Funbio 3

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Questions and Answers

What is the central dogma of molecular biology?

The central dogma of molecular biology is the flow of information from DNA to RNA to proteins.

What is the role of cAMP in cell signaling?

cAMP acts as a secondary messenger that transfers the effects of hormones like glucagon and adrenaline into the cell.

How is a gene activated for protein synthesis?

A gene is activated when a cell requires a specific protein, triggering transcription of RNA followed by translation.

What happens to ATP during the signaling process involving cAMP?

During signaling, ATP is broken down to ADP, producing cAMP as a leftover molecule. Signup and view all the answers

What are genes and what do they encode?

Genes are sequences of nucleotides in chromosomic DNA that encode the synthesis of RNA or proteins. Signup and view all the answers

What is the main structural component of biological membranes?

The main structural component of biological membranes is the phospholipid bilayer. Signup and view all the answers

How do steroids differ structurally from other lipids?

Steroids have a structure consisting of four fused carbon rings, making them distinct from other lipids. Signup and view all the answers

What role do carotenoids play in plants and other organisms?

Carotenoids are responsible for the red, orange, and yellow colors in foods and flowers. Signup and view all the answers

What are the two main types of nucleic acids found in cells and their primary functions?

The two main types of nucleic acids are DNA and RNA, which store and express genomic information, respectively. Signup and view all the answers

What are nucleotides and what roles do they play in cellular processes?

Nucleotides are the building blocks of nucleic acids and act as messengers for signal transduction and provide energy for cellular processes. Signup and view all the answers

What two components make up a nucleoside?

A pentose sugar and a nitrogenous base. Signup and view all the answers

Describe the significance of the P-O-P bond in ATP.

The P-O-P bond in ATP is the major source of energy in the cell. Signup and view all the answers

What are the nitrogenous bases found in DNA, and what are their pairing rules?

The nitrogenous bases in DNA are adenine (A), cytosine (C), guanine (G), and thymine (T), with A pairing with T and C pairing with G. Signup and view all the answers

Explain the direction in which a polynucleotide chain grows during RNA formation.

A polynucleotide chain grows from the 5’ to 3’ direction. Signup and view all the answers

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

The primary function of mRNA is to carry genetic information from DNA to the cytoplasm for protein synthesis. Signup and view all the answers

What role does transfer RNA (tRNA) play in protein synthesis?

tRNA assembles the protein by delivering specific amino acids to the ribosome. Signup and view all the answers

How does DNA's structure enable self-replication?

DNA's structure allows it to serve as a template for producing complementary strands. Signup and view all the answers

Compare the structure of DNA and RNA.

DNA is double-stranded and helical, while RNA is single-stranded and linear. Signup and view all the answers

What are the main classifications of lipid molecules?

The main classifications of lipid molecules include fats, oils, waxes, phospholipids, carotenoids, and steroids. Signup and view all the answers

How do fatty acids contribute to the body's functions?

Fatty acids provide energy storage, form cell membranes, and have roles in hormone production and protection of vital organs. Signup and view all the answers

Describe the structure of triglycerides and their function.

Triglycerides consist of three fatty acids linked to a glycerol molecule through ester bonds, serving as the primary energy storage lipids. Signup and view all the answers

What distinguishes saturated fatty acids from unsaturated ones?

Saturated fatty acids contain no double bonds between carbon atoms, while unsaturated fatty acids have one or more double bonds. Signup and view all the answers

What is the composition of phospholipids and their role in cell membranes?

Phospholipids consist of two fatty acid molecules, one phosphate group, and a glycerol molecule, and they maintain the structural integrity of cell membranes. Signup and view all the answers

Explain the importance of phosphoryl group in phospholipids.

The phosphoryl group in phospholipids is crucial for maintaining healthy bones, teeth, and DNA structures. Signup and view all the answers

What are pyrimidines and purines in the context of nucleic acids?

Pyrimidines and purines are the two types of nitrogenous bases that form the building blocks of nucleotides, essential for DNA and RNA. Signup and view all the answers

What is the significance of ATP in cellular processes?

ATP, formed from nucleotides, serves as the primary energy carrier in cells, powering various biochemical reactions. Signup and view all the answers

Study Notes

Biological Molecules: Lipids and Nucleic Acids

Class: Foundation Year
Course: Fundamentals of Human Biology
Code: FUNBIO 3
Lecturer: Dr. Kulwinder Kaur
Date: 02-10-2024

Learning Outcomes

Outline the classification system for lipid molecules.
Describe the basic structure of fatty acids and explain their role in the body.
Describe the structure of triglycerides and explain their role in cell membranes.
Discuss pyrimidines and purines and the formation of nucleosides, nucleotides, and ATP.
Outline the basic structure of polynucleotides, RNA, and DNA.

Lipids - Background

Biomolecules that are water-insoluble but soluble in organic solvents (e.g., chloroform or ethanol).
Fatty acids are carboxylic acids typically containing between 12 and 20 carbon atoms.
Lipid types with fatty acids: fats, oils, waxes, phospholipids, carotenoids.
Lipid types without fatty acids: steroids.
Biological importance: energy storage, cell membrane, protection (cushioning vital organs), vision, hormones.

