DNA and RNA Structure
What is the shape of a DNA molecule
Double helix
What is the end result of meiosis?
Four haploid daughter cells, which are genetically distinct from the parent cell.
Define genetic engineering
The deliberate modification of an organism's genetic material, often involving the transfer of genes between species
Define what an enzyme is in terms of its chemical composition and function.
Enzymes are biological catalysts, usually proteins, that speed up chemical reactions in cells without being consumed in the process.
What is the best biological definition of a mutation?
A change in the sequence of nucleotides of a DNA or RNA molecule that may result in a change in the protein product.
What sugar is in DNA vs RNA
DNA contains deoxyribose; RNA contains ribose.
Is DNA copied before Meiosis II?
No, only before Meiosis I
What is the function of ligase in DNA modification
To join DNA fragments together
What part of an enzyme binds specifically to the substrate?
The active site.
What type of mutation occurs only in gametes and can be inherited?
Germ-line mutations.
What is the function of RNA?
What happens to the chromosome number during meiosis?
It is reduced by half (e.g., in humans, from 46 to 23).
What is the purpose of a restriction enzyme?
To cut DNA at specific nucleotide sequences
Explain the "Lock and Key" theory of enzyme action.
The substrate (key) fits precisely into the active site (lock) of the enzyme based on specific shape and chemical attraction, forming an enzyme-substrate complex.
What type of mutation involves a single nucleotide change?
Point mutation (e.g., Silent, Missense, Nonsense).
What holds the DNA strands together
How many cells are produced at the end of meiosis?
Four genetically distinct haploid
What are plasmids, and why are they used?
Small rings of bacterial DNA used as vectors to insert foreign genes.
What is the "Induced Fit" model?
A more accurate model where the active site changes shape slightly as the substrate approaches, ensuring a tighter binding to catalyze the reaction
What kind of mutation occurs when a segment of a chromosome breaks off and attaches to another chromosome?
Translocation
Which base is found only in RNA?
Uracil
What occurs during Metaphase I?
Homologous pairs (tetrads) line up at the equator.
What is a "transgenic" organism?
An organism containing genes transferred from another species
How do enzymes affect the activation energy of a reaction
Enzymes decrease the activation energy required, allowing the reaction to proceed faster.
What is the term for a mutation where a piece of a chromosome is removed?
Deletion.