Genetics and Molecular Biology: Practice Questions
Multiple-Choice Questions
- Which of the following statements correctly describes Archibald Garrod’s hypothesis for how “inborn errors of metabolism” such as alkaptonuria occur? D
- A particular triplet of bases in the template strand of DNA is 5′-AGT-3′. What would be the corresponding codon for the mRNA that is transcribed? A
- The genetic code is essentially the same for all organisms. From this, one can logically assume which of the following statements to be true? A
- The figure shows a simple metabolic
Key Discoveries in Genetics and Molecular Biology
Pioneering Scientists and Their Contributions
- Frederick Griffith: Observed bacteria causing pneumonia.
- Andrei Nikolaevich Belozersky: Isolated DNA in a pure state.
- Archibald Garrod: Suggested that some inherited diseases are caused by blockages of metabolic reactions in the body.
- Edwin Chargaff: Found that in a segment of DNA, the amounts of adenine and thymine were equal.
- Beadle and Tatum: Searched for mutations by observing consequences.
Fundamentals of Nucleic Acids
Nucleic acids: Organic molecules
Read MoreDNA and RNA: Structure, Function, and Genetic Role
Nucleic Acids: DNA and RNA
Components of Nucleic Acids
Nucleic acids are polymers formed by a sequence of nucleotides linked through phosphodiester bonds. Partial nucleotide hydrolysis yields orthophosphoric acid and a core consisting of an aldopentose and a nitrogenous base.
- Pentose: β-ribofuranose or β-deoxyribofuranose.
- Nitrogenous Bases: Heterocyclic compounds of two main types:
- Pyrimidines: Derived from pyrimidine; these include cytosine, thymine, and uracil.
- Purines: Adenine and guanine.
Nucleosides
Nucleosides
Read MoreSensory Receptors and Sense Organs: A Detailed Look
Sensory Receptors
Sensory receptors are responsible for perceiving and receiving stimuli, which they convert into nerve impulses.
Types of Sensory Receptors
According to the Stimulus
- Photoreceptors: Detect light stimuli and are located in the eye. They respond to dim or bright light and produce black and white vision or color images.
- Mechanoreceptors: Stimulated by mechanical changes such as pressure, contact, or sound waves. Several receptors in the skin, muscles, and joints, including auditory receptors,
Transcription and Translation: Initiation & Termination
Translation Initiation
| How does translation begin? | Protein Synthesis | |
|---|---|---|
| Bacteria | Depends on the recognition of mRNA by ribosomes.
Because of multiple Shine-Dalgarno sequences, bacterial mRNA can be polycistronic (coding for more than one protein) while eukaryal mRNA is monocistronic. The Shine-Dalgarno sequence attaches |
Understanding the Human Nervous System
The nervous system relies on neurons to function. It comprises three interconnected systems:
- The Central Nervous System (CNS): Consists of the brain (cerebrum, cerebellum, and brainstem) and part of the spinal cord. Structurally protected by the skull and spine. The brain has three main structures: the cerebrum, cerebellum, and brainstem. The brain lobes are often color-coded: pink for parietal, green for temporal, and blue for occipital. The visual cortex is located at the back of the brain.
- Peripheral