DNA and RNA Comparison Quiz

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Questions and Answers

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

To transport amino acids to the ribosome

To carry instructions for protein synthesis to the ribosome (correct)

To serve as a template for DNA repair

To replicate DNA before cell division

Which types of RNA are involved in translating mRNA into proteins?

rRNA and mRNA only

tRNA and DNA

mRNA and tRNA only

rRNA and tRNA (correct)

What is a codon?

A type of protein structure

A sequence of three mRNA nucleotides coding for an amino acid (correct)

A sequence of three DNA nucleotides

The process of DNA unwinding

Why is DNA replication important before cell division?

To ensure each daughter cell receives identical DNA Signup and view all the answers

During which phase of the cell cycle does DNA replication take place?

During interphase Signup and view all the answers

Which codon signals the start of protein synthesis?

AUG Signup and view all the answers

What occurs if there is a mistake during DNA replication?

The DNA repair mechanisms will correct most errors Signup and view all the answers

Which bile salt contains taurine as its alipathic group?

Taurocholate Signup and view all the answers

What type of fats are predominantly saturated and solid at room temperature?

Fats Signup and view all the answers

Which type of fat is considered 'good fat' and includes omega-3 and omega-6 fatty acids?

Polyunsaturated fats Signup and view all the answers

Which chemical reaction is the reverse of esterification in triacylglycerols?

Hydrolysis Signup and view all the answers

What is a characteristic property of waxes?

They are water-repellent. Signup and view all the answers

What are fatty acids characterized as?

Amphipathic Signup and view all the answers

What is the solubility in water for short-chain fatty acids?

Sparingly soluble due to the polar carboxylic group Signup and view all the answers

Which fatty acids are typically solid at room temperature?

Saturated fatty acids Signup and view all the answers

How does an increase in the number of double bonds affect the solubility of fatty acids?

Increases solubility in water Signup and view all the answers

What is a characteristic of saturated fatty acids in relation to cholesterol?

They are considered bad cholesterol Signup and view all the answers

What structural feature of fatty acids contributes to their amphipathic nature?

Both hydrophobic and hydrophilic groups Signup and view all the answers

What happens to the solubility of fatty acids as the hydrocarbon chain gets longer?

Solubility decreases Signup and view all the answers

Which fatty acids are generally considered better for health?

Unsaturated fatty acids Signup and view all the answers

What type of fatty acids has fewer double bonds generally leading to lower water solubility?

Saturated fatty acids Signup and view all the answers

What is the reason to eat before taking aspirin?

It acts as a neutralizer against stomach acids. Signup and view all the answers

What is the primary role of thromboxanes?

Increasing platelet aggregation. Signup and view all the answers

Why are trans fatty acids considered unhealthy?

They can easily pack tightly and disrupt metabolism. Signup and view all the answers

What effect does aspirin have that is contraindicated in dengue fever?

Acts as an anti-platelet agent and anticoagulant. Signup and view all the answers

Which fatty acid is a precursor for leukotrienes?

20:4(n-6) Arachidonic acid. Signup and view all the answers

What is a characteristic of prostaglandins?

They include hydroxyl groups and conjugated double bonds. Signup and view all the answers

What effect does LTB4 have in the body?

Increases vascular permeability and T-cell proliferation. Signup and view all the answers

What is the basic structure in eicosanoids?

A 20-carbon fatty acid. Signup and view all the answers

Which of the following is a function of leukotrienes?

Increases bronchoconstriction and vascular permeability. Signup and view all the answers

How does aspirin affect gastric function?

Blocks prostaglandin action, decreasing mucus and increasing secretion. Signup and view all the answers

What are cerebrosides composed of?

Ceramide and sugar Signup and view all the answers

What type of cerebroside is formed when glucose is the sugar component?

Glucocerebroside Signup and view all the answers

Which component is linked to ceramide in gangliosides?

Oligosaccharide Signup and view all the answers

What type of linkage connects NANA to the oligosaccharide in gangliosides?

Alpha linkage Signup and view all the answers

What is the primary function of sphingomyelin in the human body?

Myelin sheath formation Signup and view all the answers

What percentage of all lipids in humans are sphingolipids?

25% Signup and view all the answers

What is cholesterol primarily known as in the body?

A steroid Signup and view all the answers

What action does bile acid perform in relation to fatty acids?

Emulsifies them Signup and view all the answers

What is the structure of cholesterol based on?

Cyclopentanoperhydropenanthrene Signup and view all the answers

Where is bile acid primarily stored in the body?

