Biomolecules Part 3 and 4: Proteins

Questions and Answers

What is a primary role of proteins in the body?

Regulating cellular communication

Facilitating the structure, function, and regulation of tissues and organs (correct)

Transporting genetic information

Providing energy for cellular processes

What function do enzymatic proteins primarily serve?

Transporting oxygen in the blood

Catalyzing biological reactions (correct)

Building cellular structures

Regulating hormone levels

What is the role of regulatory or signal proteins?

To transport neurotransmitters across synapses

To provide structural support to cells

To act as enzymes in metabolic pathways

To regulate physiology and behavior by transmitting signals to target organs (correct)

What is one characteristic of transport proteins?

They are embedded in the plasma membrane facilitating molecule movement. Signup and view all the answers

How do enzymes affect chemical reactions?

They weaken bonds to lower activation energy. Signup and view all the answers

What function do antibodies serve in the immune system?

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

Which of the following is NOT classified as a structural protein?

Antibody Signup and view all the answers

What is the primary role of collagen in the body?

To provide structural support to connective tissues Signup and view all the answers

What characteristic is associated with elastin?

It can stretch and recoil like a rubber band Signup and view all the answers

Which of the following proteins is primarily responsible for structural support in hair and nails?

Keratins Signup and view all the answers

What is the role of actin filaments within the cytoplasm of cells?

To provide a colloidal network for structural rigidity and movement Signup and view all the answers

What type of protein mainly interacts with actin filaments to create movement?

Myosin Signup and view all the answers

Which statement about structural proteins is true?

They provide shape and structural integrity to organisms. Signup and view all the answers

What are proteins primarily made of?

Amino acids Signup and view all the answers

What type of bond holds amino acids together in a protein?

Peptide bond Signup and view all the answers

Which of the following describes the primary structure of a protein?

The sequence of amino acids in a polypeptide Signup and view all the answers

Which component is not part of an amino acid?

Hydrogen group Signup and view all the answers

Which storage protein is correctly matched?

Albumin Signup and view all the answers

What is the process called where cells link amino acids to form proteins?

Dehydration synthesis Signup and view all the answers

Which is the correct representation of the components of an amino acid?

Amino group, carboxyl group, and side group Signup and view all the answers

Which protein function is incorrectly matched?

Structural protein: Hemoglobin Signup and view all the answers

Which structure of proteins consists of more than one amino acid chain?

Quaternary Structure Signup and view all the answers

Which of the following is not a component of a nucleotide?

Glycerol Signup and view all the answers

What type of RNA serves as a temporary copy of a gene in DNA?

Messenger RNA (mRNA) Signup and view all the answers

Which nitrogenous base is found in DNA but not in RNA?

Thymine Signup and view all the answers

What type of bond connects nucleotides in a nucleic acid strand?

Phosphodiester Bond Signup and view all the answers

What is the directionality of a nucleic acid strand?

5’ to 3’ Signup and view all the answers

Which component distinguishes RNA from DNA?

Ribose Signup and view all the answers

What type of RNA creates peptide bonds between amino acids?

Ribosomal RNA (rRNA) Signup and view all the answers

Study Notes

Proteins

Proteins are essential macromolecules that perform vital functions in the body, including structural roles and regulatory tasks.
Composed of 20 different amino acids, proteins are long chains called polypeptides that vary in sequence and structure.

Types of Proteins

Enzymatic Proteins (Enzymes): Biological catalysts that speed up chemical reactions by lowering activation energy.
Regulatory Proteins: Often hormones, these proteins send signals to distant organs to regulate physiological functions and behavior.
Transport Proteins: Located in the plasma membrane, they facilitate the movement of molecules across cell membranes (e.g., hemoglobin).
Defense Proteins (Antibodies): Large Y-shaped proteins that play a crucial role in the immune system by neutralizing pathogens.
Structural Proteins: Provide support and shape to cells and tissues; examples include collagen (for skin elasticity), keratin (in hair and nails), and elastin (in ligaments and arteries).
Storage Proteins: Act as reservoirs of amino acids, used later for growth and development (e.g., albumin).

Structure of Amino Acids

Amino acids comprise a central carbon atom bonded to an amino group (-NH2), carboxyl group (-COOH), hydrogen atom (-H), and a variable side group (R).
The side chain determines the specific characteristics of each amino acid, being either hydrophilic or hydrophobic.

Linking Amino Acids

Amino acids are linked through dehydration synthesis to form peptide bonds, creating a polypeptide chain.

Protein Structure Levels

Primary Structure: The linear sequence of amino acids in a polypeptide.
Secondary Structure: The folding of the polypeptide into alpha-helices or beta-pleated sheets.
Tertiary Structure: Three-dimensional shape formed by interactions between R groups.
Quaternary Structure: Assembly of multiple polypeptide chains into a functional protein.

Nucleic Acids

Nucleic acids store hereditary information and encode the instructions for protein synthesis; two main types are DNA and RNA.
Composed of nucleotides, each consisting of a phosphate group, a pentose sugar (deoxyribose in DNA, ribose in RNA), and a nitrogenous base.

Nucleotide Structure

Nucleotides are linked via phosphodiester bonds, connecting the 5’ carbon of one nucleotide to the 3’ carbon of another, resulting in a directional strand (5’ to 3’).

RNA Functions

RNA types include:
- mRNA (Messenger RNA): Carries the genetic code from DNA for protein synthesis.
- tRNA (Transfer RNA): Helps translate the genetic code into a sequence of amino acids.
- rRNA (Ribosomal RNA): Combines with proteins to form ribosomes and catalyze peptide bonds.
RNA typically exists as a single-stranded molecule and is shorter than DNA.

Differences Between DNA and RNA

Sugar: DNA contains deoxyribose; RNA contains ribose.
Strands: DNA is double-stranded; RNA is single-stranded.
Nitrogenous Bases: DNA has thymine; RNA has uracil instead. Both contain adenine, cytosine, and guanine.
Location: DNA is found in the nucleus; RNA is mostly located in the cytoplasm.

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Description

Explore the fascinating world of proteins in this quiz from Biomolecules Part 3 and 4. Learn about their complex structures, critical functions, and various types based on their roles in the body. This quiz will test your understanding of enzymatic proteins and their importance in biological processes.