genetics intro lecture Flashcards
Key Genetic Terms
What is a trait?
An observable characteristic of an organism.
Key Genetic Terms
What is a phenotype?
The expression of traits in an organism.
Key Genetic Terms
What is a genotype?
The genetic makeup of a cell.
DNA as Genetic Material
What was the first evidence that DNA carries genetic information?
Avery & McCarty’s experiment suggested DNA was the genetic material.
DNA as Genetic Material
When was DNA widely accepted as the genetic material?
In the 1950s, after insulin sequencing confirmed it.
DNA Structure & Components
What are the three components of a nucleotide?
A nitrogenous base, a sugar, and a phosphate group.
DNA Structure & Components
Which bases are purines?
Adenine (A) and Guanine (G).
DNA Structure & Components
Which bases are pyrimidines?
Thymine (T), Cytosine (C), and Uracil (U in RNA).
Functions of Nucleotides
What are three main functions of nucleotides?
Energy release (ATP), carrying chemical groups, and acting as signaling molecules (cAMP).
DNA Bonding & Synthesis
What type of bond links nucleotides in DNA?
A phosphodiester bond between the 3’ carbon of one nucleotide and the 5’ carbon of the next.
DNA Bonding & Synthesis
In which direction does DNA synthesis occur?
Always in the 5’ to 3’ direction.
Discovery of DNA
Who discovered the double-helix structure of DNA?
Watson & Crick in 1953.
Discovery of DNA
What was Rosalind Franklin’s contribution to DNA discovery?
She provided crucial X-ray diffraction data, which helped reveal the DNA structure.
Discovery of DNA
What is Chargaff’s rule?
In DNA, the amount of Adenine (A) equals Thymine (T), and Guanine (G) equals Cytosine (C).
Watson-Crick DNA Model
What are the key features of the Watson-Crick model of DNA?
DNA is a double-stranded, right-handed, antiparallel helix. The sugar-phosphate backbone is on the outside, and bases form hydrogen bonds on the inside.
Watson-Crick DNA Model
Why are hydrogen bonds important in DNA?
They allow easy unwinding for replication and transcription.
Genes & Genetic Code
What is the classical definition of a gene?
A unit of inheritance that carries a characteristic from parent to offspring.
Genes & Genetic Code
How big can genes be in humans?
They range from a few hundred to 2 million base pairs.
Genes & Genetic Code
What is the genome?
The complete set of genes in an organism.
Genes & Genetic Code
What is a locus?
The specific position of a gene on a chromosome.
What are chromosomes?
Discrete units of the genome that carry many genes.
Types of Mutations
What happens in a point mutation (substitution)?
One base is incorrectly replaced by another during replication.
Types of Mutations
What disease is caused by a point mutation?
Sickle-cell anemia.
Types of Mutations
What happens in an insertion mutation?
Extra nucleotides are added, often causing a frameshift.
Types of Mutations
What disease is caused by an insertion mutation?
Beta-thalassemia.
Types of Mutations
What happens in a deletion mutation?
One or more nucleotides are removed, often causing a frameshift.
Types of Mutations
What disease is caused by a deletion mutation?
Cystic fibrosis.
