biological molecules

Question 1

What is the structure of a water molecule?

Answer 1

Two hydrogen atoms covalently bonded to one oxygen atom; polar molecule due to uneven charge distribution.

Question 2

Why is water a good solvent?

Answer 2

Its polarity allows it to dissolve ionic and polar substances by surrounding them and separating their ions.

Question 3

How does water help in temperature regulation in organisms?

Answer 3

High specific heat capacity means it buffers temperature changes.

Question 4

What are the three main types of carbohydrates?

Answer 4

Monosaccharides, disaccharides, and polysaccharides.

Question 5

What is the difference between alpha and beta glucose?

Answer 5

The OH group on carbon 1 is below the ring in alpha and above in beta.

Question 6

What type of bond forms between two monosaccharides?

Answer 6

A glycosidic bond.

Question 7

What is the structure and function of starch?

Answer 7

Made of amylose (helical) and amylopectin (branched); energy storage in plants.

Question 8

What are the monomers of proteins?

Answer 8

Amino acids.

Question 9

What type of bond forms between amino acids?

Answer 9

Peptide bond.

Question 10

What are the four levels of protein structure?

Answer 10

Primary, secondary (alpha-helix, beta-sheet), tertiary, quaternary.

Question 11

What is the difference between globular and fibrous proteins?

Answer 11

Globular are soluble and functional (e.g. enzymes), fibrous are insoluble and structural (e.g. collagen).

Question 12

What are the components of a triglyceride?

Answer 12

Three fatty acids and one glycerol molecule.

Question 13

What is the difference between saturated and unsaturated fatty acids?

Answer 13

Saturated have no double bonds; unsaturated have at least one double bond.

Question 14

What are phospholipids and their role?

Answer 14

Two fatty acids, glycerol, and a phosphate group; form bilayers in cell membranes.

Question 15

What is the role of calcium ions (Ca2+)?

Answer 15

Involved in bone formation, muscle contraction, and nerve transmission.

Question 16

What is the role of phosphate ions (PO4^3−)?

Answer 16

Important in ATP, DNA, and RNA structure.

Question 17

What test is used for reducing sugars?

Answer 17

Benedict’s test; forms brick-red precipitate.

Question 18

What test is used for starch?

Answer 18

Iodine solution turns blue-black.

Question 19

What test is used for proteins?

Answer 19

Biuret test; turns purple.

Question 20

What test is used for lipids?

Answer 20

Emulsion test; white emulsion forms.

Question 21

What is colorimetry used for?

Answer 21

Quantitative measurement of concentration of a substance using light absorption.

Question 22

What are biosensors?

Answer 22

Devices that combine a biological component with a detector to measure the presence of chemicals.

Question 23

What is an ion?

Answer 23

An atom with an electric charge.

Question 24

What is an inorganic ion?

Answer 24

An ion that does not contain carbon (with some exceptions).

Question 25

What is a cation?

Answer 25

An ion with a positive charge.

Question 26

What is an anion?

Answer 26

An ion with a negative charge.

Question 27

What is the symbol for calcium and its roles?

Answer 27

Ca²⁺ - Nerve impulse transmission, muscle contraction, cofactor for enzymes.

Question 28

What is the symbol for sodium and its roles?

Answer 28

Na⁺ - Generating nerve impulses, muscle contraction, co-transport of glucose and amino acids.

Question 29

What is the symbol for potassium and its roles?

Answer 29

K⁺ - Generating nerve impulses, muscle contraction, regulating fluid balance.

Question 30

What is the symbol for hydrogen and its roles?

Answer 30

H⁺ - Determines pH of solutions, used in photosynthesis reactions.

Question 31

What is the symbol for ammonium and its role?

Answer 31

NH₄⁺ - Source of nitrogen for plants.

Question 32

What is the symbol for iron and its role?

Answer 32

Fe²⁺ - Binds to oxygen within haemoglobin.

Question 33

What is the symbol for chloride and its roles?

Answer 33

Cl⁻ - Maintains blood pH in gas exchange, cofactor for amylase enzyme.

Question 34

What is the symbol for phosphate and its roles?

Answer 34

PO₄³⁻ - Component of nucleotides and phospholipids, bonds store energy in ATP.

Question 35

What is the symbol for hydroxide and its role?

Answer 35

OH⁻ - Determines the pH of solutions.

Question 36

What is the symbol for nitrate and its role?

Answer 36

NO₃⁻ - Source of nitrogen.

Question 37

What is the symbol for hydrogencarbonate and its role?

Answer 37

HCO₃⁻ - Maintains blood pH.

Question 38

What is the solvent role of water?

Answer 38

Many substances dissolve in water.

Question 39

What is the temperature control role of water?

Answer 39

Water can buffer sudden temperature changes.

Question 40

What is the cooling mechanism role of water?

Answer 40

Evaporation of water in sweat cools the skin in mammals.

Question 41

How does water serve as a habitat?

Answer 41

Many organisms can survive and reproduce in water.

Question 42

How is water a metabolite?

Answer 42

Many chemical reactions involve water.

Question 43

How does water help in transport?

Answer 43

Organisms can use water to move substances.