Saturated and Unsaturated Fatty Acids

Saturated fatty acids: only single bonds.
Monounsaturated fatty acids: one double bond.
Polyunsaturated fatty acids: two or more double bonds.
Example: Corn oil contains 86% unsaturated fatty acids and 14% saturated fatty acids.

Triglycerides (Animal Fats & Vegetable Oils)

Three fatty acid residues joined to glycerol by ester bonds.
Most abundant lipids in living organisms.
When metabolized, yield twice as much energy as carbohydrates.
Carbohydrates and proteins can be transformed into fats by enzymes.

Phospholipids

The main constituent of cell membranes.
Consist of fatty acid molecules, one phosphate group, and one glycerol molecule.
Amphipathic lipids (hydrophilic head and hydrophobic tail).
Aid in maintaining the functional and structural integrity of cell membranes.

Phospholipid & Phospholipid Bilayer

Phosphorus is crucial for maintaining healthy bones, teeth, and DNA.
The fundamental structure of the membrane is the phospholipid bilayer, forming a stable barrier between two aqueous compartments.

Steroids

Carbon atoms in four fused/attached rings.
Do not structurally resemble other lipids.
Included in the lipid category because they are hydrophobic and insoluble in water.
Involved in regulating metabolism, growth, reproduction, inflammation, and immunosuppression.
Example: Cholesterol is the most common steroid, mainly synthesized in the liver. Cortisol regulates the body's stress response.

Carotenoids

Lipid molecules synthesized by algae, fungi, plants, and photosynthetic bacteria.
Over 700 forms have been identified.
Responsible for red, orange, and yellow colors in foods and flowers.
Consist of isoprene units.
Convert to vitamin A.

Nucleic Acids

Large biomolecules vital for all cells and viruses.
Involved in storing and expressing genomic information and transmitting hereditary information.
Determine what proteins a cell manufactures.
Two main types: Deoxyribonucleic acid (DNA) and Ribonucleic acid (RNA).
Polymers of nucleotides.

Nucleotides

The building blocks of nucleic acids (RNA & DNA).
Messengers for signal transduction.
Provide energy for cellular processes.
Structure: pentose sugar (five carbon sugar), phosphate group, and organic base (purine or pyrimidine).

Pentose Sugar

Can be either ribose (in RNA) or deoxyribose (in DNA).
Deoxyribose has one less oxygen than ribose.

Nucleosides

Pentose sugar + nitrogenous base (no phosphate).
Examples: Ribonucleoside, Deoxy-ribonucleoside

Nucleoside vs. Nucleotide

A nucleoside is just a sugar and base
A nucleotide adds a phosphate group

Nucleotides as energy deposit: Adenosine triphosphate (ATP) Molecule

The chemical bond between phosphates (P-O-P) is the major source of energy in the cell.
When needed, ATP is dephosphorylated, releasing energy.
Same reactions can occur in the opposite direction for energy storage.

Deoxyribonucleic Acid (DNA)

The double-helix model revealed that genetic information is encoded in the sequences of nitrogenous bases.
The modality in which DNA self-replicates in daughter cells is a fundamental process in passing on genetic information.
Adenine (A), Cytosine (C), Guanine (G), and Thymine (T) follow base pairing rules (A with T and C with G).

Nitrogenous Bases

Interact with each other complementarily.
At actual size, a human cell's DNA totals about 3 meters in length.

Ribonucleic Acid (RNA)

Nucleotides are joined by phosphodiester linkages.
RNA is a single-stranded linear chain.
Carries instructions for synthesizing proteins and regulating genes.
A phosphoric acid molecule bridges C3 of one nucleotide and C5 of another.
Polynucleotide chains grow from 5′ to 3′.

DNA-RNA-Protein

DNA information is passed to RNA in the cell nucleus.
Messenger RNA (mRNA) carries protein-making information out of the nucleus and into the cytoplasm.
Translation takes place in the cytoplasm.
- mRNA interacts with a ribosome.
- The ribosome "reads" the mRNA sequence of codons (3 nucleotides).
- Each codon usually codes for one amino acid.
- Transfer RNA (tRNA) assembles the protein, one amino acid at a time.
Translation continues until a stop codon is reached.
Known as the central dogma.

Gene Expression

Gene is a sequence of nucleotides in DNA that encodes the synthesis of a gene product (RNA or protein).
Chromosomes carry DNA in cells; Genes give unique characteristics.
When a cell needs a specific protein, it activates the gene, and transcription of RNA molecule occurs, followed by translation.

Cyclic Adenosine Monophosphate (cAMP)

Cell signaling molecule.
Transfers effects of hormones that cannot pass through the plasma membrane, e.g., glucagon, adrenaline.
Involved in the activation of protein kinases (ATP-ADP).

ATP-cAMP

Adenyl cyclase catalyzes the conversion of ATP to cAMP.

Overview of Biological Molecules

A table summarizing the different biological macromolecules (carbohydrates, lipids, proteins, nucleic acids) providing their monomers and functions.
A diagram showing the relationships among biological macromolecules.

Chapter 3 - The Chemistry of Life' - Organic Compounds

Textbook information for lipids (p56-59) and nucleic acids (p68-69).

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Description

Explore the fundamental concepts of molecular biology through this informative quiz. Test your understanding of DNA structure, RNA functions, and the mechanisms behind protein synthesis and cell signaling. Perfect for students seeking to strengthen their grasp on biological processes.