Gallbladder Signup and view all the answers

Study Notes

DNA vs RNA

DNA is found in the cell nucleus and stores/transfers genetic info
RNA is found in all parts of a cell and is involved in protein synthesis
DNA is double-stranded, has deoxyribose sugar, bases C, G, A, T, and self-replicates
RNA is single-stranded, has ribose sugar, bases C, G, A, U, and can't self-replicate

Purines vs Pyrimidines

There are five nitrogenous bases in total
Purines are double-ring structures (Guanine, Adenine)
Pyrimidines are single-ring structures (Cytosine, Thymine, Uracil)
Purines pair with pyrimidines (e.g., Guanine with Cytosine)

Nucleoside Formation

The nitrogenous base is connected to the sugar at C1
The sugar is differentiated from H and OH at C2
The phosphate group attaches at C5

Structural Characteristics of DNA

DNA is comprised of two anti-parallel polynucleotides
One strand runs 5' to 3', the other 3' to 5'
The sugar-phosphate backbone is on the outside
The hydrophobic bases are on the inside

Base Pairing

A pyrimidine always pairs with a purine
A pairs with T (2 H-bonds), and G pairs with C (3 H-bonds)
These base pairings are called Watson-Crick base pairs

Central Dogma

Replication: identical copies of DNA are made
Transcription: genetic messages are read and carried out of the nucleus to the ribosomes for protein synthesis
Translation: genetic messages are decoded to make proteins

DNA Replication Steps

Helicase unwinds and separates the DNA strands
Primase adds RNA primers
Polymerase III copies each strand
Polymerase I replaces primers with DNA nucleotides
Ligase seals up the DNA segments

RNA and Protein Synthesis

Ribosomal RNA (rRNA) is part of the ribosome
Transfer RNA (tRNA) carries amino acids to the ribosome
Messenger RNA (mRNA) carries genetic info from DNA to the ribosome

Translation

mRNA is translated to protein
Codons (3 mRNA nucleotides) code for specific amino acids
The order of codons determines the order of amino acids in a polypeptide chain
Start codon (AUG) and stop codons (UAA, UAG, UGA)

Mutations

Changes in DNA sequence at a particular gene locus
Can be harmful, beneficial, or neutral
Types include point mutations (silent, missense, nonsense) and frameshift mutations (deletion, duplication, inversion, translocation)

Lipids

Organic compounds that are insoluble in water but soluble in non-polar solvents.
Classified based on solubility not functional groups
Contain fatty acids
Examples of lipid classes include
- fatty acids
- triglycerides (triacylglycerols)
- phospholipids
- sphingolipids
- steroids
- waxes

Fatty Acids

Members of carboxylic acids
Hydrocarbon chain with one terminal carboxyl group (COOH).
Saturated vs Unsaturated:
- saturated: solid at room temperature, no double bonds
- unsaturated: liquid at room temperature, one or more double bonds

Prostaglandins

c20 fatty acid derivative
Cyclopentane ring with oxygen-containing functional groups
Involved in raising body temperature, inhibiting gastric secretions, increasing mucus secretion in stomach, altering water & electrolyte balance, and intensifying pain/inflammation responses.

Eicosanoids

20-carbon fatty acids
Precursors are prostaglandins
Include prostaglandins and leukotrienes

Essential fatty acids (EFAs)

Animals cannot synthesize these on their own and it's crucial to consume them in their diet.

Cholesterol

Major steroid in the body.
Important component of cell membranes and precursor for other steroids (e.g., hormones and bile acids)
Includes:
- bile acids
- hormones (sex hormones, adrenal cortical hormones)

Protein Structural Organization

Primary, secondary, tertiary, and quaternary structures are levels of protein structure organisation.
Proteins are formed from a chain of amino acids.

Amino Acids & Protein Organization

Building blocks of proteins
Vary by their side chains (R groups).
Also categorized based on the polarity of the R group (neutral, acidic, basic) and whether they are essential (must consume them) or non-essential (body can synthesize).

Amino Acid Properties

Amino acids are typically zwitterions (dipolar ions) at physiological pH, having both a positively charged amino group and a negatively charged carboxyl group.
The side chain (R group) determines the specific chemical properties of each amino acid.

Isoelectric Point (pI)

pH at which an amino acid solution has no net charge.

Sterochemistry of Amino Acids

Amino acids have chiral (asymmetric) carbon centers, leading to stereoisomers.
L-amino acids are predominant in proteins.

Models of Substrate-Enzyme Binding

Lock and key, induced-fit (enzyme shape changes on substrate binding)

Enzyme Kinetics

Measure the rate of enzyme-catalyzed reactions
Km (Michaelis-Menten constant) reflects the enzyme's affinity for the substrate.

Enzyme Inhibition

Competitive, non-competitive, and uncompetitive inhibition are all types of enzyme inhibition in which an enzyme is bound to its inhibitor.

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Description

Test your knowledge on the differences between DNA and RNA. This quiz covers their structures, functions, and the significance of purines and pyrimidines. Challenge yourself to understand nucleoside formation and the overall characteristics of DNA.