biology notes Flashcards
mitosis
a type of cell division that produces cells for growth and repair
sex chromosome
a chromosome that helps determine an organisms sex
adenine
the base that combines with thymine to form a base pair
crossing over
the swapping of genes between chromosomes in a homologous pair
generation
members of a family that are born and live at about the same time
metaphase
a stage of cell division in which the chromosomes line up
recessive trait
a feature that only appears when two alleles are present
cell cycle
the repeated process of cell growth and division
double helix
a structure consisting of two chains twisted around each other
inheritance
the passing down of traits via genes from one generation to the next
prophase
a stage of cell division in which the chromosomes condense
cell division
the splitting of a cell to from new cells
fertilization
the joining of an egg and a sperm to form a new organism
interphase
the stage of the cell cycle in which a cell grows and copies its DNA
protein
a large molecule made up of amino acids
chromosome
a DNA molecule that condenses during cell division
gene
a unit of genetic information
meiosis
a type of cell division that produces sex cells for reproduction
recessive allele
a version of a gene that is only expressed when two copies are present
genotype
a pair of alleles that influence the appearance of a particular trait
cytosine
the base that combines with guanine to form a base pair
allele
a version of a gene
simple inheritance
when the appearance of a trait controlled by a single gene
mutation
a permanent change in the sequence of bases that make up a gene
guanine
the base that combines with cytosine to form a base pair
daughter cell
any new cell formed by cell division
amino acid
a small molecule that joins with others to form proteins
telophase
a stage of cell division in which two nuclei form
parent cell
any cell that divides to form new cells
heterozygous
a genotype in which the two alleles are different
DNA
a molecule that contains genetic information
anaphase
a stage of cell division in which the chromosomes separate
thymine
the base that combines with adenine to form a base pair
pedigree
a family tree that shows how a trait is passed down through generations
homologous pair
two chromosomes that contain versions of the same genes
dominant allele
a version of a gene that is expressed even when only one copy is present
base
part of a DNA molecule that comes in four type: A,C,G,T
trait
a feature of an organism
phenotype
the collection of traits observable in an organism
homozygous
a genotype in which the two alleles are the same
dominant trait
a feature that appears when at least one allele is present
base pair
two bases joined together
