Biology Chapter: Enzymes and Sugars

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Questions and Answers

What is the role of an enzyme in a chemical reaction?

To permanently change the substrate structure

To increase the activation energy required for the reaction

To act as a substrate in the reaction

To speed up the reaction by lowering activation energy (correct)

What happens to an enzyme when it is exposed to extreme pH levels?

It increases in size and mass

It becomes more effective at catalyzing reactions

It is destroyed or denatured (correct)

It changes the shape of the substrate

Which of the following best describes the lock and key model of enzyme action?

Enzyme can work with any substrate due to flexibility

Substrate fits exactly into a specific active site (correct)

Enzyme changes shape to fit the substrate

Active site can accommodate multiple substrates at once

What distinguishes aldose sugars from ketose sugars?

Aldose sugars have their carbonyl group located at the end of the carbon chain. Signup and view all the answers

What is the optimum pH level for pepsin, an enzyme found in the stomach?

pH 3 Signup and view all the answers

Which sugar is an example of a triose?

Glyceraldehyde Signup and view all the answers

How does the specificity of an enzyme relate to its active site?

The active site matches the shape of only a specific substrate Signup and view all the answers

How many carbon atoms are in pentose sugars?

5 C atoms Signup and view all the answers

What is a common feature of glucose, galactose, and fructose?

They share the same molecular formula but differ in structure. Signup and view all the answers

Which functional group is characteristic of monosaccharides?

Carbonyl group (C=O) Signup and view all the answers

Which of the following fatty acids can be synthesized by the body?

Linolenic acid Signup and view all the answers

What is the primary function of triglycerides in the body?

Energy storage Signup and view all the answers

What basic structure composes a phospholipid?

1 glycerol, 2 fatty acids, and 1 phosphate group Signup and view all the answers

Which of the following statements is true regarding non-essential amino acids?

They can be synthesized by the body. Signup and view all the answers

What is the main component responsible for providing buoyancy in aquatic animals?

Triglycerides Signup and view all the answers

Which process describes the formation of a dipeptide?

Removal of water from two amino acids Signup and view all the answers

What differentiates essential amino acids from non-essential amino acids?

Essential amino acids need to be obtained from food. Signup and view all the answers

Which molecule is indicated as the major component of cell membranes?

Phospholipids Signup and view all the answers

What characterizes quaternary protein structure?

It is formed by the joining of two or more polypeptide chains. Signup and view all the answers

Which of the following is NOT a bond that occurs in tertiary or quaternary protein structures?

Peptide bond Signup and view all the answers

Which type of protein predominantly forms long, parallel filaments or strands?

Fibrous proteins Signup and view all the answers

What role do fibrous proteins primarily serve in biological systems?

Mechanical and structural support Signup and view all the answers

Which of the following does NOT describe globular proteins?

They consist primarily of a secondary structure. Signup and view all the answers

Which specific protein is an example of quaternary structure?

Hemoglobin Signup and view all the answers

What type of interaction occurs primarily between R groups in proteins?

Hydrophobic (van der Waals) interaction Signup and view all the answers

How are proteins classified based on their structure?

Fibrous, globular, and conjugated Signup and view all the answers

What is the primary role of an enzyme in biochemical reactions?

To act as a biological catalyst Signup and view all the answers

Which statement best describes the specificity of enzymes?

Each enzyme is specific to a particular substrate Signup and view all the answers

In the induced fit model, what happens when the substrate binds to the enzyme?

The active site undergoes a conformational change to fit the substrate Signup and view all the answers

Which factor is NOT typically a direct influence on enzyme activity?

Color of the enzyme Signup and view all the answers

What distinguishes a reversible catalyst from an irreversible catalyst?

Reversible catalysts can bind and release substrates multiple times Signup and view all the answers

What is the primary difference between DNA and RNA regarding their structure?

DNA consists of two polynucleotide chains twisted into a double helix. Signup and view all the answers

Which base pairing rules apply in DNA?

Adenine pairs with thymine and cytosine pairs with guanine. Signup and view all the answers

What connects two nucleotides in a dinucleotide?

Phosphodiester bonds between the OH groups. Signup and view all the answers

What is the role of DNA in living organisms?

DNA carries genetic information that controls the activities of a cell. Signup and view all the answers

How are adenine and thymine held together in DNA?

By two hydrogen bonds. Signup and view all the answers

What process is used to break down nucleotides in DNA?

Hydrolysis. Signup and view all the answers

Which components make up the backbone of a DNA strand?

Sugar and phosphate units. Signup and view all the answers

What type of bonds hold the complementary base pairs of DNA together?

Hydrogen bonds. Signup and view all the answers

Study Notes

Biological Molecules

Biological macromolecules are the building blocks of all living things
Polymers are molecules made up of multiple monomers
Four major types of biological macromolecules include carbohydrates, lipids, proteins, and nucleic acids

Carbohydrates

Composed of carbon, hydrogen, and oxygen atoms
Ratio of C:H:O is approximately 1:2:1 (CH₂O)n
Monosaccharides are simple sugars with 3-7 carbon atoms
Disaccharides are formed by two monosaccharides joined by a glycosidic bond
Polysaccharides are polymers of monosaccharides
Functions include energy storage and structural support

Lipids

Consist mainly of carbon and hydrogen atoms with few oxygen atoms
Hydrophobic molecules, insoluble in water
Major types: fats, phospholipids, and steroids
Fats are triglycerides, formed from glycerol and three fatty acids
Phospholipids are amphipathic, containing hydrophilic heads and hydrophobic tails
Steroids have a distinct four-ring structure

Proteins

Polymers formed from amino acid monomers
Amino acids have a central carbon atom bonded to hydrogen, an amino group, a carboxyl group, and a variable R group
Twenty types of amino acids combine in varying sequences to make the unique proteins within organisms
Dipeptides and polypeptides are formed from multiple amino acids joined by peptide bonds
Proteins can have a primary, secondary, tertiary, or quaternary structure, which determines their function
Function in a wide range of functions within organisms including transport, structural support, and catalysis

Nucleic Acids

Polymers of nucleotides
Nucleotides consist of a pentose sugar (either ribose or deoxyribose), a nitrogenous base (adenine, thymine, guanine, cytosine, or uracil), and a phosphate group
DNA has two polynucleotide chains arranged antiparallel that form a double helix structure
RNA is a single stranded polynucleotide made up of ribose, uracil, guanine, adenine, and cytosine

ATP

Adenosine triphosphate
Composed of adenine, ribose, and three phosphate groups
High energy phosphate bonds
Releases energy when a phosphate bond is broken to form ADP (adenosine diphosphate)
Functions as an energy carrier for biological processes

Water

Polar molecule with unequal sharing of electrons, thus creating a slightly positive charge on one side and a slightly negatively charged side
Holds together via hydrogen bonds
Important properties include high specific heat capacity, high latent heat of vaporisation and high surface tension and maximum density at 4°C

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Description

This quiz covers key concepts related to enzymes and sugars, including their roles in chemical reactions, models of enzyme action, and structural distinctions among different sugar types. Test your knowledge on enzyme specificity, pH levels, and the classification of carbohydrates and fats.