DNA Structure & Function and Mendelian Genetics

This set of flashcards covers key concepts related to DNA structure and function, as well as Mendelian genetics, to aid in exam preparation.

Nucleic acids

Biomolecules that store life's information in the form of polymers of nucleotide monomers.

Nucleotide

The basic building block of nucleic acids, comprising a 5-carbon sugar, a phosphate group, and a nitrogenous base.

Phosphodiester linkage

The bond formed between nucleotides in a polynucleotide chain, creating a sugar-phosphate backbone.

Purines

Nitrogenous bases with a two-ring structure; includes Adenine (A) and Guanine (G).

Pyrimidines

Nitrogenous bases with a one-ring structure; includes Cytosine (C), Thymine (T) in DNA and Uracil (U) in RNA.

Antiparallel strands

Refers to the opposing orientation of the two DNA strands in a double helix, running 5' to 3' and 3' to 5'.

Base pairing rules

In DNA: Adenine pairs with Thymine (A=T) and Guanine pairs with Cytosine (G≡C).

Chargaff's rules

A discovery by Erwin Chargaff stating that the amount of adenine equals thymine and the amount of guanine equals cytosine in DNA.

DNA polymerase

An enzyme responsible for synthesizing DNA by adding nucleotides to a growing DNA strand during DNA replication.

Leading strand

The strand of DNA that is synthesized continuously in the direction of the replication fork during DNA replication.

Lagging strand

The strand of DNA that is synthesized discontinuously, creating Okazaki fragments, opposite to the direction of the replication fork.

Okazaki fragments

Short sequences of DNA synthesized on the lagging strand during DNA replication.

Telomerase

An enzyme that adds repetitive nucleotide sequences to the ends of chromosomes (telomeres), helping to maintain their integrity.

Allele

A variant form of a gene that arises by mutation and is found at a specific locus on a chromosome.

Genotype

The genetic makeup of an organism, representing the combination of alleles for a given trait.

Phenotype

The observable physical or biochemical characteristics of an organism, determined by both genetic makeup and environmental influences.

Mendelian genetics

The study of how traits are inherited through generations based on the principles established by Gregor Mendel.

Monohybrid cross

A genetic cross between individuals focusing on a single trait, showcasing the principle of segregation.

Dihybrid cross

A genetic cross between individuals focusing on two traits, showcasing independent assortment.

Independent assortment

The principle stating that alleles of different genes assort independently of one another during gamete formation.

Linkage

The tendency of genes that are located close together on a chromosome to be inherited together.

Codominance

A genetic scenario in which both alleles in a heterozygote are fully expressed, leading to a phenotype that is not a blend.

Incomplete dominance

A genetic scenario in which the heterozygous phenotype is intermediate between the two homozygous phenotypes.