Biology Lecture Notes on DNA, RNA, and Genetics

These flashcards cover key concepts related to DNA, RNA, and genetics, including vocabularies, definitions, and rules.

Nucleotide

The basic structural unit of DNA and RNA made of a sugar, a phosphate group, and a nitrogenous base.

Sugar-phosphate backbone

The outer structure of DNA made of alternating deoxyribose sugars and phosphate groups that provides stability and shape.

DNA double helix

The twisted ladder shape of a DNA molecule.

DNA base-pairing rule

A pairs with T, and G pairs with C.

Purines

Nitrogen bases with two rings; adenine and guanine are examples.

Pyrimidines

Nitrogen bases with one ring; cytosine and thymine are examples in DNA.

Antiparallel DNA strands

DNA strands that run in opposite directions, one from 5’ to 3’ and the other from 3’ to 5’.

Helicase

The enzyme that unzips DNA by breaking hydrogen bonds between base pairs.

Semiconservative replication

A type of replication where each new DNA molecule has one original strand and one newly made strand.

Mutation

A change in the DNA sequence.

Point mutation

A mutation that changes one nucleotide pair.

Silent mutation

A mutation that does not change the amino acid sequence of the protein.

Cell cycle

The series of stages a cell goes through as it grows and divides.

Interphase

The stage where the cell grows, does normal activities, copies DNA, and prepares for division.

Mitosis

Cell division that produces two genetically identical daughter cells.

Homozygous

Having two identical alleles for a trait, such as TT or tt.

Heterozygous

Having two different alleles for a trait, such as Tt.

Genotype

The allele combination an organism has, such as TT, Tt, or tt.

Phenotype

The visible or expressed trait of an organism, such as tall or short.

Law of Segregation

Allele pairs separate during gamete formation, so each gamete gets only one allele.

Meiosis

Cell division that produces gametes with half the normal chromosome number.

Crossing over

The exchange of genetic material between homologous chromosomes during meiosis.

Central Dogma

The flow of genetic information from DNA to RNA to protein.

Transcription

The process where DNA is copied into mRNA.

Translation

The process where ribosomes read mRNA to build proteins.