily used for in the body?

Answer 13

Energy storage

They form adipose tissue and are a major energy source in plants.

Question 14

What are phospholipids composed of?

Answer 14

• Glycerol
• Two fatty acids
• Phosphate molecule

They form bilayers in cell membranes.

Question 15

What is the primary structure of a protein?

Answer 15

Specific sequence of amino acids

This sequence is joined by peptide bonds to form a polypeptide.

Question 16

What are the two types of secondary structure in proteins?

Answer 16

• Alpha helix
• Beta pleated sheet

These structures are formed via hydrogen bonding between adjacent amino acids.

Question 17

What determines the properties of an amino acid?

Answer 17

R-group

The R-group affects pH, size, and polarity.

Question 18

What is the quaternary structure of a protein?

Answer 18

Interaction of two or more polypeptides

Not all proteins have a quaternary structure.

Question 19

What are structural proteins also known as?

Answer 19

Fibrous proteins

Examples include collagen, elastin, and keratin.

Question 20

Enzymes are functional proteins that serve as _______.

Answer 20

Biological catalysts

They speed up reactions without being used up.

Question 21

What is the region of an enzyme where the substrate fits called?

Answer 21

Active site

The enzyme-substrate complex forms when the substrate binds to the active site.

Question 22

What are the two models for enzyme action?

Answer 22

• Lock and key model
• Induced fit model

These models describe how substrates interact with enzymes.

Question 23

What factors affect enzyme activity?

Answer 23

• Temperature
• pH
• Enzyme/substrate concentration

Each enzyme has optimum values for pH and temperature.

Question 24

What happens to enzymes at high temperatures?

Answer 24

Denaturation

The active site changes shape, preventing substrate binding.

Question 25

What are the two types of nucleic acid?

Answer 25

* DNA * RNA ## Footnote DNA contains genetic information, while RNA is involved in protein synthesis.

Question 26

What are the building blocks of nucleic acids called?

Answer 26

Nucleotides ## Footnote Each nucleotide consists of a phosphate group, a ribose sugar, and a nitrogenous base.

Question 27

What is the role of ATP in cellular functions?

Answer 27

Energy release ## Footnote When the bond between the second and third phosphate is broken, energy is released.

Question 28

What type of bond forms between nucleotides in polynucleotides?

Answer 28

Phosphodiester bond ## Footnote This bond is formed between the pentose sugar of one nucleotide and the phosphate group of the next.

Question 29

What is the structure of DNA?

Answer 29

Double-helix ## Footnote It is formed from two polynucleotide strands joined by hydrogen bonds.

Question 30

In DNA, adenine pairs with _______.

Answer 30

Thymine ## Footnote Cytosine pairs with guanine, known as complementary base pairing.

Question 31

What is the function of mRNA?

Answer 31

Transfers genetic information from DNA to ribosomes ## Footnote It is transcribed from a gene and leaves the nucleus for protein synthesis.

Question 32

What are the two other types of RNA besides mRNA?

Answer 32

* Ribosomal RNA (rRNA) * Transfer RNA (tRNA) ## Footnote rRNA forms ribosomes, while tRNA links mRNA to amino acids.

Question 33

What are errors in DNA replication called?

Answer 33

Mutations ## Footnote They can affect protein structure and function, but most have no effect.

Question 34

What is the term for the complete set of genetic information in an organism?

Answer 34

Genome ## Footnote Each cell contains a full copy of the genome.