Biomolecules Part 3 and 4: Proteins

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Questions and Answers

What is the primary role of enzymatic proteins?

To provide structural support to cells

To act as biological catalysts (correct)

To regulate the body's temperature

To transport molecules across membranes

How do enzymes affect the activation energy of chemical reactions?

They lower the activation energy needed (correct)

They eliminate the need for activation energy completely

They have no effect on activation energy

They increase the activation energy required

What defines regulatory or signal proteins?

They serve as channels for transporting water

They break down nutrients for energy

They are produced by glands and regulate physiology (correct)

They act mainly as structural components of cells

What is the function of transport proteins in cellular membranes?

To allow molecules to enter or exit the cell Signup and view all the answers

Which of the following is NOT a type of protein based on function?

Structural proteins Signup and view all the answers

What role do storage proteins serve in organisms?

They act as reserves of amino acids for growth. Signup and view all the answers

What is the primary role of antibodies in the immune system?

To neutralize pathogens such as bacteria and viruses Signup and view all the answers

Which of the following proteins is primarily responsible for maintaining the structural integrity of connective tissues?

Collagen Signup and view all the answers

Which of the following amino acid groups is hydrophobic?

Side group. Signup and view all the answers

What is the primary structure of a protein?

The specific sequence of amino acids in a protein. Signup and view all the answers

What type of reaction is responsible for linking amino acids together?

Dehydration synthesis. Signup and view all the answers

Which structural protein is primarily found in hair, nails, and the outer layer of the skin?

Keratins Signup and view all the answers

What function do the actin filaments primarily serve within cells?

Providing structural rigidity and movement Signup and view all the answers

What characteristic of elastin allows it to perform its function?

Its stretchable and rubber-like properties Signup and view all the answers

Which protein acts alongside actin filaments to facilitate muscle contractions?

Myosin Signup and view all the answers

Which group contains a nitrogen atom in an amino acid?

Amino group. Signup and view all the answers

Which protein is mismatched with its function?

Structural protein: Hemoglobin. Signup and view all the answers

Which of the following statements about RNA synthesis is true?

Only one strand of DNA serves as a template. Signup and view all the answers

How many different amino acids are there that make up proteins?

<ol start="20"> <li></li> </ol> Signup and view all the answers

What components are found in an amino acid?

Carboxyl group, amino group, side group, and carbon. Signup and view all the answers

Which of the following components is present in all nucleotides?

Pentose Sugar Signup and view all the answers

How do collagen fibers contribute to the features of skin and ligaments?

By offering rigidity and resistance to stretching Signup and view all the answers

What type of network is formed by contractile proteins in the cytoplasm of cells?

Colloidal network Signup and view all the answers

Which structure of proteins consists of multiple amino acid chains?

Quaternary Structure Signup and view all the answers

What distinguishes the sugar component of DNA from that of RNA?

Deoxyribose in DNA, Ribose in RNA Signup and view all the answers

Which of the following is not a type of RNA?

Regulatory RNA (rRNA) Signup and view all the answers

Which nitrogenous base is present in DNA but absent in RNA?

Thymine Signup and view all the answers

What is the primary function of messenger RNA (mRNA)?

Encodes proteins based on the genetic code Signup and view all the answers

What type of bond links nucleotides together in a nucleic acid strand?

Phosphodiester bond Signup and view all the answers

Study Notes

Proteins

Large, complex molecules essential for the structure, function, and regulation of tissues and organs.
Perform various critical roles in cellular processes.

Types of Proteins Based on Function

Enzymatic Proteins (Enzymes): Biological catalysts that accelerate chemical reactions by lowering activation energy.
Regulatory Proteins: Includes hormones, signaling molecules from glands that regulate physiological functions.
Transport Proteins: Embedded in plasma membranes, facilitate the movement of molecules in and out of cells.
Defense Proteins: Antibodies (immunoglobulins) produced by plasma cells to neutralize pathogens like bacteria and viruses.
Structural Proteins: Maintain structural integrity; examples include collagen, keratin, and elastin.

Structural Proteins Details

Collagen: Provides rigid support in connective tissues.
Elastin: A stretchy protein that allows tissues to resume shape after stretching.
Keratins: Contribute to the structure of hair, nails, and skin.

Storage Proteins

Serve as reserves of amino acids for growth and development; albumin is a notable example.

Amino Acids

The building blocks of proteins; there are 20 different amino acids.
Each amino acid contains a central carbon atom, an amino group, a carboxyl group, hydrogen, and a side group (R group) that determines its properties.

Protein Synthesis

Amino acids are linked by peptide bonds through dehydration synthesis.
The sequence of amino acids constitutes the primary structure, known as a polypeptide chain.

Nucleic Acids

Serve to store hereditary information and provide instructions for building proteins.
Two main types exist: DNA and RNA.

Structure of Nucleic Acids

Composed of nucleotides, which include a phosphate group, pentose sugar (deoxyribose in DNA, ribose in RNA), and a nitrogenous base.
Nucleotides form strands linked by phosphodiester bonds, featuring directionality from 5’ to 3’.

Types of RNA

Messenger RNA (mRNA): Temporary gene copy directing amino acid sequence in proteins.
Transfer RNA (tRNA): Assists in translating amino acid sequences during protein synthesis.
Ribosomal RNA (rRNA): Forms peptide bonds between amino acids in polypeptides.

Differences Between DNA and RNA

DNA: Deoxyribose sugar, double-stranded, contains thymine.
RNA: Ribose sugar, single-stranded, contains uracil instead of thymine.

Key Review Questions

Storage protein example: Albumin.
Contractile protein example: Myosin.
Structural protein incorrectly matched: Hemoglobin.
Not a component of an amino acid: Phosphate group.
Protein structure with multiple chains: Quaternary structure.
Not a nucleotide component: Glycerol.
Nitrogenous base found in DNA but not in RNA: Thymine.

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Description

This quiz covers the essential information about proteins, which are complex molecules critical for various functions in the body. Learn about the types of proteins based on their functions and their roles in cellular processes. Test your knowledge of enzymatic proteins and their significance in biochemistry.