DNA Structure, Cell Cycle, and Genetics Review Flashcards

These flashcards cover key concepts related to DNA structure, cell cycle, mitosis, genetics, and heredity, providing definitions and explanations for important terms and principles.

Sugar-phosphate backbone

The structural framework of DNA consisting of alternating sugar and phosphate groups that helps stabilize the DNA.

Antiparallel strands

DNA strands that run in opposite directions, which is crucial for replication and function.

Helicase

An enzyme that unwinds and separates the double-stranded DNA during replication.

Semiconservative replication

Method of DNA replication where each new DNA molecule consists of one original strand and one new strand.

Nucleotide

The basic building block of DNA, consisting of a sugar, a phosphate group, and a nitrogenous base.

Hydrogen bonds in base pairs

Weak bonds that hold the complementary nitrogenous bases together in the DNA double helix.

Complementary DNA strand for GATTACA

CTAATGT.

Interphase

The phase of the cell cycle where cells spend most of their time preparing for mitosis.

S phase of interphase

The phase during which DNA is replicated.

Spindle fibers

Structures that separate sister chromatids during mitosis.

Cytokinesis

The process that separates the cytoplasm of a parental cell into two daughter cells following mitosis.

Mitosis

A type of cell division that results in two genetically identical daughter cells.

Genotype vs. phenotype

Genotype refers to the genetic makeup, while phenotype refers to the physical expression of a trait.

Heterozygous

An organism that has two different alleles for a trait.

Law of Segregation

The principle that alleles for a trait segregate during gamete formation.

Pedigree

A diagram that shows the occurrence of a genetic trait across generations and is used to analyze inheritance patterns.

Polygenic trait

A trait that is controlled by multiple genes, resulting in a continuous range of variation.

Crossing over

The exchange of genetic material between homologous chromosomes during meiosis that increases genetic variation.

Central Dogma of molecular biology

The process of DNA being transcribed to RNA and then translated into proteins.

Codon

A sequence of three nucleotides in mRNA that codes for a specific amino acid.

Silent mutation

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

Recessive allele expression

A recessive allele is expressed in the phenotype only when two copies are present.

Human gametes chromosome count

Human gametes contain only 23 chromosomes due to meiosis, which reduces the chromosome number by half.