Amino Acids and pKa Values Quiz

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Questions and Answers

What is the primary function of transfer RNA (tRNA)?

To carry genetic information from the DNA to the ribosomes

To form the structural components of ribosomes

To synthesize RNA from DNA

To translate the genetic code from mRNA and bring specific amino acids for protein synthesis (correct)

How many different tRNAs correspond to the codons that specify amino acids?

61 (correct)

What proportion of ribosomal RNA (rRNA) and proteins compose ribosomes?

75% rRNA and 25% proteins

50% rRNA and 50% proteins

65% rRNA and 35% proteins (correct)

80% rRNA and 20% proteins

What structural feature allows tRNA to function effectively?

It possesses a tertiary structure that is L-shaped Signup and view all the answers

Which of the following best describes the role of messenger RNA (mRNA)?

It carries the genetic code from DNA to ribosomes for protein synthesis Signup and view all the answers

What is considered the most fundamental unit of life?

Cell Signup and view all the answers

Which of the following is NOT classified as a macromolecule?

Glucose Signup and view all the answers

According to Rudolf Virchow, what is the origin of cells?

Every cell comes from a cell. Signup and view all the answers

Which term describes the mechanisms a cell uses to maintain stable internal conditions?

Homeostasis Signup and view all the answers

Which of the following is an example of a multicellular organism?

Human Signup and view all the answers

What component of the cell is responsible for responding to environmental stimuli?

Cells Signup and view all the answers

Which of the following is NOT a type of tissue?

Chromosomal Signup and view all the answers

What is the role of organ systems in an organism?

They perform a specific function necessary for survival. Signup and view all the answers

What happens to amino groups and carboxylic acids at low pH?

Both are protonated. Signup and view all the answers

What is the pKa range for amino groups?

9 to 10 Signup and view all the answers

What does the term 'zwitterionic form' refer to?

A molecule with both positive and negative charges, but no net charge. Signup and view all the answers

How does pH affect the state of amines and carboxylates at a neutral pH?

Amines are protonated and carboxylates are deprotonated. Signup and view all the answers

What is the characteristic symptom of Kwashiorkor?

Swollen abdomen. Signup and view all the answers

What defines an essential amino acid?

An amino acid that must be obtained from dietary sources. Signup and view all the answers

What is a dipeptide?

A chain of two covalently linked amino acids. Signup and view all the answers

What does Marasmus refer to?

Wasting away due to inadequate protein intake. Signup and view all the answers

What is the role of helicase during DNA replication?

To unwind sections of parent DNA Signup and view all the answers

How is the lagging strand synthesized during DNA replication?

In short sections called Okazaki fragments Signup and view all the answers

Which of the following correctly describes the composition of RNA nucleotides?

Ribose sugar, phosphate group, and Uracil Signup and view all the answers

In what way does RNA differ from DNA?

RNA contains Uracil instead of Thymine Signup and view all the answers

What is the function of DNA ligase during DNA replication?

To join Okazaki fragments together Signup and view all the answers

Which strand of DNA serves as the template during transcription?

Template strand Signup and view all the answers

What is the role of RNA polymerase in transcription?

To synthesize mRNA from the DNA template Signup and view all the answers

What happens to introns during the processing of pre-RNA?

They are spliced out Signup and view all the answers

In which direction does RNA polymerase move along the DNA template?

3’ to 5’ direction Signup and view all the answers

What are the components joined to form mRNA after splicing?

Exons only Signup and view all the answers

Which of the following is NOT involved in the transcription process?

tRNA Signup and view all the answers

Which component of RNA replaces thymine found in DNA?

Uracil (U) Signup and view all the answers

Where does transcription take place in eukaryotic cells?

Nucleus Signup and view all the answers

Study Notes

pKa and Protein Behavior

pKa values for amino groups typically range from 9 to 10; carboxylic acids have pKa values between 2 and 5.
At low pH (pH=1), amino acids exist in a protonated state (+H3N – CH2 - COOH) due to high proton concentrations.
At neutral pH (pH=7), amino acids are zwitterionic (+H3N – CH2 – COO-), with protonated amines and deprotonated carboxylic acids.
High pH (pH=12) leads to deprotonation of both functional groups (H2N - CH2- COO-).

Protein-Energy Malnutrition

Kwashiorkor: Characterized by swollen abdomen; comes from the Ghanaian term for "the disease the first child gets when the new child arrives." Energy intake may be adequate, but protein intake is too low.
Marasmus: Defined as "to waste away"; occurs due to severely limited energy intake, leading to inadequate proteins, causing malnutrition.

Essential Amino Acids

Essential amino acids must be consumed through diet as the body cannot synthesize them.
The list of essential amino acids is critical for proper body function.

Molecular Organization of Cells

The cell is the fundamental unit of life, organized from simpler atoms into larger structures.
Organism classification ranges from cells (e.g., myocytes, neurons) to tissues (muscle, epithelial) up to organ systems (e.g., cardiovascular).

DNA Replication Process

Helicase unwinds DNA sections at replication forks.
DNA polymerase synthesizes the leading strand (5’-3’ direction), while the lagging strand is made in short segments known as Okazaki fragments (3’-5’ direction).
DNA ligase joins Okazaki fragments to create a continuous strand.

RNA Structure and Function

RNA consists of ribose sugar, phosphate group, and nitrogenous bases (adenine, uracil, cytosine, guanine).
Unique differences between RNA and DNA include:
- RNA uses ribose; DNA uses deoxyribose.
- RNA is single-stranded; DNA is double-stranded.
- RNA contains uracil (U) instead of thymine (T).
- RNA is found inside and outside the nucleus; DNA is confined to the nucleus.

Types of RNA

Three main RNA types:
- Messenger RNA (mRNA): Carries genetic information from DNA to ribosomes.
- Transfer RNA (tRNA): Delivers specific amino acids to the ribosome; has an L-shaped tertiary structure.
- Ribosomal RNA (rRNA): Structural component of ribosomes involved in protein synthesis.

Protein Synthesis Overview

Involves transcription (formation of mRNA from DNA in the nucleus) and translation (conversion of mRNA to protein at the ribosome in the cytoplasm).
RNA polymerase synthesizes mRNA by moving along the DNA template in the 3’-5’ direction.

mRNA Processing

Eukaryotic genes contain exons (coding) and introns (non-coding), requiring pre-mRNA to undergo processing before translation.
Introns are removed via splicing facilitated by small nuclear RNA (snRNA), joining exons to form mature mRNA.

Codon and Anticodon Relationships

Codons are triplet sequences of nucleotides that code for specific amino acids.
Each tRNA has an anticodon that pairs with the corresponding codon on the mRNA, ensuring the correct amino acid is added during protein synthesis.

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Description

Test your knowledge on the pKa values of amino acids and their behavior at different pH levels. This quiz covers essential concepts related to amino group abbreviations and proton concentration in various conditions. Review the significance of pH in biochemical contexts.