Lecture 4 Flashcards
(14 cards)
What is the central dogma of molecular biology?
The central dogma states that genetic information flows from DNA to RNA to protein.
Mnemonic: Visualize a “DNA to RNA to Protein” highway with arrows pointing from one to the next, like a delivery route.
What is the role of mRNA in the process of gene expression?
mRNA serves as a messenger that carries the genetic code from DNA in the nucleus to the ribosome for protein synthesis.
Mnemonic :Think of mRNA as a delivery truck with a genetic message being transported to the ribosome “factory.”
What is the difference between bacterial and eukaryotic cells in terms of transcription?
In bacterial cells, transcription occurs directly in the cytoplasm, while in eukaryotic cells, transcription occurs in the nucleus and mRNA is processed before it exits to the cytoplasm.
Mnemonic: a nuclear envelope as a wall separating the “office” (nucleus) from the “workplace” (cytoplasm) in eukaryotic cel
What is mRNA splicing, and why is it important in eukaryotic cells?
mRNA splicing removes non-coding regions (introns) and joins coding regions (exons) to produce a mature mRNA. It increases protein diversity without adding more genes.
Mnemonic (back of card):
Imagine a scissors cutting and rejoining a paper with important instructions, removing unnecessary parts to make it more useful.
How many codons exist, and how do they function in protein synthesis?
There are 64 codons, 61 of which code for amino acids, and 3 are “stop” codons to terminate translation.
Mnemonic (back of card):
Visualize a “64-piece puzzle,” where 3 pieces are marked as “stop” and the remaining pieces represent amino acids.
What does the C-value paradox refer to?
The C-value paradox refers to the observation that genome size (C-value) does not correlate with the complexity of an organism.
Mnemonic (back of card):
Imagine a simple toolbox with more tools than a complex machine, illustrating that complexity isn’t always tied to size.
What does “redundancy but not ambiguity” mean in the context of the genetic code?
It means that multiple codons can code for the same amino acid, but no codon specifies more than one amino acid.
Mnemonic (back of card):
Think of a synonym dictionary: multiple words (codons) for one meaning (amino acid), but no word (codon) can mean two things at once.
Why must codons be read in the correct reading frame?
If codons are not read in the correct frame, the resulting protein will be incorrect, as the amino acid sequence will be altered.
How does the structure of DNA and proteins relate to their function?
DNA simplifies its structure from quaternary to primary to function efficiently, while proteins increase their complexity from primary to quaternary to function properly.
Mnemonic (back of card):
Visualize DNA as a scroll of instructions and proteins as a folded-up map that gets more detailed as it’s used.
What is the significance of the nearly universal genetic code?
The genetic code is nearly universal across species, meaning genes can be transcribed and translated even when transplanted between species.
Mnemonic (back of card):
Picture a universal translator that allows information to be understood across different “species” of cells.
What are the four levels of structural complexity in nucleic acids and proteins?
DNA and proteins can have four levels of structural complexity: primary, secondary, tertiary, and quaternary. These levels are crucial for efficient function, with DNA simplifying and proteins becoming more complex.
Mnemonic (back of card):
Imagine DNA as a simple line (primary) that folds (secondary), twists (tertiary), and interacts (quaternary), while proteins unfold from simplicity to intricate design.
How does the complexity of DNA and proteins relate to their function?
DNA simplifies its complexity from quaternary to primary structure for efficient information flow, while proteins need to increase their complexity from primary to quaternary to perform specific functions.
Mnemonic (back of card):
Picture DNA as an unfolding document and proteins as an intricate machine that grows more complex to perform specialized tasks.
What is the significance of the evolution of the genetic code?
The genetic code is nearly universal across all organisms, from bacteria to animals, which means genes can be transplanted between species and still be transcribed and translated.
Mnemonic (back of card):
Imagine a universal translator allowing communication between different species, enabling genetic information to work across boundaries.
What is an example of gene transplantation demonstrating the universality of the genetic code?
A tobacco plant expressing a firefly gene and a pig expressing a jellyfish gene are examples of how the genetic code is universal, allowing genes to function in different species.
Mnemonic (back of card):
Visualize a glowing firefly gene planted into a tobacco plant, and a pig with jellyfish-like fluorescence, showing that genes can “travel” across species.
